Abstract

Eight strains of Bradyrhizobium japonicum were isolated from the root nodules of soybean cultivar PK 472 collected from Adaptive Trial Centre, Bundi, India. All the isolates were authenticated through plant assay test in germination pouches. Growth of the isolated strains on different pH levels was observed and three strains namely Bj-3, Bj-5 and Bj-8 were found to be able to grow up to pH 8.5. Symbiotic efficiency of these isolates was determined under the mist house conditions in the sterilized sandy soil (pH 8.4). Maximum and minimum nodulation and vegetative growth were observed in Bj-3 and Bj-2 inoculated soybean plants, respectively. Three pH tolerant strains could also pose better results in the efficiency determination experiment. Considerable variability in terms of the symbiotic effectiveness was found in the tested strains.

Key words: Identification, symbiotic effectiveness, Bradyrhizobium japonicum, pH, soybean, nutrient, soil.