Agronomic traits and genetic parameters in vegetable soybean evaluated in Puerto Rico

In tropical regions of the Western Hemisphere, consumption of high-protein soybean [Glycine max (L.) Merr.] could improve the human diet. It would be necessary however, to develop adapted cultivars of appropriate seed size. T he objectives of this study were to estimate heritability and phenotypic an d genotypic correlations of agronomic traits, and to compare agronomic and reproductive traits of soybeans grown at different planting dates in Puerto Rico. Eighty-nine F-4:5 individual plants from the cross of IAC-8 [Maturit y Group (MG) IX, not adapted for human consumption, and intermediate seed s ize] x Kanto-101 (MG III, large-seeded cultivar developed for human consump tion), the parents, and checks were planted in December 1992. F-4:6 lines w ere evaluated in replicated tests in June and August 1993. Dates of full bl oom (R2), of full seed (R6), and of full maturity (R8), plant height, pod w idth, and 100-seed weight were recorded. On an entry-mean basis, heritabili ty values of all traits were moderately high (0.56) to high (0.96). Phenoty pic and genotypic correlations ranged from zero to high (0.96). Rank correl ations were moderately high, positive and significant, ranging from 0.41 to 0.79. In general for all traits, genotypes selected in the top 10% in the plantings of June and August, on the basis of entry means, would also have been selected as individual plants in the December planting. These results suggest that in the tropics genotypes may be selected in different planting seasons within the year, initially on the basis of individual plant perfor mance, and later in replicated experiments.