Heritability of Seed‐Filling Period Estimates in Soybean

Abstract

Soybean [Glycine max (L.) Merr.] yield has been positively associated with seed‐filling period, and soybean genotypes have been identified that exhibit significant differences in seed‐filling period. This experiment was conducted to obtain heritability estimates of the seed‐filling period duration based on effective filling period (EFP) and growth stage measurements, to determine the effect of stem termination type on the heritability estimates, and to measure the correlations between seed‐filling period length, and maturity and seed size. Data were collected on four populations in the F2, F2:3, and F2:4 generations from 1983 through 1986 at Lexington, KY on a Maury silt loam (fine, mixed, mesic Typic Paleodalfs) soil. Parent (F2:3)‐progeny (F2:4) regression gave nonsignificant heritability timates for EFP in all four populations (−0.11–0.22), highly significant estimates for duration of the R5 to R7 period in three of the four populations (0.16–0.63), and highly significant estimates all populations for duration of the R1 to R8 period (0.37–0.82). Seed size was rarely correlated with filling‐period duration. For the four populations, maturity was positively correlated with R1 to R8 in three, with R5 to R7 in two, and with EFP in none. Stem termination class did not affect heritability estimates. In populations segregating for stem termination, however, determinate genotypes were preferentially identified as having long R5 to R7 periods. The EFP was not a useful selection criterion in these segregating populations. For the duration of the R5 to R7 period to be a useable selection criterion, selection will need to be performed in separate subpopulations of the different stem termination types with attention being paid to the maturity of the genotypes selected.