Diversity, effectiveness and biochemical characterization of Bambara groundnut symbiotic Rhizobia strains in tropical Nigerian soils

Bambara groundnut (BG) has a high nutritious content, is under-utilized with the potential to eradicate malnutrition, yet has very low production rates. Rhizobia inoculant can enhance it’s production, but, inadequate information about the diversity and suitability of rhizobia strains is known. Diversities of Bambara-symbiotic-rhizobia in soils (54) collected across three states in Nigeria were characterized morphologically and biochemically. Strains were evenly distributed between; Niger (36%), Kaduna (35%), and Kano (29%), but significantly different between local governments. Rhizobia strains were Gram negative rods, 10% were highly effective, while 81% were infective. Strains couldn’t hydrolyse starch but showed varied utilization abilities for different carbon sources, 73% hydrolysed gelatin and 66% produced catalase enzyme. A wide diversity of Bambara-symbiotic-strains were present in the soils, but only 10% effectively fixed nitrogen. Although there is a rich diversity of Bamabara-symbiotic-strains in these soils, it is necessary to apply suitable effective rhizobia strains as inoculant.