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• 1. [Article] The breeding behavior of forage yield in two populations of tall fescue, (Festuca arundinacea, Schreb.)

  The single-cross and most F₂ progenies of 19 genotypes of tall fescue (Festuca arundinacea, Schreb. ) were used to study the breeding behavior of forage yield. Parental genotypes were selected for high ...

  Citation × Citation Citation Abstract Copy Title: The breeding behavior of forage yield in two populations of tall fescue, (Festuca arundinacea, Schreb.) Author: Matheson, Keith Isom The single-cross and most F₂ progenies of 19 genotypes of tall fescue (Festuca arundinacea, Schreb. ) were used to study the breeding behavior of forage yield. Parental genotypes were selected for high self-sterility, high chromogen and high crude protein. These were studied in two groups of nine intermediate and ten late-flowering genotypes. Progenies were grown on the Hyslop Agronomy Farm, Corvallis, Oregon as plants spaced one foot apart with three feet between rows. Ten plants of each cross for each generation were arranged in a randomized block design with four replications. Variables measured were plant width, natural plant height, plant spread, leaf length, total plant height of regrowth tissue, plant density and forage yield. The collected data were converted to plant means. Broad- and narrow-sense estimates of heritability were obtained from expected mean squares according to Griffing's analysis (random model, method four) and compared with estimates of heritability obtained by F₂-single-cross regression. General and specific combining ability effects were observed and the single-cross-F₂ inbreeding depressions were studied. The F₂ families were obtained by the self-pollination of five single-cross plants. General combining ability mean squares averaged from two to nine times greater than the mean squares for specific combining ability, with the largest difference being 54.7 times greater. The two populations responded similarly for the variables measured except for total plant height and plant spread. Greater progress from selection could be expected in the late- maturing group with the exception of these two traits. In most cases, single-cross progenies performed better than their corresponding F₂ progenies. The average of all single-crosses differed from the average of all F₂ progenies in 12 of 20 analyses in 1963, but in only 2 of 12 in 1964. The inbreeding characteristic was most pronounced for forage yield. High-performing single-crosses for the traits studied tended to produce high-performing F₂ progenies. Little or no heterosis was expressed and the expression of inbreeding depression appeared to be influenced greatly by the environment. Heritability estimates indicated that most traits could be studied more effectively after the second year of plant establishment. The environmental influence appeared to be less pronounced at that time. Where the coefficient of determination was high between the single-cross and F₂ generations, traits were less influenced by the environment and the disparity between the estimates of heritability was less. When used on cross-pollinated polyploid grasses, the method of diallel analysis proposed by Griffing does not appear to remove all environmental influence and thus overestimates heritability. Forage yield in the two populations of tall fescue studied was governed principally by additive gene action. Heterosis expressed was mostly in crosses involving low-performing parents. Title: The breeding behavior of forage yield in two populations of tall fescue, (Festuca arundinacea, Schreb.) Author: Matheson, Keith Isom The single-cross and most F₂ progenies of 19 genotypes of tall fescue (Festuca arundinacea, Schreb. ) were used to study the breeding behavior of forage yield. Parental genotypes were selected for high self-sterility, high chromogen and high crude protein. These were studied in two groups of nine intermediate and ten late-flowering genotypes. Progenies were grown on the Hyslop Agronomy Farm, Corvallis, Oregon as plants spaced one foot apart with three feet between rows. Ten plants of each cross for each generation were arranged in a randomized block design with four replications. Variables measured were plant width, natural plant height, plant spread, leaf length, total plant height of regrowth tissue, plant density and forage yield. The collected data were converted to plant means. Broad- and narrow-sense estimates of heritability were obtained from expected mean squares according to Griffing's analysis (random model, method four) and compared with estimates of heritability obtained by F₂-single-cross regression. General and specific combining ability effects were observed and the single-cross-F₂ inbreeding depressions were studied. The F₂ families were obtained by the self-pollination of five single-cross plants. General combining ability mean squares averaged from two to nine times greater than the mean squares for specific combining ability, with the largest difference being 54.7 times greater. The two populations responded similarly for the variables measured except for total plant height and plant spread. Greater progress from selection could be expected in the late- maturing group with the exception of these two traits. In most cases, single-cross progenies performed better than their corresponding F₂ progenies. The average of all single-crosses differed from the average of all F₂ progenies in 12 of 20 analyses in 1963, but in only 2 of 12 in 1964. The inbreeding characteristic was most pronounced for forage yield. High-performing single-crosses for the traits studied tended to produce high-performing F₂ progenies. Little or no heterosis was expressed and the expression of inbreeding depression appeared to be influenced greatly by the environment. Heritability estimates indicated that most traits could be studied more effectively after the second year of plant establishment. The environmental influence appeared to be less pronounced at that time. Where the coefficient of determination was high between the single-cross and F₂ generations, traits were less influenced by the environment and the disparity between the estimates of heritability was less. When used on cross-pollinated polyploid grasses, the method of diallel analysis proposed by Griffing does not appear to remove all environmental influence and thus overestimates heritability. Forage yield in the two populations of tall fescue studied was governed principally by additive gene action. Heterosis expressed was mostly in crosses involving low-performing parents. Close