Growth and yield response of wheat to inoculation with auxin producing plant growth promoting rhizobacteria

Effectiveness of rhizobacteria for promoting the growth and yield of different cultivars of wheat was evaluated by conducting Leonard jar and pot trials. Thirty one cultures of bacteria isolated from wheat rhizosphere soil were screened oil the basis of their auxin producing ability in vitro. They were further tested for their growth promoting activity by conducting Leonard jar experiments on four cultivars of wheat under axenic conditions. Based upon the data recorded regarding auxin production in vitro, and screening in Leonard jar experiments, four isolates (W-9, W-11, W-14. and W-29) were selected to conduct pot experiment in the wire house under non-axenic conditions and considered as plant growth-promoting rhizobacteria (PGPR). Seeds of four Wheat cultivars (Pasban-90. Inqlab-91, Watan-93, and Punjab-96) inoculated with these four PGPR isolates were sown in pots. Uninoculated control was kept for comparison in each cultivar. To eliminate any nutritional Stress, nutrients were applied as NPK @ 120-75-50 kg ha(-1), respectively. Results showed that selected PGPR isolates significantly increased plant height (up to 9.9%), number of tillers (up to 32.3%), spike length (up to 6.8%), spikelets spike(-1) (up to 14.0%), straw and grain yields (up to 16.1 and 29.0%, respectively) in all the tested cultivars of wheat with different degree of efficacy. Among the various PGPR isolates tested, W-11 was found the most effective in promoting growth and yield of different cultivars of wheat compared to control. Overall, the response to inoculation with various PGPR isolates varied with cultivars.