Effect of Growth Habit on Yield Components of Late‐Planted Soybean

Abstract

Late‐planted soybean [Glycine max (L.) Merr.] yields are usually lower than full‐season soybean yields. Indeterminate growth habit may be superior to the traditional determinate growth habit for late planting in the southeastern USA. The objective of our study was to determine the effect of determinate and indeterminate growth habit genes on yield components of late‐planted near‐isogenic fines of soybean. Twenty‐three determinate and 23 indeterminate near‐isogenic lines (near‐isolines) of soybean from three populations were compared in the field at Brewton, Tallassee, and Shorter, AL, in 1991 and 1992. Determinates had lower lowest‐pod heights, more mainstem branches per plant, and more two‐seeded pods than indeterminates. Growth habit did not affect total pods per plant, mainstem or branch pods per plant, seeds per plant, seed mass, or number of three‐seeded pods per plant. The growth habit × population and growth habit × location interactions were significant for most traits, but the growth habit × year interactions were nonsignificant or small. Number of mainstem pods was the only yield component correlated with yield (r = 0.36**). We conclude that (i) growth habit genes have little consistent effect on most yield component traits, (ii) growth habit effects are site‐ and population‐specific in the southeastern USA, and (iii) seed yield is not correlated with yield component traits in late‐planted soybean.