nifH gene diversity and symbiotic effectiveness of Bradyrhizobium yuanmingense strains obtained from nodules of soybean cultivated in India.

Restriction fragment length polymorphism (RFLP) of nifH gene with three endonucleases revealed three different nifH genotypes among twenty one indigenous Bradyrhizobium yuanmingense strains. The interactive symbiotic effectiveness on soybean cv. JS335, nodulation and plant growth of these B. yuanmingense strains were comparatively evaluated with B. japonicum ASR011 under greenhouse conditions. Significant variation in symbiotic potential among native B. yuanmingense strains was observed and few of them exhibited significantly superior symbiotic performance over B. japonicum ASR011 and B. yuanmingense CCBAU 61071 type strain. A considerable difference in nitrogen-fixing characteristics was detected among B. yuanmingense strains which shared identical nifH gene sequence. This, to our knowledge, is the first study on symbiotic effectiveness of B. yuanmingense strains obtained from nodules of soybean cultivated in India. The symbiotically efficient B. yuanmingense strains may have applications in the formulation of appropriate inocula to improve soybean crop yield in Indian soils. [ABSTRACT FROM AUTHOR]