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• 211. [Article] Estimating nitrogen mineralization in organic potato production

  Published January 2008. Reviewed July 2013. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog

  Citation × Citation Citation Abstract Copy Title: Estimating nitrogen mineralization in organic potato production Author: Horneck, Donald Arthur, Sullivan, Dan M. (Dan Matthew), 1954-, McQueen, John Paul Gainer, Oregon State University. Extension Service Published January 2008. Reviewed July 2013. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Title: Estimating nitrogen mineralization in organic potato production Author: Horneck, Donald Arthur, Sullivan, Dan M. (Dan Matthew), 1954-, McQueen, John Paul Gainer, Oregon State University. Extension Service Published January 2008. Reviewed July 2013. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Close

• 212. [Article] Winter wheat and spring grains in continuous cropping systems (low precipitation zone)

  Revised November 2006. Reviewed July 2012. Please check for active titles in the OSU Extension Service Catalog: http://extension.oregonstate.edu/catalog

  Citation × Citation Citation Abstract Copy Title: Winter wheat and spring grains in continuous cropping systems (low precipitation zone) Author: Wysocki, Donald John, 1952-, Lutcher, L. K. (Lawrence K.), Horneck, Donald Arthur, Oregon State University. Extension Service Revised November 2006. Reviewed July 2012. Please check for active titles in the OSU Extension Service Catalog: http://extension.oregonstate.edu/catalog Title: Winter wheat and spring grains in continuous cropping systems (low precipitation zone) Author: Wysocki, Donald John, 1952-, Lutcher, L. K. (Lawrence K.), Horneck, Donald Arthur, Oregon State University. Extension Service Revised November 2006. Reviewed July 2012. Please check for active titles in the OSU Extension Service Catalog: http://extension.oregonstate.edu/catalog Close

• 213. [Article] Species Composition and Diversity on Northwestern Bunchgrass Prairie Rangelands

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  Citation × Citation Citation Abstract Copy Title: Species Composition and Diversity on Northwestern Bunchgrass Prairie Rangelands Author: Damiran, Daalkhaijav, Clark, Abe, Taylor, Robert, Darambazar, Enkhjargal, DelCurto, Timothy pdf Title: Species Composition and Diversity on Northwestern Bunchgrass Prairie Rangelands Author: Damiran, Daalkhaijav, Clark, Abe, Taylor, Robert, Darambazar, Enkhjargal, DelCurto, Timothy pdf Close

• 214. [Article] Tanoak (Lithocarpus densiflorus (Hook & Arn.) Rehd.) root dieback : below- and aboveground site occupancy by stump-sprouts in southwest Oregon

  Residual roots from previous stand components are often cited as a major benefit to stump-sprouts of tanoak in southwest Oregon and northern California. Established patterns of belowground carbon allocation ...

  Citation × Citation Citation Abstract Copy Title: Tanoak (Lithocarpus densiflorus (Hook & Arn.) Rehd.) root dieback : below- and aboveground site occupancy by stump-sprouts in southwest Oregon Author: Ahrens, Glenn R. Residual roots from previous stand components are often cited as a major benefit to stump-sprouts of tanoak in southwest Oregon and northern California. Established patterns of belowground carbon allocation and root/shoot maintenance suggest that residual root systems of stumps will be reduced by carbohydrate depletion and root mortality and by shifts in allocation priority. A chronosequence approach was taken to relate changes in tanoak fine-root biomass to aboveground development during the first ten years after cutting of mature tanoak stands. Tanoak stump sprouts did not maintain preexisting fine roots. Proportional to values in the mature forest, root surface area for 3-year sprouts was 15, 52, and 82% in root diameter classes <.25, .25-1, and 1-2 mm respectively. A strong correlation between elevated soil temperature and dead root proportions suggests that increased respiratory depletion of carbohydrate supplies is the major cause of root mortality. Root dieback increased (in relative and absolute terms) with decreasing root size, which emphasizes the importance of high resolution in belowground studies. As a result of increased root mortality and reduced root growth relative to shoot growth, the new sprout stands regained the root/shoot equilibrium found in mature forests within 4 years. This supports a general theory of functional equilibrium between root and shoot. Rapid initial rates of leaf area growth declined to a lower, stable level of relative growth rate by age 4, coinciding with the time of minimum tanoak root density and root/shoot recovery. This may be the time of minimum dominance potential for tanoak stump-sprouts. The link between aboveground and belowground growth suggests that more extensive studies of tanoak dominance potential may be focused on aboveground characteristics. In combination with the overall decrease in tanoak roots, a pattern of increased dieback in openings between sprout clumps (until age 4) suggests that competition from residual tanoak roots will not entirely preclude the benefits of increased light for other species in openings. However, invading herbs (primarily bracken fern) may account for substantial soil moisture depletion during tanoak sprout recovery. Compared to the fully occupied mature forest, soil moisture depletion in sprout stands was substantially reduced only in the first summer after burning. To meet conifer management objectives, tanoak control treatments may be most effective if applied when sprout stands reach minimum root occupancy (age 4 in this study). In terms of competition, compensatory effects of invading herbs and shrubs are very important in moderating interactions between long-term dominants. Douglas-fir is the major potential crop tree on tanoak dominated sites. To effectively shift dominance to Douglas-fir in tanoak sprout stands, planting of large seedlings and herbaceous weed control are recommended in addition to tanoak control measures. Title: Tanoak (Lithocarpus densiflorus (Hook & Arn.) Rehd.) root dieback : below- and aboveground site occupancy by stump-sprouts in southwest Oregon Author: Ahrens, Glenn R. Residual roots from previous stand components are often cited as a major benefit to stump-sprouts of tanoak in southwest Oregon and northern California. Established patterns of belowground carbon allocation and root/shoot maintenance suggest that residual root systems of stumps will be reduced by carbohydrate depletion and root mortality and by shifts in allocation priority. A chronosequence approach was taken to relate changes in tanoak fine-root biomass to aboveground development during the first ten years after cutting of mature tanoak stands. Tanoak stump sprouts did not maintain preexisting fine roots. Proportional to values in the mature forest, root surface area for 3-year sprouts was 15, 52, and 82% in root diameter classes <.25, .25-1, and 1-2 mm respectively. A strong correlation between elevated soil temperature and dead root proportions suggests that increased respiratory depletion of carbohydrate supplies is the major cause of root mortality. Root dieback increased (in relative and absolute terms) with decreasing root size, which emphasizes the importance of high resolution in belowground studies. As a result of increased root mortality and reduced root growth relative to shoot growth, the new sprout stands regained the root/shoot equilibrium found in mature forests within 4 years. This supports a general theory of functional equilibrium between root and shoot. Rapid initial rates of leaf area growth declined to a lower, stable level of relative growth rate by age 4, coinciding with the time of minimum tanoak root density and root/shoot recovery. This may be the time of minimum dominance potential for tanoak stump-sprouts. The link between aboveground and belowground growth suggests that more extensive studies of tanoak dominance potential may be focused on aboveground characteristics. In combination with the overall decrease in tanoak roots, a pattern of increased dieback in openings between sprout clumps (until age 4) suggests that competition from residual tanoak roots will not entirely preclude the benefits of increased light for other species in openings. However, invading herbs (primarily bracken fern) may account for substantial soil moisture depletion during tanoak sprout recovery. Compared to the fully occupied mature forest, soil moisture depletion in sprout stands was substantially reduced only in the first summer after burning. To meet conifer management objectives, tanoak control treatments may be most effective if applied when sprout stands reach minimum root occupancy (age 4 in this study). In terms of competition, compensatory effects of invading herbs and shrubs are very important in moderating interactions between long-term dominants. Douglas-fir is the major potential crop tree on tanoak dominated sites. To effectively shift dominance to Douglas-fir in tanoak sprout stands, planting of large seedlings and herbaceous weed control are recommended in addition to tanoak control measures. Close

• 215. [Article] Effects of irrigation scheduling, using remotely sensed canopy-air temperature differentials, on water relations, yield, and quality of snap beans (Phaseolus vulgaris L.)

  Field experiments were conducted in 1981 and 1982 to develop a method for using remotely measured leaf canopy-air temperature differences (stress-degree-days (SDD)) to schedule irrigations and to evaluate ...

  Citation × Citation Citation Abstract Copy Title: Effects of irrigation scheduling, using remotely sensed canopy-air temperature differentials, on water relations, yield, and quality of snap beans (Phaseolus vulgaris L.) Author: Bonanno, A. Richard Field experiments were conducted in 1981 and 1982 to develop a method for using remotely measured leaf canopy-air temperature differences (stress-degree-days (SDD)) to schedule irrigations and to evaluate the effects of differential irrigation on snap bean cultivars, 'Oregon 1604' and 'Galamor'. Effects on soil water potential (SWP), leaf water potential (Ψ), leaf osmotic potential (fir ), leaf turgor potential (Ψp), leaf transpiration, leaf diffusive resistance, plant growth and development, yield components, and pod quality factors were measured. To schedule irrigations, various levels of positive SDD's, measured daily at midday, were allowed to accumulate between irrigations. When air vapor pressure deficits (VPD) were small, water stressed plants had positive. SDD's and well watered plants had negative SDD's. When VPD's were large, SDD's were always negative (i.e., canopy temperatures were cooler than air temperature). At these high VPD's, temperature differences between leaves of well watered and stressed plants were as much as 5-7 C. A model is presented in which SDD's can be adjusted based on the expected SDD of well watered plants at a given VPD. With this modification, irrigations can be adequately scheduled using only canopy temperatures, air temperatures, and relative humidity measurements. In both seasons, yield was strongly related to average SWP at 0-45 cm depth. In 1981, evaporative demand on the crop was much higher than in 1982. As a result, yields in 1982 were at least 5 t/ha greater at a given SWP than in 1981. Under water stress, total leaf area per plant was reduced more by a decrease in area per leaf than by a reduction in leaf number. Leaf water potential was not consistent with level of plant water stress. Although some osmotic adjustment occurred in stressed plants, Ψp was still generally lower than in well watered plants throughout the day. As Ψ decreased from early morning through midday, transpiration rates increased due to increasing evaporative demand. Leaf diffusive resistance also increased with decreasing V, but a "threshold value" for stomatal closure was not demonstrated. Title: Effects of irrigation scheduling, using remotely sensed canopy-air temperature differentials, on water relations, yield, and quality of snap beans (Phaseolus vulgaris L.) Author: Bonanno, A. Richard Field experiments were conducted in 1981 and 1982 to develop a method for using remotely measured leaf canopy-air temperature differences (stress-degree-days (SDD)) to schedule irrigations and to evaluate the effects of differential irrigation on snap bean cultivars, 'Oregon 1604' and 'Galamor'. Effects on soil water potential (SWP), leaf water potential (Ψ), leaf osmotic potential (fir ), leaf turgor potential (Ψp), leaf transpiration, leaf diffusive resistance, plant growth and development, yield components, and pod quality factors were measured. To schedule irrigations, various levels of positive SDD's, measured daily at midday, were allowed to accumulate between irrigations. When air vapor pressure deficits (VPD) were small, water stressed plants had positive. SDD's and well watered plants had negative SDD's. When VPD's were large, SDD's were always negative (i.e., canopy temperatures were cooler than air temperature). At these high VPD's, temperature differences between leaves of well watered and stressed plants were as much as 5-7 C. A model is presented in which SDD's can be adjusted based on the expected SDD of well watered plants at a given VPD. With this modification, irrigations can be adequately scheduled using only canopy temperatures, air temperatures, and relative humidity measurements. In both seasons, yield was strongly related to average SWP at 0-45 cm depth. In 1981, evaporative demand on the crop was much higher than in 1982. As a result, yields in 1982 were at least 5 t/ha greater at a given SWP than in 1981. Under water stress, total leaf area per plant was reduced more by a decrease in area per leaf than by a reduction in leaf number. Leaf water potential was not consistent with level of plant water stress. Although some osmotic adjustment occurred in stressed plants, Ψp was still generally lower than in well watered plants throughout the day. As Ψ decreased from early morning through midday, transpiration rates increased due to increasing evaporative demand. Leaf diffusive resistance also increased with decreasing V, but a "threshold value" for stomatal closure was not demonstrated. Close

• 216. [Article] Evaluation of early generation testing in a diallel cross involving four winter wheat cultivars (Triticum aestivum Vill., host)

  Factors which influence the effectiveness of making early generation selections within bulk populations were investigated. Material utilized included the parents, F₁, and F₂ through F₅ bulk populations resulting ...

  Citation × Citation Citation Abstract Copy Title: Evaluation of early generation testing in a diallel cross involving four winter wheat cultivars (Triticum aestivum Vill., host) Author: Daaloul, Abderrazak Factors which influence the effectiveness of making early generation selections within bulk populations were investigated. Material utilized included the parents, F₁, and F₂ through F₅ bulk populations resulting from a diallel cross. Information concerning the response of two traits, plant height and grain yield, was obtained for these populations at three diverse experimental sites. Estimates of gene action were determined by calculating heterosis, inbreeding depression, narrow-sense heritability, and combining ability values. Results obtained suggested that selections for plant height could be effectively made as early as the F₂ generation since this trait was largely controlled by additive gene action. Grain yield was found to be influenced significantly by non-additive gene action; however most populations were stabilized by the F₃ generations where high yielding populations could be identified and effective selection practiced. Results from this study suggested that genotype x environment interaction could influence early generation selection by masking the additive genetic effects. Under very favorable growing conditions the non-additive gene action x environment interaction dominated the additive effects for grain yield and to a lesser degree plant height. However, under dry land conditions both non-additive and additive genetic effects were masked by the environment and could not be expressed fully for grain yield. It is evident that for simply inherited traits like plant height, selection in the F₂ generation must be practiced under an environment where there is full expression for that trait, while selection for grain yield must be conducted under the same environments where the potential varieties are to be grown. The use of Average Combining Ability as an indirect method to evaluate the contribution of parents to performance of the progency was found to be valid by the predicted results obtained for the simply inherited trait plant height. This method could be used with some confidence to estimate contribution of parents for a complex trait like grain yield. Two parents were identified as the best combiners for grain yield. This confirms what was learned about them after fifteen years of actual experience indicating the importance of a technique whereby the breeder can determine in a very short period of time which parents to cross and then concentrate his efforts within the more promising segregating populations. Title: Evaluation of early generation testing in a diallel cross involving four winter wheat cultivars (Triticum aestivum Vill., host) Author: Daaloul, Abderrazak Factors which influence the effectiveness of making early generation selections within bulk populations were investigated. Material utilized included the parents, F₁, and F₂ through F₅ bulk populations resulting from a diallel cross. Information concerning the response of two traits, plant height and grain yield, was obtained for these populations at three diverse experimental sites. Estimates of gene action were determined by calculating heterosis, inbreeding depression, narrow-sense heritability, and combining ability values. Results obtained suggested that selections for plant height could be effectively made as early as the F₂ generation since this trait was largely controlled by additive gene action. Grain yield was found to be influenced significantly by non-additive gene action; however most populations were stabilized by the F₃ generations where high yielding populations could be identified and effective selection practiced. Results from this study suggested that genotype x environment interaction could influence early generation selection by masking the additive genetic effects. Under very favorable growing conditions the non-additive gene action x environment interaction dominated the additive effects for grain yield and to a lesser degree plant height. However, under dry land conditions both non-additive and additive genetic effects were masked by the environment and could not be expressed fully for grain yield. It is evident that for simply inherited traits like plant height, selection in the F₂ generation must be practiced under an environment where there is full expression for that trait, while selection for grain yield must be conducted under the same environments where the potential varieties are to be grown. The use of Average Combining Ability as an indirect method to evaluate the contribution of parents to performance of the progency was found to be valid by the predicted results obtained for the simply inherited trait plant height. This method could be used with some confidence to estimate contribution of parents for a complex trait like grain yield. Two parents were identified as the best combiners for grain yield. This confirms what was learned about them after fifteen years of actual experience indicating the importance of a technique whereby the breeder can determine in a very short period of time which parents to cross and then concentrate his efforts within the more promising segregating populations. Close

• 217. [Article] Mechanisms of uptake and some factors influencing the toxicity of 2-chloro-2', 6'-diethyl-N-(methoxymethyl) acetanilide (alachlor) for selected plant species

  A number of studies with ¹⁴C-labeled 2-chloro-2', 6'-diethyl- N-(methoxymethyl) acetanilide (alachlor) were conducted to obtain information about the mechanisms of uptake of this herbicide. In other studies, ...

  Citation × Citation Citation Abstract Copy Title: Mechanisms of uptake and some factors influencing the toxicity of 2-chloro-2', 6'-diethyl-N-(methoxymethyl) acetanilide (alachlor) for selected plant species Author: Groenwold, Bareld Egge, 1939- A number of studies with ¹⁴C-labeled 2-chloro-2', 6'-diethyl- N-(methoxymethyl) acetanilide (alachlor) were conducted to obtain information about the mechanisms of uptake of this herbicide. In other studies, technical alachlor as well as the emulsifiable concentrate formulation of the chemical were used to investigate the effect of several factors on the toxicity of the herbicide. Corn and oats absorbed alachor primarily in a passive way. The uptake of the herbicide in both species was slightly reduced in the presence of metabolic inhibitors. The reduction was somewhat stronger in corn than in oats. A raise in temperature increased the uptake of alachlor only slightly. Q₁₀ values of about 1.2 were found. The part of the total uptake affected by metabolic inhibitors followed Michaelis-Menten kinetics over the alachlor concentration range of 0.1 mM to 0.5 mM. Uptake of alachlor was measured in the presence of an analog, propachlor. Propachlor reduced the uptake of alachlor at a concentra- tion of 0.3 mM for both chemicals. At a concentration of 0.03 mM for each herbicide alachlor uptake was less reduced. Total uptake by corn and oats was nearly identical up to a concentration of 0.1 mM. At higher concentrations alachlor absorption by oats was about twice as high as by corn. This would suggest that selective uptake by the two species could at least partly account for the difference in tolerance towards alachlor. A study was conducted to determine if P, K and Ca levels in oat plants were affected by alachlor treatment. P and Ca content was not affected by the presence of alachlor, but a gradual decrease in K level with increasing herbicide concentrations was observed. Uptake of alachlor through the shoot region exceeded absorption by the roots in the two monocotyledonous species, corn and oats. Two dictos, soybean and cucumber, absorbed higher amounts of the herbicide through the roots. Shoot exposure of corn and cucumber was most damaging to the plant, while root exposure was more damaging to oats and soybean. The effect of alachlor on the growth of oats and cucumber at various levels of sub-irrigation and carrier volume could be explained on the basis of differences in effective absorption regions in the plants. Photoperiod had, in contrast with light intensity, no effect on the activity of the herbicide to corn, cucumber and oats. An increase in light intensity up to 1600 ft-c increased the toxicity of alachlor in corn and cucumber, but not in oats. The activity at 2000 ft-c was only slightly higher than at 60 ft-c, and less than at 660 ft-c. In the case of cucumber, an increase in alachlor concentration had very little effect at 2000 ft-c, in contrast with the other light intensities. Title: Mechanisms of uptake and some factors influencing the toxicity of 2-chloro-2', 6'-diethyl-N-(methoxymethyl) acetanilide (alachlor) for selected plant species Author: Groenwold, Bareld Egge, 1939- A number of studies with ¹⁴C-labeled 2-chloro-2', 6'-diethyl- N-(methoxymethyl) acetanilide (alachlor) were conducted to obtain information about the mechanisms of uptake of this herbicide. In other studies, technical alachlor as well as the emulsifiable concentrate formulation of the chemical were used to investigate the effect of several factors on the toxicity of the herbicide. Corn and oats absorbed alachor primarily in a passive way. The uptake of the herbicide in both species was slightly reduced in the presence of metabolic inhibitors. The reduction was somewhat stronger in corn than in oats. A raise in temperature increased the uptake of alachlor only slightly. Q₁₀ values of about 1.2 were found. The part of the total uptake affected by metabolic inhibitors followed Michaelis-Menten kinetics over the alachlor concentration range of 0.1 mM to 0.5 mM. Uptake of alachlor was measured in the presence of an analog, propachlor. Propachlor reduced the uptake of alachlor at a concentra- tion of 0.3 mM for both chemicals. At a concentration of 0.03 mM for each herbicide alachlor uptake was less reduced. Total uptake by corn and oats was nearly identical up to a concentration of 0.1 mM. At higher concentrations alachlor absorption by oats was about twice as high as by corn. This would suggest that selective uptake by the two species could at least partly account for the difference in tolerance towards alachlor. A study was conducted to determine if P, K and Ca levels in oat plants were affected by alachlor treatment. P and Ca content was not affected by the presence of alachlor, but a gradual decrease in K level with increasing herbicide concentrations was observed. Uptake of alachlor through the shoot region exceeded absorption by the roots in the two monocotyledonous species, corn and oats. Two dictos, soybean and cucumber, absorbed higher amounts of the herbicide through the roots. Shoot exposure of corn and cucumber was most damaging to the plant, while root exposure was more damaging to oats and soybean. The effect of alachlor on the growth of oats and cucumber at various levels of sub-irrigation and carrier volume could be explained on the basis of differences in effective absorption regions in the plants. Photoperiod had, in contrast with light intensity, no effect on the activity of the herbicide to corn, cucumber and oats. An increase in light intensity up to 1600 ft-c increased the toxicity of alachlor in corn and cucumber, but not in oats. The activity at 2000 ft-c was only slightly higher than at 60 ft-c, and less than at 660 ft-c. In the case of cucumber, an increase in alachlor concentration had very little effect at 2000 ft-c, in contrast with the other light intensities. Close

• 218. [Article] The incidence of infection and decay caused by Heterobasidion annosum in managed second-growth noble fir on the Warm Springs Indian Reservation, Oregon

  Improved accessibility in remote noble fir (Abies procera Rehd.) stands and the realization of the value of noble fir wood have led to increased pressure to enter and actively manage noble fir stands in ...

  Citation × Citation Citation Abstract Copy Title: The incidence of infection and decay caused by Heterobasidion annosum in managed second-growth noble fir on the Warm Springs Indian Reservation, Oregon Author: Sullivan, Kelly F. Improved accessibility in remote noble fir (Abies procera Rehd.) stands and the realization of the value of noble fir wood have led to increased pressure to enter and actively manage noble fir stands in Oregon and Washington. This study examined the incidence of infection and decay caused by Heterobasidion annosum Bref. in two previously thinned and wounded noble fir stands. The project was designed to gain a better understanding of the biology and population structure of H. annosum on a little studied host, and ultimately to provide land managers with a means for reducing the incidence and severity of annosus root and butt rot. Data for the study were collected from two study sites on the Warm Springs Indian Reservation (WSIR), Oregon. Thirty potential crop trees per stand, both wounded and unwounded, were selected. Trees were sampled using the following techniques: 1) collection of basic tree data; 2) destructive tree dissections or non-destructive wood chip extraction with subsequent isolation analysis; and 3) thirty foot circular stump plots collecting pertinent stump data. Vegetative compatibility (VC) tests were conducted to analyze the clonal distribution of H. annosum within individual trees and ultimately to examine the relative importance of primary and secondary spread. Many VC groups were present in individual trees suggesting the importance of primary spore infection. Starch gel electrophoresis was used to analyze isozyme patterns and determine the intersterility group (biological species) of a subsample of H. annosum isolates recovered from live noble fir trees. All isolates belonged to the S type intersterility group. Multiple linear regression analysis was used to determine if tree, stump and wound variables were associated with H. annosum infection and decay. Results suggested that percent H. annosum infection increased as the total surface area of wounds below breast height and total tree height increased. Additionally, percent decay volume increased as the mean diameter of surrounding true fir stumps and mean wound age increased. The major conclusions of this study are as follows: 1) the incidence of H. annosum infection is high in thinned and wounded noble fir stands; 2) wounded trees are significantly more decayed than unwounded trees, however, the presence of H. annosum was not significantly associated with the presence of wounds and/or decay columns; 3) both wounds and stumps are involved in disease spread, and wounds may exacerbate the decay process; 4) decay volumes steadily increase with time; and 5) manager's should treat stumps with borax, or an equivalent protectant, and take measures to minimize wounding. Title: The incidence of infection and decay caused by Heterobasidion annosum in managed second-growth noble fir on the Warm Springs Indian Reservation, Oregon Author: Sullivan, Kelly F. Improved accessibility in remote noble fir (Abies procera Rehd.) stands and the realization of the value of noble fir wood have led to increased pressure to enter and actively manage noble fir stands in Oregon and Washington. This study examined the incidence of infection and decay caused by Heterobasidion annosum Bref. in two previously thinned and wounded noble fir stands. The project was designed to gain a better understanding of the biology and population structure of H. annosum on a little studied host, and ultimately to provide land managers with a means for reducing the incidence and severity of annosus root and butt rot. Data for the study were collected from two study sites on the Warm Springs Indian Reservation (WSIR), Oregon. Thirty potential crop trees per stand, both wounded and unwounded, were selected. Trees were sampled using the following techniques: 1) collection of basic tree data; 2) destructive tree dissections or non-destructive wood chip extraction with subsequent isolation analysis; and 3) thirty foot circular stump plots collecting pertinent stump data. Vegetative compatibility (VC) tests were conducted to analyze the clonal distribution of H. annosum within individual trees and ultimately to examine the relative importance of primary and secondary spread. Many VC groups were present in individual trees suggesting the importance of primary spore infection. Starch gel electrophoresis was used to analyze isozyme patterns and determine the intersterility group (biological species) of a subsample of H. annosum isolates recovered from live noble fir trees. All isolates belonged to the S type intersterility group. Multiple linear regression analysis was used to determine if tree, stump and wound variables were associated with H. annosum infection and decay. Results suggested that percent H. annosum infection increased as the total surface area of wounds below breast height and total tree height increased. Additionally, percent decay volume increased as the mean diameter of surrounding true fir stumps and mean wound age increased. The major conclusions of this study are as follows: 1) the incidence of H. annosum infection is high in thinned and wounded noble fir stands; 2) wounded trees are significantly more decayed than unwounded trees, however, the presence of H. annosum was not significantly associated with the presence of wounds and/or decay columns; 3) both wounds and stumps are involved in disease spread, and wounds may exacerbate the decay process; 4) decay volumes steadily increase with time; and 5) manager's should treat stumps with borax, or an equivalent protectant, and take measures to minimize wounding. Close

• 219. [Article] Effect of sulfur on dinitrogen fixation of alfalfa (Medicago sativa L.)

  Field experiments were established in 1982 and 1983 on a Woodburn silt loam soil (Aquultic Argixeroll) to examine the effect of S fertilizer on dinitrogen fixation and dry matter yield of 10 week-old seedling ...

  Citation × Citation Citation Abstract Copy Title: Effect of sulfur on dinitrogen fixation of alfalfa (Medicago sativa L.) Author: Lopez-Jurado, Gerardo Field experiments were established in 1982 and 1983 on a Woodburn silt loam soil (Aquultic Argixeroll) to examine the effect of S fertilizer on dinitrogen fixation and dry matter yield of 10 week-old seedling alfalfa (Medicago sativa L. cv. 'Apollo'). Six levels of S fertilizer (0 to 67.2 kg S/ha) were applied as powdered gypsum. The experimental design was a split-block with one half of the seeds inoculated with commercial inoculum, and the other half non-inoculated. Inoculation effects were highly significant in both years, indicating that the indigenous population of Rhizobium meliloti at the experimental sites was ineffective in N₂-fixation. Dry matter yields were higher in inoculated than in non-inoculated treatments. Inoculated plants also showed a significantly higher acetylene reduction rate, N concentration, and total tissue N and S. No significant differences in any of these parameters were detected for the different S treatments. Sulfur fertilization increased the S concentration of non-inoculated plants more than inoculated plants, and decreased the N:S ratio in the forage by increasing tissue S content. The highest value of N₂-fixed by the inoculated plants was obtained from the 44.8 kg S/ha treatment. Greenhouse experiments were performed to evaluate the effect of varied nutrient solution concentrations of sulfate on the yield, nodulation, dinitrogen fixation, N and S concentrations, and partitioning of N and S into shoots and roots of six week-old alfalfa seedlings. Four levels of S (0, 1, 2.5, and 25 mg S/L) were applied in a randomized complete block design, with three replications. Seeds were inoculated with commercial inoculum, planted in plastic containers of acid-washed sand, and irrigated with nutrient solution for one minute, at 2 h intervals. The addition of 2.5 mg S/L to the nutrient solution resulted in the highest total dry matter, acetylene reduction rate, total N content, percent S recovery, and percent increase in N due to dinitrogen fixation. N:S ratios were 50% higher in shoots (16:1) than roots (9:1), with S fertilization decreasing the N:S ratios. Data from field and greenhouse experiments support the conclusion that S fertilization will increase seedling alfalfa yield when S levels in the plant are below 2.5 mg S/g (0.25%). In inoculated plants S fertilization increased both total N and S, demonstrating the importance of S in symbiotic N₂-fixation and the quality of forage produced. Title: Effect of sulfur on dinitrogen fixation of alfalfa (Medicago sativa L.) Author: Lopez-Jurado, Gerardo Field experiments were established in 1982 and 1983 on a Woodburn silt loam soil (Aquultic Argixeroll) to examine the effect of S fertilizer on dinitrogen fixation and dry matter yield of 10 week-old seedling alfalfa (Medicago sativa L. cv. 'Apollo'). Six levels of S fertilizer (0 to 67.2 kg S/ha) were applied as powdered gypsum. The experimental design was a split-block with one half of the seeds inoculated with commercial inoculum, and the other half non-inoculated. Inoculation effects were highly significant in both years, indicating that the indigenous population of Rhizobium meliloti at the experimental sites was ineffective in N₂-fixation. Dry matter yields were higher in inoculated than in non-inoculated treatments. Inoculated plants also showed a significantly higher acetylene reduction rate, N concentration, and total tissue N and S. No significant differences in any of these parameters were detected for the different S treatments. Sulfur fertilization increased the S concentration of non-inoculated plants more than inoculated plants, and decreased the N:S ratio in the forage by increasing tissue S content. The highest value of N₂-fixed by the inoculated plants was obtained from the 44.8 kg S/ha treatment. Greenhouse experiments were performed to evaluate the effect of varied nutrient solution concentrations of sulfate on the yield, nodulation, dinitrogen fixation, N and S concentrations, and partitioning of N and S into shoots and roots of six week-old alfalfa seedlings. Four levels of S (0, 1, 2.5, and 25 mg S/L) were applied in a randomized complete block design, with three replications. Seeds were inoculated with commercial inoculum, planted in plastic containers of acid-washed sand, and irrigated with nutrient solution for one minute, at 2 h intervals. The addition of 2.5 mg S/L to the nutrient solution resulted in the highest total dry matter, acetylene reduction rate, total N content, percent S recovery, and percent increase in N due to dinitrogen fixation. N:S ratios were 50% higher in shoots (16:1) than roots (9:1), with S fertilization decreasing the N:S ratios. Data from field and greenhouse experiments support the conclusion that S fertilization will increase seedling alfalfa yield when S levels in the plant are below 2.5 mg S/g (0.25%). In inoculated plants S fertilization increased both total N and S, demonstrating the importance of S in symbiotic N₂-fixation and the quality of forage produced. Close

• 220. [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