Evaluation of some physiological characteristics of Rhizobium leguminosarum bv. viciae native to Iranian soils

Nitrogen is one the most important and most in need element for plants growth. In agriculture, the need of plants to nitrogen supplied through chemical fertilizers that causes many environmental problems. Biological nitrogen fixation is one of the exceptional natural phenomena that accomplished by some of bacteria including Rhizobia. Rhizobium leguminosarum bv. viciae is the specific symbiotic nitrogen fixer of fababean. Plant infection test is one of the inexpensive and reliable methods for detection of Rhizobium. In this research the sampling of Rhizobium root nodules of fababean in 50% flowering stage in fields of farmers from Khouzestan, Lorestan, Golestan, Mazandaran and Gilan provinces was accomplished. A total, 168 Rhizobium root nodules were collected from these areas. After isolation of bacteria from nodules, various morphological and physiological tests are performed on the isolates. Accordingly, 101 isolates were purified and detected. Plant infection test revealed that 42 isolates are able to form root nodules on fababean. The symbiotic effectiveness of selected isolates was 5-165. Thecae isolates showed diversity about antibiotic resistance.