Selection for Caryopsis Percentage in Oats1

Abstract

Three populations of oats (Avena saliva L.) were developed to study caryopsis percentage, the proportion of whole kernel that is caryopsis. Information was obtained on the heritability of the character, the relative importance of component changes in effecting changes in caryopsis percentage, and the relationship of the character to other important agronomic characteristics. F2‐derived F4 families were grown in the field in 1970 and bi‐directional selection was practiced for caryopsis percentage. A group of random lines also was used to provide an estimate of the unselected population mean. Selected and random lines were evaluated at two locations in 1971. Effectiveness of selection was measured by comparing selected with random line means. Realized heritability estimates were calculated for caryopsis percentage, and correlated responses were calculated for several important agronomic traits. Selection for caryopsis percentage was effective in all three populations. Differences in the magnitude of response among populations agreed well with theoretical expectations. Small but significant genotype × location interactions were detected. Realized heritability estimates for caryopsis percentage ranged from 0.34 to 0.72, all statistically significant. Genetic variability for caryopsis percentage was considerably reduced by a single cycle of selection. Progress in selection for caryopsis percentage could be attributed to changes in either caryopsis weight or hull weight or to changes in both. Correlated responses of agronomic characters were not consistent across populations and were not of sufficient magnitude to be a serious consideration when selecting for high caryopsis percentage.