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• 1. [Article] Effect of seed protein content on plant growth of barley and wheat

  The purpose of this study was to evaluate the effect of seed protein content on plant growth of barley (Hordeum vulgare L. ) and wheat (Triticum aestivum L. ). The effects of nitrogen application on chemical ...

  Citation × Citation Citation Abstract Copy Title: Effect of seed protein content on plant growth of barley and wheat Author: Lopez, Arturo The purpose of this study was to evaluate the effect of seed protein content on plant growth of barley (Hordeum vulgare L. ) and wheat (Triticum aestivum L. ). The effects of nitrogen application on chemical and morphological characteristics of the seed were also studied. Seeds of 'Casbon' winter barley and 'Nugaines' winter wheat with different protein content were obtained by field applications of various amounts of nitrogen at seeding time (fall) and tillering time (spring). The increase in protein content from high nitrogen rates was accompanied by a decrease in seed size and yield. The protein increase occurred primarily in the endosperm. Neither protein content nor size of the embryo was affected by rates of nitrogen application. The effect of seed protein content on plant growth was evaluated in terms of inhibition and respiration, speed of germination and subsequent seedling growth, root and shoot elongation at 15, 20 and 25C, and dry matter production when grown in low and high nitrogen soils in the green house. A positive relationship was found between seed protein content and plant performance. The rates of water absorption and oxygen consumption of germinating barley and wheat seed increased as a result of high protein content. High protein seed had a faster speed of germination and developed into larger seedlings with a higher dry matter content when grown in nitrogen-deficient soil. In nitrogen-enriched soil, seed protein content had little effect on seedling growth. The beneficial effects of seed protein content are more clearly expressed under stress conditions and are more evident when plant growth depends on the nutrients available from the seed. During initiation of germination, temperature influences the expression of the protein effect. After the seedling has formed and is capable of photosynthesis, the nitrogen availability in the soil influences the effect of seed protein content on plant growth. The relationship between seed protein content and plant growth can be an important factor in crop production because the increase in protein can be controlled by field application of nitrogen. However, since the high rates of nitrogen necessary to produce high seed protein levels are not consistent with the optimum nitrogen rates for yield, growers would probably be reluctant to apply such high rates unless some type of incentive were given them to do so. For seed production, it could still be important to strive for high protein levels in spite of some loss in yield if improved performance from high protein seeds proves to be of economic value. The results of this study indicate that producing and planting seeds rich in protein may be an effective method of achieving faster stand establishment of cereal crops. Additional research will determine the effects of high protein on yield. Title: Effect of seed protein content on plant growth of barley and wheat Author: Lopez, Arturo The purpose of this study was to evaluate the effect of seed protein content on plant growth of barley (Hordeum vulgare L. ) and wheat (Triticum aestivum L. ). The effects of nitrogen application on chemical and morphological characteristics of the seed were also studied. Seeds of 'Casbon' winter barley and 'Nugaines' winter wheat with different protein content were obtained by field applications of various amounts of nitrogen at seeding time (fall) and tillering time (spring). The increase in protein content from high nitrogen rates was accompanied by a decrease in seed size and yield. The protein increase occurred primarily in the endosperm. Neither protein content nor size of the embryo was affected by rates of nitrogen application. The effect of seed protein content on plant growth was evaluated in terms of inhibition and respiration, speed of germination and subsequent seedling growth, root and shoot elongation at 15, 20 and 25C, and dry matter production when grown in low and high nitrogen soils in the green house. A positive relationship was found between seed protein content and plant performance. The rates of water absorption and oxygen consumption of germinating barley and wheat seed increased as a result of high protein content. High protein seed had a faster speed of germination and developed into larger seedlings with a higher dry matter content when grown in nitrogen-deficient soil. In nitrogen-enriched soil, seed protein content had little effect on seedling growth. The beneficial effects of seed protein content are more clearly expressed under stress conditions and are more evident when plant growth depends on the nutrients available from the seed. During initiation of germination, temperature influences the expression of the protein effect. After the seedling has formed and is capable of photosynthesis, the nitrogen availability in the soil influences the effect of seed protein content on plant growth. The relationship between seed protein content and plant growth can be an important factor in crop production because the increase in protein can be controlled by field application of nitrogen. However, since the high rates of nitrogen necessary to produce high seed protein levels are not consistent with the optimum nitrogen rates for yield, growers would probably be reluctant to apply such high rates unless some type of incentive were given them to do so. For seed production, it could still be important to strive for high protein levels in spite of some loss in yield if improved performance from high protein seeds proves to be of economic value. The results of this study indicate that producing and planting seeds rich in protein may be an effective method of achieving faster stand establishment of cereal crops. Additional research will determine the effects of high protein on yield. Close

• 2. [Article] Influence of different nitrogen and moisture levels on the expression of grain yield and protein content in selected wheat (Triticum aestivum, L. em Thell) and barley (Hordeum vulagre, L. em Lam.) cultivars

  This investigation was conducted to provide information regarding 1) the relationship between the nitrogen percentage in the vegetative tissue of wheat and barley at various growth stages with grain protein and ...

  Citation × Citation Citation Abstract Copy Title: Influence of different nitrogen and moisture levels on the expression of grain yield and protein content in selected wheat (Triticum aestivum, L. em Thell) and barley (Hordeum vulagre, L. em Lam.) cultivars Author: Gomez-Pando, Luz This investigation was conducted to provide information regarding 1) the relationship between the nitrogen percentage in the vegetative tissue of wheat and barley at various growth stages with grain protein and 2) to evaluate the possible association between grain yield and grain protein as influenced by different cultivars, nitrogen levels and available moisture. Five wheat and four barley cultivars were selected based on their diverse genetic backgrounds and potential differences for the 12 attributes measured. These experimental materials were grown at low and high rainfall sites and under two different nitrogen levels. In wheat a decrease in the percentage of nitrogen in the flag leaves was found as the plants developed. The highest values were observed at the boot stage. In contrast, the highest percentage of nitrogen in the flag leaves of barley was observed at anthesis. Wheat cultivars which had the greatest genetic potential for grain protein usually had the highest percentage of nitrogen in the flag leaves at the boot stage and the lowest percentage in the vegetative tissue at harvest. This was especially true under high rainfall conditions. A similar relationship was found for the barley cultivars. At both experimental sites higher grain yields were accompanied by negative associations with grain protein for wheat. However, for barley no association was found between these two traits at either site or fertility level. Higher grain protein values were found for both wheat and barley at the high rainfall site. Title: Influence of different nitrogen and moisture levels on the expression of grain yield and protein content in selected wheat (Triticum aestivum, L. em Thell) and barley (Hordeum vulagre, L. em Lam.) cultivars Author: Gomez-Pando, Luz This investigation was conducted to provide information regarding 1) the relationship between the nitrogen percentage in the vegetative tissue of wheat and barley at various growth stages with grain protein and 2) to evaluate the possible association between grain yield and grain protein as influenced by different cultivars, nitrogen levels and available moisture. Five wheat and four barley cultivars were selected based on their diverse genetic backgrounds and potential differences for the 12 attributes measured. These experimental materials were grown at low and high rainfall sites and under two different nitrogen levels. In wheat a decrease in the percentage of nitrogen in the flag leaves was found as the plants developed. The highest values were observed at the boot stage. In contrast, the highest percentage of nitrogen in the flag leaves of barley was observed at anthesis. Wheat cultivars which had the greatest genetic potential for grain protein usually had the highest percentage of nitrogen in the flag leaves at the boot stage and the lowest percentage in the vegetative tissue at harvest. This was especially true under high rainfall conditions. A similar relationship was found for the barley cultivars. At both experimental sites higher grain yields were accompanied by negative associations with grain protein for wheat. However, for barley no association was found between these two traits at either site or fertility level. Higher grain protein values were found for both wheat and barley at the high rainfall site. Close

• 3. [Article] Two Studies Addressing Practical Needs of Wheat Farmers, Processors, and Breeders : Changes in Falling Number and Alpha-amylase During Grain Storage, and Improved Predictions of Wheat-flour Dough Properties

  Wheat (Triticum aestivum) is a globally traded staple food crop. The diverse and pleasing nature of wheat-derived products is a result of the complex interactions of the polymeric components from the wheat ...

  Citation × Citation Citation Abstract Copy Title: Two Studies Addressing Practical Needs of Wheat Farmers, Processors, and Breeders : Changes in Falling Number and Alpha-amylase During Grain Storage, and Improved Predictions of Wheat-flour Dough Properties Author: Adams, Mike R. Wheat (Triticum aestivum) is a globally traded staple food crop. The diverse and pleasing nature of wheat-derived products is a result of the complex interactions of the polymeric components from the wheat endosperm. Changes in the functionality of these polymeric components, as a result of changes in growing conditions or different genetics, impacts market price and end-product quality and directly affects farmers and processors. Wheat is of particular economic importance to the U.S. Pacific Northwest and, specifically, to the state of Oregon. Providing quality wheat for export is paramount to the survival of the Oregon wheat industry. This dissertation focuses on wheat quality from the perspective of serving the practical needs of farmers, processors, and wheat breeders. The first study, split into two portions, concerns pre-harvest sprouting (PHS) and grain storage. PHS increases alpha amylase (αA) activity in wheat, which, in excess, reduces wheat end-product quality. Falling Number (FN) is the primary test used by industry to gauge PHS damage in wheats. Direct measurement of αA activity is the fundamental frame of reference. The objective of these studies was to determine if FN and αA activity of wheat samples changed during storage and if changes were a function of storage time, storage temperature, and degree of PHS damage. Samples from three Idaho locations were used. These captured a wide range of PHS degree, and therefore, wide ranges of FN values and αA activities. Samples were subdivided and stored at -20°C, +20°C, and +40°C. Low FN values and high αA activities were observed in soft wheats from locations that had rain events prior to harvest. Overall, FN and αA activity had the curvilinear relationship expected from the literature, indicating the validity of the sample set with regard to the FN/αA relationship. Changes in FN and αA activity were observed over a 90 day period of grain storage. FN differed between growing environments, wheat varieties, and storage temperatures. αA activity also differed between growing environments and wheat varieties, but not between storage temperatures. Highest rates of increase in FN were observed in hard wheats with high initial (day 0) FN values. Lowest rates of increase in FN were observed in soft wheats with low day 0 FN values. This contrasted with the changes that occurred in αA activity. Decreases in αA activity over storage time were most prevalent in soft wheats, particularly sprouted soft wheats (i.e. those with day 0 αA activities > 0.1 Ceralpha Units: CU). There were small decreases in αA activity in hard wheats but the distinction between high and low αA activity samples was not as evident as in the soft wheats because the vast majority of hard wheat samples tested had αA activities < 0.1 CU. Decreases in αA activity were in general not associated with corresponding increases in FN values over grain storage time. Increases in FN values occurred at a higher rates as storage temperature increased, particularly in hard wheats with high day 0 FN. Grain storage was successful as a way to raise FN values to > 300 s in very few cases. Storage was not effective in decreasing αA activity from > 0.1 CU to < 0.1 CU. Increases in FN over storage time for the hard wheats significantly differed between locations. However, decreases in αA activities over storage time for the hard wheats were not significantly different between locations. This again highlights a lack of correspondence between increased FN and decreased αA activity, suggesting that these two factors are somewhat decoupled when looking at changes in stored grain. Temperature-induced gluten crosslinking was explored as possible explanation for drastic increases in unsprouted hard wheat FN observed in samples from one location. Total polymeric protein (TPP) content was assessed at the end of the study for unsprouted hard wheats stored at +40°C and -20°C as well as sprouted hard wheats from stored at -20°C. TPP content was assessed as % large unextractable polymeric proteins (%LUPP) and % total unextractable polymeric proteins (%TUPP) using size exclusion high performance liquid chromatography (HPSEC). TPP content was not significantly different between storage temperatures for wheat varieties from the same location. %TUPP, but not % LUPP, was significantly lower in wheat varieties affected by PHS. Changes in FN at high storage temperature were not likely due to increased protein crosslinking. The second study aimed to validate the use of a rapid method for predicting dough strength at early generations in hard wheat breeding programs. Early generation quality screening improves breeding program efficiency. Hard wheats are used to make leavened bread products. The gluten proteins, particularly high molecular weight glutenin subunits (HMW-GS), form large, ramifying networks called the glutenin macropolymer (GMP). High GMP content is associated with increased dough strength and bread quality. Genetic differences in HMW-GS, and by inference, GMP, are responsible for differing dough properties between varieties. The Mixograph is used to measure dough mixing properties and predict end-product quality in breeding programs. GMP can also be measured as total polymeric protein (TPP) via HPSEC. The Solvent Retention Capacity (SRC) test has been proposed to predict hard wheat quality, specifically lactic acid SRC (LASRC). The objectives of this research were to provide preliminary information on the usefulness of using LASRC, on its own, to predict dough mixing properties, specifically as applied to early generation screening in a wheat breeding program, and to assess the relationship between LASRC and TPP. Wheat samples were categorized by flour protein concentration (FPC). Mixograph analysis was used as the baseline for dough properties and was analyzed both by eye and by the proprietary Mixsmart software. TPP content was assessed as %LUPP and %%TUPP. As a result of redundancy between the two TPP measures, only %LUPP was used for statistical analysis. Dough mixing parameters were slightly better correlated with LASRC than %LUPP. Correlations between LASRC, %LUPP, and dough mixing parameters were different between FPC categories, particularly in low FPC samples. A strict cutoff of 115% LASRC effectively screened out the bottom 10% of low quality hard wheats but retained a nearly equal amount of low quality hard wheats that would have been screened out by mixograph analysis. LASRC and %LUPP are not likely to be effective predictors of dough properties, but may have some value to screen for hard wheat quality in the early generations of a wheat breeding cycle. Title: Two Studies Addressing Practical Needs of Wheat Farmers, Processors, and Breeders : Changes in Falling Number and Alpha-amylase During Grain Storage, and Improved Predictions of Wheat-flour Dough Properties Author: Adams, Mike R. Wheat (Triticum aestivum) is a globally traded staple food crop. The diverse and pleasing nature of wheat-derived products is a result of the complex interactions of the polymeric components from the wheat endosperm. Changes in the functionality of these polymeric components, as a result of changes in growing conditions or different genetics, impacts market price and end-product quality and directly affects farmers and processors. Wheat is of particular economic importance to the U.S. Pacific Northwest and, specifically, to the state of Oregon. Providing quality wheat for export is paramount to the survival of the Oregon wheat industry. This dissertation focuses on wheat quality from the perspective of serving the practical needs of farmers, processors, and wheat breeders. The first study, split into two portions, concerns pre-harvest sprouting (PHS) and grain storage. PHS increases alpha amylase (αA) activity in wheat, which, in excess, reduces wheat end-product quality. Falling Number (FN) is the primary test used by industry to gauge PHS damage in wheats. Direct measurement of αA activity is the fundamental frame of reference. The objective of these studies was to determine if FN and αA activity of wheat samples changed during storage and if changes were a function of storage time, storage temperature, and degree of PHS damage. Samples from three Idaho locations were used. These captured a wide range of PHS degree, and therefore, wide ranges of FN values and αA activities. Samples were subdivided and stored at -20°C, +20°C, and +40°C. Low FN values and high αA activities were observed in soft wheats from locations that had rain events prior to harvest. Overall, FN and αA activity had the curvilinear relationship expected from the literature, indicating the validity of the sample set with regard to the FN/αA relationship. Changes in FN and αA activity were observed over a 90 day period of grain storage. FN differed between growing environments, wheat varieties, and storage temperatures. αA activity also differed between growing environments and wheat varieties, but not between storage temperatures. Highest rates of increase in FN were observed in hard wheats with high initial (day 0) FN values. Lowest rates of increase in FN were observed in soft wheats with low day 0 FN values. This contrasted with the changes that occurred in αA activity. Decreases in αA activity over storage time were most prevalent in soft wheats, particularly sprouted soft wheats (i.e. those with day 0 αA activities > 0.1 Ceralpha Units: CU). There were small decreases in αA activity in hard wheats but the distinction between high and low αA activity samples was not as evident as in the soft wheats because the vast majority of hard wheat samples tested had αA activities < 0.1 CU. Decreases in αA activity were in general not associated with corresponding increases in FN values over grain storage time. Increases in FN values occurred at a higher rates as storage temperature increased, particularly in hard wheats with high day 0 FN. Grain storage was successful as a way to raise FN values to > 300 s in very few cases. Storage was not effective in decreasing αA activity from > 0.1 CU to < 0.1 CU. Increases in FN over storage time for the hard wheats significantly differed between locations. However, decreases in αA activities over storage time for the hard wheats were not significantly different between locations. This again highlights a lack of correspondence between increased FN and decreased αA activity, suggesting that these two factors are somewhat decoupled when looking at changes in stored grain. Temperature-induced gluten crosslinking was explored as possible explanation for drastic increases in unsprouted hard wheat FN observed in samples from one location. Total polymeric protein (TPP) content was assessed at the end of the study for unsprouted hard wheats stored at +40°C and -20°C as well as sprouted hard wheats from stored at -20°C. TPP content was assessed as % large unextractable polymeric proteins (%LUPP) and % total unextractable polymeric proteins (%TUPP) using size exclusion high performance liquid chromatography (HPSEC). TPP content was not significantly different between storage temperatures for wheat varieties from the same location. %TUPP, but not % LUPP, was significantly lower in wheat varieties affected by PHS. Changes in FN at high storage temperature were not likely due to increased protein crosslinking. The second study aimed to validate the use of a rapid method for predicting dough strength at early generations in hard wheat breeding programs. Early generation quality screening improves breeding program efficiency. Hard wheats are used to make leavened bread products. The gluten proteins, particularly high molecular weight glutenin subunits (HMW-GS), form large, ramifying networks called the glutenin macropolymer (GMP). High GMP content is associated with increased dough strength and bread quality. Genetic differences in HMW-GS, and by inference, GMP, are responsible for differing dough properties between varieties. The Mixograph is used to measure dough mixing properties and predict end-product quality in breeding programs. GMP can also be measured as total polymeric protein (TPP) via HPSEC. The Solvent Retention Capacity (SRC) test has been proposed to predict hard wheat quality, specifically lactic acid SRC (LASRC). The objectives of this research were to provide preliminary information on the usefulness of using LASRC, on its own, to predict dough mixing properties, specifically as applied to early generation screening in a wheat breeding program, and to assess the relationship between LASRC and TPP. Wheat samples were categorized by flour protein concentration (FPC). Mixograph analysis was used as the baseline for dough properties and was analyzed both by eye and by the proprietary Mixsmart software. TPP content was assessed as %LUPP and %%TUPP. As a result of redundancy between the two TPP measures, only %LUPP was used for statistical analysis. Dough mixing parameters were slightly better correlated with LASRC than %LUPP. Correlations between LASRC, %LUPP, and dough mixing parameters were different between FPC categories, particularly in low FPC samples. A strict cutoff of 115% LASRC effectively screened out the bottom 10% of low quality hard wheats but retained a nearly equal amount of low quality hard wheats that would have been screened out by mixograph analysis. LASRC and %LUPP are not likely to be effective predictors of dough properties, but may have some value to screen for hard wheat quality in the early generations of a wheat breeding cycle. Close

• 4. [Article] Detection and Quantification of Pratylenchus thornei in DNA Extracted from Soil Using Real-Time PCR

  This is the publisher’s final pdf. The published article is copyrighted by American Phytopathological Society and can be found at: www.apsnet.org/.

  Citation × Citation Citation Abstract Copy Title: Detection and Quantification of Pratylenchus thornei in DNA Extracted from Soil Using Real-Time PCR Author: Smiley, Richard W., Okubara, Patricia A., Yan, Guiping This is the publisher’s final pdf. The published article is copyrighted by American Phytopathological Society and can be found at: www.apsnet.org/. Title: Detection and Quantification of Pratylenchus thornei in DNA Extracted from Soil Using Real-Time PCR Author: Smiley, Richard W., Okubara, Patricia A., Yan, Guiping This is the publisher’s final pdf. The published article is copyrighted by American Phytopathological Society and can be found at: www.apsnet.org/. Close

• 5. [Article] Evaluation of parental performance for grain yield in two populations of wheat (Triticum aestivum Vill., Host)

  Six winter wheat cultivars were evaluated for their breeding value in transmitting superior genetic factors for grain yield to subsequent progeny. The cultivars were selected on the basis of their potential ...

  Citation × Citation Citation Abstract Copy Title: Evaluation of parental performance for grain yield in two populations of wheat (Triticum aestivum Vill., Host) Author: Alcala de Stefano, Maximino Six winter wheat cultivars were evaluated for their breeding value in transmitting superior genetic factors for grain yield to subsequent progeny. The cultivars were selected on the basis of their potential grain yield and divided into two populations. Population I was comprised of three cultivars which have been in commercial production for several years and are regarded as intermediate for grain yield. Population II was represented by three recently developed cultivars which have superior grain yielding potential. Each of the three parents within each population were crossed in a diallel manner Hence, the parents and subsequent F₁, F₂, and BC progeny made up the experimental populations. These populations were grown at two environmentally diverse sites within the state of Oregon. Morphological characters measured were: (1) tillers per plant; (2) kernels per spike; (3) plant height; (4) weight of 300 kernels; and (5) grain yield. To detect which parental combination had the greatest potential for transmitting superior performance to the subsequent progeny for the components of yield and grain yield, the following parameters were determined for both populations: (1) the amount and nature of the genetic variance associated with each population; (2) average combining ability of each parent within the populations; (3) estimates of heterosis and heterobeltiosis in the F₁ and (4) the possible influence of the genotype-environmental interactions on the parameters measured. Also information concerning the desirability of using top crosses and double crosses rather than single crosses was obtained. In an effort to compare the relative performance between the populations, Pullman Selection 101, which is a good general combining winter wheat cultivar, was used as a tester for both populations. The values obtained in this investigation reflect the properties of the populations studied and should not be interpreted as applying to all wheat populations. Considerable genetic variability was found within both populations for the characters studied. This variability was largely due to genetic factors which were additive. Tillers per plant and grain yield were influenced by both additive and nonadditive genetic variance. The higher yielding parents in Population II were found to be higher in their average combining ability for kernels per spike and grain yield per plant whereas the lower yielding parents in Population I were higher for tiller number, weight of 300 kernels and plant height. Parental combinations identified as being promising, for grain yield in a conventional program, where nearly homozygous lines are desired, were also the same parental combinations which resulted in a maximum expression of heterobeltiosis and would be of most interest in a hybrid program. The desirability of using multiple crosses to maximize the number of favorable factors need further study inctuding additional parents and different combinations plus an evaluation of the performance of such crosses in later generations. In this investigation, the single crosses appeared to be the most promising; however, inbreeding depression due to segregation within top and double crosses influenced the values obtained. Also, the population sizes should be increased to measure the total potential of such crosses. Significant genotype-environmental interactions were observed between locations for plant height and weight of 300 kernels. The estimates obtained for average combining ability, heterosis and heterobeltiosis for the other characters measured also suggested that it will be necessary to identify the most promising hybrid combinations based on the performance of the parents at the specific location. To make the most rapid progress in developing high yielding cultivars in either conventional or hybrid programs, the wheat breeder needs to emphasize crosses between unrelated high yielding cultivars. However, the need to provide superior parental lines which include such factors as disease resistance, should be evaluated. The development of elite germ plasm by geneticists will be mandatory if plant breeders are to continue to improve grain yield. Title: Evaluation of parental performance for grain yield in two populations of wheat (Triticum aestivum Vill., Host) Author: Alcala de Stefano, Maximino Six winter wheat cultivars were evaluated for their breeding value in transmitting superior genetic factors for grain yield to subsequent progeny. The cultivars were selected on the basis of their potential grain yield and divided into two populations. Population I was comprised of three cultivars which have been in commercial production for several years and are regarded as intermediate for grain yield. Population II was represented by three recently developed cultivars which have superior grain yielding potential. Each of the three parents within each population were crossed in a diallel manner Hence, the parents and subsequent F₁, F₂, and BC progeny made up the experimental populations. These populations were grown at two environmentally diverse sites within the state of Oregon. Morphological characters measured were: (1) tillers per plant; (2) kernels per spike; (3) plant height; (4) weight of 300 kernels; and (5) grain yield. To detect which parental combination had the greatest potential for transmitting superior performance to the subsequent progeny for the components of yield and grain yield, the following parameters were determined for both populations: (1) the amount and nature of the genetic variance associated with each population; (2) average combining ability of each parent within the populations; (3) estimates of heterosis and heterobeltiosis in the F₁ and (4) the possible influence of the genotype-environmental interactions on the parameters measured. Also information concerning the desirability of using top crosses and double crosses rather than single crosses was obtained. In an effort to compare the relative performance between the populations, Pullman Selection 101, which is a good general combining winter wheat cultivar, was used as a tester for both populations. The values obtained in this investigation reflect the properties of the populations studied and should not be interpreted as applying to all wheat populations. Considerable genetic variability was found within both populations for the characters studied. This variability was largely due to genetic factors which were additive. Tillers per plant and grain yield were influenced by both additive and nonadditive genetic variance. The higher yielding parents in Population II were found to be higher in their average combining ability for kernels per spike and grain yield per plant whereas the lower yielding parents in Population I were higher for tiller number, weight of 300 kernels and plant height. Parental combinations identified as being promising, for grain yield in a conventional program, where nearly homozygous lines are desired, were also the same parental combinations which resulted in a maximum expression of heterobeltiosis and would be of most interest in a hybrid program. The desirability of using multiple crosses to maximize the number of favorable factors need further study inctuding additional parents and different combinations plus an evaluation of the performance of such crosses in later generations. In this investigation, the single crosses appeared to be the most promising; however, inbreeding depression due to segregation within top and double crosses influenced the values obtained. Also, the population sizes should be increased to measure the total potential of such crosses. Significant genotype-environmental interactions were observed between locations for plant height and weight of 300 kernels. The estimates obtained for average combining ability, heterosis and heterobeltiosis for the other characters measured also suggested that it will be necessary to identify the most promising hybrid combinations based on the performance of the parents at the specific location. To make the most rapid progress in developing high yielding cultivars in either conventional or hybrid programs, the wheat breeder needs to emphasize crosses between unrelated high yielding cultivars. However, the need to provide superior parental lines which include such factors as disease resistance, should be evaluated. The development of elite germ plasm by geneticists will be mandatory if plant breeders are to continue to improve grain yield. Close

• 6. [Article] Yield and other agronomic characters of winter wheat cultivars as affected by five seeding rates and three different environmental conditions

  Five newly released and two Eastern European winter wheat cultivars were grown under five different seeding rates (80, 160, 240, 320, 400 seeds per m²). Four of these newly released cultivars were grown ...

  Citation × Citation Citation Abstract Copy Title: Yield and other agronomic characters of winter wheat cultivars as affected by five seeding rates and three different environmental conditions Author: Güler, Mengü Five newly released and two Eastern European winter wheat cultivars were grown under five different seeding rates (80, 160, 240, 320, 400 seeds per m²). Four of these newly released cultivars were grown at three different locations which have different environmental conditions. Data were obtained on grain yield, tiller number per plant, 1000 kernel weight, seed number per spike, plant and spike number per unit area, plant height, heading and maturity dates. At the lowest rate of seeding the grain yield was significantly lower at all three locations. Although there were no significant differences for grain yield for all the other seeding rates, maximum yields were obtained from lower seeding rates at Ryan while at Hyslop and Madras, which had better moisture conditions, maximum yields were obtained at higher seeding rates. This situation was not observed for the Yamhill cultivar in which maximum yields were obtained at 160 seeds per m² seeding rate at all three locations. Tillers per plant value decreased as the seeding rate increased. Hyslop and McDermid produced significantly higher number of tillers per plant from the other cultivars. Significantly highest 1000 kernel weight values were obtained at the lowest seeding rate. Yamhill produced the highest significant 1000 kernel weight while Paha produced the lowest. Seeds per spike value followed the same order as tillers per plant and 1000 kernel weight showing a continuous decrease with the increased rates of seeding. The number of plants per m² was a direct linear function of seeding rate. The number of spikes per m² increased curvilinearly with the increased seeding rate. Hyslop and McDermid produced the highest significant number of spikes per m² because of their higher tillering ability. Plant height increased with increased rates of seeding because of the increased competition for light. Yamhill and Paha were significantly the tallest cultivars. The tallest plants were observed at Hyslop. There was a decrease in the number of days in heading and maturity as the rates of seeding increased. The cultivars ranked in the order Paha > Yamhill > Hyslop > McDermid for heading and maturity dates. Heading first occurred at Hyslop followed by Ryan and Madras while maturity occurred first at Ryan followed by Hyslop and Madras. Highly positive correlations were observed among plants per m², spikes per m and seeding rate while these factors correlated negatively with tillers per plant, 1000 kernel weight and seeds per spike. The regression equations showed that maturity date, heading date and spikes per m² values were the most important factors for predicting yield. Title: Yield and other agronomic characters of winter wheat cultivars as affected by five seeding rates and three different environmental conditions Author: Güler, Mengü Five newly released and two Eastern European winter wheat cultivars were grown under five different seeding rates (80, 160, 240, 320, 400 seeds per m²). Four of these newly released cultivars were grown at three different locations which have different environmental conditions. Data were obtained on grain yield, tiller number per plant, 1000 kernel weight, seed number per spike, plant and spike number per unit area, plant height, heading and maturity dates. At the lowest rate of seeding the grain yield was significantly lower at all three locations. Although there were no significant differences for grain yield for all the other seeding rates, maximum yields were obtained from lower seeding rates at Ryan while at Hyslop and Madras, which had better moisture conditions, maximum yields were obtained at higher seeding rates. This situation was not observed for the Yamhill cultivar in which maximum yields were obtained at 160 seeds per m² seeding rate at all three locations. Tillers per plant value decreased as the seeding rate increased. Hyslop and McDermid produced significantly higher number of tillers per plant from the other cultivars. Significantly highest 1000 kernel weight values were obtained at the lowest seeding rate. Yamhill produced the highest significant 1000 kernel weight while Paha produced the lowest. Seeds per spike value followed the same order as tillers per plant and 1000 kernel weight showing a continuous decrease with the increased rates of seeding. The number of plants per m² was a direct linear function of seeding rate. The number of spikes per m² increased curvilinearly with the increased seeding rate. Hyslop and McDermid produced the highest significant number of spikes per m² because of their higher tillering ability. Plant height increased with increased rates of seeding because of the increased competition for light. Yamhill and Paha were significantly the tallest cultivars. The tallest plants were observed at Hyslop. There was a decrease in the number of days in heading and maturity as the rates of seeding increased. The cultivars ranked in the order Paha > Yamhill > Hyslop > McDermid for heading and maturity dates. Heading first occurred at Hyslop followed by Ryan and Madras while maturity occurred first at Ryan followed by Hyslop and Madras. Highly positive correlations were observed among plants per m², spikes per m and seeding rate while these factors correlated negatively with tillers per plant, 1000 kernel weight and seeds per spike. The regression equations showed that maturity date, heading date and spikes per m² values were the most important factors for predicting yield. Close

• 7. [Article] Evaluation of three methods of selection in relation to yield and yield stability in winter wheat (Triticum aestivum Vill., Host)

  The effectiveness of early generation selection for yield and yield stability and the possible identification of superior parental combinations were studied in winter wheat populations representing different ...

  Citation × Citation Citation Abstract Copy Title: Evaluation of three methods of selection in relation to yield and yield stability in winter wheat (Triticum aestivum Vill., Host) Author: Charoenwatana, Terd, 1937- The effectiveness of early generation selection for yield and yield stability and the possible identification of superior parental combinations were studied in winter wheat populations representing different levels of genetic diversity. Experimental material for evaluating yield stability consisted of nine bulk and seven modified bulk populations derived from nine parental combinations which represented the F₈, F₉, and F₁₀ generations. The F₉ and F₁₀ generations of nine bulk, nine modified bulk and two modified pedigree populations along with the respective parental populations were studied to determine the relationship of yield to genetic diversity. Linear regression of the mean yield of individual entries on the mean yield of all entries for each year was used to describe yield stability. Grain yield differences among populations and crosses were analyzed by a functional analysis of variance. The modified bulk populations were found to be superior to their respective parents in yield and to the bulk populations in yield and yield stability. The modified pedigree populations had the highest yield of all populations measured. It was concluded that populations with high genetic diversity not only do not produce the highest yield but may not provide the greatest stability of yield. Selection for grain yield in the F₄ generation was effective in identifying superior segregates. It was also possible to develop populations which had more yield stability. The highest yielding progeny were obtained from crosses between the medium yielding parents rather than between the highest yielding parents. This suggested that parental performance was of limited value in predicting the yielding ability of their resulting progeny. Therefore, selection for suitable parental combinations could not be based on their individual performance in the present study. It appeared that genetic factors for adaptability are as important as the level of genetic diversity in determining yield stability. A breeding system that allows the breeder to identify and incorporate genetic factors for adaptability and still maintain some genetic diversity in a new variety is suggested. Such a breeding system would prolong the length of time a variety could remain in commercial production and would allow such a variety to be grown over a more extensive range of environments. Title: Evaluation of three methods of selection in relation to yield and yield stability in winter wheat (Triticum aestivum Vill., Host) Author: Charoenwatana, Terd, 1937- The effectiveness of early generation selection for yield and yield stability and the possible identification of superior parental combinations were studied in winter wheat populations representing different levels of genetic diversity. Experimental material for evaluating yield stability consisted of nine bulk and seven modified bulk populations derived from nine parental combinations which represented the F₈, F₉, and F₁₀ generations. The F₉ and F₁₀ generations of nine bulk, nine modified bulk and two modified pedigree populations along with the respective parental populations were studied to determine the relationship of yield to genetic diversity. Linear regression of the mean yield of individual entries on the mean yield of all entries for each year was used to describe yield stability. Grain yield differences among populations and crosses were analyzed by a functional analysis of variance. The modified bulk populations were found to be superior to their respective parents in yield and to the bulk populations in yield and yield stability. The modified pedigree populations had the highest yield of all populations measured. It was concluded that populations with high genetic diversity not only do not produce the highest yield but may not provide the greatest stability of yield. Selection for grain yield in the F₄ generation was effective in identifying superior segregates. It was also possible to develop populations which had more yield stability. The highest yielding progeny were obtained from crosses between the medium yielding parents rather than between the highest yielding parents. This suggested that parental performance was of limited value in predicting the yielding ability of their resulting progeny. Therefore, selection for suitable parental combinations could not be based on their individual performance in the present study. It appeared that genetic factors for adaptability are as important as the level of genetic diversity in determining yield stability. A breeding system that allows the breeder to identify and incorporate genetic factors for adaptability and still maintain some genetic diversity in a new variety is suggested. Such a breeding system would prolong the length of time a variety could remain in commercial production and would allow such a variety to be grown over a more extensive range of environments. Close

• 8. [Article] Influence of Soft Wheat Characteristics on Quality of Batter-based Products

  Wheat is a globally traded staple crop. Wheat is important in human diets because of its agronomic adaptability, physical characteristics, functionality for the production of leavened products and nutritional ...

  Citation × Citation Citation Abstract Copy Title: Influence of Soft Wheat Characteristics on Quality of Batter-based Products Author: Fajardo Centeno, Carlos A. Wheat is a globally traded staple crop. Wheat is important in human diets because of its agronomic adaptability, physical characteristics, functionality for the production of leavened products and nutritional value. Two significant characteristics make wheat an important staple food-crop. First, the proteins present in wheat endosperm have attributes that enable gas retention after the proteins are hydrated and mechanically worked during dough production. Second, a wider variety of products can be made out of wheat compared to other cereals. Wheat quality is defined in terms of suitability for specific end-uses. This is important for breeders, farmers, flour millers, and food producers and consumers. In the U.S. Pacific Northwest (PNW) climatic conditions favor production of soft wheat. Three soft wheat types are planted in the PNW, soft white winter (SWW), soft white spring (SWS), and club (CLUB). Batter-based products are important applications for soft wheats and include a wide range of products such as pancakes and waffles, cakes, and coatings. Pancakes are produced from fluid batters using a single step mixing process and contain sugar concentrations < 30% in their formulations. Cakes are complex food systems where their classification is based on mixing process to produce the batters and the sugar-flour ratio concentrations in their formulations. This dissertation is focused on the functionality, analysis, and selection of soft wheat quality traits that affect end-product performance and also developing a methodology to rapidly predict cake quality. The first study (Chapter 3) was concerned with the functionality of SWW wheats in pancake making. The aim of this study was to observe the differences in genotype and protein concentration on batter flow and pancake making performance of a collection of SWW wheats. Two formulations were used in the study: one based on Finnie et al (2006) called "old" and another based on the AACC-I Approved Method 10-80.01 called "new". The "new" lean formulation had an improved ability to distinguish the performance of different flours compared with the “old” as a result of wider range of pancake diameters. This study showed that pancake making performance would not be optimized by conventional superior high-quality soft wheat flours with soft kernel texture, high break flour yield, and low water-, carbonate-, and sucrose SRCs. From our results it appears that for unchlorinated flours, at least for thicker pancakes, the most appropriate flour would have higher water and sucrose SRCs and be grown under management conditions conductive to higher protein. The second study (Chapter 4) was a meta-analysis of data collected by the USDA Western Wheat Quality Laboratory (Pullman, WA). This study was done to advance understanding soft wheat quality traits that differentially affect sugar-snap cookie diameter (CODI) and Japanese sponge cake (SC) volume (CAVOL). Principal component analysis (PCA) and partial least square (PLS) regression models were used to obtain useful actionable information from the data. The overall data showed that break flour yield (BKFY) was the single most important trait positively associated with both CAVOL and CODI. SWW wheats showed CVs > 10% for kernel hardness (SKHRD), grain and flour protein concentrations, ash, sucrose-, and lactic acid SRCs. These observations suggested that hardness, protein, ash, and the two SRCs were more sensitive to G&E effects than were the end-product traits that had CVs < 10%. The third study (Chapter 5) was built on the second study by adding two additional quality tests, oxidative gelation capacity (PeakOXI) and median particle size, to the potential prediction of CODI and CAVOL. Similar to the second study, BKFY was the single most important trait positively associated with both CAVOL and CODI. Virtual selection of SWWs based on either BKFY or SKHRD alone showed (in both the second and third studies) that using these enabled a gain of 134 mL for CAVOL and 0.6 cm for CODI using SKHRD and 122 mL for CAVOL and 0.58 cm for CODI using BKFY (Chapter 5). PeakOXI was significantly correlated with CODI but not with CAVOL. This contrasted with our hypothesis that PeakOXI would affect both products similarly. Notably 13 SWW samples had PeakOXI values higher than 800 cP. PeakOXI values this high have never been observed in soft wheats prior to this study. This is a valuable genetic resource for further studies that may lead to ways to better exploit oxidative gelation. The fourth study (Chapter 6) expanded the concepts in previous studies and included the use of a test to measure cake-batter viscosity in an attempt to predict cake quality. This study investigated the relationships between wheat quality traits, cake batters, and cake making quality in three cake types: SC, layer cake (LC), and pound cake (PoC). This study differed from the studies in Chapters 4 and 5 and was similar to Chapter 3 as the samples were fewer but specifically chosen to span the entire range of typical SWW quality. In this study we also developed a viscosity-based method to predict SC and LC quality that takes only eight minutes. This could be useful for screening or selection for cake quality in soft wheat breeding programs. In SC, there were no significant differences in cake quality traits between varieties. However, SC volume had a strong negative association with PeakOXI. For LC, the variety Tubbs, with harder kernel and higher absorption characteristics, had the largest LC volume. In contrast to SC, LC volume was significantly and positively associated with PeakOXI. In PoC, Kaseburg, with the highest protein content, had the largest cake volume. PoC was significantly and positively associated with flour protein concentration suggesting that flour proteins were important for larger volumes and confirming other observations in the literature. In contrast to LC and SC, PoC was not significantly associated with PeakOXI. The overall impact of the studies reported is: - For pancakes, the most important soft wheat trait is flour protein concentration. Water-, and sucrose SRCs were potentially useful parameters for predicting pancake quality. - For SC and sugar-snap cookies, break flour yield was the most important single trait in predicting higher SC volumes and larger cookie diameters. Therefore, selection in soft wheat breeding should be focused on kernel hardness and break flour yields as primary factors. Title: Influence of Soft Wheat Characteristics on Quality of Batter-based Products Author: Fajardo Centeno, Carlos A. Wheat is a globally traded staple crop. Wheat is important in human diets because of its agronomic adaptability, physical characteristics, functionality for the production of leavened products and nutritional value. Two significant characteristics make wheat an important staple food-crop. First, the proteins present in wheat endosperm have attributes that enable gas retention after the proteins are hydrated and mechanically worked during dough production. Second, a wider variety of products can be made out of wheat compared to other cereals. Wheat quality is defined in terms of suitability for specific end-uses. This is important for breeders, farmers, flour millers, and food producers and consumers. In the U.S. Pacific Northwest (PNW) climatic conditions favor production of soft wheat. Three soft wheat types are planted in the PNW, soft white winter (SWW), soft white spring (SWS), and club (CLUB). Batter-based products are important applications for soft wheats and include a wide range of products such as pancakes and waffles, cakes, and coatings. Pancakes are produced from fluid batters using a single step mixing process and contain sugar concentrations < 30% in their formulations. Cakes are complex food systems where their classification is based on mixing process to produce the batters and the sugar-flour ratio concentrations in their formulations. This dissertation is focused on the functionality, analysis, and selection of soft wheat quality traits that affect end-product performance and also developing a methodology to rapidly predict cake quality. The first study (Chapter 3) was concerned with the functionality of SWW wheats in pancake making. The aim of this study was to observe the differences in genotype and protein concentration on batter flow and pancake making performance of a collection of SWW wheats. Two formulations were used in the study: one based on Finnie et al (2006) called "old" and another based on the AACC-I Approved Method 10-80.01 called "new". The "new" lean formulation had an improved ability to distinguish the performance of different flours compared with the “old” as a result of wider range of pancake diameters. This study showed that pancake making performance would not be optimized by conventional superior high-quality soft wheat flours with soft kernel texture, high break flour yield, and low water-, carbonate-, and sucrose SRCs. From our results it appears that for unchlorinated flours, at least for thicker pancakes, the most appropriate flour would have higher water and sucrose SRCs and be grown under management conditions conductive to higher protein. The second study (Chapter 4) was a meta-analysis of data collected by the USDA Western Wheat Quality Laboratory (Pullman, WA). This study was done to advance understanding soft wheat quality traits that differentially affect sugar-snap cookie diameter (CODI) and Japanese sponge cake (SC) volume (CAVOL). Principal component analysis (PCA) and partial least square (PLS) regression models were used to obtain useful actionable information from the data. The overall data showed that break flour yield (BKFY) was the single most important trait positively associated with both CAVOL and CODI. SWW wheats showed CVs > 10% for kernel hardness (SKHRD), grain and flour protein concentrations, ash, sucrose-, and lactic acid SRCs. These observations suggested that hardness, protein, ash, and the two SRCs were more sensitive to G&E effects than were the end-product traits that had CVs < 10%. The third study (Chapter 5) was built on the second study by adding two additional quality tests, oxidative gelation capacity (PeakOXI) and median particle size, to the potential prediction of CODI and CAVOL. Similar to the second study, BKFY was the single most important trait positively associated with both CAVOL and CODI. Virtual selection of SWWs based on either BKFY or SKHRD alone showed (in both the second and third studies) that using these enabled a gain of 134 mL for CAVOL and 0.6 cm for CODI using SKHRD and 122 mL for CAVOL and 0.58 cm for CODI using BKFY (Chapter 5). PeakOXI was significantly correlated with CODI but not with CAVOL. This contrasted with our hypothesis that PeakOXI would affect both products similarly. Notably 13 SWW samples had PeakOXI values higher than 800 cP. PeakOXI values this high have never been observed in soft wheats prior to this study. This is a valuable genetic resource for further studies that may lead to ways to better exploit oxidative gelation. The fourth study (Chapter 6) expanded the concepts in previous studies and included the use of a test to measure cake-batter viscosity in an attempt to predict cake quality. This study investigated the relationships between wheat quality traits, cake batters, and cake making quality in three cake types: SC, layer cake (LC), and pound cake (PoC). This study differed from the studies in Chapters 4 and 5 and was similar to Chapter 3 as the samples were fewer but specifically chosen to span the entire range of typical SWW quality. In this study we also developed a viscosity-based method to predict SC and LC quality that takes only eight minutes. This could be useful for screening or selection for cake quality in soft wheat breeding programs. In SC, there were no significant differences in cake quality traits between varieties. However, SC volume had a strong negative association with PeakOXI. For LC, the variety Tubbs, with harder kernel and higher absorption characteristics, had the largest LC volume. In contrast to SC, LC volume was significantly and positively associated with PeakOXI. In PoC, Kaseburg, with the highest protein content, had the largest cake volume. PoC was significantly and positively associated with flour protein concentration suggesting that flour proteins were important for larger volumes and confirming other observations in the literature. In contrast to LC and SC, PoC was not significantly associated with PeakOXI. The overall impact of the studies reported is: - For pancakes, the most important soft wheat trait is flour protein concentration. Water-, and sucrose SRCs were potentially useful parameters for predicting pancake quality. - For SC and sugar-snap cookies, break flour yield was the most important single trait in predicting higher SC volumes and larger cookie diameters. Therefore, selection in soft wheat breeding should be focused on kernel hardness and break flour yields as primary factors. Close

• 9. [Article] Compensating effects and gene action estimates for the components of grain yield in winter wheat (Triticum aestivum, L. em Thell)

  Five winter wheat cultivars and their diallel crosses were evaluated for plant height, harvest index, deading-maturity duration, the components of yield, (spikes per plant, spikelets per spike, kernel ...

  Citation × Citation Citation Abstract Copy Title: Compensating effects and gene action estimates for the components of grain yield in winter wheat (Triticum aestivum, L. em Thell) Author: Abi-Antoun, Michel Five winter wheat cultivars and their diallel crosses were evaluated for plant height, harvest index, deading-maturity duration, the components of yield, (spikes per plant, spikelets per spike, kernel weight and kernels per spikelet)and total plant yield. Two diverse locations, Moro, a dryland site (250 mm annually) located in central Oregon and the Hyslop Agronomy Farm, a high rainfall site (over 1000 mm annually) located in the Willamette Valley, were utilized for one and two cropping seasons, respectively. Three rates of seeding were used as main plots in a split-plot design that was replicated four times. A modified blend method of seeding was used to simulate solid seeding conditions. Experimental seeds were planted 30.5 centimeters apart within the row over a filler cultivar in equally spaced (30.5 centimeters) rows. The data were analyzed by analysis of variance, Griffing's diallel analysis (Method 4, Model 1), correlation, path-coefficient analysis and by parent progeny regression. The correlation between grain yield, its components, harvest index, maturity-duration and plant height was dependent on the particula. r environment of the test. The re waspoorcorrelationbetween yield, tiller number and seed size under all the conditions of these studies. Negative associations between the components of yield indicated the sequential compensatory behavior of these characters under all environments. It would be very hard to select for large grain and short stature wheat because of the positive correlation between plant height and seed size within this population. The low correlations of yield with tiller number and seed size were mainly caused by indirect negative effects through one or more of the other yield components. Harvest index, maturity-duration and plant height had very small direct or indirect influences on grain yield. It was concluded that maximum yield would be obtained from a plant type which produces enough tillers to cover a particular unit of field area with large, fertile spikes, having medium to large kernels and semi-dwarf stature. No significant differences existed between parents and single crosses in the expression of the yield components. Nevertheless, hybrids outyielded their parents in grain yield and demonstrated that heterosis for complex traits was a consequence of multiplicative relationships among the components of these traits. Significant interactions between the genotypes and locations, seeding rates and years were observed in the expression of all characters studied. These interactions indicated that using data from non-competitive conditions to assess performance under competitive conditions could not be justified. Also, limiting the number of testing sites may lead to unsound generalizations and erroneous recommendations regarding gene action estimates of yield and the components of grain yield and three associated characters. Under non-competitive conditions, estimates of the additive type of gene action were more significant and contributed larger effects than the non-additive type for all traits. As competition increased at higher seeding rates, the effects of specific combining ability became more important in the expression of yield, number of spikes, spikelets per spike, and plant height. Heritability estimates confirmed these results except for yield. Of the agronomic characters, harvest index, maturity-duration and plant height, only harvest index showed some promise as a selection criterion under noncompetitive conditions. A breeding procedure utilizing the component approach consisted of selecting early generations under spaced planting with emphasis on avoiding extreme values in any of the components of yield. The balanced combinations of the components of yield should be tested under solid seeding conditions. Title: Compensating effects and gene action estimates for the components of grain yield in winter wheat (Triticum aestivum, L. em Thell) Author: Abi-Antoun, Michel Five winter wheat cultivars and their diallel crosses were evaluated for plant height, harvest index, deading-maturity duration, the components of yield, (spikes per plant, spikelets per spike, kernel weight and kernels per spikelet)and total plant yield. Two diverse locations, Moro, a dryland site (250 mm annually) located in central Oregon and the Hyslop Agronomy Farm, a high rainfall site (over 1000 mm annually) located in the Willamette Valley, were utilized for one and two cropping seasons, respectively. Three rates of seeding were used as main plots in a split-plot design that was replicated four times. A modified blend method of seeding was used to simulate solid seeding conditions. Experimental seeds were planted 30.5 centimeters apart within the row over a filler cultivar in equally spaced (30.5 centimeters) rows. The data were analyzed by analysis of variance, Griffing's diallel analysis (Method 4, Model 1), correlation, path-coefficient analysis and by parent progeny regression. The correlation between grain yield, its components, harvest index, maturity-duration and plant height was dependent on the particula. r environment of the test. The re waspoorcorrelationbetween yield, tiller number and seed size under all the conditions of these studies. Negative associations between the components of yield indicated the sequential compensatory behavior of these characters under all environments. It would be very hard to select for large grain and short stature wheat because of the positive correlation between plant height and seed size within this population. The low correlations of yield with tiller number and seed size were mainly caused by indirect negative effects through one or more of the other yield components. Harvest index, maturity-duration and plant height had very small direct or indirect influences on grain yield. It was concluded that maximum yield would be obtained from a plant type which produces enough tillers to cover a particular unit of field area with large, fertile spikes, having medium to large kernels and semi-dwarf stature. No significant differences existed between parents and single crosses in the expression of the yield components. Nevertheless, hybrids outyielded their parents in grain yield and demonstrated that heterosis for complex traits was a consequence of multiplicative relationships among the components of these traits. Significant interactions between the genotypes and locations, seeding rates and years were observed in the expression of all characters studied. These interactions indicated that using data from non-competitive conditions to assess performance under competitive conditions could not be justified. Also, limiting the number of testing sites may lead to unsound generalizations and erroneous recommendations regarding gene action estimates of yield and the components of grain yield and three associated characters. Under non-competitive conditions, estimates of the additive type of gene action were more significant and contributed larger effects than the non-additive type for all traits. As competition increased at higher seeding rates, the effects of specific combining ability became more important in the expression of yield, number of spikes, spikelets per spike, and plant height. Heritability estimates confirmed these results except for yield. Of the agronomic characters, harvest index, maturity-duration and plant height, only harvest index showed some promise as a selection criterion under noncompetitive conditions. A breeding procedure utilizing the component approach consisted of selecting early generations under spaced planting with emphasis on avoiding extreme values in any of the components of yield. The balanced combinations of the components of yield should be tested under solid seeding conditions. Close

• 10. [Article] Nature of inheritance, genotype-environment interaction and association of selected agronomic characters in crosses of winter X spring wheats (triticum aestivum L. em Thell)

  This investigation was motivated by the apparent increase in genetic variability resulting from the systematic combining of gene pools represented by winter and spring types of wheats. It was the objective ...

  Citation × Citation Citation Abstract Copy Title: Nature of inheritance, genotype-environment interaction and association of selected agronomic characters in crosses of winter X spring wheats (triticum aestivum L. em Thell) Author: Brajcich, P. This investigation was motivated by the apparent increase in genetic variability resulting from the systematic combining of gene pools represented by winter and spring types of wheats. It was the objective of this study to provide information regarding the nature of this genetic variability for nine agronomic characters in populations resulting from winter x spring crosses. Evaluations were made for: 1) the amount of total genetic variability; 2) the nature of the gene action making up this genetic variability using parent-progeny regression and combining ability analysis and 3) possible direct and indirect associations for traits which influence grain yield. Experimental populations which involved parents, Fl, F2 and backcross generations were grown at two locations where a spring and a winter environment could be utilized. At the winter site, the research was evaluated over a two year period. When the two experimental sites were compared, greater genetic diversity was observed at the spring site for maturity date, plant height, tillers per plant, kernel weight and grain yield. At the winter site, heading date, grain filling period, harvest index and kernels per spike were found to have more total genetic variation. From the expected mean square values, it would appear that the winter parents contributed more to the total genetic variation for most traits measured at both locations. A large genotype-location interaction was also noted suggesting that estimates of gene action and selection for adapted plant types can be done only at the specific winter or spring site. A large portion of the total genetic variation controlling the traits measured was due to additive gene action. However, at the winter site there was also a large influence of non-additive gene action associated with heading date, plant height, harvest index, tillers per plant, kernel weight, kernels per spike and grain yield. Of special interest was that at the winter site the most promising parental combinations could be predicted based on the general combining ability effects of the individual cultivars for each trait studied. Such data were not available for the spring site. Consistent and high correlations were observed between tillers per plant, kernels per spike and, to a lesser extent, kernel weight and grain yield at the winter location. Some negative associations were observed at the spring location between these traits and grain yield suggesting that yield component compensations were involved in the final expression of grain yield. The other characters measured did not reflect significant correlations with yield. When the correlation values were considered in terms of direct and indirect effects for specific traits, a large direct effect was noted for the three components and grain yield. The other traits exhibited small or no direct effects on grain yield but did have a slight influence on grain yield through tillers per plant, kernels per spike or kernel weight. Title: Nature of inheritance, genotype-environment interaction and association of selected agronomic characters in crosses of winter X spring wheats (triticum aestivum L. em Thell) Author: Brajcich, P. This investigation was motivated by the apparent increase in genetic variability resulting from the systematic combining of gene pools represented by winter and spring types of wheats. It was the objective of this study to provide information regarding the nature of this genetic variability for nine agronomic characters in populations resulting from winter x spring crosses. Evaluations were made for: 1) the amount of total genetic variability; 2) the nature of the gene action making up this genetic variability using parent-progeny regression and combining ability analysis and 3) possible direct and indirect associations for traits which influence grain yield. Experimental populations which involved parents, Fl, F2 and backcross generations were grown at two locations where a spring and a winter environment could be utilized. At the winter site, the research was evaluated over a two year period. When the two experimental sites were compared, greater genetic diversity was observed at the spring site for maturity date, plant height, tillers per plant, kernel weight and grain yield. At the winter site, heading date, grain filling period, harvest index and kernels per spike were found to have more total genetic variation. From the expected mean square values, it would appear that the winter parents contributed more to the total genetic variation for most traits measured at both locations. A large genotype-location interaction was also noted suggesting that estimates of gene action and selection for adapted plant types can be done only at the specific winter or spring site. A large portion of the total genetic variation controlling the traits measured was due to additive gene action. However, at the winter site there was also a large influence of non-additive gene action associated with heading date, plant height, harvest index, tillers per plant, kernel weight, kernels per spike and grain yield. Of special interest was that at the winter site the most promising parental combinations could be predicted based on the general combining ability effects of the individual cultivars for each trait studied. Such data were not available for the spring site. Consistent and high correlations were observed between tillers per plant, kernels per spike and, to a lesser extent, kernel weight and grain yield at the winter location. Some negative associations were observed at the spring location between these traits and grain yield suggesting that yield component compensations were involved in the final expression of grain yield. The other characters measured did not reflect significant correlations with yield. When the correlation values were considered in terms of direct and indirect effects for specific traits, a large direct effect was noted for the three components and grain yield. The other traits exhibited small or no direct effects on grain yield but did have a slight influence on grain yield through tillers per plant, kernels per spike or kernel weight. Close

• 11. [Article] Nature of inheritance and association of time, duration and rate of grain filling and subsequent grain yield in crosses of winter and spring wheats (Triticum aestivum L. em Thell)

  The nature of inheritance and possible associations for traits influencing earliness and grain yield were investigated using a four parent diallel of winter and spring wheat cultivars. More genetic variability ...

  Citation × Citation Citation Abstract Copy Title: Nature of inheritance and association of time, duration and rate of grain filling and subsequent grain yield in crosses of winter and spring wheats (Triticum aestivum L. em Thell) Author: Choi, Byung Han The nature of inheritance and possible associations for traits influencing earliness and grain yield were investigated using a four parent diallel of winter and spring wheat cultivars. More genetic variability was observed for the traits measured in segregating populations resulting from crosses between winter and spring type wheats in contrast to spring x spring or winter x winter crosses. The one exception was plant height where more genetic variability resulted from spring x spring crosses. Narrow sense heritability estimates were high for time and duration of heading, anthesis, grain filling and physiological maturity and for plant height. Smaller values were noted for rate of grain filling, kernel number, harvest index, tiller number, kernel weight, whole plant dry weight and grain yield. Estimates of the coefficient of heritability and the parent-offspring correlation coefficient were similar in magnitude except for the traits grain yield, tiller number, kernel weight and whole plant dry weight where large variations due to the environment were encountered. Using the Jinks-Hayman model, no maternal effects were noted nor were any nonallelic interactions observed for total duration of grain filling and lag period. The actual grain filling period was influenced to some degree by such interactions. The spring cultivars also appeared to have more dominant genes for longer total duration of grain filling and lag period. In contrast the winter parents had more dominant genes for the longer actual grain filling period. Estimates of general and specific combining ability provided similar evidence in terms of the nature of gene action. Both additive and nonadditive gene action was present for all traits, the relative magnitudes depending on the specific trait. Based on individual combining ability effects, the winter x spring cross Yamhill x Siete Cerros would appear to provide the highest proportion of desired segregates when combining earliness and acceptable grain yield. From the direct and indirect associations of grain yield, it would appear that a shorter duration of grain filling along with a shorter lag period from heading to anthesis are important for higher rates of grain filling if negative associations between earliness and grain yield are to be avoided. Title: Nature of inheritance and association of time, duration and rate of grain filling and subsequent grain yield in crosses of winter and spring wheats (Triticum aestivum L. em Thell) Author: Choi, Byung Han The nature of inheritance and possible associations for traits influencing earliness and grain yield were investigated using a four parent diallel of winter and spring wheat cultivars. More genetic variability was observed for the traits measured in segregating populations resulting from crosses between winter and spring type wheats in contrast to spring x spring or winter x winter crosses. The one exception was plant height where more genetic variability resulted from spring x spring crosses. Narrow sense heritability estimates were high for time and duration of heading, anthesis, grain filling and physiological maturity and for plant height. Smaller values were noted for rate of grain filling, kernel number, harvest index, tiller number, kernel weight, whole plant dry weight and grain yield. Estimates of the coefficient of heritability and the parent-offspring correlation coefficient were similar in magnitude except for the traits grain yield, tiller number, kernel weight and whole plant dry weight where large variations due to the environment were encountered. Using the Jinks-Hayman model, no maternal effects were noted nor were any nonallelic interactions observed for total duration of grain filling and lag period. The actual grain filling period was influenced to some degree by such interactions. The spring cultivars also appeared to have more dominant genes for longer total duration of grain filling and lag period. In contrast the winter parents had more dominant genes for the longer actual grain filling period. Estimates of general and specific combining ability provided similar evidence in terms of the nature of gene action. Both additive and nonadditive gene action was present for all traits, the relative magnitudes depending on the specific trait. Based on individual combining ability effects, the winter x spring cross Yamhill x Siete Cerros would appear to provide the highest proportion of desired segregates when combining earliness and acceptable grain yield. From the direct and indirect associations of grain yield, it would appear that a shorter duration of grain filling along with a shorter lag period from heading to anthesis are important for higher rates of grain filling if negative associations between earliness and grain yield are to be avoided. Close

• 12. [Article] Effects of irrigation frequency on yields of winter wheat

  Deliberately underirrigating a crop may yield economic benefits. The optimal use of water by an irrigator should be achieved under a deficit irrigation regime. It is important to know how water deficits ...

  Citation × Citation Citation Abstract Copy Title: Effects of irrigation frequency on yields of winter wheat Author: Nakamura, Brian Clifford Deliberately underirrigating a crop may yield economic benefits. The optimal use of water by an irrigator should be achieved under a deficit irrigation regime. It is important to know how water deficits affect yields and the interaction of the deficits with the scheduling of irrigations. A field experiment was conducted during the 1981 irrigation season to investigate the effects of high and low frequency deficit irrigation on yields of winter wheat. Yield and water use data were used to construct three production functions. The relationship between the level of water use and the resulting yield were determined for three irrigation frequency regimes. Field plots under daily (high frequency), weekly (normal frequency), and stress (reduced frequency) regimes were included in the field experiment as well as two dryland production plots. The relationships derived from this project were characterized by a large degree of scatter in the results. Highly favorable weather conditions offset the effects of irrigation deficits on plant yields throughout the irrigation season. At this time, a second year of data is in the process of compilation. The results of a regression analysis showed no statistically significant difference in the water use-yield relationships of the three irrigation frequency regimes. The effect of frequency did not lead to any readily apparent differences in the three production functions. The efficiency of water use of the different irrigation frequencies increases with decreasing amount of applied water for the 1981 crop year. The most efficient treatment, i.e., least water use per unit of yield, was the pre-plant irrigated, dryfarmed plots. The density of the wheat, a measure of crop quality also increased with decreased water use in this experiment. The optimal irrigation treatment (measured by production and quality) was the two-week frequency set. Title: Effects of irrigation frequency on yields of winter wheat Author: Nakamura, Brian Clifford Deliberately underirrigating a crop may yield economic benefits. The optimal use of water by an irrigator should be achieved under a deficit irrigation regime. It is important to know how water deficits affect yields and the interaction of the deficits with the scheduling of irrigations. A field experiment was conducted during the 1981 irrigation season to investigate the effects of high and low frequency deficit irrigation on yields of winter wheat. Yield and water use data were used to construct three production functions. The relationship between the level of water use and the resulting yield were determined for three irrigation frequency regimes. Field plots under daily (high frequency), weekly (normal frequency), and stress (reduced frequency) regimes were included in the field experiment as well as two dryland production plots. The relationships derived from this project were characterized by a large degree of scatter in the results. Highly favorable weather conditions offset the effects of irrigation deficits on plant yields throughout the irrigation season. At this time, a second year of data is in the process of compilation. The results of a regression analysis showed no statistically significant difference in the water use-yield relationships of the three irrigation frequency regimes. The effect of frequency did not lead to any readily apparent differences in the three production functions. The efficiency of water use of the different irrigation frequencies increases with decreasing amount of applied water for the 1981 crop year. The most efficient treatment, i.e., least water use per unit of yield, was the pre-plant irrigated, dryfarmed plots. The density of the wheat, a measure of crop quality also increased with decreased water use in this experiment. The optimal irrigation treatment (measured by production and quality) was the two-week frequency set. Close

• 13. [Article] The need to breed crop varieties suitable for organic farming using wheat, tomato and broccoli as examples: A review

  This is the author's peer-reviewed final manuscript, as accepted by the publisher. The article is copyrighted by the Royal Netherlands Society for Agricultural Sciences and published by Elsevier. It can ...

  Citation × Citation Citation Abstract Copy Title: The need to breed crop varieties suitable for organic farming using wheat, tomato and broccoli as examples: A review Author: Leifert, C., Myers, J. R., Lammerts van Bueren, E. T., Messmer, M. M., Murphy, K. M., Jones, S. S., Tamm, L. This is the author's peer-reviewed final manuscript, as accepted by the publisher. The article is copyrighted by the Royal Netherlands Society for Agricultural Sciences and published by Elsevier. It can be found at: http://www.journals.elsevier.com/njas-wageningen-journal-of-life-sciences/. Title: The need to breed crop varieties suitable for organic farming using wheat, tomato and broccoli as examples: A review Author: Leifert, C., Myers, J. R., Lammerts van Bueren, E. T., Messmer, M. M., Murphy, K. M., Jones, S. S., Tamm, L. This is the author's peer-reviewed final manuscript, as accepted by the publisher. The article is copyrighted by the Royal Netherlands Society for Agricultural Sciences and published by Elsevier. It can be found at: http://www.journals.elsevier.com/njas-wageningen-journal-of-life-sciences/. Close

• 14. [Article] Remote-sensing and geographic information system techniques to map spatial variation of wheat grain yield

  Farmers and researchers are aware of spatial variation in grain yield within farms or fields. Fertilizer management may be improved if techniques can be developed to identify grain yield variations in ...

  Citation × Citation Citation Abstract Copy Title: Remote-sensing and geographic information system techniques to map spatial variation of wheat grain yield Author: Roberts, Michael C. (Michael Coy), 1951- Farmers and researchers are aware of spatial variation in grain yield within farms or fields. Fertilizer management may be improved if techniques can be developed to identify grain yield variations in wheat fields. Aerial color infrared (CIR) photography was used to identify winter wheat (Triticum aestivum L.) canopy biomass variability in the Spring of the growing season. Low yielding areas identified from CIR photography were associated with shallow soil profiles consistent with soil forming factors of the region, and were significantly different from average and high yielding areas. The high yielding areas were located within a few meters of a drainage way, and were not significantly different than the average yielding areas except in one field with a deep soil profile and low variance. Fields with heterogeneous CIR photographs had high variances because of many dissimilar inclusions. CIR photography, although useful to distinguish vegetational differences, requires complex timing, ground verification, and correction to estimate yield variability. A geographic information system (GIS) was used to overlay photo interpreted biomass and soil map units. The overlay analysis allowed construction of a higher (first) order soil map indicating inclusions. Area calculation of the inclusions and map units using a GIS function combined with estimated yield (no variance estimates or confidence intervals associated with the estimated yield) data suggests fertilizer management with a first order soil map to increase fertilizer efficiency by up to six percent. Future research combining remotely-sensed subsidiary variables correlated with moisture supply capacity estimates from soil survey methods may assess, using relatively new spatially dependent interpolation methods, the local and regional variation in wheat grain yield. Title: Remote-sensing and geographic information system techniques to map spatial variation of wheat grain yield Author: Roberts, Michael C. (Michael Coy), 1951- Farmers and researchers are aware of spatial variation in grain yield within farms or fields. Fertilizer management may be improved if techniques can be developed to identify grain yield variations in wheat fields. Aerial color infrared (CIR) photography was used to identify winter wheat (Triticum aestivum L.) canopy biomass variability in the Spring of the growing season. Low yielding areas identified from CIR photography were associated with shallow soil profiles consistent with soil forming factors of the region, and were significantly different from average and high yielding areas. The high yielding areas were located within a few meters of a drainage way, and were not significantly different than the average yielding areas except in one field with a deep soil profile and low variance. Fields with heterogeneous CIR photographs had high variances because of many dissimilar inclusions. CIR photography, although useful to distinguish vegetational differences, requires complex timing, ground verification, and correction to estimate yield variability. A geographic information system (GIS) was used to overlay photo interpreted biomass and soil map units. The overlay analysis allowed construction of a higher (first) order soil map indicating inclusions. Area calculation of the inclusions and map units using a GIS function combined with estimated yield (no variance estimates or confidence intervals associated with the estimated yield) data suggests fertilizer management with a first order soil map to increase fertilizer efficiency by up to six percent. Future research combining remotely-sensed subsidiary variables correlated with moisture supply capacity estimates from soil survey methods may assess, using relatively new spatially dependent interpolation methods, the local and regional variation in wheat grain yield. Close

• 15. [Article] The effect of seeding rate on yield and yield components of two winter wheat varieties

  Wheat is an important cereal crop in the Willamette Valley of Oregon and the stiff-strawed, high-yielding varieties are the predominant types grown. Observation of the effect of seeding rates on the yield ...

  Citation × Citation Citation Abstract Copy Title: The effect of seeding rate on yield and yield components of two winter wheat varieties Author: Rana, Prakriti Shumshere Jung Bahadur Wheat is an important cereal crop in the Willamette Valley of Oregon and the stiff-strawed, high-yielding varieties are the predominant types grown. Observation of the effect of seeding rates on the yield and yield components are useful in determining which of the components contributes most to the yield of a winter wheat variety and in developing optimum seeding rate recommendations. The experiments were conducted in 1963-1964, 1964-1965, and 1965-1966. The purpose of these studies was to determine the effect of various seeding rates on the yield and yield components of two winter wheat varieties and to find the optimum seeding rates for these varieties. A further objective was to determine if reasonable yields could be obtained from low rates of seeding for both varieties. The yield was measured in terms of bushels per acre. The yield components studied were (1) the number of spikes per unit area, (2) number of spikelets per spike, (3) number of kernels per spike, and (4) the weight of 100 kernels. The results were obtained and comparisons were made between the two varieties and their performance over a three-year period. There was considerable fluctuation in the yields involving both varieties for all seeding rates in the different seasons. The 1966 season was most favorable for Gaines and the 1964 season for Druchamp. Druchamp gave higher yields than Gaines for all seeding rates. The number of spikes per unit area for both varieties was most effected by differences in seeding rate in each year, while the other components showed no response. High yield of Druchamp was due to the result of more spikes per unit area, heavy kernels, and resistance to stripe rust. The yield of Gaines was the result of more kernels per spike. The higher seeding rates for both varieties produced the highest yields. Title: The effect of seeding rate on yield and yield components of two winter wheat varieties Author: Rana, Prakriti Shumshere Jung Bahadur Wheat is an important cereal crop in the Willamette Valley of Oregon and the stiff-strawed, high-yielding varieties are the predominant types grown. Observation of the effect of seeding rates on the yield and yield components are useful in determining which of the components contributes most to the yield of a winter wheat variety and in developing optimum seeding rate recommendations. The experiments were conducted in 1963-1964, 1964-1965, and 1965-1966. The purpose of these studies was to determine the effect of various seeding rates on the yield and yield components of two winter wheat varieties and to find the optimum seeding rates for these varieties. A further objective was to determine if reasonable yields could be obtained from low rates of seeding for both varieties. The yield was measured in terms of bushels per acre. The yield components studied were (1) the number of spikes per unit area, (2) number of spikelets per spike, (3) number of kernels per spike, and (4) the weight of 100 kernels. The results were obtained and comparisons were made between the two varieties and their performance over a three-year period. There was considerable fluctuation in the yields involving both varieties for all seeding rates in the different seasons. The 1966 season was most favorable for Gaines and the 1964 season for Druchamp. Druchamp gave higher yields than Gaines for all seeding rates. The number of spikes per unit area for both varieties was most effected by differences in seeding rate in each year, while the other components showed no response. High yield of Druchamp was due to the result of more spikes per unit area, heavy kernels, and resistance to stripe rust. The yield of Gaines was the result of more kernels per spike. The higher seeding rates for both varieties produced the highest yields. Close

• 16. [Article] Adaptability of winter wheat cultivars to dryland conditions and their response to water stress

  Winter wheat cultivars (Triticum aestivum) were evaluated for their response to water stress and adaptability to a wide range of moisture limited environments. Grain yield was analyzed for ten cultivars ...

  Citation × Citation Citation Abstract Copy Title: Adaptability of winter wheat cultivars to dryland conditions and their response to water stress Author: Keim, Don Lee Winter wheat cultivars (Triticum aestivum) were evaluated for their response to water stress and adaptability to a wide range of moisture limited environments. Grain yield was analyzed for ten cultivars at six locations across four years. Regression of the cultivar mean on the year-location mean was used as a measure of the environmental response of a particular cultivar, Plant water status (leaf osmotic potential and water potential) during the grain filling period, along with grain yield and yield components were determined at three locations for fifteen cultivars under space-planted conditions in 1972 and for ten cultivars under solid-seeding in 1973. Five cultivars were evaluated for plant water status and rates of growth during reproductive development and for final grain yield and yield components at a severely stressed location in 1973. Drought resistance, described as yielding ability under severe soil moisture stress, was found to be the result of avoidance, tolerance and escape characteristics. Plant water status influenced the components of yield when their development occurred during a period of high external stress. However, the relative importance of plant water status to final yield varied depending on the magnitude of the direct effect of spike number on yield. Drought avoidance was the ability to maintain a high plant water status when under high external stress conditions. In the cultivar Yamhill, the stable growth rate during inflorescence development and the extended period of grain filling may have resulted from the ability of this cultivar to avoid drought. These characteristics, also, may explain the large spikelet number and the high kernel weight of Yamhill. Even though Hyslop and Wanser had a moderate and high internal water stress, respectively, they were relatively tolerant of stress in terms of high growth rates during the grain filling period. The high yielding ability of Wanser and McDermid under high stress conditions was primarily related to a large number of spikes. This trait was considered an escape characteristic because tillering was established before the onset of severe stress. The club wheats neither avoided or tolerated internal water stress under solid-seeded conditions nor did they have sufficient tillering capacity to compensate for the effect of stress on the laterdeveloped components.of yield. Nugaines, Hyslop and Rew maintained a moderate internal stress during later development but differed in their yield component responses. The yield of Nugaines depended primarily on a high tillering capacity, whereas the yield of Hyslop and Rew depended on a balance of contributions from all the components of yield. Widely adapted cultivars, such as Hyslop and McDermid, not only yielded well under severe stress conditions but had the genetic potential to respond adequately to more favorable moisture conditions. Cultivars specifically, adapted to lower yielding environments, such as Yamhill and Wanser, were able to avoid, tolerate or escape drought but were limited in one or more of their yield component responses to better conditions. Conversely, cultivars specifically adapted to high yielding environments, such as Nugaines and Paha, lacked the ability to consistently yield well under high stress environments but had a high response to more favorable moisture conditions. Cultivars best adapted to dryland cultivation should have the highest yield under stress conditions as expressed through the components of yield by one or a combination of avoidance, tolerance or escape characteristics. These cultivars should also have the maximum expression in, and balance among, the components of yield for maximum response to more favorable moisture conditions. This goal may be obtained by selection in favorable as well as stressed environments and by testing throughout the range of the environments where the cultivar is expected to be grown. Because high yield under stress was found in this study to be manifested through different characteristics of the plant the breeder should be aware of traits which may contribute to drought resistance, but he should not be restricted to a particular ideotype when breeding for yield under conditions of high moisture stress. Title: Adaptability of winter wheat cultivars to dryland conditions and their response to water stress Author: Keim, Don Lee Winter wheat cultivars (Triticum aestivum) were evaluated for their response to water stress and adaptability to a wide range of moisture limited environments. Grain yield was analyzed for ten cultivars at six locations across four years. Regression of the cultivar mean on the year-location mean was used as a measure of the environmental response of a particular cultivar, Plant water status (leaf osmotic potential and water potential) during the grain filling period, along with grain yield and yield components were determined at three locations for fifteen cultivars under space-planted conditions in 1972 and for ten cultivars under solid-seeding in 1973. Five cultivars were evaluated for plant water status and rates of growth during reproductive development and for final grain yield and yield components at a severely stressed location in 1973. Drought resistance, described as yielding ability under severe soil moisture stress, was found to be the result of avoidance, tolerance and escape characteristics. Plant water status influenced the components of yield when their development occurred during a period of high external stress. However, the relative importance of plant water status to final yield varied depending on the magnitude of the direct effect of spike number on yield. Drought avoidance was the ability to maintain a high plant water status when under high external stress conditions. In the cultivar Yamhill, the stable growth rate during inflorescence development and the extended period of grain filling may have resulted from the ability of this cultivar to avoid drought. These characteristics, also, may explain the large spikelet number and the high kernel weight of Yamhill. Even though Hyslop and Wanser had a moderate and high internal water stress, respectively, they were relatively tolerant of stress in terms of high growth rates during the grain filling period. The high yielding ability of Wanser and McDermid under high stress conditions was primarily related to a large number of spikes. This trait was considered an escape characteristic because tillering was established before the onset of severe stress. The club wheats neither avoided or tolerated internal water stress under solid-seeded conditions nor did they have sufficient tillering capacity to compensate for the effect of stress on the laterdeveloped components.of yield. Nugaines, Hyslop and Rew maintained a moderate internal stress during later development but differed in their yield component responses. The yield of Nugaines depended primarily on a high tillering capacity, whereas the yield of Hyslop and Rew depended on a balance of contributions from all the components of yield. Widely adapted cultivars, such as Hyslop and McDermid, not only yielded well under severe stress conditions but had the genetic potential to respond adequately to more favorable moisture conditions. Cultivars specifically, adapted to lower yielding environments, such as Yamhill and Wanser, were able to avoid, tolerate or escape drought but were limited in one or more of their yield component responses to better conditions. Conversely, cultivars specifically adapted to high yielding environments, such as Nugaines and Paha, lacked the ability to consistently yield well under high stress environments but had a high response to more favorable moisture conditions. Cultivars best adapted to dryland cultivation should have the highest yield under stress conditions as expressed through the components of yield by one or a combination of avoidance, tolerance or escape characteristics. These cultivars should also have the maximum expression in, and balance among, the components of yield for maximum response to more favorable moisture conditions. This goal may be obtained by selection in favorable as well as stressed environments and by testing throughout the range of the environments where the cultivar is expected to be grown. Because high yield under stress was found in this study to be manifested through different characteristics of the plant the breeder should be aware of traits which may contribute to drought resistance, but he should not be restricted to a particular ideotype when breeding for yield under conditions of high moisture stress. Close

• 17. [Article] Estimates of heterosis for five agronomic traits in selected winter x spring and winter x winter wheat crosses (Triticum aestivum L. em Thell)

  Concern regarding the lack of genetic variability and the apparent yield plateau reached in wheat breeding have prompted this investigation. The systematic crossing of spring and winter wheat types which ...

  Citation × Citation Citation Abstract Copy Title: Estimates of heterosis for five agronomic traits in selected winter x spring and winter x winter wheat crosses (Triticum aestivum L. em Thell) Author: Brajcich, P. Concern regarding the lack of genetic variability and the apparent yield plateau reached in wheat breeding have prompted this investigation. The systematic crossing of spring and winter wheat types which have evolved to form somewhat different gene pools, may provide a source of additional usable genetic variability for future yield increases. Five winter and five spring wheat cultivars with different degrees of genetic similarities in their pedigrees were crossed to obtain F1's and F2's. The parents plus winter x spring F1's were planted in two growing seasons at Hyslop Agronomy Farm near Corvallis, Oregon. During the second season the winter x spring F2 and winter x winter F1 crosses were also included. Agronomic traits were measured on an individual plant basis. These traits were plant height, number of tillers per plant, 100 kernel weight, number of kernels per spike and grain yield. Analyses of variance were conducted for each trait. Estimates of the amount of usable genetic variation were determined by heterosis values, inbreeding depression and parent-progeny standard regressions. Possible interactions between years and the above five characters were determined for the winter x spring F1's. Evidence of non-additive gene action was found in the expression of heterosis and subsequent inbreeding depression which depended on the specific trait measured and the parents involved in the cross. The greatest heterosis values were noted for grain yield per plant. Crosses with the winter parent, Weique Red Mace, resulted in the highest estimates for grain yield. This was due to the late maturity of these hybrids and to the diverse genetic background of this winter parent compared to the five spring parents. Parent-progeny regressions indicated that a large amount of additive genetic variance was present for plant height, 100 kernel weight and grain yield an intermediate amount for kernels per spike and tillers per plant. Winter x spring F1 crosses resulted in higher heterosis estimates and a wider range of values between crosses than winter x winter F1 crosses. Parent-progeny regression estimates were similar in value for the two types of F1 populations. Thus, these results indicate that the systematic crossing between winter and spring wheats will produce greater total genetic variability for further wheat improvement. This is true for the development of hybrid wheat (non-additive) and may also be promising for conventional breeding programs when only the additive portion of the total genetic variance can be used. The data support the general conclusion that the amount of heterosis is a function of genetic diversity between the two parents. Those breeders working on hybrid wheat may wish to look at winter x spring crosses as a means of maximizing heterosis. However, since a significant interaction between years x F1's was noted for the traits measured, more than one year of evaluation will be necessary if winter x spring crosses are employed. Title: Estimates of heterosis for five agronomic traits in selected winter x spring and winter x winter wheat crosses (Triticum aestivum L. em Thell) Author: Brajcich, P. Concern regarding the lack of genetic variability and the apparent yield plateau reached in wheat breeding have prompted this investigation. The systematic crossing of spring and winter wheat types which have evolved to form somewhat different gene pools, may provide a source of additional usable genetic variability for future yield increases. Five winter and five spring wheat cultivars with different degrees of genetic similarities in their pedigrees were crossed to obtain F1's and F2's. The parents plus winter x spring F1's were planted in two growing seasons at Hyslop Agronomy Farm near Corvallis, Oregon. During the second season the winter x spring F2 and winter x winter F1 crosses were also included. Agronomic traits were measured on an individual plant basis. These traits were plant height, number of tillers per plant, 100 kernel weight, number of kernels per spike and grain yield. Analyses of variance were conducted for each trait. Estimates of the amount of usable genetic variation were determined by heterosis values, inbreeding depression and parent-progeny standard regressions. Possible interactions between years and the above five characters were determined for the winter x spring F1's. Evidence of non-additive gene action was found in the expression of heterosis and subsequent inbreeding depression which depended on the specific trait measured and the parents involved in the cross. The greatest heterosis values were noted for grain yield per plant. Crosses with the winter parent, Weique Red Mace, resulted in the highest estimates for grain yield. This was due to the late maturity of these hybrids and to the diverse genetic background of this winter parent compared to the five spring parents. Parent-progeny regressions indicated that a large amount of additive genetic variance was present for plant height, 100 kernel weight and grain yield an intermediate amount for kernels per spike and tillers per plant. Winter x spring F1 crosses resulted in higher heterosis estimates and a wider range of values between crosses than winter x winter F1 crosses. Parent-progeny regression estimates were similar in value for the two types of F1 populations. Thus, these results indicate that the systematic crossing between winter and spring wheats will produce greater total genetic variability for further wheat improvement. This is true for the development of hybrid wheat (non-additive) and may also be promising for conventional breeding programs when only the additive portion of the total genetic variance can be used. The data support the general conclusion that the amount of heterosis is a function of genetic diversity between the two parents. Those breeders working on hybrid wheat may wish to look at winter x spring crosses as a means of maximizing heterosis. However, since a significant interaction between years x F1's was noted for the traits measured, more than one year of evaluation will be necessary if winter x spring crosses are employed. Close

• 18. [Article] The influence of various climate and edaphic factors on the toxicity of 2-tert. butylamino-4-ethylamino-6-methylthio-s-triazine (Igran) to winter wheat (Triticum aestivum Vill., Host)

  Several studies were conducted to determine the influence of various environmental factors on the toxicity of 2-tert.butylamino- 4-ethylamino-6-methylthio-s-triazirxe (Igran) to winter wheat. The effect ...

  Citation × Citation Citation Abstract Copy Title: The influence of various climate and edaphic factors on the toxicity of 2-tert. butylamino-4-ethylamino-6-methylthio-s-triazine (Igran) to winter wheat (Triticum aestivum Vill., Host) Author: Figuerola, Luis Fernan Several studies were conducted to determine the influence of various environmental factors on the toxicity of 2-tert.butylamino- 4-ethylamino-6-methylthio-s-triazirxe (Igran) to winter wheat. The effect of temperature on Igran toxicity was studied by growing wheat plants in pots submerged in water baths to control soil temperature and in controlled-environment chambers. Igran was more toxic to the test plants at 20-25 C than at 5-10 C. The lesser toxicity at low temperature appeared to be correlated in part with lower rates of absorption and translocation of the chemical. Light intensity was shown to influence the activity of Igran. High light intensity produced an effect similar to that of high temperature and it was difficult to separate the individual action for either climatic factor. The effect of Igran on photosynthesis of wheat plants was studied by measuring the CO₂ uptake with an infrared gas analyzer. The activity of Igran was more pronounced at high light intensity. Water availability in the soil influenced Igran action on winter wheat. The higher the water content in the soil, under high temperature and light intensity conditions, the higher the apparent absorption and translocation of Igran. This effect was related to the adsorptive capacity of soil particles. With increased water content in the soil, Igran apparently becomes more available to the roots than under low moisture conditions. High nitrogen content in the growth medium favored Igran toxic action on winter wheat. With lower nitrogen levels, although the growth rate was diminished, chlorosis and necrosis were not as noticeable as under high nitrogen content conditions. Igran was less toxic when applied directly to the soil surface than when incorporated into the soil. When the herbicide was placed close to the root system, the toxicity was greatly increased. Postemergence applications of Igran to the soil under high illumination (2500-3000 ft-c) and high temperature (20-30 C) produced severe injury to wheat even at low rates and at several stages of growth. At low light intensity (500-800 ft-c) and low temperature (5-10 C) few or no injury symptoms were observed. The determination of the factors affecting the toxicity of Igran on winter wheat will aid in making improved recommendations for its use to control a broad spectrum of undesired vegetation with a minimum chance for damage to wheat plants. Title: The influence of various climate and edaphic factors on the toxicity of 2-tert. butylamino-4-ethylamino-6-methylthio-s-triazine (Igran) to winter wheat (Triticum aestivum Vill., Host) Author: Figuerola, Luis Fernan Several studies were conducted to determine the influence of various environmental factors on the toxicity of 2-tert.butylamino- 4-ethylamino-6-methylthio-s-triazirxe (Igran) to winter wheat. The effect of temperature on Igran toxicity was studied by growing wheat plants in pots submerged in water baths to control soil temperature and in controlled-environment chambers. Igran was more toxic to the test plants at 20-25 C than at 5-10 C. The lesser toxicity at low temperature appeared to be correlated in part with lower rates of absorption and translocation of the chemical. Light intensity was shown to influence the activity of Igran. High light intensity produced an effect similar to that of high temperature and it was difficult to separate the individual action for either climatic factor. The effect of Igran on photosynthesis of wheat plants was studied by measuring the CO₂ uptake with an infrared gas analyzer. The activity of Igran was more pronounced at high light intensity. Water availability in the soil influenced Igran action on winter wheat. The higher the water content in the soil, under high temperature and light intensity conditions, the higher the apparent absorption and translocation of Igran. This effect was related to the adsorptive capacity of soil particles. With increased water content in the soil, Igran apparently becomes more available to the roots than under low moisture conditions. High nitrogen content in the growth medium favored Igran toxic action on winter wheat. With lower nitrogen levels, although the growth rate was diminished, chlorosis and necrosis were not as noticeable as under high nitrogen content conditions. Igran was less toxic when applied directly to the soil surface than when incorporated into the soil. When the herbicide was placed close to the root system, the toxicity was greatly increased. Postemergence applications of Igran to the soil under high illumination (2500-3000 ft-c) and high temperature (20-30 C) produced severe injury to wheat even at low rates and at several stages of growth. At low light intensity (500-800 ft-c) and low temperature (5-10 C) few or no injury symptoms were observed. The determination of the factors affecting the toxicity of Igran on winter wheat will aid in making improved recommendations for its use to control a broad spectrum of undesired vegetation with a minimum chance for damage to wheat plants. Close

• 19. [Article] The influence on winter wheat yields of competitive weedy species

  A study was conducted to compare the competitive ability with weeds of the short-strawed Gaines variety wheat and taller growing varieties under different fertility levels at three experimental locations. ...

  Citation × Citation Citation Abstract Copy Title: The influence on winter wheat yields of competitive weedy species Author: Albeke, William Edgar A study was conducted to compare the competitive ability with weeds of the short-strawed Gaines variety wheat and taller growing varieties under different fertility levels at three experimental locations. The experiments were designed so that the effects of variety, nitrogen fertilization, and weed competition could be evaluated. The interactions between these factors were also studied. Ryegrass (Loolium app.) and downy brome (Bromus tectorum) were the two weed species studied. Under high winter rainfall and ryegrass competition yields of wheat were seriously impaired in both the short and tall growing wheat varieties tested. As rates of nitrogen increased yields of wheat did not increase where a medium or heavy stand of ryegrass was present. Yield of wheat was reduced under high nitrogen and high ryegrass competition. A response to 60 pounds of nitrogen per acre was noted where no ryegrass competition was present. One hundred twenty pounds of nitrogen did not increase yields appreciably, especially in the Gaines variety. In the two remaining experiments, response to nitrogen fertilization was not as prominent due to lack of moisture throughout the growing season. However, downy brome competition decreased yields at one location under all three fertility levels. At the other location a poor stand of downy brome and arid conditions accounted for the lack of competitive effects. No differences were noted in competing abilities of the tall vs. the short growing varieties. In general it was concluded that in order to get maximum response from nitrogen fertilization in wheat, weeds would have to be controlled. Title: The influence on winter wheat yields of competitive weedy species Author: Albeke, William Edgar A study was conducted to compare the competitive ability with weeds of the short-strawed Gaines variety wheat and taller growing varieties under different fertility levels at three experimental locations. The experiments were designed so that the effects of variety, nitrogen fertilization, and weed competition could be evaluated. The interactions between these factors were also studied. Ryegrass (Loolium app.) and downy brome (Bromus tectorum) were the two weed species studied. Under high winter rainfall and ryegrass competition yields of wheat were seriously impaired in both the short and tall growing wheat varieties tested. As rates of nitrogen increased yields of wheat did not increase where a medium or heavy stand of ryegrass was present. Yield of wheat was reduced under high nitrogen and high ryegrass competition. A response to 60 pounds of nitrogen per acre was noted where no ryegrass competition was present. One hundred twenty pounds of nitrogen did not increase yields appreciably, especially in the Gaines variety. In the two remaining experiments, response to nitrogen fertilization was not as prominent due to lack of moisture throughout the growing season. However, downy brome competition decreased yields at one location under all three fertility levels. At the other location a poor stand of downy brome and arid conditions accounted for the lack of competitive effects. No differences were noted in competing abilities of the tall vs. the short growing varieties. In general it was concluded that in order to get maximum response from nitrogen fertilization in wheat, weeds would have to be controlled. Close

• 20. [Article] Association of selected traits with visual selection for yield in wheat (Triticum aestivum, L. em Thell.)

  Visual selection for grain yield may be a limiting factor in identifying superior yielding genotypes in a breeding program. This investigation was conducted (1) to compare the effectiveness of visual selection ...

  Citation × Citation Citation Abstract Copy Title: Association of selected traits with visual selection for yield in wheat (Triticum aestivum, L. em Thell.) Author: Marciniak, Michael E. Visual selection for grain yield may be a limiting factor in identifying superior yielding genotypes in a breeding program. This investigation was conducted (1) to compare the effectiveness of visual selection for grain yield by three selector groups representing different levels of plant breeding experience, and (2) to examine the association of selected traits with the process of evaluating plots visually for grain yield. The germplasm evaluated consisted of fifty non-segregating, diverse genotypes selected to include a wide range of expression for phenotypic characters. They were grown in solid-seeded, two-row plots with three replications in a randomized block design during 1981-1982. Data were collected on a plot basis for grain yield and twenty-two agronomic traits. Eighteen selectors were placed in three groups comprised of two plant breeders, eight graduate students, and eight summer student workers, respectively, from the Oregon State University cereal breeding program. Evaluations were made on two separate days by scoring each of the 150 plots on a scale of 1 to 5 for grain yield. The plant breeder selectors were the most successful of the three groups in discriminating both high and low yielding plots. The two best graduate student selectors were similar in ability to the plant breeders in scoring plots for high yield, although not in scoring for low yield. The remaining graduate student and summer worker selectors were generally not able to score more low and high yielding plots "correctly" than would be expected if selection were done at random. Considered individually, the most effective selectors failed to select several high yielding plots. However, when selections of the four most effective selectors were combined, only one of the twenty highest yielding plots was omitted. Results comparing trait association with actual plot grain yield and with selector scoring for plot grain yield suggested "biases" for or against certain traits. Biases for later heading and maturing plant types with wide flag leaves were common to all selector groups when visually selecting for high yield, as were earlier heading and maturing entries with narrower flag leaves when selecting for low yield. The plant breeder selectors were notable for lack of trait biases relative to other selector groups. In contrast, the summer worker selectors tended to overemphasize several spike characteristics whether selecting for high or low yield. Results suggested several other trait biases of individual selectors and selector groups. Title: Association of selected traits with visual selection for yield in wheat (Triticum aestivum, L. em Thell.) Author: Marciniak, Michael E. Visual selection for grain yield may be a limiting factor in identifying superior yielding genotypes in a breeding program. This investigation was conducted (1) to compare the effectiveness of visual selection for grain yield by three selector groups representing different levels of plant breeding experience, and (2) to examine the association of selected traits with the process of evaluating plots visually for grain yield. The germplasm evaluated consisted of fifty non-segregating, diverse genotypes selected to include a wide range of expression for phenotypic characters. They were grown in solid-seeded, two-row plots with three replications in a randomized block design during 1981-1982. Data were collected on a plot basis for grain yield and twenty-two agronomic traits. Eighteen selectors were placed in three groups comprised of two plant breeders, eight graduate students, and eight summer student workers, respectively, from the Oregon State University cereal breeding program. Evaluations were made on two separate days by scoring each of the 150 plots on a scale of 1 to 5 for grain yield. The plant breeder selectors were the most successful of the three groups in discriminating both high and low yielding plots. The two best graduate student selectors were similar in ability to the plant breeders in scoring plots for high yield, although not in scoring for low yield. The remaining graduate student and summer worker selectors were generally not able to score more low and high yielding plots "correctly" than would be expected if selection were done at random. Considered individually, the most effective selectors failed to select several high yielding plots. However, when selections of the four most effective selectors were combined, only one of the twenty highest yielding plots was omitted. Results comparing trait association with actual plot grain yield and with selector scoring for plot grain yield suggested "biases" for or against certain traits. Biases for later heading and maturing plant types with wide flag leaves were common to all selector groups when visually selecting for high yield, as were earlier heading and maturing entries with narrower flag leaves when selecting for low yield. The plant breeder selectors were notable for lack of trait biases relative to other selector groups. In contrast, the summer worker selectors tended to overemphasize several spike characteristics whether selecting for high or low yield. Results suggested several other trait biases of individual selectors and selector groups. Close

• 21. [Article] Association between length of grain filling period and grain yield in two wheat populations (Triticum aestivum L. em Thell.)

  The objective of this study was to determine interrelationships among agronomic traits in early and late maturing populations. Two populations were obtained from the crosses, Roussalka/Tesopaco 76 and ...

  Citation × Citation Citation Abstract Copy Title: Association between length of grain filling period and grain yield in two wheat populations (Triticum aestivum L. em Thell.) Author: Min, Hwang Kee The objective of this study was to determine interrelationships among agronomic traits in early and late maturing populations. Two populations were obtained from the crosses, Roussalka/Tesopaco 76 and Yamhill/Aspen. Seeds were space planted with split plot design and nine agronomic traits were observed. In comparative studies between early and late populations, the early population was earlier in heading date, maturity date, longer maturity duration, heavier kernel weight, and higher harvest index. However, it was shorter in plant height, had fewer tillers, kernels and lower grain yield than the late population. Grain filling duration expressed positive relationships with grain yield in both crosses, although the correlation coefficient with grain yield was very low compared to other agronomic traits. Grain filling duration showed consistent positive relationships with kernel weight in both populations and with kernel number in the late population. No relationship was found between grain filling duration and tiller number. Grain filling duration influenced grain yield mainly by the indirect effects of kernel weight and kernel number. Yield components generally showed high positive relationships with grain yield; tiller number being the most important, followed by kernel number, and kernel weight. Competition among yield components was minimal in this space planted study. Heading date showed a negative association while plant height and harvest index expressed high positive relationships with grain yield. Title: Association between length of grain filling period and grain yield in two wheat populations (Triticum aestivum L. em Thell.) Author: Min, Hwang Kee The objective of this study was to determine interrelationships among agronomic traits in early and late maturing populations. Two populations were obtained from the crosses, Roussalka/Tesopaco 76 and Yamhill/Aspen. Seeds were space planted with split plot design and nine agronomic traits were observed. In comparative studies between early and late populations, the early population was earlier in heading date, maturity date, longer maturity duration, heavier kernel weight, and higher harvest index. However, it was shorter in plant height, had fewer tillers, kernels and lower grain yield than the late population. Grain filling duration expressed positive relationships with grain yield in both crosses, although the correlation coefficient with grain yield was very low compared to other agronomic traits. Grain filling duration showed consistent positive relationships with kernel weight in both populations and with kernel number in the late population. No relationship was found between grain filling duration and tiller number. Grain filling duration influenced grain yield mainly by the indirect effects of kernel weight and kernel number. Yield components generally showed high positive relationships with grain yield; tiller number being the most important, followed by kernel number, and kernel weight. Competition among yield components was minimal in this space planted study. Heading date showed a negative association while plant height and harvest index expressed high positive relationships with grain yield. Close

• 22. [Article] Multi-location analysis for the identification of quantitative trait loci underlying disease resistance against Cephalosporium gramineum and Puccinia striiformis f. sp. tritici by linkage mapping in wheat (Triticum aestivum L.)

  Wheat (Triticum aestivum L.) is one of the major crops produced in the U.S. Pacific Northwest, a region known for its wheat production for international export. Wheat production in the region is threatened ...

  Citation × Citation Citation Abstract Copy Title: Multi-location analysis for the identification of quantitative trait loci underlying disease resistance against Cephalosporium gramineum and Puccinia striiformis f. sp. tritici by linkage mapping in wheat (Triticum aestivum L.) Author: Vazquez, Maria Dolores Wheat (Triticum aestivum L.) is one of the major crops produced in the U.S. Pacific Northwest, a region known for its wheat production for international export. Wheat production in the region is threatened by diseases such as Cephalosporium stripe and stripe rust. Cephalosporium stripe is a vascular wilt disease of wheat caused by the persistent soil-borne fungus and suspected necrotrophic pathogen Cephalosporium gramineum Nisikado & Ikata, and is a recurring disease in many localities when susceptible cultivars are grown. Stripe rust, a foliar disease of wheat caused by the air-borne biotrophic fungus Puccinia striformis f. sp. tritici is a disease present in every region around the world where commercial wheat is grown. Attaining durable resistance to stripe rust would greatly benefit wheat producers in the region. Combining stripe rust resistance with resistance to other diseases, such as Cephalosporium stripe, is challenging. Wheat cultivars with high levels of resistance to several diseases are favorable candidates for genetic studies to determine the inheritance of resistance and facilitate the development of a method to genotypically select for disease resistance. Two populations of recombinant inbred lines were developed from 'Tubbs'/'NSA-98-0995' (TxN) and 'Einstein'/'Tubbs' (ExT) with population sizes of 271 and 259 F[subscript (5:6)], respectively. Tubbs is susceptible to stripe rust and Cephalosporium stripe while Einstein and NSA-98-0995 demonstrate moderate to high resistance to both diseases. Both populations were assessed across seven environments (combinations of locations and years) for stripe rust resistance under natural infection and four environments for Cephalosporium stripe resistance under artificial inoculation. The populations were mapped using diversity array technology (DArT) and simple sequence repeat (SSR) markers for quantitative trait loci (QTL) analysis. Results for Cephalosporium stripe resistance was quantitatively inherited with several QTL detected (>5), including some QTL in the same chromosome location in both populations. For stripe rust resistance, seven QTL were identified in the TxN population, suggesting quantitative resistance contributed by several minor genes. In the ExT population two QTL with major effects and with epistatic interactions between them were identified. One of them, a major QTL from Tubbs on chromosome 2AS that may be Yr17, was not expressed in the TxN population or in Tubbs, perhaps owing to suppressor(s). Expression of the 2AS QTL in the ExT population may be due to interaction with the QTL on chromosome 6AL from the resistant parent Einstein or to any other gene in the background of the population. QTL on chromosomes 2AS, 5AL, and 6BS were associated with resistance to both Cephalosporium stripe and stripe rust. These results highlight a complex set of interactions among major genes, minor genes, the presence of different stripe rust races, epistasis, genetic background, and possibly a suppressor of resistance. Results from this study are expected to assist in selecting molecular markers to genotypically select for resistance to these diseases, improving the chances of developing wheat cultivars with durable resistance to both diseases in the future. Title: Multi-location analysis for the identification of quantitative trait loci underlying disease resistance against Cephalosporium gramineum and Puccinia striiformis f. sp. tritici by linkage mapping in wheat (Triticum aestivum L.) Author: Vazquez, Maria Dolores Wheat (Triticum aestivum L.) is one of the major crops produced in the U.S. Pacific Northwest, a region known for its wheat production for international export. Wheat production in the region is threatened by diseases such as Cephalosporium stripe and stripe rust. Cephalosporium stripe is a vascular wilt disease of wheat caused by the persistent soil-borne fungus and suspected necrotrophic pathogen Cephalosporium gramineum Nisikado & Ikata, and is a recurring disease in many localities when susceptible cultivars are grown. Stripe rust, a foliar disease of wheat caused by the air-borne biotrophic fungus Puccinia striformis f. sp. tritici is a disease present in every region around the world where commercial wheat is grown. Attaining durable resistance to stripe rust would greatly benefit wheat producers in the region. Combining stripe rust resistance with resistance to other diseases, such as Cephalosporium stripe, is challenging. Wheat cultivars with high levels of resistance to several diseases are favorable candidates for genetic studies to determine the inheritance of resistance and facilitate the development of a method to genotypically select for disease resistance. Two populations of recombinant inbred lines were developed from 'Tubbs'/'NSA-98-0995' (TxN) and 'Einstein'/'Tubbs' (ExT) with population sizes of 271 and 259 F[subscript (5:6)], respectively. Tubbs is susceptible to stripe rust and Cephalosporium stripe while Einstein and NSA-98-0995 demonstrate moderate to high resistance to both diseases. Both populations were assessed across seven environments (combinations of locations and years) for stripe rust resistance under natural infection and four environments for Cephalosporium stripe resistance under artificial inoculation. The populations were mapped using diversity array technology (DArT) and simple sequence repeat (SSR) markers for quantitative trait loci (QTL) analysis. Results for Cephalosporium stripe resistance was quantitatively inherited with several QTL detected (>5), including some QTL in the same chromosome location in both populations. For stripe rust resistance, seven QTL were identified in the TxN population, suggesting quantitative resistance contributed by several minor genes. In the ExT population two QTL with major effects and with epistatic interactions between them were identified. One of them, a major QTL from Tubbs on chromosome 2AS that may be Yr17, was not expressed in the TxN population or in Tubbs, perhaps owing to suppressor(s). Expression of the 2AS QTL in the ExT population may be due to interaction with the QTL on chromosome 6AL from the resistant parent Einstein or to any other gene in the background of the population. QTL on chromosomes 2AS, 5AL, and 6BS were associated with resistance to both Cephalosporium stripe and stripe rust. These results highlight a complex set of interactions among major genes, minor genes, the presence of different stripe rust races, epistasis, genetic background, and possibly a suppressor of resistance. Results from this study are expected to assist in selecting molecular markers to genotypically select for resistance to these diseases, improving the chances of developing wheat cultivars with durable resistance to both diseases in the future. Close

• 23. [Article] Combining ability and gene action estimates and the association of the components of yield in winter wheat crosses

  A diallel cross consisting of ten parents was grown on the Hyslop Agronomy Farm near Corvallis, Oregon, in order to obtain estimates of the gene action contributing to yield and its components in wheat. ...

  Citation × Citation Citation Abstract Copy Title: Combining ability and gene action estimates and the association of the components of yield in winter wheat crosses Author: Kronstad, Warren E. (Warren Ervind), 1932- A diallel cross consisting of ten parents was grown on the Hyslop Agronomy Farm near Corvallis, Oregon, in order to obtain estimates of the gene action contributing to yield and its components in wheat. Gene action estimates were obtained by two methods of diallel analysis and from narrow sense heritability values calculated by parent-progeny regressions involving both parental and F[subscript 1] data. In addition, path-coefficient analysis was utilized to investigate the direct and indirect associations of five variables on yield. The morphological characters measured were: (1) total yield per plant, (2) weight per kernel, (3) number of kernels per spikelet, (4) number of spikelets per spike, (5) number of spikes per plant and, (6) plant height. A large portion of the total genetic variation associated with the yield components, weight per kernel, kernels per spikelet, spikelets per spike and spikes per plant was the result of additive gene action. When the five variables were considered in terms of their associations with yield it was observed that weight per kernel, number of kernels per spikelet and the number of spikelets per spike mainly exerted direct effects on yield. The number of spikes per plant had no direct effect, but an indirect effect on yield through the other variables. A similar indirect association was noted for plant height. The data obtained from the path-coefficient analysis indicated further that the number of kernels per spikelet had the greatest direct effect on yield. Results obtained with correlation coefficients suggested that a negative association exists between weight per kernel and kernels per spikelet. Also such a negative association was found between the number of spikes per plant with weight per kernel and kernels per spikelet. These results would suggest the possible existence of a biological limitation between several of the components of yield. The diallel cross analysis for general and specific combining ability gave similar estimates of gene action when they were compared to narrow sense heritability values. However, when the Jinks-Hayman method was compared with the other two methods of estimating gene action, several discrepancies were observed. This lack of agreement was possibly due to the inability of this experimental material to meet one or all of the genetic assumptions required by the Jinks-Hayman method. The results of this study indicate that a breeding program with emphasis on increases in yield which considers each of the components separately, or in combination of two or more would offer the most promise. By this procedure the breeder could take advantage of the large amount of additive genetic variance associated with each of the components and at the same time, take into consideration any biological limitations which may exist. In utilizing the information obtained in this study in such a breeding procedure the plant breeder would be able to better evaluate the methods for selecting the best parents to be hybridized and in selecting the best lines from hybrid progeny. Title: Combining ability and gene action estimates and the association of the components of yield in winter wheat crosses Author: Kronstad, Warren E. (Warren Ervind), 1932- A diallel cross consisting of ten parents was grown on the Hyslop Agronomy Farm near Corvallis, Oregon, in order to obtain estimates of the gene action contributing to yield and its components in wheat. Gene action estimates were obtained by two methods of diallel analysis and from narrow sense heritability values calculated by parent-progeny regressions involving both parental and F[subscript 1] data. In addition, path-coefficient analysis was utilized to investigate the direct and indirect associations of five variables on yield. The morphological characters measured were: (1) total yield per plant, (2) weight per kernel, (3) number of kernels per spikelet, (4) number of spikelets per spike, (5) number of spikes per plant and, (6) plant height. A large portion of the total genetic variation associated with the yield components, weight per kernel, kernels per spikelet, spikelets per spike and spikes per plant was the result of additive gene action. When the five variables were considered in terms of their associations with yield it was observed that weight per kernel, number of kernels per spikelet and the number of spikelets per spike mainly exerted direct effects on yield. The number of spikes per plant had no direct effect, but an indirect effect on yield through the other variables. A similar indirect association was noted for plant height. The data obtained from the path-coefficient analysis indicated further that the number of kernels per spikelet had the greatest direct effect on yield. Results obtained with correlation coefficients suggested that a negative association exists between weight per kernel and kernels per spikelet. Also such a negative association was found between the number of spikes per plant with weight per kernel and kernels per spikelet. These results would suggest the possible existence of a biological limitation between several of the components of yield. The diallel cross analysis for general and specific combining ability gave similar estimates of gene action when they were compared to narrow sense heritability values. However, when the Jinks-Hayman method was compared with the other two methods of estimating gene action, several discrepancies were observed. This lack of agreement was possibly due to the inability of this experimental material to meet one or all of the genetic assumptions required by the Jinks-Hayman method. The results of this study indicate that a breeding program with emphasis on increases in yield which considers each of the components separately, or in combination of two or more would offer the most promise. By this procedure the breeder could take advantage of the large amount of additive genetic variance associated with each of the components and at the same time, take into consideration any biological limitations which may exist. In utilizing the information obtained in this study in such a breeding procedure the plant breeder would be able to better evaluate the methods for selecting the best parents to be hybridized and in selecting the best lines from hybrid progeny. Close

• 24. [Article] Oxidative gelation and functionality of wheat flour : effects of grain storage, flour aging, and grain type (hard or soft)

  This study examined changes in flour functionality during storage of grain and subsequent aging of flour milled from the grain. Freshly harvested grain was stored for 24 weeks and flour milled from the ...

  Citation × Citation Citation Abstract Copy Title: Oxidative gelation and functionality of wheat flour : effects of grain storage, flour aging, and grain type (hard or soft) Author: Mattson, Jacob E. This study examined changes in flour functionality during storage of grain and subsequent aging of flour milled from the grain. Freshly harvested grain was stored for 24 weeks and flour milled from the grain at specified time intervals after harvest (0, 3, 6, 12, and 24 weeks). For each milling date flour functionality was measured on the day of milling (day 0) and at specified intervals after milling (1, 3, 6, 13, 27, and 62 days). Storage and aging were conducted at 23 ± 1°C. The functional properties examined were flour absorption characteristics, quantified using the solvent retention capacity (SRC) test, and oxidative gelation capacity (OGC), which was measured viscometrically, using a Rapid Visco Analyzer (RVA). SRC measures absorption capacity of flour emphasizing different flour polymers in each of the four solvents (water, all polymers: sucrose, arabinoxylans (AX) and gliadins: sodium carbonate, damaged starch: lactic acid, glutenins). Oxidative gelation is a process whereupon a weak gel is formed in a hydrated flour system under oxidative conditions and is thought to be largely a function of the reactivity of ferulic acid residues esterified to AX, although proteins are also involved. To determine if oxidation of flour lipids might accompany changes in OGC, the concentration of malondialdehyde (MDA), a lipid oxidation byproduct, was measured. Four soft-wheat varieties with divergent functionalities were selected to examine the effects of storage and aging. Additionally, a survey was conducted to examine the range of OGC in a selection of hard-grained wheat varieties from the Oregon State University wheat-breeding program. From this survey, one variety with high and one variety with low OGC were selected for a pilot study to determine the effect of hydrogen peroxide and azodicarbonamide (ADA) concentrations on OGC in straight grade flour. Variety was the strongest factor in determining flour functionality expressed as SRC and OGC. This is unsurprising, because varieties were chosen based on differences in absorption characteristics and OGC as indicated by preliminary testing. In contrast, variety was the weakest factor in determining changes in MDA concentration. As a function of grain storage time, water, sucrose and sodium carbonate SRC values increased. In contrast, lactic acid SRC values declined. Although many of these changes were statistically significant, their functional significance remains unclear. As a function of grain storage time, OGC initially increased to week 3 then declined to week 24. Not only was this change statistically significant, but the magnitude of the change could be considered functionally significant. Because OGC is a trait that currently only has theoretical value in food processing (i.e. OGC is not a trait currently taken into consideration during food processing), it is difficult to definitively conclude what constitutes functional significance. Grain storage time had the strongest influence on changes in MDA concentration. The trend of changes in MDA concentration was similar to that observed for OGC. Flour age was the weakest contributor to changes in SRC. Looking at individual SRC solvents, flour aging time did not significantly influence changes in water SRC values. However, as flour aged, sucrose SRC values significantly increased and sodium carbonate and lactic acid SRC values decreased. Although changes in sucrose, sodium carbonate, and lactic acid SRCs were statistically significant, their functional significance was again unclear. As a function of flour age, OGC increased. As a function of flour age, MDA concentration initially increased, but subsequently declined and remained constant from day 6 to day 62. Each variety appeared to show a different relationship between peroxide peak viscosity (PPV) and peroxide peak breakdown viscosity (PPBV). Proportional PPBV also appeared to differ between varieties, and the relationships (PPBV% vs PPV) were nonlinear. This suggested that there was a maximum PPV for each variety at which PPBV no longer increased. Data suggest qualitative differences in the gels formed in each variety that require further investigation. Speculation allows the idea that the RVA method used here could provide a way of expressing functional differences in OGC that might relate to structure differences in AX. Title: Oxidative gelation and functionality of wheat flour : effects of grain storage, flour aging, and grain type (hard or soft) Author: Mattson, Jacob E. This study examined changes in flour functionality during storage of grain and subsequent aging of flour milled from the grain. Freshly harvested grain was stored for 24 weeks and flour milled from the grain at specified time intervals after harvest (0, 3, 6, 12, and 24 weeks). For each milling date flour functionality was measured on the day of milling (day 0) and at specified intervals after milling (1, 3, 6, 13, 27, and 62 days). Storage and aging were conducted at 23 ± 1°C. The functional properties examined were flour absorption characteristics, quantified using the solvent retention capacity (SRC) test, and oxidative gelation capacity (OGC), which was measured viscometrically, using a Rapid Visco Analyzer (RVA). SRC measures absorption capacity of flour emphasizing different flour polymers in each of the four solvents (water, all polymers: sucrose, arabinoxylans (AX) and gliadins: sodium carbonate, damaged starch: lactic acid, glutenins). Oxidative gelation is a process whereupon a weak gel is formed in a hydrated flour system under oxidative conditions and is thought to be largely a function of the reactivity of ferulic acid residues esterified to AX, although proteins are also involved. To determine if oxidation of flour lipids might accompany changes in OGC, the concentration of malondialdehyde (MDA), a lipid oxidation byproduct, was measured. Four soft-wheat varieties with divergent functionalities were selected to examine the effects of storage and aging. Additionally, a survey was conducted to examine the range of OGC in a selection of hard-grained wheat varieties from the Oregon State University wheat-breeding program. From this survey, one variety with high and one variety with low OGC were selected for a pilot study to determine the effect of hydrogen peroxide and azodicarbonamide (ADA) concentrations on OGC in straight grade flour. Variety was the strongest factor in determining flour functionality expressed as SRC and OGC. This is unsurprising, because varieties were chosen based on differences in absorption characteristics and OGC as indicated by preliminary testing. In contrast, variety was the weakest factor in determining changes in MDA concentration. As a function of grain storage time, water, sucrose and sodium carbonate SRC values increased. In contrast, lactic acid SRC values declined. Although many of these changes were statistically significant, their functional significance remains unclear. As a function of grain storage time, OGC initially increased to week 3 then declined to week 24. Not only was this change statistically significant, but the magnitude of the change could be considered functionally significant. Because OGC is a trait that currently only has theoretical value in food processing (i.e. OGC is not a trait currently taken into consideration during food processing), it is difficult to definitively conclude what constitutes functional significance. Grain storage time had the strongest influence on changes in MDA concentration. The trend of changes in MDA concentration was similar to that observed for OGC. Flour age was the weakest contributor to changes in SRC. Looking at individual SRC solvents, flour aging time did not significantly influence changes in water SRC values. However, as flour aged, sucrose SRC values significantly increased and sodium carbonate and lactic acid SRC values decreased. Although changes in sucrose, sodium carbonate, and lactic acid SRCs were statistically significant, their functional significance was again unclear. As a function of flour age, OGC increased. As a function of flour age, MDA concentration initially increased, but subsequently declined and remained constant from day 6 to day 62. Each variety appeared to show a different relationship between peroxide peak viscosity (PPV) and peroxide peak breakdown viscosity (PPBV). Proportional PPBV also appeared to differ between varieties, and the relationships (PPBV% vs PPV) were nonlinear. This suggested that there was a maximum PPV for each variety at which PPBV no longer increased. Data suggest qualitative differences in the gels formed in each variety that require further investigation. Speculation allows the idea that the RVA method used here could provide a way of expressing functional differences in OGC that might relate to structure differences in AX. Close

• 25. [Article] A study of methods of parental evaluation using testers to predict subsequent progeny performance in winter wheat (Triticum aestivum L.)

  The major objective of this study was to determine why certain winter wheat cultivars, when hybridized, will produce a greater proportion of desirable plants in subsequent, segregating generations. Three ...

  Citation × Citation Citation Abstract Copy Title: A study of methods of parental evaluation using testers to predict subsequent progeny performance in winter wheat (Triticum aestivum L.) Author: Alexander, William Larry The major objective of this study was to determine why certain winter wheat cultivars, when hybridized, will produce a greater proportion of desirable plants in subsequent, segregating generations. Three winter wheat parents were chosen as the experimental material, based on their known performance as parents. Yamhill and Pullman Selection 101 are recognized as cultivars with good combining abilities for grain yield. Crosses with Nugaines have been disappointing, even though the cultivar itself is high yielding. Each parent was crossed to a series of five testers. These testers were chosen on the basis of their genetic diversity, especially for the components of yield. This parent x tester crossing scheme was analyzed as a 3 x 5 factorial, where the main effects due to parents and testers were their general combining ability effect estimates. The interactions of these main effects were their specific combining abilities. F₁ hybrids were evaluated for two years and F₂ populations for one year to characterize the parents' capacity to transmit selected attributes to their resulting progeny. These generations were evaluated on a per plant basis for their grain yields and the primary components of yield, tillers per plant, kernels per spike, and 1000 kernel weight. The four methods of evaluating parents assessed were parental performance, midparent-progeny correlations, examination of individual crosses, and combining ability analysis. Midparent-progeny correlations usually were not significant within the progeny of each parent. Significant differences were not found for grain yields among the parents in either year. However, significant differences existed for their expressions of yield components. Parental expressions of the yield components were generally more erratic than those of their F₁ progenies. Significant differences occurred for estimates of general combining ability effects in both years and for each generation in all traits. These estimates for a particular parent were relatively consistent. Specific combining ability was not found to be a dependable means of identifying superior combinations. Associations between the parental general combining ability effect estimates for kernels per spike and 1000 kernel weight were positive. Relationships between other yield component combinations were negative with regard to general combining ability effects. Trends observed in single crosses reflected the relative general combining abilities of the parents. Crosses involving Yamhill generally had fewer tillers with a higher number of kernels per spike, heavier kernel weights, and superior grain yields to those of the other parents. Progeny of Pullman Selection 101 were usually high in tillering, intermediate for number of kernels per spike, low in kernel weights, and intermediate for grain yields. The progeny of Nugaines were characterized by high tillering, a low number of kernels per spike, low kernel weights, and also low grain yields. The parent x tester crossing scheme was found to be an effective way of determining the potentials of the three parents by estimating their general combining abilities, as well as minimizing the number of crosses required. If, as found in this study, the general combining ability effect estimates of the parents for grain yield accurately predict performance of later generations, this parent x tester crossing scheme would be an efficient method of assessing the potentials of prospective parents in breeding programs. Title: A study of methods of parental evaluation using testers to predict subsequent progeny performance in winter wheat (Triticum aestivum L.) Author: Alexander, William Larry The major objective of this study was to determine why certain winter wheat cultivars, when hybridized, will produce a greater proportion of desirable plants in subsequent, segregating generations. Three winter wheat parents were chosen as the experimental material, based on their known performance as parents. Yamhill and Pullman Selection 101 are recognized as cultivars with good combining abilities for grain yield. Crosses with Nugaines have been disappointing, even though the cultivar itself is high yielding. Each parent was crossed to a series of five testers. These testers were chosen on the basis of their genetic diversity, especially for the components of yield. This parent x tester crossing scheme was analyzed as a 3 x 5 factorial, where the main effects due to parents and testers were their general combining ability effect estimates. The interactions of these main effects were their specific combining abilities. F₁ hybrids were evaluated for two years and F₂ populations for one year to characterize the parents' capacity to transmit selected attributes to their resulting progeny. These generations were evaluated on a per plant basis for their grain yields and the primary components of yield, tillers per plant, kernels per spike, and 1000 kernel weight. The four methods of evaluating parents assessed were parental performance, midparent-progeny correlations, examination of individual crosses, and combining ability analysis. Midparent-progeny correlations usually were not significant within the progeny of each parent. Significant differences were not found for grain yields among the parents in either year. However, significant differences existed for their expressions of yield components. Parental expressions of the yield components were generally more erratic than those of their F₁ progenies. Significant differences occurred for estimates of general combining ability effects in both years and for each generation in all traits. These estimates for a particular parent were relatively consistent. Specific combining ability was not found to be a dependable means of identifying superior combinations. Associations between the parental general combining ability effect estimates for kernels per spike and 1000 kernel weight were positive. Relationships between other yield component combinations were negative with regard to general combining ability effects. Trends observed in single crosses reflected the relative general combining abilities of the parents. Crosses involving Yamhill generally had fewer tillers with a higher number of kernels per spike, heavier kernel weights, and superior grain yields to those of the other parents. Progeny of Pullman Selection 101 were usually high in tillering, intermediate for number of kernels per spike, low in kernel weights, and intermediate for grain yields. The progeny of Nugaines were characterized by high tillering, a low number of kernels per spike, low kernel weights, and also low grain yields. The parent x tester crossing scheme was found to be an effective way of determining the potentials of the three parents by estimating their general combining abilities, as well as minimizing the number of crosses required. If, as found in this study, the general combining ability effect estimates of the parents for grain yield accurately predict performance of later generations, this parent x tester crossing scheme would be an efficient method of assessing the potentials of prospective parents in breeding programs. Close

• 26. [Article] The effect of row spacing, rate and date of planting on yield and yield components of four winter wheat cultivars (Triticum aestivum L. em Thell)

  Four winter wheat cultivars, Bezostaya, Maris-Hobbit, Roussalka and Stephens, selected on the basis of the diversity of their pedigree and phenotype, were planted at Hyslop Experiment Station near Corvallis ...

  Citation × Citation Citation Abstract Copy Title: The effect of row spacing, rate and date of planting on yield and yield components of four winter wheat cultivars (Triticum aestivum L. em Thell) Author: Nadjib, Benacef Four winter wheat cultivars, Bezostaya, Maris-Hobbit, Roussalka and Stephens, selected on the basis of the diversity of their pedigree and phenotype, were planted at Hyslop Experiment Station near Corvallis in Western Oregon to study their performance at three different row spacings (10, 16 and 24 cm), three seeding rates (100, 160, and 240 Kg/ha) and at two seeding dates (October 13 and November 12). A similar experiment was conducted at the Sherman Experiment Station, Moro in Eastern Oregon, using only two winter wheat cultivars, Stephens and Jackmar. Data were obtained on grain yield, tillers and spikes per square meter, heading and anthesis date, plant height, kernels per spike, 1000 kernel weight, test weight and harvest index. At Hyslop Experiment Station, Stephens, Bezostaya and Roussalka produced maximum grain yield at 10 cm row spacing and 160 Kg/ha seeding rate, and Maris-Hobbit at 24 cm row spacing and 160 Kg/ha seeding rate. At Sherman Experiment Station, 30 cm row spacing and 90 Kg/ha seeding rate constitutes the best combination for Stephens, and 30 cm row spacing and 120 Kg/ha seeding rate for the club wheat Jackmar. The interaction between row spacings x cultivars and seeding rates x cultivars indicated that all the cultivars produced high numbers of tillers and spikes per m² at narrow (10 cm) row spacing and high (240 Kg/ha) seeding rate. There were no significant differences between row spacings for heading and anthesis date. Lower seeding rate resulted in later heading date. The cultivar Roussalka was the earliest and Maris-Hobbit the latest in average heading date, Plant height decreased with increased row spacing and increased with increased seeding rate. The plants of the four cultivars were shorter at the second date than at the first. More kernels per spike were produced at the second than at the first date. An increase in seeding rates was accompanied by a decrease in the number of kernels per spike. There were no significant differences between the three row spacings, the three seeding rates and the four cultivars for test weight. The different row spacings and seeding rates did not affect the TOGO kernel weight. Considering the cultivars, Stephens produced a higher 1000 kernel weight at the two seeding dates than Maris- Hobbit, Bezostaya and Roussalka. Title: The effect of row spacing, rate and date of planting on yield and yield components of four winter wheat cultivars (Triticum aestivum L. em Thell) Author: Nadjib, Benacef Four winter wheat cultivars, Bezostaya, Maris-Hobbit, Roussalka and Stephens, selected on the basis of the diversity of their pedigree and phenotype, were planted at Hyslop Experiment Station near Corvallis in Western Oregon to study their performance at three different row spacings (10, 16 and 24 cm), three seeding rates (100, 160, and 240 Kg/ha) and at two seeding dates (October 13 and November 12). A similar experiment was conducted at the Sherman Experiment Station, Moro in Eastern Oregon, using only two winter wheat cultivars, Stephens and Jackmar. Data were obtained on grain yield, tillers and spikes per square meter, heading and anthesis date, plant height, kernels per spike, 1000 kernel weight, test weight and harvest index. At Hyslop Experiment Station, Stephens, Bezostaya and Roussalka produced maximum grain yield at 10 cm row spacing and 160 Kg/ha seeding rate, and Maris-Hobbit at 24 cm row spacing and 160 Kg/ha seeding rate. At Sherman Experiment Station, 30 cm row spacing and 90 Kg/ha seeding rate constitutes the best combination for Stephens, and 30 cm row spacing and 120 Kg/ha seeding rate for the club wheat Jackmar. The interaction between row spacings x cultivars and seeding rates x cultivars indicated that all the cultivars produced high numbers of tillers and spikes per m² at narrow (10 cm) row spacing and high (240 Kg/ha) seeding rate. There were no significant differences between row spacings for heading and anthesis date. Lower seeding rate resulted in later heading date. The cultivar Roussalka was the earliest and Maris-Hobbit the latest in average heading date, Plant height decreased with increased row spacing and increased with increased seeding rate. The plants of the four cultivars were shorter at the second date than at the first. More kernels per spike were produced at the second than at the first date. An increase in seeding rates was accompanied by a decrease in the number of kernels per spike. There were no significant differences between the three row spacings, the three seeding rates and the four cultivars for test weight. The different row spacings and seeding rates did not affect the TOGO kernel weight. Considering the cultivars, Stephens produced a higher 1000 kernel weight at the two seeding dates than Maris- Hobbit, Bezostaya and Roussalka. Close

• 27. [Article] Growth rate and phosphorus uptake of wheat (Triticum aestivum VILL., Host) as a function of soil water suction and soil temperature

  The effect of soil temperature and soil water suction on the rate of phosphorus uptake and growth rate of wheat (Triticum aestivum VILL. , Host) was studied. Plants were grown in perlite slabs separated ...

  Citation × Citation Citation Abstract Copy Title: Growth rate and phosphorus uptake of wheat (Triticum aestivum VILL., Host) as a function of soil water suction and soil temperature Author: Fazilat, Mohammad The effect of soil temperature and soil water suction on the rate of phosphorus uptake and growth rate of wheat (Triticum aestivum VILL. , Host) was studied. Plants were grown in perlite slabs separated from an osmotic solution by a semi-permeable membrane. Measurements were made at temperatures of 10.0, 18.3, 23.9, 32.2, and 35.0°C, and soil water suctions of 0.35 and 2.5 bars. Five week old wheat seedlings were exposed to these conditions. The dry weight of shoots and roots was determined at two day intervals. Plant material extracted was analyzed for phosphorus concentration. The color intensity was measured on a Bausch and Lomb spectronic 20 spectrophotometer of 420 millimicrons. In general, a constant growth rate, which was approached exponentially during the experimental period was found in all treatment combinations. Growth rate for both shoots and roots was slow at low root temperatures and had a maximum rate at a root temperature of 24.0°C. High soil water suction was a limiting factor in growth rate. Phosphorus concentration of shoots and roots was found to approach a constant value during the experimental period according to the equation y = a+be[superscript]-0.07t[superscript]3/2 where y is the phosphorus concentration, t is the time in days, and a and b are constants. Over the entire range of soil temperatures considered the phosphorus concentration of the shoots increased linearlly with the root temperature, but the phosphorus concentration of the roots slightly decreased by increasing soil temperature and did not increase until the root temperature was about 32.0°C. There was no evidence of much variation in percent of total phosphorus uptake transported to the shoot in the experiments. Trans location of phosphorus from roots to shoots did not appear to be a limiting factor for phosphorus uptake at the low root temperature. It was suggested that the low rates of phosphorus uptake at the low root temperatures resulted from the low level of metabolic activity. Title: Growth rate and phosphorus uptake of wheat (Triticum aestivum VILL., Host) as a function of soil water suction and soil temperature Author: Fazilat, Mohammad The effect of soil temperature and soil water suction on the rate of phosphorus uptake and growth rate of wheat (Triticum aestivum VILL. , Host) was studied. Plants were grown in perlite slabs separated from an osmotic solution by a semi-permeable membrane. Measurements were made at temperatures of 10.0, 18.3, 23.9, 32.2, and 35.0°C, and soil water suctions of 0.35 and 2.5 bars. Five week old wheat seedlings were exposed to these conditions. The dry weight of shoots and roots was determined at two day intervals. Plant material extracted was analyzed for phosphorus concentration. The color intensity was measured on a Bausch and Lomb spectronic 20 spectrophotometer of 420 millimicrons. In general, a constant growth rate, which was approached exponentially during the experimental period was found in all treatment combinations. Growth rate for both shoots and roots was slow at low root temperatures and had a maximum rate at a root temperature of 24.0°C. High soil water suction was a limiting factor in growth rate. Phosphorus concentration of shoots and roots was found to approach a constant value during the experimental period according to the equation y = a+be[superscript]-0.07t[superscript]3/2 where y is the phosphorus concentration, t is the time in days, and a and b are constants. Over the entire range of soil temperatures considered the phosphorus concentration of the shoots increased linearlly with the root temperature, but the phosphorus concentration of the roots slightly decreased by increasing soil temperature and did not increase until the root temperature was about 32.0°C. There was no evidence of much variation in percent of total phosphorus uptake transported to the shoot in the experiments. Trans location of phosphorus from roots to shoots did not appear to be a limiting factor for phosphorus uptake at the low root temperature. It was suggested that the low rates of phosphorus uptake at the low root temperatures resulted from the low level of metabolic activity. Close

• 28. [Article] Effect of moisture stress on yield and quality of winter wheat seed

  Two experiments were conducted to determine the effects of moisture stress on physiological changes that occur during the vegetative and reproductive stages of the wheat (Triticum aestivum L.) plant, and ...

  Citation × Citation Citation Abstract Copy Title: Effect of moisture stress on yield and quality of winter wheat seed Author: Assuncao, Marcos Vinicius Two experiments were conducted to determine the effects of moisture stress on physiological changes that occur during the vegetative and reproductive stages of the wheat (Triticum aestivum L.) plant, and to relate these effects to seed yield, quality and performance. In a field experiment, different levels of moisture stress were obtained by establishing plots in two rainfall areas, and by planting on three different dates in the dryland area. Seed development and maturation occurred under extreme moisture stress in Moro (254mm annual rainfall), while stress at Corvallis (1020 mm annual rainfall) was low. Plants from the early fall planting were subjected to the most stress because of the greater fall growth which removed much of the soil moisture. Lowest seed yields occurred under the greatest moisture stress conditions, primarily because of a reduced number of seeds per spike. Seed size was the quality component most affected by moisture stress. Smaller seed size was associated with lower soil water potential, higher leaf area index during vegetative growth, and higher specific leaf weight and water soluble carbohydrate content of the plants after anthesis. Water soluble carbohydrate content was particularly high in the rachises of the most severely stressed plants, indicating a reduced rate of translocation to the developing seeds. Embryo weight was also reduced in the more stressed plants in proportioa to the reduction in seed weight. The protein contents of seeds from all three moisture stress levels at Moro were similar. Seeds developed under the most severe water stress had the highest respiratory quotient and lowest glutamic acid decarboxylase activity. The growth rate of seedlings produced by these seeds was 29% lower than that from seeds from the less stressed plots. A greenhouse experiment was conducted to study the effects of water stress under controlled conditions. Plants were grown under three moisture regimes (600, 300 and 150 ml water/pot/day) from the time awns were first visible on the main stem until maturity. Water-stressed plants had smaller leaf area and leaf dry weight, higher specific leaf weight, earlier leaf senescence, lower dry weight, and lower seed yield. On the other hand, water-stressed plants produced larger seeds, with heavier embryos, higher protein content, lower CO₂ evolution and lower respiratory quotient. These seeds in turn produced seedlings with greater vigor in terms of seedling growth rate. Because of the compensation ability of the wheat plant, development of management practices to decrease certain yield components in favor of enhanced seed quality is worthy of further study. Title: Effect of moisture stress on yield and quality of winter wheat seed Author: Assuncao, Marcos Vinicius Two experiments were conducted to determine the effects of moisture stress on physiological changes that occur during the vegetative and reproductive stages of the wheat (Triticum aestivum L.) plant, and to relate these effects to seed yield, quality and performance. In a field experiment, different levels of moisture stress were obtained by establishing plots in two rainfall areas, and by planting on three different dates in the dryland area. Seed development and maturation occurred under extreme moisture stress in Moro (254mm annual rainfall), while stress at Corvallis (1020 mm annual rainfall) was low. Plants from the early fall planting were subjected to the most stress because of the greater fall growth which removed much of the soil moisture. Lowest seed yields occurred under the greatest moisture stress conditions, primarily because of a reduced number of seeds per spike. Seed size was the quality component most affected by moisture stress. Smaller seed size was associated with lower soil water potential, higher leaf area index during vegetative growth, and higher specific leaf weight and water soluble carbohydrate content of the plants after anthesis. Water soluble carbohydrate content was particularly high in the rachises of the most severely stressed plants, indicating a reduced rate of translocation to the developing seeds. Embryo weight was also reduced in the more stressed plants in proportioa to the reduction in seed weight. The protein contents of seeds from all three moisture stress levels at Moro were similar. Seeds developed under the most severe water stress had the highest respiratory quotient and lowest glutamic acid decarboxylase activity. The growth rate of seedlings produced by these seeds was 29% lower than that from seeds from the less stressed plots. A greenhouse experiment was conducted to study the effects of water stress under controlled conditions. Plants were grown under three moisture regimes (600, 300 and 150 ml water/pot/day) from the time awns were first visible on the main stem until maturity. Water-stressed plants had smaller leaf area and leaf dry weight, higher specific leaf weight, earlier leaf senescence, lower dry weight, and lower seed yield. On the other hand, water-stressed plants produced larger seeds, with heavier embryos, higher protein content, lower CO₂ evolution and lower respiratory quotient. These seeds in turn produced seedlings with greater vigor in terms of seedling growth rate. Because of the compensation ability of the wheat plant, development of management practices to decrease certain yield components in favor of enhanced seed quality is worthy of further study. Close

• 29. [Article] Effects of three herbicides on yields of five cultivars of winter wheat (Triticum aestivum L. em Thell)

  With the development of new selective herbicides and the frequent change in commercial wheat cultivars, information is needed as to the possible interaction between cultivars and herbicides. The responses of ...

  Citation × Citation Citation Abstract Copy Title: Effects of three herbicides on yields of five cultivars of winter wheat (Triticum aestivum L. em Thell) Author: Yahyaoui, Amor With the development of new selective herbicides and the frequent change in commercial wheat cultivars, information is needed as to the possible interaction between cultivars and herbicides. The responses of five genotypically diverse wheat cultivars (Bezostaya, Daws, Maris Hobbit, Stephens and Yamhill) to diuron [3-(3,4-dichloropheny1)-1,1- dimethylurea], diclofop methyl 2-[4-(2,4-dichlorophenoxy)phenoxy] propanoate and 2,4-D (2,4-dichlorophenoxy acetic acid) herbicides were compared under field and greenhouse conditions during the 1979-80 growing season. Grain yield was considered as a measure of herbicide injury when compared to the control plots for each cultivar. Effect on components of yield, plant height and grain protein content also were investigated. Differences in yield performance and related agronomic characters could be attributed to specific herbicides, designated rates and growth stages at the time of application. The lower (1.4 kg/ha) rate of diuron, diclofop and 2,4-D reduced yields less than the higher rate (2.8 kg/ha). Diuron and diclofop applied at the earlier (three to to five leaf) growth stage caused greater yield reductions than when applied at the later (five to six tiller) growth stage. Differential yield responses were found among and within the five winter wheat cultivars. The higher rate of diuron (2.8 kg/ha) caused the most injury in all of the cultivars tested. Major injury from diclofop occurred on the cultivar Maris Hobbit with minor effects on the other four cultivars. The primary reduction in yield from application of 2,4-D was to the cultivar Bezostaya. Among the five wheat cultivars tested in this experiment, Daws was the most tolerant to the three herbicides tested. Among the yield components (number of spikes per unit area, kernels per spike and 1000 kernel weight), number of kernels per spike accounted for most of the variation in yield. The data showed a direct relationship between kernel number and grain yield. Grain protein percentage of Daws, Maris Hobbit, Stephens and Yamhill significantly increased at the higher rate of diuron; whereas a similar increase was noted only in Bezostaya at the lower rate of 2,4-D. These increases in protein were associated with significant decreases in yield. Yield reductions due to herbicide treatments were generally lower than those due to weed competition. Reductions in yield and corresponding changes in the other agronomic characteristics observed in this experiment were the result of concentrations which are higher than those normally used in spraying wheat for weed control. This high chemical dosage was chosen for each herbicide to assure a greater differential response among and within the wheat cultivars. It also provided information for the plant breeder as to which cultivars had higher levels of tolerance. Such information is important when making hybrid combinations for the development of future varieties if higher levels of tolerance to specific herbicides are required. Title: Effects of three herbicides on yields of five cultivars of winter wheat (Triticum aestivum L. em Thell) Author: Yahyaoui, Amor With the development of new selective herbicides and the frequent change in commercial wheat cultivars, information is needed as to the possible interaction between cultivars and herbicides. The responses of five genotypically diverse wheat cultivars (Bezostaya, Daws, Maris Hobbit, Stephens and Yamhill) to diuron [3-(3,4-dichloropheny1)-1,1- dimethylurea], diclofop methyl 2-[4-(2,4-dichlorophenoxy)phenoxy] propanoate and 2,4-D (2,4-dichlorophenoxy acetic acid) herbicides were compared under field and greenhouse conditions during the 1979-80 growing season. Grain yield was considered as a measure of herbicide injury when compared to the control plots for each cultivar. Effect on components of yield, plant height and grain protein content also were investigated. Differences in yield performance and related agronomic characters could be attributed to specific herbicides, designated rates and growth stages at the time of application. The lower (1.4 kg/ha) rate of diuron, diclofop and 2,4-D reduced yields less than the higher rate (2.8 kg/ha). Diuron and diclofop applied at the earlier (three to to five leaf) growth stage caused greater yield reductions than when applied at the later (five to six tiller) growth stage. Differential yield responses were found among and within the five winter wheat cultivars. The higher rate of diuron (2.8 kg/ha) caused the most injury in all of the cultivars tested. Major injury from diclofop occurred on the cultivar Maris Hobbit with minor effects on the other four cultivars. The primary reduction in yield from application of 2,4-D was to the cultivar Bezostaya. Among the five wheat cultivars tested in this experiment, Daws was the most tolerant to the three herbicides tested. Among the yield components (number of spikes per unit area, kernels per spike and 1000 kernel weight), number of kernels per spike accounted for most of the variation in yield. The data showed a direct relationship between kernel number and grain yield. Grain protein percentage of Daws, Maris Hobbit, Stephens and Yamhill significantly increased at the higher rate of diuron; whereas a similar increase was noted only in Bezostaya at the lower rate of 2,4-D. These increases in protein were associated with significant decreases in yield. Yield reductions due to herbicide treatments were generally lower than those due to weed competition. Reductions in yield and corresponding changes in the other agronomic characteristics observed in this experiment were the result of concentrations which are higher than those normally used in spraying wheat for weed control. This high chemical dosage was chosen for each herbicide to assure a greater differential response among and within the wheat cultivars. It also provided information for the plant breeder as to which cultivars had higher levels of tolerance. Such information is important when making hybrid combinations for the development of future varieties if higher levels of tolerance to specific herbicides are required. Close

• 30. [Article] Selective control of volunteer wheat (Triticum aestivum (L.) em. Thell.) in new seedlings of alfalfa (Medicago sativa L.) with fluazifop-butyl and sethoxydim

  Volunteer winter wheat (Triticum aestivum 'Daws') severely suppressed growth of fall-planted alfalfa (Medicago sativa (L.) 'Vernal') seedlings. Wheat competition began soon after alfalfa emerged and continued until ...

  Citation × Citation Citation Abstract Copy Title: Selective control of volunteer wheat (Triticum aestivum (L.) em. Thell.) in new seedlings of alfalfa (Medicago sativa L.) with fluazifop-butyl and sethoxydim Author: Ott, Pablo Volunteer winter wheat (Triticum aestivum 'Daws') severely suppressed growth of fall-planted alfalfa (Medicago sativa (L.) 'Vernal') seedlings. Wheat competition began soon after alfalfa emerged and continued until the first forage harvest the following May. Alfalfa yield at the first cutting was reduced by 1% for each day volunteer wheat was allowed to grow within the period of 20 to 41 days after planting. When the wheat remained until harvest, alfalfa yield was reduced by 85%. Fluazifop-butyl (+) -butyl 2-[4-[[5-(trifluoromethyl)- 2- pyridinyl] oxy] phenoxy] propanoate and sethoxydim 2- (1- (ethoxyimino)butyl] 5- [2- (ethylthio)propyl] -3-hydroxy- 2-cyclohexen-l-one at rates as high as 3.2 kg/ha (plus phytobland oil at 2.3 L/ha) did not injure the alfalfa or reduce the yield of alfalfa hay when applied at any stage of growth from the unifoliate to the fully developed stages. Control of wheat was better when fluazifop-butyl and sethoxydim were applied in the fall than in the summer. Both herbicides controlled wheat slightly better when applied in the one- to five- tiller stages than at earlier or later stages of growth. In general, fluazifop-butyl was more effective than sethoxydim when applied at any given rate. Under favorable conditions, rates of fluazifop-butyl and sethoxydim as low as 0.12 and 0.18 kg/ha, respectively, killed wheat. Wheat growth was suppressed at even lower rates. However, higher rates (0.2 and 0.4 kg/ha of fluazifop- butyl and sethoxydim, respectively) were required to provide a long term effect under a broad range of conditions. The activity of fluazifop-butyl applied at the twotiller stage of wheat took place mainly through foliar rather than root exposure. Fluazifop-butyl at 0.2 kg/ha killed wheat regardless of the soil moisture content (8% vs 15%). The activity of fluazifop-butyl at 0.12, 0.18, and 0.24 kg/ha on wheat was severely reduced when combined with the dimethylamine salt of 2,4-DB [4- (2,4- dichlorophenoxy) butyric acid] at 1.8 kg/ha, but the antagonism was overcome by increasing the rate of the grass killer to 0.36 kg/ha. Title: Selective control of volunteer wheat (Triticum aestivum (L.) em. Thell.) in new seedlings of alfalfa (Medicago sativa L.) with fluazifop-butyl and sethoxydim Author: Ott, Pablo Volunteer winter wheat (Triticum aestivum 'Daws') severely suppressed growth of fall-planted alfalfa (Medicago sativa (L.) 'Vernal') seedlings. Wheat competition began soon after alfalfa emerged and continued until the first forage harvest the following May. Alfalfa yield at the first cutting was reduced by 1% for each day volunteer wheat was allowed to grow within the period of 20 to 41 days after planting. When the wheat remained until harvest, alfalfa yield was reduced by 85%. Fluazifop-butyl (+) -butyl 2-[4-[[5-(trifluoromethyl)- 2- pyridinyl] oxy] phenoxy] propanoate and sethoxydim 2- (1- (ethoxyimino)butyl] 5- [2- (ethylthio)propyl] -3-hydroxy- 2-cyclohexen-l-one at rates as high as 3.2 kg/ha (plus phytobland oil at 2.3 L/ha) did not injure the alfalfa or reduce the yield of alfalfa hay when applied at any stage of growth from the unifoliate to the fully developed stages. Control of wheat was better when fluazifop-butyl and sethoxydim were applied in the fall than in the summer. Both herbicides controlled wheat slightly better when applied in the one- to five- tiller stages than at earlier or later stages of growth. In general, fluazifop-butyl was more effective than sethoxydim when applied at any given rate. Under favorable conditions, rates of fluazifop-butyl and sethoxydim as low as 0.12 and 0.18 kg/ha, respectively, killed wheat. Wheat growth was suppressed at even lower rates. However, higher rates (0.2 and 0.4 kg/ha of fluazifop- butyl and sethoxydim, respectively) were required to provide a long term effect under a broad range of conditions. The activity of fluazifop-butyl applied at the twotiller stage of wheat took place mainly through foliar rather than root exposure. Fluazifop-butyl at 0.2 kg/ha killed wheat regardless of the soil moisture content (8% vs 15%). The activity of fluazifop-butyl at 0.12, 0.18, and 0.24 kg/ha on wheat was severely reduced when combined with the dimethylamine salt of 2,4-DB [4- (2,4- dichlorophenoxy) butyric acid] at 1.8 kg/ha, but the antagonism was overcome by increasing the rate of the grass killer to 0.36 kg/ha. Close

• 31. [Article] The influence of plant densities on gene action estimates and associations in seven winter wheat parents and their F₂ progeny

  The F₂ progeny from a diallel cross involving seven winter wheat parents along with the parents were grown at the Hyslop Agronomy Farm near Corvallis, Oregon to determine the influence of three plant densities ...

  Citation × Citation Citation Abstract Copy Title: The influence of plant densities on gene action estimates and associations in seven winter wheat parents and their F₂ progeny Author: Saini, Surinder Kumar The F₂ progeny from a diallel cross involving seven winter wheat parents along with the parents were grown at the Hyslop Agronomy Farm near Corvallis, Oregon to determine the influence of three plant densities on gene action estimates for yield and its primary components. The plant densities were designed to provide different levels of competitions involving solid, six and 12 inch spacing within the rows with one foot spacing between the rows. Gene action estimates were obtained by the combining ability analysis as well as narrow sense heritability estimates. In addition, path-coefficient analysis was utilized to investigate the direct and indirect associations of the primary components of yield under different stresses of competition resulting from the changes in population densities. The morphological characters measured were 1) total yield per plant, 2) kernel weight 3) number of kernels per spikelet, 4) number of spikelets per spike, 5) tiller number and 6) plant height. A small additive gene action for yield was noted in the six inch spacing while additive gene action effects could not be detected in the 12 inch and solid plantings. Yield being a complex trait seems to be affected by the environmental changes resulting from different plant densities. Consistent general combining ability estimates were observed for kernel weight and plant height in all the plant densities, indicating a small genotype-environment interaction. In the spaced plantings additive gene action estimates were obtained for tiller number and spikelets per spike while there was no evidence of additive gene effects in the solid planting. No additive gene action was noted for kernels per spikelet in the 12 inch planting while six inch and solid plantings revealed considerable genetic variability. These results would suggest that the genotypes are susceptible to environmental fluctuations for the traits tiller number, spikelets per spike and kernels per spikelet. The correlation coefficients reveal that in spaced plantings tiller number, spikelets per spike and kernels per spikelet are significantly and positively related to yield. In the solid seeding only spikelets per spike was significantly associated to yield. When the four variables were considered in terms of their associations with yield it was observed in the F₂ that in spaced plantings all the four components of yield have direct positive influence on yield. In the solid seedings however, spikelets per spike and kernels per spikelet had high positive direct effects on yield while tiller number and kernel weight showed a negative direct influence on yield. The data revealed that spikelets per spike and kernels per spikelet are the most important traits contributing towards yield. However, the results obtained with correlation coefficients indicate that a negative association existed between these two traits as well as between kernels per spikelet and tiller number suggesting the possible existence of a biological limitation between these components of yield. The results indicate that a breeding program with emphasis on the selection of plants in competitive conditions in the early generations may make the selection work more efficient. Moreover, increases in yield which considers each of the components separately or in combination of two or more would offer the most promise. By this procedure the breeder would take advantage of the large amount of additive genetic variances associated with each of the components and at the same time take into consideration any biological limitations which may exist. Title: The influence of plant densities on gene action estimates and associations in seven winter wheat parents and their F₂ progeny Author: Saini, Surinder Kumar The F₂ progeny from a diallel cross involving seven winter wheat parents along with the parents were grown at the Hyslop Agronomy Farm near Corvallis, Oregon to determine the influence of three plant densities on gene action estimates for yield and its primary components. The plant densities were designed to provide different levels of competitions involving solid, six and 12 inch spacing within the rows with one foot spacing between the rows. Gene action estimates were obtained by the combining ability analysis as well as narrow sense heritability estimates. In addition, path-coefficient analysis was utilized to investigate the direct and indirect associations of the primary components of yield under different stresses of competition resulting from the changes in population densities. The morphological characters measured were 1) total yield per plant, 2) kernel weight 3) number of kernels per spikelet, 4) number of spikelets per spike, 5) tiller number and 6) plant height. A small additive gene action for yield was noted in the six inch spacing while additive gene action effects could not be detected in the 12 inch and solid plantings. Yield being a complex trait seems to be affected by the environmental changes resulting from different plant densities. Consistent general combining ability estimates were observed for kernel weight and plant height in all the plant densities, indicating a small genotype-environment interaction. In the spaced plantings additive gene action estimates were obtained for tiller number and spikelets per spike while there was no evidence of additive gene effects in the solid planting. No additive gene action was noted for kernels per spikelet in the 12 inch planting while six inch and solid plantings revealed considerable genetic variability. These results would suggest that the genotypes are susceptible to environmental fluctuations for the traits tiller number, spikelets per spike and kernels per spikelet. The correlation coefficients reveal that in spaced plantings tiller number, spikelets per spike and kernels per spikelet are significantly and positively related to yield. In the solid seeding only spikelets per spike was significantly associated to yield. When the four variables were considered in terms of their associations with yield it was observed in the F₂ that in spaced plantings all the four components of yield have direct positive influence on yield. In the solid seedings however, spikelets per spike and kernels per spikelet had high positive direct effects on yield while tiller number and kernel weight showed a negative direct influence on yield. The data revealed that spikelets per spike and kernels per spikelet are the most important traits contributing towards yield. However, the results obtained with correlation coefficients indicate that a negative association existed between these two traits as well as between kernels per spikelet and tiller number suggesting the possible existence of a biological limitation between these components of yield. The results indicate that a breeding program with emphasis on the selection of plants in competitive conditions in the early generations may make the selection work more efficient. Moreover, increases in yield which considers each of the components separately or in combination of two or more would offer the most promise. By this procedure the breeder would take advantage of the large amount of additive genetic variances associated with each of the components and at the same time take into consideration any biological limitations which may exist. Close

• 32. [Article] Sulfhydryl and disulfide changes in young wheat seedlings during vernalization

  A study of the SH and SS content levels during vernalization of wheat was made. In order to carry out the study, a rapid analytical technique was worked out which allowed fast sequential analyses of the ...

  Citation × Citation Citation Abstract Copy Title: Sulfhydryl and disulfide changes in young wheat seedlings during vernalization Author: Ellis, Robert William A study of the SH and SS content levels during vernalization of wheat was made. In order to carry out the study, a rapid analytical technique was worked out which allowed fast sequential analyses of the samples of wheat tissue. Two techniques were used: a) an amperometric titration method and b) a fluorescence quenching method. The amperometric titration method consisted of adding aliquots of samples of wheat tissue homogenate to the system and noting the decrease in current, due to a tie-up of Ag⁺ by the SH groups of the sample. The system consisted of a rotating platinum electrode connected to a mercury-mercuric oxide reference cell. The supporting electrolyte was a 0.14M solution of tris at pH 7.4. The fluorescence quenching method consisted of adding aliquots of sample to a solution of fluorescien mercuric acetate (FMA) in a 1N NaOH media. The SH and SS groups reacted with FMA in a one:one ratio. The reacted FMA was unable to fluoresce, thus making possible a quantitative assay for SH and SS groups in solution. Red Bobs, a spring wheat, and Elgin, a winter wheat, were grown in the dark at 3° C. and at 20° C. The SH and SS contents of the shoots were measured throughout a period of five weeks in the group grown at 3° C. and a period of 48 hours in the group grown at 20° C. The results of the analyses showed that the SH, SS, and SH+SS contents based on fresh weights were present in greater quantities in the tissues of Red Bobs grown at 20° than in the Elgin tissues grown at 20°. The high SH and SS concentrations present in the warm-grown Red Bobs tissues were due to a high concentration of protein extracted from that tissue. The SH, SS, and SH+SS contents per fresh weight were quite similar in the cold-grown tissues of both varieties during the growth period. These constituents present in the cold-grown tissues occurred in quantities that were less than those found in warm-grown Red Bobs tissues and greater than those present in the warm-grown Elgin tissues. Both varieties grown at both temperatures showed a similar decrease in SH and SS contents based on fresh weights as maturation progressed. The analyses indicated that SH, SS, and SH+SS contents based on protein levels were similar in Elgin and Red Bobs tissues grown at 20°. Both varieties grown at 3° contained greater concentrations of SH, SS, and SH+SS groups based on protein levels than those present in the tissues grown at 20°. The Elgin tissues at 3° underwent a fluctuation of these values as growth progressed, while the Red Bobs tissues at 3° maintained relatively constant levels of SH, SS, and SH+SS contents based on protein levels present during the growth period. It was concluded that the levels or patterns of SH and SS groups in young spring and winter wheat shoots were not correlated with the capacity of these plants to flower. Title: Sulfhydryl and disulfide changes in young wheat seedlings during vernalization Author: Ellis, Robert William A study of the SH and SS content levels during vernalization of wheat was made. In order to carry out the study, a rapid analytical technique was worked out which allowed fast sequential analyses of the samples of wheat tissue. Two techniques were used: a) an amperometric titration method and b) a fluorescence quenching method. The amperometric titration method consisted of adding aliquots of samples of wheat tissue homogenate to the system and noting the decrease in current, due to a tie-up of Ag⁺ by the SH groups of the sample. The system consisted of a rotating platinum electrode connected to a mercury-mercuric oxide reference cell. The supporting electrolyte was a 0.14M solution of tris at pH 7.4. The fluorescence quenching method consisted of adding aliquots of sample to a solution of fluorescien mercuric acetate (FMA) in a 1N NaOH media. The SH and SS groups reacted with FMA in a one:one ratio. The reacted FMA was unable to fluoresce, thus making possible a quantitative assay for SH and SS groups in solution. Red Bobs, a spring wheat, and Elgin, a winter wheat, were grown in the dark at 3° C. and at 20° C. The SH and SS contents of the shoots were measured throughout a period of five weeks in the group grown at 3° C. and a period of 48 hours in the group grown at 20° C. The results of the analyses showed that the SH, SS, and SH+SS contents based on fresh weights were present in greater quantities in the tissues of Red Bobs grown at 20° than in the Elgin tissues grown at 20°. The high SH and SS concentrations present in the warm-grown Red Bobs tissues were due to a high concentration of protein extracted from that tissue. The SH, SS, and SH+SS contents per fresh weight were quite similar in the cold-grown tissues of both varieties during the growth period. These constituents present in the cold-grown tissues occurred in quantities that were less than those found in warm-grown Red Bobs tissues and greater than those present in the warm-grown Elgin tissues. Both varieties grown at both temperatures showed a similar decrease in SH and SS contents based on fresh weights as maturation progressed. The analyses indicated that SH, SS, and SH+SS contents based on protein levels were similar in Elgin and Red Bobs tissues grown at 20°. Both varieties grown at 3° contained greater concentrations of SH, SS, and SH+SS groups based on protein levels than those present in the tissues grown at 20°. The Elgin tissues at 3° underwent a fluctuation of these values as growth progressed, while the Red Bobs tissues at 3° maintained relatively constant levels of SH, SS, and SH+SS contents based on protein levels present during the growth period. It was concluded that the levels or patterns of SH and SS groups in young spring and winter wheat shoots were not correlated with the capacity of these plants to flower. Close