Genetic studies in interspecific crosses of soybean Glycine max (L.) merill. x Glycine formosona. III. selection indices

The selection indices by discriminant function analysis were constructed based on the data of a population of 1600 F₂ plants developed by crossing a wild species, Glycine fonnosona, with five cultivars of G. max. Majority of selection indices were found to be more efficient than straight selection based on yield alone. The selection index consisting of seed yield, pods/plant, seed weight, and oil content gave the highest relative efficiency, followed by the index consisting of seed yield, pods/plant and seed weight. Inclusion of pods/plant in selection index appears to increase its relative efficiency. The efficiency of the index improved with increase in the number of characters up to four, after which it decreased.