Genetic diversity in rhizobial isolates determined by RAPDs

Nine soil rhizobia isolated from different field locations were subjected to RAPD analysis to study the diversity. It was found that Rhizobium isolates from Agricultural Research Station - Aliyar Nagar (ALN 7),Department of Agricultural Microbiology (SOB 1), isolates from TNAU Eastern block field No.36 (EB 36) and Millet Breeding station field: 9 (MBS 19) were clustered together to form cluster 1 followed byRhizobium isolates Millet Breeding station field: 8 (MBS 9), isolates from the Department of Agrl. Microbiology, TNAU 14 and COG 15 belongs to cluster 2 and isolates of Cotton Breeding station fieldNo: 9 (CBS 9) and Aliyar Nagar (ALN 2) formed the fourth cluster. Department of Agricultural Microbiology isolate, COG 15 with TNAU 14 and SOB 1 with Rhizobium ALN 7 were clustered together with more than 50 per cent similarity. Isolate from Cotton Breeding station field No: 12 (CBS 12) was found to have more divergence (>90 per cent) to make the separate cluster. The results indicated that RAPD is a very discriminative and efficient method for differentiating and studying genetic diversity of Rhizobium strains