Heritable and Nonheritable Relationships and Variability of Oil Content and Agronomic Characters in the F2 Generation of Soybean Crosses 1

OECENT studies on quantitatively inherited characters in '••-plants and animals have been directed toward the separation of their phenotypic expression into genetic and environmental portions. Information concerning heritability of quantitatively inherited attributes and their associated genetic and environmental variances and co-variances may be useful as a tool for improving the efficiency of selection in segregating populations. These components of variation have been modeled mathematically and the models actually applied to segregating and nonsegregating populations. It has been shown mathematically that the expected variance ol: any nonsegregating population is environmental variance; thus, total variance of a segregating population would be genetic variance plus environmental variance. By "genetic variance" is meant the effects of additive action of the genes concerned, while "genotypic variance" includes, in addition to genetic variance, the variance largely due to dominance and epistasis. In a discussion of heritability of characters in animals, Lush (1) defines heritability and describes its usage in both the broad and narrow aspects. In the broad sense heritability refers to the functioning of the whole genotype as a unit and is used in contrast with environmental effects. In the narrow sense heritability largely includes only the average effects of genes transmitted additively from parent to progeny. Griffmg, in a study on tomatoes, calculated the components in analyses of variances and covariances of nonsegre-