Isolation and characterization of Azospirillum strains from rainfed areas of Raichur district of Northern Karnataka, India

Azospirillum spp. strains were isolated from the root bits of sorghum grown in forty different locations in Raichur district of northern Karnataka. Based on the morphology of the cells, gram reaction and biochemical characteristics, 40 Azospirillum isolates were screened for nitrogen fixation. Out of the 40 isolates, 28 were identified as A. lipoferum and remaining 12 as A. brasilense. The distribution and characterization of these strains varied with soil characteristics and environmental factors.