Potential for narrow leaves in vogetable-type soybeans.

Abstract

The purpose of this study was to determine advantages and disadvantages of the narrow leaf trait in vegetable-type soybeans and to study the effects of narrow leaves on factors associated with seed yield. Six pairs of narrow and broad leaf genotypes were studied in 1982, and a different set of six pairs of near isogenic lines differing in leaf shape were studied in 1983. No significant differences in seed yield were observed between leaf shape types in 1982 or in 1983. In 1983, narrow leaf types had 8% more seeds per pod but 6% smaller seed. These differences cancelled each other resulting in the same weight of seeds per pod. Therefore, there was no advantage for either leaf shape types for seed yield or hand-shelling efficiency. In both years, narrow leaf genotypes had a significantly lower leaf area index (LAI) at the vegetative stage, but not at the reproductive stage. At growth stage V7-V9, LAI of narrow leaf types was significantly (14%) less, but at growth stage R4-R5 LAI was only 7% less and the difference was not statistically significant. The smaller percentage difference at R4-R5 apparently resulted from narrow leaf types retaining 11% more leaflets on the stem, as a result of better light distribution throughout the canopy.