Genetic Assessment of Combining Ability for Seed-Yield and Its Related Traits in Soybean [Glycine max (L.) Merrill]

Crosses were made in line × tester mating design between a set of five IITA soybean released varieties and three plant introduced (PI) accessions obtained from World Vegetable Center, Taiwan. In order to produce sufficient seeds, F1 crosses were selfed, subsequently F2 populations along with their parents were planted in a randomized complete block design at two locations in Nigeria with three replications. Agronomic traits viz. days to flowering, days to poding, plant height, number of pods/plant and seed yield/plant were measured. Testers and lines showed significant differences for all the measured traits except days to flowering for testers. Considering the significance and magnitude of general combining ability (GCA) effect, line TGx 1988-5F was observed desirable for earliness, while line TGx 1989-19F was the best combiner for number of pods/plant and seed yield/plant. On the other hand, best tester for seed yield was PI 230970. Crosses TGx 1835-10E × PI 459025B and TGx 1987-62F × PI 459025B had significant and highest SCA effect for seed yield/plant. These two crosses appeared to be most promising for soybean yield improvement programme.