Isolation and biochemical characterization of native rhizobium species

The present study was aimed to isolate the beneficial nitrogen fixing Rhizobium from root nodules of Green gram (Vignaradiata) plant. Root nodules of legume plant were alsocollected from different rhizospheres. Isolation of Rhizobium was done from root nodules on YEMA medium (selective media). One hundred thirteen strains were characterized by biochemical assay. Morphological studies of all the strains were performed. Out of 113 strains 86 isolates were fast growing indicated by white and pink coloured colonies of rhizobia. They were producing gummy colonies on YEMA after 2 days of incubation, at 37°C. All strains were gram-negative, rod shapedand capable of producing poly hydroxyl butyrate. All strains utilized glucose, mannitol,and lactose as fermentation sugar. The isolates from present study may be useful to increase the symbiotic nitrogen fixation in legume plants.