Evaluation of potential of biological nitrogen fixation of Rhizobium strains in legume crops in West Azerbaijan province

Biological nitrogen fixation is important for supplement of nitrogen needs of host plant. Growth chamber experiments were conducted to test the nitrogen fixing abilities of isolate of Rhizobium strains collected from 10 cities (Urmieh, Khoy, Makuee, Salmas, Mahabad, Miandoab, Tekab, Sardasht, Shahindege and Piranshar) of West Azerbaijan province in symbiotic relation with alfalfa, chickpea, clover and bean cultivars. Seedlings of test plants were inoculated with proprietary Rhizobium strains. Inoculated and control seedlings of each plants were planted in pots containing sterilized perlit. The experiment was conducted using completely randomized design with three replications. The pots were irrigated with free nitrogen Hoagland solution. Results showed that the highest number of nodule and the lowest nodule dry weight was for clover and bean, respectively.. Symbiotic of Rhizobium strain of Miandoab for alfalfa, Mahabad for clover and Urmieh for bean had the highest values for most of traits. Nitrogen fixation correlated with total dry matter, and it seems this trait may be used as an indirect criterion of nitrogen fixation. This findings imply the possibility of replacing biologically fixed nitrogen with chemical fertilizers.