Enrichment of Restraint to Endmost Salinity and Outmost pH Circumstance in Common Bean (Phaseolus vulgaris L.) Nodulating Rhizobial Isolates from Eastern Hararghe Lowlands around Babile, Eastern Ethiopia, through Mutagenesis.

This study was committed to examining the symbiotic efficacy difference between wild and mutant rhizobial isolates from lowlands of eastern Ethiopia around Babile, and at the same time to appreciate the enrichment effect of mutagenesis on restraint of common bean (Phaseolus vulgaris L.) nodulating rhizobia to Endmost Salinity and Outmost pH Circumstance. A total of 50 wild rhizobia isolate, and 8 mutant isolates; after mutagenesis were selected based on their ability to endure endmost salt and outmost pH circumstances at laboratory condition. All of the mutants were found to be symbiotically effective. Among the observed rhizobium isolates, wild isolates HUCR (3D, 3A), HUCR 2D, and mutant isolate HUCRM 2D showed the highest symbiotic efficacy. Only the mutant isolates HUCRM2D (tolerated 12% NaCl, and pH4 and pH12), HUCRM5C (tolerated 12% NaCl and pH 4), HUCRM3B (tolerated 12% NaCl) and HUCRM9C (tolerated 11% NaCl) were growing effectively at the point out utmost conditions. Therefore, based on their restraint to utmost conditions and symbiotic efficacy, the above mentioned wild and mutant rhizobia isolates were suggested as nominees for the future development of common bean biofertilizer that grown under endmost saline and outmost pH conditions.