Rita Singh and S.K. Kavimandan
Abstract
Fate of four wild strains (ND24, ND43, DN77 and DN9 I) of Rhizobium sp. (Cicer) and their streptomycin and kanamycin resistant mutants (ND24Str, ND43Kan, ND77Str and DN9 I Kan) in the rhizosphere of chickpea cv. BG 256 was investigated. Nodulation-the phenotypic expression of symbiosis of Rhizobium- chickpea plants, the nitrogenase activity of root nodules and the consequent gain in biomass and nutrient absorption was recorded. Nodule occupancy varied between 30 to 73%. A positive correlation (r=0.684) between nodule occupancy and rhizosphere competence of wild and genetically modified strains was observed at six week stage of plant growth. Acquisition of streptomycin resistance in Rhizobium sp. (Cicer) strains ND24 str and ND77Str did not alter the symbiotic properties. Resistance to kanamycin was associated with both positive (ND43Kan) and negative (DN9 I Kan) changes in the symbiotic efficiency.