Abstract
Standard unit heritabilities for grain yield of common bean (Phaseolus vulgaris L.) were determined for F2‐derived F4 and F5 progenies and for F2 individual plants and their F3 progenies of three common bean crosses. Standard unit heritabilities were determined by correlating F2‐derived F4 line grain yields with F2‐derived F5 line grain yields. Heritabilities were determined for direct selection (F4 and F5 lines in the same cropping system) and indirect selection (F4 and F5 lines in different cropping systems). Selection gains were also estimated for direct selection, indirect selection, and for selection based on the means of both systems. Parent‐offspring genotypic correlations were determined for the F2‐derived F4 and F5 progenies. Standardized correlated responses to selection for grain yield based on selection for harvest index were estimated for F2 individual plants. Standard unit heritabilities were larger in intercrop than in sole crop. The difference in heritability between cropping systems was larger for F2 plants than for the F2‐derived F4 progenies. Direct selection in intercrop and sole crop was always superior to indirect selection in the alternate cropping system. Indirect selection in intercrop for sole crop gave the lowest gains. Direct selection in intercrop or in sole crop gave the highest genetic gains in each respective cropping system. Selection on the mean of both systems gave gains in each system almost as high as those of direct selection. Selection in sole crop for improvement in the mean of both systems resulted in lower gains than selection on the mean of both systems, but was better than selection in intercrop. Standardized correlated responses in grain yield by selection for harvest index were larger in intercrop than in sole crop. Single plant selection for yield may be effective for beans which are intercropped.
Published Version
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