Genetic variability and selection indices for improving seed yield in soybean (Glycine max L. Merrill)

Variability and selection indices were studied involving 100 germplasm lines of soybean. High heritability was accompanied by high genetic advance and moderate to high GCV observed for all the characters under consideration, indicating the possibility of improving these traits through selection. Discriminant function analysis indicated that almost all the selection indices were found to be more efficient than straight selection based on seed yield alone. Selection efficiency of the function was improved by increasing number of characters in the index. The index consisting of all the six traits gave the highest genetic gain and selection efficiency. Inclusion of pods per plant in selection index appears to increase its relative efficiency. For practical view point, the selection index based on four characters, viz., clusters per plant + pods per plant + biological yield per plant + harvest index, is recommended for yield improvement in soybean.