Heritability and Advance from Selection for Six Soybean Seed‐quality Characters1

Abstract

Seed harvested from F3, F5, and F6 lines of six soybean [Glycine max (L) Merr.] crosses were evaluated for field emergence percentage and visually rated for defective seedcoat, wrinkled seedcoat, shriveled cotyledons, green cotyledons, and overall appearance. Correlations between field emergence percentage and the visually rated characters were low, although low incidence and severity of the visually rated characters were generally associated with high field‐emergence percentages. The overall rating generally was equal to any other rating as an indicator of relative field emergence.Heritability estimates for field‐emergence percentage were low, due to low genetic variability for the character in the F5 and F6 generations and to the large error associated with estimating the field emergence potential of a seed lot. Estimates of heritability for the visual ratings generally were higher than for field emergence, with heritability of green cotyledons usually being lower than the other visually rated characters.Selecting for high field‐emergence percentage resulted in no significant advance for the character. Advances from selection were somewhat higher for the visually rated characters. The results of this and previous studies suggest that the most efficient means of improving soybean seed quality in a breeding program is to use an overall visual rating and a laboratory germination test in which normal seedlings are counted early in the germinating period, probably at 5 days. An alternative method is to concentrate on improving visually rated characters by selection when environmental conditions cause adequate expressivity.