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Genetic Variation Among And Within S1 Progenies Of Maize, R. J. Getschman, A. R. Hallauer
Genetic Variation Among And Within S1 Progenies Of Maize, R. J. Getschman, A. R. Hallauer
Journal of the Iowa Academy of Science: JIAS
Inbred line development consumes a great portion of the breeder's time and resources in maize (Zea mays L.) breeding programs. Source populations for line development often are developed by selfing F2 populations developed from elite line crosses. Visual selection is practiced among and within selfed progenies during the selection process for one or two generations before evaluated in testcrosses for combining ability. Effective discrimination among and within inbred and testcross progenies depends on the amount of genetic variation present. The objective of this study was to determine the effectiveness of selection among and within S1 progenies developed from crosses …
Hybrid Performance Of Sorghum Parental Lines Developed By Mass Selection And S1 Yield Testing, K. R. Ess, R. E. Atkins
Hybrid Performance Of Sorghum Parental Lines Developed By Mass Selection And S1 Yield Testing, K. R. Ess, R. E. Atkins
Journal of the Iowa Academy of Science: JIAS
Experiments were conducted co obtain information on the effects of two methods of developing parental lines from a random-mating population of sorghum (Sorghum bicolor L. Moench) on hybrid performance. Gridded mass selection for threshed panicle weight was used in developing IAP1R(M)C3: and a sister population, IAP4R(S1)C3, was advanced each cycle on the basis of grain yield of S1 families in replicated yield trials. Hybrids with male parents developed by mass selection did not differ significantly for grain yield and panicles/plant from those with parents chosen on the basis of S1 yield tests. The S1-selection hybrids …
Estimates Of Genetic Variability In F2 Maize Populations, Geng-Chen Han, A. R. Hallauer
Estimates Of Genetic Variability In F2 Maize Populations, Geng-Chen Han, A. R. Hallauer
Journal of the Iowa Academy of Science: JIAS
Maize (Zea mays L.) breeders emphasize selection within F2 populations derived from crosses of inbred lines: Studies of the inheritance of quantitative traits in maize have been conducted primarily for generically broad-based populations. Objectives of our study were to estimate the generic variability in F2 populations developed from crosses of related and unrelated lines and to determine the effects of five generations of random intermating of plants within F2 populations on the estimates of genetic variability. Estimates of additive genetic variability were greater in the unrelated line crosses, but the estimates were not significantly different before and …