Evaluation of The Effect of Epiphytic, Endophytic And Rhizosphere Bacteria On Seed Germination And Seedling Characteristics

During 2013 and 2014, in order to investigate the effect of bacteria on the characteristics and growth rate of cotton seedlings, isolated epiphytic, endophytic and rhizospheric bacteria from cotton plants in Golestan province. Based on biochemical and phenotypic tests, amplification and sequencing of 16S rRNA gene, were identified strains. Isolates of Bacillus pumilus MR11, B. pumilus MR12, B. pumilus MR13, B. safensis MR21, B. safensis MR22 and Stenotrophomonas pavanii MR31 identified as superior endophytes and rhizosphere. Also Pseudomonas fluorescens , P. syringae and Pantoea annanatis were identified as epiphytic from plants and seeds. These isolates were evaluated to effect on seedling growth characteristics. Based on results, the six-day-old seedlings treated with Bacillus pumilus MR11 and B. pumilus MR12 had the highest root and shoot length and fresh shoot weight. Due to the fact that B. pumilus MR12 and S. pavanii MR31 isolates had the highest percentage and germination rate, so their use as seed treatment can increase the percentage and germination rate of seeds and be effective in reducing the damage caused by seedling diseases. This is the first report of isolation of B. safensis , B. pumilus and S. pavanii bacteria from rhizosphere and cotton endophytes in Iran.