Brown, Paul D.; Ahmad, Mohammed, H.
Author Affiliation, Ana.
Competitive interaction among strains of Rhizobiun leguminosarum by phaseoli in the nodulation of kidney beans (Phaseolus vulgaris L.)
Biology and fertility of soils
Date of Publication
Examined the competitiveness of five effective Rhizobium leguminosarum biovar phaseoli strains in the nodulation of kidney beans (Phaseolus vulgaris L.), either alone or in pairwise combination, against the indigenous strains. The results showed that the introduced Rhizobium sp. strains (B2, B17, B36, T2 or CIAT 652) occupying 64-79% of the total nodules (as single in-ocula) were more competitive in nodulation than the native rhizobia. However, the competitiveness of the indigenous Rhizobium sp. strain either increased or decreased when used in a pairwise combination of double-strain in-ocula. For example, strain B17, although quite competitive against the indigenous population (68% nodule occupancy), became poorly competitive in the presence of strain B2 (reduced from 68 to 2.5%). A similar reduction in nodule occupancy by strain B17 was observed in the presence of B36 or CIAT 652, indicating that two competitive strains may not always be compatible. These results suggest that it is important to co-select competitive as well as compatible rhizobia for multistain inoculant formulation.....