The effects of rhizobium strains on drought resistance, yield and yield components of common bean in dry land conditions.

Investigations have shown that the seed inoculation with rhizobium bacteria was caused higher nitrogen fixation and consequently higher grain yield of bean in dry lands. To investigate the effects of the seed inoculation with rhizobium bacteria’s strains on yield and drought resistance of common bean, two years' study (greenhouse and field) was conducted on split plot experiment using Complete Block Design with 12 treatments in three replications 2018 and 2019 years. The experimental factors were irrigation methods 30, 60 and 80 % of soil field capacity (FC) as a main plots and four inoculants, including 54, 58, 160 and 177 rhizobia strains as a sub plots. In field the seed yield, biologic yield, irrigation water content, water use efficiency, 100seed weight, pods per plant and seed per pod were determined. In greenhouse the plant height, left area and number leaves per plant, fresh and dry tissue weight, plant nitrogen percent, nodule dry mater and nodule number per plant were determined. The results in two years’ pooled data showed that; the main effects of irrigation methods and rhizobia treatments have significant (P<0.05 %) effects on seed yield and water use efficiency. The highest yield (3066 kgha-1) and water use efficiency (0.81 kgm-3), were obtained at 60 % FC irrigation level with application of 160 strains with no significant difference with 80 % FC. The results showed that; inoculation of seed bean with rhizobium strains mitigates some of the negative effects of drought stress.