Abstract
SUMMARY: Azospirillum brasilensewas treated with nitrosoguanidine and two mutants isolated which were resistant to 500 μg streptomycin/ml. Ultraviolet sensitivity, photoreactivation and effect of acriflavin on pre- and post-irradiation were studied. Chick pea showed an increase in grain yield, nodule dry weight, N2ase activity and active iron content of nodules when inoculated withA. brasilenseor its mutants together withRhizobium. The interaction betweenRhizobiumstrains and genotypes of chick pea was significant.