Inheritance of Harves Index and Related Traits in Oats1

Abstract

Harvest index of cereals is the ratio of grain to total plant yield. Harvest index and its components, plant weight and grain yield, and heading date, plant height, and 100‐seed weight, were studied in 15 crosses among 30 oat (Arena sativa L.) lines. F2‐derived lines from each cross, parents, and 10 check cultivars were tested in hill plots in 3 experiments. One experiment contained F2 derived lines tested in both F3 and F4, enabling direct comparisons between the two generations.Dominance was not of major importance in the inheritance of heading date, plant height, and 100‐seed weight. These traits showed small deviations of cross means from midparental values, little change of means and variances from F3 to F4, and no appreciable skewness. Plant weight and grain yield showed substantial dominance, as indicated by large deviations of cross means from mid‐parental values, large reductions in means and variances from F3 to F4 and negative skewness. Harvest index showed primarily additive gene action, although this conclusion was complicated by the occurrence of negative skewness. Crosses between parents that were both high in harvest index tended to show small phenotypic variation for harvest index and other traits.