Effects of Some Qualitative Genes on Soybean Performance in Late-Planted Environments
- P. L. Raymer and
- R. L. Bernard
Researchers have suggested that cultivars adapted specifically to double-crop environments should be developed. Little information is available concerning what plant traits are advantageous in these environments. Sets of near-isogenic lines (isolines) of soybean [Glycine max (L.) Merr.] can be used to evaluate specific plant traits without the confounding effects of different genetic backgrounds. Isolines in ‘Harosoy’ and ‘Clark’ genetic backgrounds that possess genes controlling maturity and stem morphology were grown in conventional and in late-planted environments at Urbana, IL in 1980, 1981, and 1982. The isolines tested provided a wide range of maturities and stem lengths, and produced wide differences in yield at both planting dates. Gene combinations that produced maturities of 96 to I01 d in the late environment were among the highest yielding in both environments. The Dt2 S gene combination, which conditions for semideterminate stem growth and shortened internodes, significantly increased yields in both environments in the later maturing backgrounds. Isoline ✕ planting date interactions were small and nonsignificant in the combined analysis over years. Thus, the genes tested conferred no more of a yield advantage in a late-planted environment than they did in a conventional early-planted environment. No evidence was found that any of these traits imparted specific adaptation to late planting. However, the improved performance in both planting times imparted by Dt2 and S is of interest.
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