Competitive ability, effectiveness, and succinate – triphenyl tetrazolium chloride reductase activity of mutant strains of chick-pea (Cicer arietinum L.) Rhizobium sp.

Abstract

Chick-pea Rhizobium strain RG 4 was treated with 200 μg/mL of N-methyl-N-nitro-N′-nitrosoguanidine and 14 mutant strains isolated. Two mutant strains were found to be nonnodulating in the absence of certain amino acids. On the basis of nodulation, two mutant strains (M 38 and M 46) were found to be equally competitive against each other. Mutant strains M 38 and M 46 when applied together produced the maximum nodulation, nitrogenase activity, phenanthroline-reactive iron, and least tetrazolium reductase activity as compared to other pairwise combinations of mutant strains. It was also observed that the correlation between tetrazolium reductase and nitrogenase activity was highly negative.