Effect of azide resistant mutants of Azotobacter chroococcum on yield and nitrogen content in two cotton genotypes

摘要

Seventeen azide resistant mutants were isolated from six strains (103, HT-54, HT-54, 10P, E-12 and MSX 9) of Azotobacter chroococcum. All the parent strains were tested for their minimal inhibitory concentration (MIC) by growing cells in liquid medium containing different concentrations of sodium azide (5 mu gml~1 to 200 mu gml~1). The strains showed different MIC values indicating that the resistance pattern varied with each individual strain. These azide resistant mutants were assessed for theirperformance on two cotton cultivars- Gossypium hirsutum var. H-117 and Gossypium herbaceum var. HD-123 under pothouse conditions for various plant parameters. Inoculation of cotton seed with Azorobacter mutants showed better results than inoculation withtheir respective parental strains. Azide resistant mutants showed increased plant height, early flowering, more yield, high biomass and high total nitrogen content. Better performance by these mutants might be due to high indole acetic acid, ammonia excretion and high nitrogenase activity.