NITRATE INHIBITION ON N2 FIXATION IN CHICKPEA (CICER-ARIETINUM L) - VARIABILITY DUE TO RHIZOBIAL STRAINS

Effect of 10 mM NO3- treatment for one week on chickpea - Rhizobium symbiosis established by 4 different rhizobial strains was studied at 50 day stage of plant growth under controlled conditions. The NO3- treatment inhibited specific activity of nitrogenase by 99.7, 90.9, 62.2 and 52.2% in nodules formed by strains, G 10-81, F 75, BG 4 and F 6, respectively. Based on relative efficiency of N2 fixation and biomass accumulation, the study suggested the possibility of selecting rhizobial strains forming symbiosis which is less prone to NO3- inhibition.