Studies on cultural, morphological and biochemical characterization of Bradyrhizobium japonicum of soybean

Abstract

Soybean (Glycine max L. Merrill), being a leguminous crop, can be fix atmospheric nitrogen through symbiotic association with effective and competitive strains of Rhizobia (Bradyrhizobium japonicum/Rhizobium japonicum) and thereby improve soil fertility as well as productivity of subsequent cereal crops. Bradyrhizobium japonicum was isolated from root nodules of Soybean (Glycine max L.) on Congo-Red Yeast Extract Mannitol Agar (CR-YEMA) medium and its morphological, cultural and biochemical-characteristics were studied. The test bacterium was circular, convex, glistening, whitish pink colonies (0-4 mm dia.) with entire margin. The bacterium was Gram-negative, non-spore forming and motile rods and showed positive reactions to Catalase oxidation, Potassium hydroxide test, and Starch hydrolysis tests.