Abstract

Bintu Nabintu Ndusha, Nancy K. Karanja, Paul L. Woomer, Jean Walangululu, Gustave N. Mushagalusa and Jean Marie Sanginga

Identification of effective indigenous Bradyrhizobium strains which nodulate soybean varieties could trigger development of an industry for inoculant production with use of strains adapted to local conditions. This study was conducted to identify and select effective local rhizobia strains nodulating soybean in South Kivu soils. One hundred and seven isolates collected from root nodules in South Kivu were tested in sterile sand using the modified Leonard’s jars and in potted field soils. Each jar and pot was inoculated by 1ml of broth culture concentrated at 109 cells per milliliter. From the first screening, only 10% of these isolates produced higher nodules number and plant shoot dry weights (pË?0.001) compared to the commercial strain USDA110 and were selected for evaluation using soils as rooting media in three liters PCV pot in the greenhouse. From the potted soils experiment, among twelve outperforming isolates, only six isolates produced higher nodules and shoots dry weight (pË?0.001) compared to the commercial strains and uninoculated controls, and were considered as effective and competitive strains. This isolates includes NAC10, NAC22, NAC37, NAC67, NAC40 and NAC75. Nodules number highly correlated with Shoot weight. There exist effective indigenous rhizobia in South Kivu soils for inoculants production.