Competitiveness and effectiveness of carbendazim-resistant mutant and indigenous Rhizobiumstrains of chick pea (Cicer arietinutnLinn.) in calcareous soil

Abstract

SummaryChick pea Rhizobiumstrain RG 4 was treated with 30 /tg/ml of N-nitrosoguanidine and four mutants isolated were resistant to 400 /tg carbendazim/ml. Only two of the mutants (M 1 and M 4) retained the capacity to form nodules. On the basis of number of nodules, their dry weight, nitrogenase activity, triphenyl tetrazolium chloride reductase activity and active iron content of nodules, mutant strains M 1 and M 4 were found to be equally effective for nitrogen fixation both with and without carbendazim (bavistine) and resulted in significantly greater grain yield than the corresponding uninoculated treatments.