Indigenous Strains of Rhizobia and Their Performance in Specific Regions of India

Abstract

The production and application of biofertilizers for leguminous crops, oilseeds, rice, millets, and other important crops (besides forest nursery plants) are very common in India. Currently, more than 95 firms belonging to public and private sectors are involved in the production of biofertilizers, with the annual capacity of 18,000 metric tons (out of which substantial amount is accounted as Rhizobium) against the total potential demand of 3.4×105confirmed metric tons. Rhizobium is one of the important nitrogen-fixing bacteria, helping the legumes to maintain soil fertility by means of their symbiotic association and nitrogen fixation. Besides the efforts taken by the government and research institutions and agricultural universities, rhizobial technology has still a long way to go to obtain maximum benefit. This may be due to the varied reasons which limit the usage of the inoculant. However, the most important difficulty lies in the performance of the inoculated strain of rhizobia. This problem may be solved by using appropriate strains of rhizobia, i.e., crop/variety-specific, location-specific, and soil-specific, to be properly isolated and screened for effectiveness in nitrogen fixation. Still, variations among the local strains is possible and is evidenced through field experiments conducted at different locations in India. Some strains performed better than the best local strains, though they originated under different agroecological conditions. However, in most cases, the best performing strain in one location did not differ significantly at other locations tested. confirmed.