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• 1. [Article] Heritability estimates for seed and plant characteristics in white clover (Trifolium repens L.)

  Genetic differences, extent of hybrid vigor, nature of gene action, heritability estimates, and associations among characteristics, and between progenies and their respective mid-parents were determined for ...

  Citation × Citation Citation Abstract Copy Title: Heritability estimates for seed and plant characteristics in white clover (Trifolium repens L.) Author: Kim, Dal Ung Genetic differences, extent of hybrid vigor, nature of gene action, heritability estimates, and associations among characteristics, and between progenies and their respective mid-parents were determined for seed and plant characteristics in white clover (Trifolium repens L.). Ten seed and seedling vigor characteristics, including seed weight, ATP content in seed, seed respiration, and seedling vigor index were studied for a diallel cross consisting of 28 single crosses, five test-crosses, four checks, and eight open-pollinated seed and seedlings. Twenty-three plant characteristics on stolon, petiole, leaf, and forage were examined on the eight clones diallel cross, five test-crosses, three checks, the eight parental clones of single crosses, and six parent clones of the test-crosses. These 14 parent clones for this study were assembled on the basis of diverse morphology and origin. Most seed and seedling vigor characteristics, except RQ values, and most plant characteristics, except internode length, LAR and diurnal ratio in SLW, expressed significant differences among and within most groups of progenies and parental clones. All seed and seedling vigor characteristics, except RQ values, responded primarily to the nonadditive type of gene action. This suggests that the plant breeder should design his breeding program to develop varieties where hybrid vigor can be used to advantage. Among the criteria used in this study to measure seed and seedling vigor, ATP content per seed was closely associated with seedling vigor index and with certain plant characteristics, including forage yield per plant. The associations of seed weight with other seed and seedling vigor characteristics were negative or poor. Most plant characteristics showed apparent hybrid vigor when progenies were compared with their respective mid-parents. With few exceptions, most plant characteristics, stolon, petiole, leaf and forage yield per plant, responded primarily to the nonadditive gene system. This indicated that the plant breeder may use the hybrid approach to white clover variety development. The exceptions were leaf ratio and SLW which responded primarily to additive gene action, and area and dry weight per leaf appeared to respond equally to additive and nonadditive gene action. Genetic differences were more readily identified for stolon number and length when measurements were taken after 70 days of growth. Yield components, such as number, length, and diameter of stolon, petiole length, number of leaves per plant, and dry weight per leaf were closely related to each other. The leaf components of yield, dry weight per leaf and number of leaves per plant, had the highest direct and indirect effects on forage yields per plant among the yield components. This study showed nonadditive gene action primarily responsible for most seed and plant characteristics. Considering the ease of vegetative propagation in this species along with the self-incompatibility, mechanisms, it is suggested that parent geneotypes may be developed by some recurrent selection procedure, then crossed on a two clone synthetic basis to form experimental lines for testing purposes. Title: Heritability estimates for seed and plant characteristics in white clover (Trifolium repens L.) Author: Kim, Dal Ung Genetic differences, extent of hybrid vigor, nature of gene action, heritability estimates, and associations among characteristics, and between progenies and their respective mid-parents were determined for seed and plant characteristics in white clover (Trifolium repens L.). Ten seed and seedling vigor characteristics, including seed weight, ATP content in seed, seed respiration, and seedling vigor index were studied for a diallel cross consisting of 28 single crosses, five test-crosses, four checks, and eight open-pollinated seed and seedlings. Twenty-three plant characteristics on stolon, petiole, leaf, and forage were examined on the eight clones diallel cross, five test-crosses, three checks, the eight parental clones of single crosses, and six parent clones of the test-crosses. These 14 parent clones for this study were assembled on the basis of diverse morphology and origin. Most seed and seedling vigor characteristics, except RQ values, and most plant characteristics, except internode length, LAR and diurnal ratio in SLW, expressed significant differences among and within most groups of progenies and parental clones. All seed and seedling vigor characteristics, except RQ values, responded primarily to the nonadditive type of gene action. This suggests that the plant breeder should design his breeding program to develop varieties where hybrid vigor can be used to advantage. Among the criteria used in this study to measure seed and seedling vigor, ATP content per seed was closely associated with seedling vigor index and with certain plant characteristics, including forage yield per plant. The associations of seed weight with other seed and seedling vigor characteristics were negative or poor. Most plant characteristics showed apparent hybrid vigor when progenies were compared with their respective mid-parents. With few exceptions, most plant characteristics, stolon, petiole, leaf and forage yield per plant, responded primarily to the nonadditive gene system. This indicated that the plant breeder may use the hybrid approach to white clover variety development. The exceptions were leaf ratio and SLW which responded primarily to additive gene action, and area and dry weight per leaf appeared to respond equally to additive and nonadditive gene action. Genetic differences were more readily identified for stolon number and length when measurements were taken after 70 days of growth. Yield components, such as number, length, and diameter of stolon, petiole length, number of leaves per plant, and dry weight per leaf were closely related to each other. The leaf components of yield, dry weight per leaf and number of leaves per plant, had the highest direct and indirect effects on forage yields per plant among the yield components. This study showed nonadditive gene action primarily responsible for most seed and plant characteristics. Considering the ease of vegetative propagation in this species along with the self-incompatibility, mechanisms, it is suggested that parent geneotypes may be developed by some recurrent selection procedure, then crossed on a two clone synthetic basis to form experimental lines for testing purposes. Close

• 2. [Article] An evaluation of creeping habit in various progenies of red fescue (Festuca rubra L.)

  Thirty-three genotypes of red fescue were selected on the basis of diverse origin, anthesis date, and type of spreading from a space-planted introduction nursery. Open-pollinated, single-cross, and top-cross ...

  Citation × Citation Citation Abstract Copy Title: An evaluation of creeping habit in various progenies of red fescue (Festuca rubra L.) Author: Kim, Dal Ung Thirty-three genotypes of red fescue were selected on the basis of diverse origin, anthesis date, and type of spreading from a space-planted introduction nursery. Open-pollinated, single-cross, and top-cross progeny nurseries were established into a randomized block with four replications, 20, 9, 8 entries, respectively, with nine plants per entry on two foot centers. Measured characteristics were plant height, plant width, and seed yield per plant. A polycross progeny row test nursery was established in a randomized block with eight replications in which 17 entries were assigned with rows 10 feet long. Measured characteristics for this progeny test were panicle length, number of branches per panicle, 100-seed weight, 20 panicles seed yield, and seed yield per row. Single-cross and top-cross progenies were compared with their mean open-pollinated progeny performance, respectively. The association between characters for various progeny testing methods was measured by simple correlation coefficients. The creeping type parents resulted in progenies with greater width, height, and seed yield per plant than the non-creeping type when the open-pollinated progeny test was used. Associations between height, width, and seed yield in open-pollinated progeny were positive and significantly correlated with each other. The behavior in the open-pollinated progeny for seed yield was similar to the polycross progeny row test. For these three characters, clonal selection of parents may be effective. In the single-cross progeny, the single-cross between creeping and creeping was greater than any other combination for plant width and seed yield. Frequently there was no significant difference between combinations of crosses and among entries. In the top-cross progeny, the creeping type crossed with the non-creeping tester was the greatest in width and seed yield. For all three characters, the creeping type crossed with the non-creeping tester and the non-creeping type crossed with the creeping tester were greater than any other combination. The open-pollinated progeny of the creeping tester genotype was always greater than the open pollinated progeny of the non-creeping tester genotype. In the comparison of the top-cross with their mean open-pollinated progeny, the behavior of the top-cross progeny was quite different from their mean open-pollinated progeny for all characteristics. The top-cross method was desirable for the study of general and specific combining ability. The study would suggest that genotypes can be quickly identified by using the top-cross progeny test with a non-creeping tester. In the polycross progeny row test the creeping types which came from two isolations were greater than the non-creeping types for all five measured characteristics. Associations between the five characteristics were positive and significantly correlated except the correlation between 100-seed weight and seed yield per row. Title: An evaluation of creeping habit in various progenies of red fescue (Festuca rubra L.) Author: Kim, Dal Ung Thirty-three genotypes of red fescue were selected on the basis of diverse origin, anthesis date, and type of spreading from a space-planted introduction nursery. Open-pollinated, single-cross, and top-cross progeny nurseries were established into a randomized block with four replications, 20, 9, 8 entries, respectively, with nine plants per entry on two foot centers. Measured characteristics were plant height, plant width, and seed yield per plant. A polycross progeny row test nursery was established in a randomized block with eight replications in which 17 entries were assigned with rows 10 feet long. Measured characteristics for this progeny test were panicle length, number of branches per panicle, 100-seed weight, 20 panicles seed yield, and seed yield per row. Single-cross and top-cross progenies were compared with their mean open-pollinated progeny performance, respectively. The association between characters for various progeny testing methods was measured by simple correlation coefficients. The creeping type parents resulted in progenies with greater width, height, and seed yield per plant than the non-creeping type when the open-pollinated progeny test was used. Associations between height, width, and seed yield in open-pollinated progeny were positive and significantly correlated with each other. The behavior in the open-pollinated progeny for seed yield was similar to the polycross progeny row test. For these three characters, clonal selection of parents may be effective. In the single-cross progeny, the single-cross between creeping and creeping was greater than any other combination for plant width and seed yield. Frequently there was no significant difference between combinations of crosses and among entries. In the top-cross progeny, the creeping type crossed with the non-creeping tester was the greatest in width and seed yield. For all three characters, the creeping type crossed with the non-creeping tester and the non-creeping type crossed with the creeping tester were greater than any other combination. The open-pollinated progeny of the creeping tester genotype was always greater than the open pollinated progeny of the non-creeping tester genotype. In the comparison of the top-cross with their mean open-pollinated progeny, the behavior of the top-cross progeny was quite different from their mean open-pollinated progeny for all characteristics. The top-cross method was desirable for the study of general and specific combining ability. The study would suggest that genotypes can be quickly identified by using the top-cross progeny test with a non-creeping tester. In the polycross progeny row test the creeping types which came from two isolations were greater than the non-creeping types for all five measured characteristics. Associations between the five characteristics were positive and significantly correlated except the correlation between 100-seed weight and seed yield per row. Close