Effects of rhizobium bacteria strains on yield components of common bean (Phaseolus vulgaris L.) in drought stress condition

The drought stress is the most important of abiotic stress for plants. In dryand regions, the implication of drought tolerant strains of rhizobia is a critical way to enhance yield and development of nitrogen fixation in beans farming.To investigate the effects of rhizobial strains on yield of common bean under drought stress, this study was performed based on randomized complete block design as a split plot experiment with 12 treatments in 3 replications during 2014 and 2015. The treatments were irrigated to achieve the values of 30, 60 and 80 % available soil moisture as drought stresses (sever-, moderate- and non-) in main plots and inoculated seeds by rhizobium bacteria strains 54, 58, 160 and 177 arranged in sub-plots. The volume of irrigation water, water use efficiency, plant nitrogen, yield and yield components were determined. The results in 2 years revealed that, the drought stress and rhizobium treatments showed significant (P-1) was obtained in irrigation level at 60 % available water (moderate stress) and seed inoculated by rhizobium bacteria strain 160. These results showed that, the application of rhizobium bacteria strain 160 increased drought tolerance without any reduction of yield in common bean.