The present study was aimed at the isolation of nitrogen fixing bacteria belonging to genus Azospirillum from wild wheat and their growth promoting effect on the bread wheat, under pot culture and filed conditions in semi-arid environment. Two bacterial strains were obtained on the NFb (N-free malate medium) medium with ability to produce phytohormone (indoleacetic acid; IAA) and fix atmospheric nitrogen. Based on 16S rRNA sequence analysis, one isolate (Sp1) showed 99% homology with Azospirillum brasilense and the second isolate (Sp2) showed 99% homology with Azospirillum zeae. Effect of these two isolated strains on bread wheat was examined under pot experiment. Both bacterial strains were found to be effective in enhancing wheat growth. However, best results were obtained with isolate Sp2. Therefore, only this strain was introduced as inoculum in field experiment, to investigate its effect on wheat yield under semi arid conditions during winter growing season 2016–2017. Based on the obtained field results, wheat inoculated with isolate Sp2 displayed an increased total grain yield by up to 18% as compared to un-inoculated plants. These results show the potential of these bacteria to be used as biofertilizer.
