SYMBIOTIC EFFECTIVENESS OF ZAMBIAN BRADYRHIZOBIUM SPP WITH US SOYA BEAN CULTIVARS

Invasiveness and efficiency of six Zambian strains of Bradyrhizobium s pp., with five U.S.-bred soya bean varieties were tested. Host genotyp e was the major determinant in symbiotic compatibility since differenc es in relative nodulating abilities of strains with genotypes were app arent. Contrary to the theory that African cowpea bradyrhizobia cannot efficiently nodulate soya bean, evidence was provided to indicate tha t some strains can be both effective and efficient nodulators of U.S. cultivars.