Аннотация:Synopsis Studies of 3 populations of F 2 families in the F 3 and F 4 generations grown at 2 locations revealed the following factors: genotype year interactions relatively large; seed yield generally more heritable than total yield; heritability of vigor lower for scores on July 1 than those on Aug. 15; and exceptionally low genetic coefficient of variation and heritability of vigor scores for the population segregating for procumbency.