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• 171. [Article] A comparative analysis of factors influencing smoking behaviors of college students, 1963-1987

  Cigarette smoking continues to be one of the country's major health concerns. It has been defined as the single largest preventable cause of disease and death in the United States. Although research has ...

  Citation × Citation Citation Abstract Copy Title: A comparative analysis of factors influencing smoking behaviors of college students, 1963-1987 Author: Gray, Nancy L. Cigarette smoking continues to be one of the country's major health concerns. It has been defined as the single largest preventable cause of disease and death in the United States. Although research has indicated that overall cigarette consumption has decreased in the nation over the past decades, cigarette smoking remains a significant problem among young people in the United States. This fact, coupled with studies indicating that cigarette smoking increases with age into the early twenties suggests that research should be conducted to determine those variables that encourage smoking behavior of late adolescents and young adults. The purpose of the study was to compare the relationship between selected predisposing factors and subsequent smoking behaviors exhibited in 1963 and 1987 respectively. Assessments of smoking behaviors of college students in Oregon in 1963-64 and 1986-87 were conducted to determine relationships between students smoking behaviors and selected socio-demographic variables. Comparisons were made between the resulting data for students in the 1963-64and 1986-87 studies. Aquestionnaire relating to smoking behavior was developed and administered to 3,786 college students attending introductory personal health classes during the 1963-64 school year at four selected colleges in the state of Oregon. During the 1986-87 school year a modified version of the questionnaire was developed and administered to college students attending introductory personal health classes at three of the same four universities that were utilized in the 1963-64 study. Stepwise logistic regression, chi square and descriptive statistics were used to analyze the data. Results indicated that there were significantly more smokers in 1963-64 and their daily consumption rates were significantly higher when compared to 1986-87 data. Although a larger percentage of females were smokers in the total population surveyed in 1963-64, there were more female smokers in the population of smokers in 1986-87. Whereas males consumed significantly more cigarettes per day than did females in 1963-64, there was no significant difference between male and female consumption rates in 1986-87. Significant numbers of smokers in 1986-87 started smoking at an earlier age than did smokers in 1963-64. When separating by gender, this was significant for females but not for males. Peer smoking was listed as the number one reason for starting to smoke by more than half of the respondents in 1986-87 as compared to 40% who listed curiosity in 1963-64. Physical reasons were indicated as the main reason for quitting by ex-smokers in 1963-64 and in 1986-87, over one half of the respondents indicated that they quit because of a concern for their physical health. Stepwise logistic regression equations were used to determine the set of variables that best accounted for smoking status in 1963-64 and 1986-87. Results indicated that the variables which predisposed individuals toward subsequent smoking behavior did differ when comparing the two studies. In 1963-64, an individual with the highest probability of smoking was one who had one or more older sisters who smoked, both parents smoked, father was a high school non-graduate and was from an urban setting. The individual with the lowest probability of smoking in 1963-64 had no older sisters who smoked, mother and father did not smoke, father was a high school graduate and lived in a rural setting. In 1986-87, the only variable to significantly increase the probability of an individual smoking was one or more older brothers who smoked. The following data were collected only for the 1986-87 population of students because questions relating to these issues were not included on the 1963-64 questionnaire. Use of alcohol, marijuana and smokeless tobacco by cigarette smokers was not significantly different when compared to non-smokers. Illicit substance use (cocaine, crack, heroin, quaaludes, etc) was significantly different for cigarette smokers and non-smokers. Smokers were more likely to use illicit substances than were non-smokers. The largest number of smokeless tobacco users were males in the 18-19 age category. Use of alcohol, marijuana and other illicit substances were significantly different for smokeless tobacco users than for non-users. Smokeless tobacco users were more likely to consume more alcohol on a weekly basis and use marijuana and illicit substances on an occasional and regular basis than were non-users of smokeless tobacco. Title: A comparative analysis of factors influencing smoking behaviors of college students, 1963-1987 Author: Gray, Nancy L. Cigarette smoking continues to be one of the country's major health concerns. It has been defined as the single largest preventable cause of disease and death in the United States. Although research has indicated that overall cigarette consumption has decreased in the nation over the past decades, cigarette smoking remains a significant problem among young people in the United States. This fact, coupled with studies indicating that cigarette smoking increases with age into the early twenties suggests that research should be conducted to determine those variables that encourage smoking behavior of late adolescents and young adults. The purpose of the study was to compare the relationship between selected predisposing factors and subsequent smoking behaviors exhibited in 1963 and 1987 respectively. Assessments of smoking behaviors of college students in Oregon in 1963-64 and 1986-87 were conducted to determine relationships between students smoking behaviors and selected socio-demographic variables. Comparisons were made between the resulting data for students in the 1963-64and 1986-87 studies. Aquestionnaire relating to smoking behavior was developed and administered to 3,786 college students attending introductory personal health classes during the 1963-64 school year at four selected colleges in the state of Oregon. During the 1986-87 school year a modified version of the questionnaire was developed and administered to college students attending introductory personal health classes at three of the same four universities that were utilized in the 1963-64 study. Stepwise logistic regression, chi square and descriptive statistics were used to analyze the data. Results indicated that there were significantly more smokers in 1963-64 and their daily consumption rates were significantly higher when compared to 1986-87 data. Although a larger percentage of females were smokers in the total population surveyed in 1963-64, there were more female smokers in the population of smokers in 1986-87. Whereas males consumed significantly more cigarettes per day than did females in 1963-64, there was no significant difference between male and female consumption rates in 1986-87. Significant numbers of smokers in 1986-87 started smoking at an earlier age than did smokers in 1963-64. When separating by gender, this was significant for females but not for males. Peer smoking was listed as the number one reason for starting to smoke by more than half of the respondents in 1986-87 as compared to 40% who listed curiosity in 1963-64. Physical reasons were indicated as the main reason for quitting by ex-smokers in 1963-64 and in 1986-87, over one half of the respondents indicated that they quit because of a concern for their physical health. Stepwise logistic regression equations were used to determine the set of variables that best accounted for smoking status in 1963-64 and 1986-87. Results indicated that the variables which predisposed individuals toward subsequent smoking behavior did differ when comparing the two studies. In 1963-64, an individual with the highest probability of smoking was one who had one or more older sisters who smoked, both parents smoked, father was a high school non-graduate and was from an urban setting. The individual with the lowest probability of smoking in 1963-64 had no older sisters who smoked, mother and father did not smoke, father was a high school graduate and lived in a rural setting. In 1986-87, the only variable to significantly increase the probability of an individual smoking was one or more older brothers who smoked. The following data were collected only for the 1986-87 population of students because questions relating to these issues were not included on the 1963-64 questionnaire. Use of alcohol, marijuana and smokeless tobacco by cigarette smokers was not significantly different when compared to non-smokers. Illicit substance use (cocaine, crack, heroin, quaaludes, etc) was significantly different for cigarette smokers and non-smokers. Smokers were more likely to use illicit substances than were non-smokers. The largest number of smokeless tobacco users were males in the 18-19 age category. Use of alcohol, marijuana and other illicit substances were significantly different for smokeless tobacco users than for non-users. Smokeless tobacco users were more likely to consume more alcohol on a weekly basis and use marijuana and illicit substances on an occasional and regular basis than were non-users of smokeless tobacco. Close

• 172. [Article] Transferrin polymorphism in a population of Nuttall's cottontail in central Oregon

  Temporal changes in gene frequencies and genotype frequencies, monthly densities, survival rates, growth rates, trap susceptibility and home ranges were evaluated from 291 Nuttall's cottontails (Sylvilagus ...

  Citation × Citation Citation Abstract Copy Title: Transferrin polymorphism in a population of Nuttall's cottontail in central Oregon Author: Skalski, John Raymond Temporal changes in gene frequencies and genotype frequencies, monthly densities, survival rates, growth rates, trap susceptibility and home ranges were evaluated from 291 Nuttall's cottontails (Sylvilagus nuttallii) captured 950 times by livetrapping and 53 cottontails collected by shooting. Electrophoretic analyses of sera revealed protein polymorphism at the transferrin locus in the Nuttall's cottontail population. The locus was characterized by three codominant alleles, Trf-A, Trf-B and Trf-C with relative mobilities of 1.04, 1.00 and 0.95, respectively. No significant relationship between transferrin genotypes of Nuttall's cottontails and their sex was observed (P > 0.05). The frequencies of the transferrin genotypes was not significantly different from expected values computed by Hardy-Weinberg equilibrium frequencies suggesting genetic inheritance at a single autosomal locus (P > 0. 05). During the summer of 1974 the occurrence of the Trf-BB genotype increased 13.3 percent between the samples of parental stock and their trappable progeny. In 1975, the Trf-BB genotype frequency decreased by 14.5 percent between parental stock and trappable progeny. Associated with the opposite trends in Trf-BB genotype frequencies between years were significant differences in the growth rates of juveniles in 1974 and 1975 (P < 0.05). Mean rate of growth for juveniles in a litter were computed by regression of weight at first capture against date of acquisition for all juveniles of a litter group. Computed rates of growth ranged from 1.51 to 3.70 grams per day for juveniles in litter groups in 1974 and from 4.28 to 5.98 grams per day in 1975. The differences in growth rates of juveniles between 1974 and 1975 were thought to be related to a 4-fold difference in precipitation falling from the time the first litter was weaned through August each year with 1.47 cm and 5.89 cm of rain, respectively. There was a significant difference in Trf-C gene frequencies between the 1974 and 1975 trappable progeny (P < 0. 05). Significant changes in the gene pool of the cottontail population were thought to have resulted from possible selection of juveniles best adapted to the prevailing environment. Apparently four litters of cottontails were produced during the 1974 and 1975 breeding seasons with an estimated total production of 305.6 and 354.1 young, respectively. Monthly estimates of population density ranged from 17.8 cottontails per 100-ha on 14 February 1974 to 241.8 cottontails per 100-ha on 31 July 1975. Estimates of cottontail density on 30 August 1974 and 1975 were 173.6 and 213.9 cottontails per 100-ha, respectively. The overall survival rate of juvenile cottontails from birth through 30 August was 42.1 and 44.4 percent, respectively, for 1974 and 1975. However, the minimum survival rate for cottontials in the trapped population was computed as 78.8 and 73.6 percent, respectively, for 1974 and 1975. Survival rates indicated a high rate of mortality for juveniles prior to their entrance into the trapped population. No differences were found in the size of home ranges or weights at first capture of cottontails of the various transferrin genotypes captured (P > 0. 05). Cottontails of the Trf-BC genotype were found to be significantly more difficult to capture than those of the Trf-BB in 1975 with 35.1 and 26.3 trapnights required per capture, respectively (P < 0. 05). Transferrin genotypes were determined for 51 of the 53 cottontails collected by shooting in September 1975. Analysis indicated no significant relationship between the transferrin genotype composition of the sample and the method of acquisition, with the comparison of cottontails livetrapped in August 1975 and those shot in September 1975 (P > 0. 05). No significant differences were found between the sex and age structure of the hunted sample of September 1975 and the trapped population of August 1975 (P > 0.05). Title: Transferrin polymorphism in a population of Nuttall's cottontail in central Oregon Author: Skalski, John Raymond Temporal changes in gene frequencies and genotype frequencies, monthly densities, survival rates, growth rates, trap susceptibility and home ranges were evaluated from 291 Nuttall's cottontails (Sylvilagus nuttallii) captured 950 times by livetrapping and 53 cottontails collected by shooting. Electrophoretic analyses of sera revealed protein polymorphism at the transferrin locus in the Nuttall's cottontail population. The locus was characterized by three codominant alleles, Trf-A, Trf-B and Trf-C with relative mobilities of 1.04, 1.00 and 0.95, respectively. No significant relationship between transferrin genotypes of Nuttall's cottontails and their sex was observed (P > 0.05). The frequencies of the transferrin genotypes was not significantly different from expected values computed by Hardy-Weinberg equilibrium frequencies suggesting genetic inheritance at a single autosomal locus (P > 0. 05). During the summer of 1974 the occurrence of the Trf-BB genotype increased 13.3 percent between the samples of parental stock and their trappable progeny. In 1975, the Trf-BB genotype frequency decreased by 14.5 percent between parental stock and trappable progeny. Associated with the opposite trends in Trf-BB genotype frequencies between years were significant differences in the growth rates of juveniles in 1974 and 1975 (P < 0.05). Mean rate of growth for juveniles in a litter were computed by regression of weight at first capture against date of acquisition for all juveniles of a litter group. Computed rates of growth ranged from 1.51 to 3.70 grams per day for juveniles in litter groups in 1974 and from 4.28 to 5.98 grams per day in 1975. The differences in growth rates of juveniles between 1974 and 1975 were thought to be related to a 4-fold difference in precipitation falling from the time the first litter was weaned through August each year with 1.47 cm and 5.89 cm of rain, respectively. There was a significant difference in Trf-C gene frequencies between the 1974 and 1975 trappable progeny (P < 0. 05). Significant changes in the gene pool of the cottontail population were thought to have resulted from possible selection of juveniles best adapted to the prevailing environment. Apparently four litters of cottontails were produced during the 1974 and 1975 breeding seasons with an estimated total production of 305.6 and 354.1 young, respectively. Monthly estimates of population density ranged from 17.8 cottontails per 100-ha on 14 February 1974 to 241.8 cottontails per 100-ha on 31 July 1975. Estimates of cottontail density on 30 August 1974 and 1975 were 173.6 and 213.9 cottontails per 100-ha, respectively. The overall survival rate of juvenile cottontails from birth through 30 August was 42.1 and 44.4 percent, respectively, for 1974 and 1975. However, the minimum survival rate for cottontials in the trapped population was computed as 78.8 and 73.6 percent, respectively, for 1974 and 1975. Survival rates indicated a high rate of mortality for juveniles prior to their entrance into the trapped population. No differences were found in the size of home ranges or weights at first capture of cottontails of the various transferrin genotypes captured (P > 0. 05). Cottontails of the Trf-BC genotype were found to be significantly more difficult to capture than those of the Trf-BB in 1975 with 35.1 and 26.3 trapnights required per capture, respectively (P < 0. 05). Transferrin genotypes were determined for 51 of the 53 cottontails collected by shooting in September 1975. Analysis indicated no significant relationship between the transferrin genotype composition of the sample and the method of acquisition, with the comparison of cottontails livetrapped in August 1975 and those shot in September 1975 (P > 0. 05). No significant differences were found between the sex and age structure of the hunted sample of September 1975 and the trapped population of August 1975 (P > 0.05). Close

• 173. [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

• 174. [Article] Genetic variation and interrelationships of acid detergent fiber, neutral detergent fiber, hemicellulose, crude protein and in vitro dry matter digestibility in tall fescue (Festuca arundinacea Schreb)

  Six parent clones and their 15 single-crosses of tall fescue (Festuca arundinaceae, Schreb) were row-planted in Corvallis, Oregon, row and sward-planted in Columbia, Missouri, and evaluated for genetic ...

  Citation × Citation Citation Abstract Copy Title: Genetic variation and interrelationships of acid detergent fiber, neutral detergent fiber, hemicellulose, crude protein and in vitro dry matter digestibility in tall fescue (Festuca arundinacea Schreb) Author: Soh, Aik-chin Six parent clones and their 15 single-crosses of tall fescue (Festuca arundinaceae, Schreb) were row-planted in Corvallis, Oregon, row and sward-planted in Columbia, Missouri, and evaluated for genetic variability, genotyp-eenvironment interactions and interrelationships in acid detergent fiber (ADF), neutral detergent fiber (NDF), hemicellulose (HCL), crude protein (CP) and in vitro dry matter digestibility (IVDMD) for each harvest in 1977 and 1978. Analyses revealed that general combining ability or additive genetic effects predominated for all the measured characteristics in the tall fescue diallel cross population. Of the genotype-environment interactions, only general combining ability x harvest interaction effects were significant enough to warrant consideration. The results also suggest that general combining ability of the parents rather than actual parental performance is a better predictor of hybrid progeny performance for all the characteristics. Parent-progeny regressions reveal that ADF is a more transmissible trait than NDF, IVDMD, HCL, or CP. ADF and NDF were highly and significantly correlated to IVDMD while HCL and CP were poorly correlated to IVDMD. It is suggested that the results obtained can have wider applicability to other tall fescue growing areas and populations. The results indicate that a selection program based on progeny testing for general combining ability for low ADF under row-planted conditions in one location for all harvest seasons over one or two years would efficiently and conveniently result in a rapid indirect selection improvement for digestibility in tall fescue. Title: Genetic variation and interrelationships of acid detergent fiber, neutral detergent fiber, hemicellulose, crude protein and in vitro dry matter digestibility in tall fescue (Festuca arundinacea Schreb) Author: Soh, Aik-chin Six parent clones and their 15 single-crosses of tall fescue (Festuca arundinaceae, Schreb) were row-planted in Corvallis, Oregon, row and sward-planted in Columbia, Missouri, and evaluated for genetic variability, genotyp-eenvironment interactions and interrelationships in acid detergent fiber (ADF), neutral detergent fiber (NDF), hemicellulose (HCL), crude protein (CP) and in vitro dry matter digestibility (IVDMD) for each harvest in 1977 and 1978. Analyses revealed that general combining ability or additive genetic effects predominated for all the measured characteristics in the tall fescue diallel cross population. Of the genotype-environment interactions, only general combining ability x harvest interaction effects were significant enough to warrant consideration. The results also suggest that general combining ability of the parents rather than actual parental performance is a better predictor of hybrid progeny performance for all the characteristics. Parent-progeny regressions reveal that ADF is a more transmissible trait than NDF, IVDMD, HCL, or CP. ADF and NDF were highly and significantly correlated to IVDMD while HCL and CP were poorly correlated to IVDMD. It is suggested that the results obtained can have wider applicability to other tall fescue growing areas and populations. The results indicate that a selection program based on progeny testing for general combining ability for low ADF under row-planted conditions in one location for all harvest seasons over one or two years would efficiently and conveniently result in a rapid indirect selection improvement for digestibility in tall fescue. Close

• 175. [Article] Heterosis and inbreeding in the progeney of genetically diverse parental clones of Festuca arundinacea Schreb

  The response of maturity, vigor, plant spread, plant height, three forage harvest yields, and total forage yield to heterosis and inbreeding was studied in tall fescue. Parent clones selected for diverse ...

  Citation × Citation Citation Abstract Copy Title: Heterosis and inbreeding in the progeney of genetically diverse parental clones of Festuca arundinacea Schreb Author: Johnson, Blaine Earl The response of maturity, vigor, plant spread, plant height, three forage harvest yields, and total forage yield to heterosis and inbreeding was studied in tall fescue. Parent clones selected for diverse anthesis date, origin, and morphology were separated into two groups based on anthesis date, those having early maturity and those having late maturity. Parents, single-cross (SX), and first generation selfed (S₁) progeny were field evaluated. Parents, S₁, and SX progeny were space planted on a . 914 x 1.219 meter basis at the Hyslop Agronomy Field Laboratory, Corvallis, Oregon, in September, 1969. A randomized block design having four blocks and 14 plant rows as entries was used. Data were collected during the spring, summer, and fall of 1972. Single-cross progeny had a mean performance better than their midparents ' mean performance for all characteristics, with all differences significant except for plant height and third harvest forage yield. Single-cross progeny averaged 7. 03, 13. 18, 13. 50, 3. 89, 42. 93, 51. 72, 15. 14, and 37. 12 percent better than their midparents for maturity rating, vigor rating, plant spread, plant height, first, second, and third harvest forage yield, and forage yield, respectively. There was a greater frequency of individual single-crosses that exhibited significant heterosis in the early x late group than in either the early x early or late x late groups. In addition the average heterotic response of the early x late group was consistently greater than that of either of the other two groups. Thus it appears significant heterosis is more likely to occur, and is likely to be of a greater magnitude, in the progeny of parents having maturity differences, and presumably, greater genetic differences. Significant variation occurred among the single-cross maturity group means for all characteristics with the early x early single crosses most often being the better performers. Consequently the additional heterosis observed in the early x late group was usually insufficient to bring performance of this group up to that of the higher performing but less heterotic early x early single-crosses. This suggests heterosis may be of little practical importance. Inbreeding depression of S₁ progeny was significant for all characteristics. The inbreeding depression was of the greatest magnitude in the progeny of the early parents. Performance of early parents and early S₁ progeny was generally better than that of their late counterparts. Heritability estimates were high, particularly those obtained by regressing single-cross progeny on midparents, although two did not differ significantly from zero. The coefficients of determination for the same associations were likewise high, with over 70 percent of progeny variation being explained by linear association with parents for most characteristics. As superior progeny came from superior parents, this high degree of association suggests clonal evaluation may be an effective screening method in tall fescue. There was strong association among the characteristics of maturity rating, plant spread, plant height, first and third forage yield, and total forage yield, with the lowest of these coefficients of determination, R² = .6031, occurring between maturity rating and plant spread. Vigor rating, second harvest yield, seedling vigor index, and panicle number showed little association among themselves or among the other characteristics, with the highest association, R² = . 3599, occurring between panicle number and third harvest yield. Seed yield was moderately associated with forage characteristics, with R² values of about .5000, but showed no association with panicle number. Title: Heterosis and inbreeding in the progeney of genetically diverse parental clones of Festuca arundinacea Schreb Author: Johnson, Blaine Earl The response of maturity, vigor, plant spread, plant height, three forage harvest yields, and total forage yield to heterosis and inbreeding was studied in tall fescue. Parent clones selected for diverse anthesis date, origin, and morphology were separated into two groups based on anthesis date, those having early maturity and those having late maturity. Parents, single-cross (SX), and first generation selfed (S₁) progeny were field evaluated. Parents, S₁, and SX progeny were space planted on a . 914 x 1.219 meter basis at the Hyslop Agronomy Field Laboratory, Corvallis, Oregon, in September, 1969. A randomized block design having four blocks and 14 plant rows as entries was used. Data were collected during the spring, summer, and fall of 1972. Single-cross progeny had a mean performance better than their midparents ' mean performance for all characteristics, with all differences significant except for plant height and third harvest forage yield. Single-cross progeny averaged 7. 03, 13. 18, 13. 50, 3. 89, 42. 93, 51. 72, 15. 14, and 37. 12 percent better than their midparents for maturity rating, vigor rating, plant spread, plant height, first, second, and third harvest forage yield, and forage yield, respectively. There was a greater frequency of individual single-crosses that exhibited significant heterosis in the early x late group than in either the early x early or late x late groups. In addition the average heterotic response of the early x late group was consistently greater than that of either of the other two groups. Thus it appears significant heterosis is more likely to occur, and is likely to be of a greater magnitude, in the progeny of parents having maturity differences, and presumably, greater genetic differences. Significant variation occurred among the single-cross maturity group means for all characteristics with the early x early single crosses most often being the better performers. Consequently the additional heterosis observed in the early x late group was usually insufficient to bring performance of this group up to that of the higher performing but less heterotic early x early single-crosses. This suggests heterosis may be of little practical importance. Inbreeding depression of S₁ progeny was significant for all characteristics. The inbreeding depression was of the greatest magnitude in the progeny of the early parents. Performance of early parents and early S₁ progeny was generally better than that of their late counterparts. Heritability estimates were high, particularly those obtained by regressing single-cross progeny on midparents, although two did not differ significantly from zero. The coefficients of determination for the same associations were likewise high, with over 70 percent of progeny variation being explained by linear association with parents for most characteristics. As superior progeny came from superior parents, this high degree of association suggests clonal evaluation may be an effective screening method in tall fescue. There was strong association among the characteristics of maturity rating, plant spread, plant height, first and third forage yield, and total forage yield, with the lowest of these coefficients of determination, R² = .6031, occurring between maturity rating and plant spread. Vigor rating, second harvest yield, seedling vigor index, and panicle number showed little association among themselves or among the other characteristics, with the highest association, R² = . 3599, occurring between panicle number and third harvest yield. Seed yield was moderately associated with forage characteristics, with R² values of about .5000, but showed no association with panicle number. Close

• 176. [Article] Supporting children who struggle with self-regulation : the role of early family risk and child care quality

  Children's early self-regulation skills have long-term implications for a variety of academic, social, and health outcomes. Unfortunately, children facing multiple family risk factors (e.g., harsh parenting, ...

  Citation × Citation Citation Abstract Copy Title: Supporting children who struggle with self-regulation : the role of early family risk and child care quality Author: Pratt, Megan E. Children's early self-regulation skills have long-term implications for a variety of academic, social, and health outcomes. Unfortunately, children facing multiple family risk factors (e.g., harsh parenting, economic disadvantage) are more likely to struggle with early self-regulation. Despite early disparities in self-regulation, promising intervention evidence suggests that high quality prekindergarten experiences can improve children's self-regulation skills, especially for children with self-regulatory challenges. At this point, few studies have examined how children's self-regulation may differ according to the unique combinations of family risks they experience during their first three years of life. Furthermore, it remains largely unknown how children's experiences in typical early care and education settings relate to their self-regulation development. To address these gaps in the literature, this dissertation includes two studies focused on understanding children with low early self-regulation. The first study addressed how distinct combinations of family risk factors (i.e., family risk profiles), as experienced during the first three years of life, predicted children's self-regulation at 36-months. Person-centered analyses indicated children's family risk experiences were captured by three distinct family risk profiles: 1) low risk, 2) low-income/low cognitive stimulation/single parent (ICS), and 3) low-income/low cognitive stimulation/high parental harshness (ICH). Each of the three profiles predicted significant differences in children's early self-regulation, with children characterized by the profile including high harshness (ICH) exhibiting the lowest self-regulation skills. Study 2 examined how two dimensions of early care and education process quality (positivity/responsivity and cognitive stimulation) experienced during children's prekindergarten year predicted their subsequent self-regulation in the fall of kindergarten. This study also considered children's earlier self-regulation as a moderator of both quality dimensions. Results indicated that higher positivity/responsivity predicted stronger self-regulation in the fall of kindergarten for children with low early self-regulation, but not for the overall sample. Cognitive stimulation did not predict children's self-regulation in kindergarten, regardless of early self-regulation skills. Overall, findings from these studies help explain why some children struggle more with early self-regulation than others, and how high quality early care and education can support children's transition to kindergarten, particularly for children with low early self-regulation. Title: Supporting children who struggle with self-regulation : the role of early family risk and child care quality Author: Pratt, Megan E. Children's early self-regulation skills have long-term implications for a variety of academic, social, and health outcomes. Unfortunately, children facing multiple family risk factors (e.g., harsh parenting, economic disadvantage) are more likely to struggle with early self-regulation. Despite early disparities in self-regulation, promising intervention evidence suggests that high quality prekindergarten experiences can improve children's self-regulation skills, especially for children with self-regulatory challenges. At this point, few studies have examined how children's self-regulation may differ according to the unique combinations of family risks they experience during their first three years of life. Furthermore, it remains largely unknown how children's experiences in typical early care and education settings relate to their self-regulation development. To address these gaps in the literature, this dissertation includes two studies focused on understanding children with low early self-regulation. The first study addressed how distinct combinations of family risk factors (i.e., family risk profiles), as experienced during the first three years of life, predicted children's self-regulation at 36-months. Person-centered analyses indicated children's family risk experiences were captured by three distinct family risk profiles: 1) low risk, 2) low-income/low cognitive stimulation/single parent (ICS), and 3) low-income/low cognitive stimulation/high parental harshness (ICH). Each of the three profiles predicted significant differences in children's early self-regulation, with children characterized by the profile including high harshness (ICH) exhibiting the lowest self-regulation skills. Study 2 examined how two dimensions of early care and education process quality (positivity/responsivity and cognitive stimulation) experienced during children's prekindergarten year predicted their subsequent self-regulation in the fall of kindergarten. This study also considered children's earlier self-regulation as a moderator of both quality dimensions. Results indicated that higher positivity/responsivity predicted stronger self-regulation in the fall of kindergarten for children with low early self-regulation, but not for the overall sample. Cognitive stimulation did not predict children's self-regulation in kindergarten, regardless of early self-regulation skills. Overall, findings from these studies help explain why some children struggle more with early self-regulation than others, and how high quality early care and education can support children's transition to kindergarten, particularly for children with low early self-regulation. Close

• 177. [Article] A comparison of three systems of phenotypic selection for grain yield in three spring barley populations

  Concerns regarding the most effective means of evaluating segregating generations of spring barley prompted this investigation. Three methods of selection were considered: bulk, pedigree, and single seed ...

  Citation × Citation Citation Abstract Copy Title: A comparison of three systems of phenotypic selection for grain yield in three spring barley populations Author: Hayes, Patrick M. Concerns regarding the most effective means of evaluating segregating generations of spring barley prompted this investigation. Three methods of selection were considered: bulk, pedigree, and single seed descent. F₆ lines derived by each method were grown in a replicated yield trial. The effectiveness of each method was measured in terms of grain yield and four other agronomic traits. Continuity of method performance was evaluated across three spring barley populations. Parents used in developing these populations were chosen on the basis"of their diverse genetic backgrounds. Experimental populations differed for all agronomic traits measured. Differences between methods of selection were only found for 100 kernel weight, with lines from the single seed descent method being superior. The pedigree method was least effective for this trait. No significant differences between selection methods were found for plant height, spikes per meter, kernels per spike or grain yield. Significant differences were found between individual lines within methods and crosses for all traits except spikes per meter. There was no conclusive superiority of lines derived by any given method for any of the five traits. Although the single seed descent method was not significantly different from the pedigree and bulk methods on a mean basis, it did derive a number of superior individual lines and preserved substantial between-line variability for all traits measured, except spikes per meter. Because of the overall efficiency achieved with the single seed descent method, it may be a useful tool for the breeder of self-pollinated species. Title: A comparison of three systems of phenotypic selection for grain yield in three spring barley populations Author: Hayes, Patrick M. Concerns regarding the most effective means of evaluating segregating generations of spring barley prompted this investigation. Three methods of selection were considered: bulk, pedigree, and single seed descent. F₆ lines derived by each method were grown in a replicated yield trial. The effectiveness of each method was measured in terms of grain yield and four other agronomic traits. Continuity of method performance was evaluated across three spring barley populations. Parents used in developing these populations were chosen on the basis"of their diverse genetic backgrounds. Experimental populations differed for all agronomic traits measured. Differences between methods of selection were only found for 100 kernel weight, with lines from the single seed descent method being superior. The pedigree method was least effective for this trait. No significant differences between selection methods were found for plant height, spikes per meter, kernels per spike or grain yield. Significant differences were found between individual lines within methods and crosses for all traits except spikes per meter. There was no conclusive superiority of lines derived by any given method for any of the five traits. Although the single seed descent method was not significantly different from the pedigree and bulk methods on a mean basis, it did derive a number of superior individual lines and preserved substantial between-line variability for all traits measured, except spikes per meter. Because of the overall efficiency achieved with the single seed descent method, it may be a useful tool for the breeder of self-pollinated species. Close

• 178. [Article] Coral-reef fishes : insights into larval dispersal and invasion ecology

  Because many coral-reef fishes are observable in situ, are amenable to transplantation, have small home ranges and short generation times, they provide a excellent system to investigate many topics within ...

  Citation × Citation Citation Abstract Copy Title: Coral-reef fishes : insights into larval dispersal and invasion ecology Author: Pusack, Timothy J. Because many coral-reef fishes are observable in situ, are amenable to transplantation, have small home ranges and short generation times, they provide a excellent system to investigate many topics within general ecology, fisheries biology, and conservation biology. The primary goal of this dissertation was to use the coral-reef fishes system to investigate two pressing sets of issues that face marine ecologists and managers of living marine resources. The first topic is the spatial and temporal patterns of larval dispersal and reproductive success in a marine metapopulation (Chapter 2). Because miniscule larvae are difficult to track in the vast pelagic environment, little is known about the patterns of larval dispersal. Yet, the more that is understood about the spatial and temporal variability in larval dispersal, the easier it will be to identify sites that are self-sustaining and exporting larvae to unprotect sites, a common goal of marine reserves. Incorporating this information into siting of marine reserves will improve their effectiveness. The second topic is fundamental in the ecology of biological invasions: species specific interactions between an invasive predator and native species. Specifically, I investigated the ability of an invasive predator to disrupt natural population regulation of a native prey species (Chapter 3), and the ability of a native predator to provide biotic resistance against the invasive species (Chapter 4). Because management of the lionfish invasion is needed throughout the Caribbean and Atlantic waters, it is necessary to understand not only how lionfish can change the native system, but also potential ways to moderate the negative effects. To address the first topic, we collected a total of 3,278 genetic tissue samples from bicolor damselfish (Stegastes partitus) over a four year period from reefs near four islands that encompass Exuma Sound, Bahamas (Chapter 2). Using a Bayesian parentage analysis, eight parent-offspring pairs were detected, which directly documented both connectivity between and self-recruitment on an ecological time scale. Remarkably, some larvae returned to the exact same reef where they were spawned, while others traveled to sites greater than 100 km distance. The only study island without a detected parent-offspring pair, Lee Stocking Island, was also the island that showed the most restrictive gene flow on evolutionary time scales. Additionally, variability was documented in the spatial and temporal signatures of sweepstakes reproduction and Wahlund effects. The variation we observed may be influenced by seasonal mesoscale gyres present in Exuma Sound, which play a prominent role in shaping local oceanographic patterns. Understanding how to identify pathways of larval dispersal is important to designing networks of marine reserves, because a common goal of reserves is to protect populations that are self-seeding and can export larvae. Thus, this research not only demonstrates that temporal variability is a prominent characteristic of larval dispersal, but provides an example of how to identify these populations. To address the second topic, two studies using both lab observations and manipulative field experiments were conducted to study the interaction between invasive Indo-Pacific red lionfish (Pterois volitans) and two different native species. In the first study (Chapter 3) three different data sets were used to document the effect of lionfish predation on their top prey species, the bridled goby (Coryphopterus glaucofraenum). The first data set was extracted from three previous studies to compare the change in abundance of bridled goby between patch reefs with lionfish and patch reefs that were predator-free. The second data set came from laboratory feeding trials to test for the presence of a size refuge for bridled goby caused by lionfish gape limitation. The third data set came from a manipulative field experiment using 22 nearshore reefs where the per capita mortality of bridled gobies was compared among four orthogonal predator treatments: (1) predator-free control, (2) a single native predator only -- the graysby grouper (Cephalopholis cruentatus) -- representing the pre-invasion system, (3) a single lionfish only, and (4) one native grouper and one lionfish, representing the invaded system. The combined results from these three data sets demonstrated that lionfish can consistently consume a significant amount and an extremely high proportion of bridled goby on small patch reefs. While small lionfish cannot eat bridled goby larger than 0.42 times their body size, large lionfish eat virtually the entire size range of bridled goby. These findings indicate that lionfish have the potential to extirpate local goby populations. In the second experiment, lionfish were exposed to different abundances of a native grouper, the Nassau grouper (Epinephelus striatus), on 28 nearshore patch reefs in the Bahamas. Lionfish persistence and growth was monitored over 10 weeks, as well as the abundance of small, < 5 cm total length (TL), native reef fishes. Nassau grouper did not affect lionfish persistence or growth. Yet, reefs with a lionfish and many Nassau grouper saw a significant increase in the abundance of small reef fishes compared to reefs with only lionfish or lionfish with few grouper. Thus, it appears that high densities of Nassau grouper provide some biotic resistance on Bahamian patch reefs by potentially interfering with lionfish predation on native fishes, perhaps by interrupting stalking behavior. This dissertation highlights the flexibility of the coral-reef fishes system for investigation of broadly different topics in basic and applied ecology. Coral-reef fishes are a tractable system for both large and small scale studies, as well as laboratory observations and manipulative field experiments. The findings of this dissertation advance the understanding of metapopulation dynamics and have implications for fisheries management and marine reserve design. This research also documents further evidence of the negative effects of lionfish, yet provides some promising findings that may indicate some native biotic resistance to this devastating of marine invasions. Title: Coral-reef fishes : insights into larval dispersal and invasion ecology Author: Pusack, Timothy J. Because many coral-reef fishes are observable in situ, are amenable to transplantation, have small home ranges and short generation times, they provide a excellent system to investigate many topics within general ecology, fisheries biology, and conservation biology. The primary goal of this dissertation was to use the coral-reef fishes system to investigate two pressing sets of issues that face marine ecologists and managers of living marine resources. The first topic is the spatial and temporal patterns of larval dispersal and reproductive success in a marine metapopulation (Chapter 2). Because miniscule larvae are difficult to track in the vast pelagic environment, little is known about the patterns of larval dispersal. Yet, the more that is understood about the spatial and temporal variability in larval dispersal, the easier it will be to identify sites that are self-sustaining and exporting larvae to unprotect sites, a common goal of marine reserves. Incorporating this information into siting of marine reserves will improve their effectiveness. The second topic is fundamental in the ecology of biological invasions: species specific interactions between an invasive predator and native species. Specifically, I investigated the ability of an invasive predator to disrupt natural population regulation of a native prey species (Chapter 3), and the ability of a native predator to provide biotic resistance against the invasive species (Chapter 4). Because management of the lionfish invasion is needed throughout the Caribbean and Atlantic waters, it is necessary to understand not only how lionfish can change the native system, but also potential ways to moderate the negative effects. To address the first topic, we collected a total of 3,278 genetic tissue samples from bicolor damselfish (Stegastes partitus) over a four year period from reefs near four islands that encompass Exuma Sound, Bahamas (Chapter 2). Using a Bayesian parentage analysis, eight parent-offspring pairs were detected, which directly documented both connectivity between and self-recruitment on an ecological time scale. Remarkably, some larvae returned to the exact same reef where they were spawned, while others traveled to sites greater than 100 km distance. The only study island without a detected parent-offspring pair, Lee Stocking Island, was also the island that showed the most restrictive gene flow on evolutionary time scales. Additionally, variability was documented in the spatial and temporal signatures of sweepstakes reproduction and Wahlund effects. The variation we observed may be influenced by seasonal mesoscale gyres present in Exuma Sound, which play a prominent role in shaping local oceanographic patterns. Understanding how to identify pathways of larval dispersal is important to designing networks of marine reserves, because a common goal of reserves is to protect populations that are self-seeding and can export larvae. Thus, this research not only demonstrates that temporal variability is a prominent characteristic of larval dispersal, but provides an example of how to identify these populations. To address the second topic, two studies using both lab observations and manipulative field experiments were conducted to study the interaction between invasive Indo-Pacific red lionfish (Pterois volitans) and two different native species. In the first study (Chapter 3) three different data sets were used to document the effect of lionfish predation on their top prey species, the bridled goby (Coryphopterus glaucofraenum). The first data set was extracted from three previous studies to compare the change in abundance of bridled goby between patch reefs with lionfish and patch reefs that were predator-free. The second data set came from laboratory feeding trials to test for the presence of a size refuge for bridled goby caused by lionfish gape limitation. The third data set came from a manipulative field experiment using 22 nearshore reefs where the per capita mortality of bridled gobies was compared among four orthogonal predator treatments: (1) predator-free control, (2) a single native predator only -- the graysby grouper (Cephalopholis cruentatus) -- representing the pre-invasion system, (3) a single lionfish only, and (4) one native grouper and one lionfish, representing the invaded system. The combined results from these three data sets demonstrated that lionfish can consistently consume a significant amount and an extremely high proportion of bridled goby on small patch reefs. While small lionfish cannot eat bridled goby larger than 0.42 times their body size, large lionfish eat virtually the entire size range of bridled goby. These findings indicate that lionfish have the potential to extirpate local goby populations. In the second experiment, lionfish were exposed to different abundances of a native grouper, the Nassau grouper (Epinephelus striatus), on 28 nearshore patch reefs in the Bahamas. Lionfish persistence and growth was monitored over 10 weeks, as well as the abundance of small, < 5 cm total length (TL), native reef fishes. Nassau grouper did not affect lionfish persistence or growth. Yet, reefs with a lionfish and many Nassau grouper saw a significant increase in the abundance of small reef fishes compared to reefs with only lionfish or lionfish with few grouper. Thus, it appears that high densities of Nassau grouper provide some biotic resistance on Bahamian patch reefs by potentially interfering with lionfish predation on native fishes, perhaps by interrupting stalking behavior. This dissertation highlights the flexibility of the coral-reef fishes system for investigation of broadly different topics in basic and applied ecology. Coral-reef fishes are a tractable system for both large and small scale studies, as well as laboratory observations and manipulative field experiments. The findings of this dissertation advance the understanding of metapopulation dynamics and have implications for fisheries management and marine reserve design. This research also documents further evidence of the negative effects of lionfish, yet provides some promising findings that may indicate some native biotic resistance to this devastating of marine invasions. Close

• 179. [Article] Bioclimatic, ecological, and phenotypic intermediacy and high genetic admixture in a natural hybrid of octoploid strawberries

  This is the publisher’s final pdf. The published article is copyrighted by Botanical Society of America and can be found at: http://www.botany.org/.

  Citation × Citation Citation Abstract Copy Title: Bioclimatic, ecological, and phenotypic intermediacy and high genetic admixture in a natural hybrid of octoploid strawberries Author: Ashnam, Tia-Lynn, Liston, Aaron, Falk, Stacey, Govindarajulu, Rajanikanth, Parks, Matthew, Salamone, Isabella This is the publisher’s final pdf. The published article is copyrighted by Botanical Society of America and can be found at: http://www.botany.org/. Title: Bioclimatic, ecological, and phenotypic intermediacy and high genetic admixture in a natural hybrid of octoploid strawberries Author: Ashnam, Tia-Lynn, Liston, Aaron, Falk, Stacey, Govindarajulu, Rajanikanth, Parks, Matthew, Salamone, Isabella This is the publisher’s final pdf. The published article is copyrighted by Botanical Society of America and can be found at: http://www.botany.org/. Close

• 180. [Article] Microsatellite Marker Development, Characterization and Mapping in European Hazelnut (Corylus avellana L.), and Investigation of Novel Sources of Eastern Filbert Blight Resistance in Corylus

  European hazelnut, an important nut crop in Oregon agriculture, is threatened by the fungal disease eastern filbert blight (EFB) caused by Anisogramma anomala (Peck) E. Müller. The hazelnut breeding program ...

  Citation × Citation Citation Abstract Copy Title: Microsatellite Marker Development, Characterization and Mapping in European Hazelnut (Corylus avellana L.), and Investigation of Novel Sources of Eastern Filbert Blight Resistance in Corylus Author: Bhattarai, Gehendra European hazelnut, an important nut crop in Oregon agriculture, is threatened by the fungal disease eastern filbert blight (EFB) caused by Anisogramma anomala (Peck) E. Müller. The hazelnut breeding program at OSU has been working on development of EFB-resistant cultivars. DNA markers allow mapping of traits using segregating progenies and identification of linked markers. The breeding of hazelnuts involves use of DNA markers to genotype individuals and facilitate selection in a procedure known as marker-assisted selection (MAS). This technique is particularly promising in tree crops with a long juvenile phase like the hazelnuts. 'Gasaway' resistance governed by a dominant allele at a single locus was identified and several EFB-resistant cultivars carrying the dominant allele from this source have been released. Infection of 'Gasaway' and some of its offspring by A. anomala isolates has been noted, and indicates an urgent need to investigate new sources of resistance, identify new resistance genes and incorporate them into the breeding effort. New microsatellite markers were developed from the genomic sequence of hazelnut cv. 'Jefferson'. A total of 17,802 simple sequence repeat (SSR) motifs exceeding 15 bp in length and consisting of tri-, tetra-, penta- and hexa- nucleotide repeats were identified in the 'Jefferson' genome. Removal of duplicates, short fragments, repeats at ends, and repeats containing only A's and T's reduced the number of unique fragments to 2,069. Visual inspection of these unique fragments alligned with genome sequences of 7 other accessions in Tablet software identified 489 sequences with variation in number of repeats but with conserved flanking regions. Amplification of a set of 24 diverse accessions and separation on agarose gels led to the development of 366 new polymorphic markers. These were used to genotype 48 diverse accessions using capillary electrophoresis for fragment sizing. An additional 15 parents were also fingerprinted at these new 366 microsatellite loci. Using the mapping population (OSU 252.146 x OSU 414.062), 213 loci were mapped. A dendrogram was constructed which showed a high level of polymorphism in hazelnut. Tightly linked markers were identified for 'Gasaway' resistance and MAS is routinely used. The hazelnut acreage in Oregon is increasing every year with the planting of these new EFB-resistant cultivars. However, concern about disease resistance breakdown prompted an investigation of 12 new EFB resistance sources. Segregating progenies were inoculated by placement of potted trees under an inoculation structure, in the greenhouse, or in the field by tying a diseased branch on each tree. A chi-square goodness-of-fit test was used compare observed with expected segregation ratios. Very few seedlings of Moscow selections N01, N01-06, and N01-07 were resistant and were likely escapes. 'Grand Traverse', C. heterophylla 'Ogyoo', 'Yoder #5', C. americana 'Rush', Moscow N23, N26, N27, and N37 segregated in 1:1 ratio, indicating resistance governed by a single locus and a dominant allele for resistance. 'Uebov' transmitted resistance to only ~15 % of its seedlings. Resistance from 'Uebov', 'Grand Traverse', and C. heterophylla 'Ogyoo' were assigned to LG6 but only 'Uebov' and 'Grand Traverse' were mapped. Resistance from 'Yoder #5', Moscow N27 and C. americana 'Rush' was assigned to LG7. Mapping of the remaining resistance sources will be completed in the future. Title: Microsatellite Marker Development, Characterization and Mapping in European Hazelnut (Corylus avellana L.), and Investigation of Novel Sources of Eastern Filbert Blight Resistance in Corylus Author: Bhattarai, Gehendra European hazelnut, an important nut crop in Oregon agriculture, is threatened by the fungal disease eastern filbert blight (EFB) caused by Anisogramma anomala (Peck) E. Müller. The hazelnut breeding program at OSU has been working on development of EFB-resistant cultivars. DNA markers allow mapping of traits using segregating progenies and identification of linked markers. The breeding of hazelnuts involves use of DNA markers to genotype individuals and facilitate selection in a procedure known as marker-assisted selection (MAS). This technique is particularly promising in tree crops with a long juvenile phase like the hazelnuts. 'Gasaway' resistance governed by a dominant allele at a single locus was identified and several EFB-resistant cultivars carrying the dominant allele from this source have been released. Infection of 'Gasaway' and some of its offspring by A. anomala isolates has been noted, and indicates an urgent need to investigate new sources of resistance, identify new resistance genes and incorporate them into the breeding effort. New microsatellite markers were developed from the genomic sequence of hazelnut cv. 'Jefferson'. A total of 17,802 simple sequence repeat (SSR) motifs exceeding 15 bp in length and consisting of tri-, tetra-, penta- and hexa- nucleotide repeats were identified in the 'Jefferson' genome. Removal of duplicates, short fragments, repeats at ends, and repeats containing only A's and T's reduced the number of unique fragments to 2,069. Visual inspection of these unique fragments alligned with genome sequences of 7 other accessions in Tablet software identified 489 sequences with variation in number of repeats but with conserved flanking regions. Amplification of a set of 24 diverse accessions and separation on agarose gels led to the development of 366 new polymorphic markers. These were used to genotype 48 diverse accessions using capillary electrophoresis for fragment sizing. An additional 15 parents were also fingerprinted at these new 366 microsatellite loci. Using the mapping population (OSU 252.146 x OSU 414.062), 213 loci were mapped. A dendrogram was constructed which showed a high level of polymorphism in hazelnut. Tightly linked markers were identified for 'Gasaway' resistance and MAS is routinely used. The hazelnut acreage in Oregon is increasing every year with the planting of these new EFB-resistant cultivars. However, concern about disease resistance breakdown prompted an investigation of 12 new EFB resistance sources. Segregating progenies were inoculated by placement of potted trees under an inoculation structure, in the greenhouse, or in the field by tying a diseased branch on each tree. A chi-square goodness-of-fit test was used compare observed with expected segregation ratios. Very few seedlings of Moscow selections N01, N01-06, and N01-07 were resistant and were likely escapes. 'Grand Traverse', C. heterophylla 'Ogyoo', 'Yoder #5', C. americana 'Rush', Moscow N23, N26, N27, and N37 segregated in 1:1 ratio, indicating resistance governed by a single locus and a dominant allele for resistance. 'Uebov' transmitted resistance to only ~15 % of its seedlings. Resistance from 'Uebov', 'Grand Traverse', and C. heterophylla 'Ogyoo' were assigned to LG6 but only 'Uebov' and 'Grand Traverse' were mapped. Resistance from 'Yoder #5', Moscow N27 and C. americana 'Rush' was assigned to LG7. Mapping of the remaining resistance sources will be completed in the future. Close