Symbiotic N fixation of several soybean varieties and mutants

Symbiotic N fixation of several soybean varieties and mutants. Research activities comprising of three experiments were carried out to screen several soybean varieties and mutants for symbiotic N fixation potential. Depending on the medium used, plant response to strains was different. In sterile medium, Rhizobium strain USDA 136, 142 and TAL 102 showed a high nitrogen potential. In soil only Rhizobium strain USDA 110 had better performance and proved to be competitive to the native strains. Nitrogen-15 dilution method was used to screen nitrogen fixing ability of several soybean varieties and mutants. Guntur variety showed a better response to high dose of N fertilizer without disturbance in its fixing ability. This variety then was considered good to be introduced in the cropping system. (author). 8 refs