SelectingRhizobium phaseoli strains for use with beans (Phaseolus vulgaris L.) in Kenya: Infectiveness and tolerance of acidity and aluminium

Abstract

Forty strains ofRhizobium phaseoli, isolated from Kenyan soils, were tested for infectiveness on common bean (Phaseolus vulgaris L.). 28 strains were infective and a cultivar × Rhizobium interaction was observed. 48 strains were screened for tolerance of acidity and Al in liquid culture. Assessment of visible turbidity after 14 days indicated 34 strains tolerant of pH 4.5 but none tolerant of pH 3.5. No strain was tolerant of 50 μM Al at pH 5.5. Three strains were tolerant of 20 μM Al at pH 5.5 and 10 μM Al at pH 4.5. Screening on a solid medium identified strains tolerant of 20 and 50 μM Al at pH 5.5 and 4.5 which were sensitive to these treatments in liquid culture. Those strains tolerant to 20 μM Al at pH 4.5 and 5.5 in liquid culture were correctly identified on the solid medium.