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 (CRD) with ۱۲ treatments in three replications ۲۰۱۸ and ۲۰۱۹ years. The experimental factors were irrigation water at three levels (۳۰, ۶۰ and ۸۰ % of soil field capacity (FC) as a main plots and rhizobium bacteria in three levels (۵۴, ۵۸, ۱۶۰ and ۱۷۷ strains) used for seed inoculated as a sub plots. In field the seed yield, biologic yield, irrigation water content, water use efficiency, ۱۰۰seed 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 drought stress and rhizobium treatments have significant (P<۰.۰۵ %) effects on seed yield and water use efficiency(WUE). The highest yield (۳۰۶۶ kgha-۱) and water use efficiency (۰.۸۱ kgm-۳), were obtained at ۶۰ % FC irrigation level with application of ۱۶۰ strains with no significant difference with ۸۰ % FC. The results showed that; inoculation of bean with rhizobium strains mitigates some of the negative effects of drought stress.

Keywords:

Bean , Drought Stress , Rhizobium , Yield