Characterization of bacterial strains and their impact on plant growth promotion and yield of wheat and microbial populations of soil

The aim of this research work is to evaluate the potentiality of bacterial strains isolated from rhizosphere of various cropping systems on growth, yield and soil microbial populations at harvest of wheat under pot and field experiments. Bacterial isolates, isolated from rhizosphere of various cropping systems. Morphological, biochemical and molecular characterization of bacterial strains were done. All the bacterial strains were rod shaped and ammonia producers. Most of the strains were Gram’s +ve and showed positive to catalase, VP, MR tests and HCN production. Pseudomonas aeuroginosa showed significantly lowest pH 4.42 of broth and solubilized 160.34 µgml-1 tri-calcium phosphates. Enterobacter sp. produced maximum 27.06 µgml-1 IAA at 100 µgml-1 tryptophan. All the bacterial strains showed >97% similarity with strains already submitted to NCBI Gene bank. Arthrobacter chlorophenolicus and Enterobacter sp. showed maximum and significantly 23.60 and 28.97% plant height in pot and field experiments at 90 days after sowing. Bacillus megaterium caused maximum and significantly 51.45 and 40.47% grain and straw yield, respectively under pot while Serratia marcescens showed 14.78 and 17.04% grain and straw yield in field as compared to control. Most of the strains showed significant effect on microbial populations of post harvest soil under pot and field. It was concluded that A. chlorophenolicus, Enterobacter sp., B. megaterium and S. marcescens are effective strains of plant growth promoting bacterial strains for wheat crop production under Indo- Gangetic plains of India.   Key words: Bacterial strains, biochemical, growth, microbial population, wheat, yield.