Zea mays L., corn, selection, testcrosses, breeding methods
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 of related and unrelated lines. Estimates of among-progeny variance were significant and, in all instances, larger than the estimate of within-progeny variance. Additive genetic variance accounted for the genetic variation among progenies of related and unrelated line crosses. Estimates of variability among and within S1 progeny testcrosses were not different from each other and were less than among and within S1 progenies themselves. In this study, it seems that the choice of testers was not appropriate to distinguish combining ability among progenies for both types of crosses, within the precision of this experiment. On the average, 70.7% greater genetic gains would be realized with among S1 progeny selection vs. within S1 progeny selection.
Journal of the Iowa Academy of Science
© Copyright 1991 by the Iowa Academy of Science, Inc.
Getschman, R. J. and Hallauer, A. R.
"Genetic Variation Among and Within S1 Progenies of Maize,"
The Journal of the Iowa Academy of Science: JIAS: Vol. 98:
, Article 6.
Available at: http://scholarworks.uni.edu/jias/vol98/iss3/6