Abstract
Hydroponic culture of four common bean (Phaseolus vulgaris L.) cultivars was assessed as a means of selecting cultivars on the basis of their capacity to fix N in symbiosis with rhizobium. Two segregants of cultivar CC 25-9 with different seed colours were included. Bean growth in hydroponic cultivation was comparable to that in the field but nodulation was higher in the greenhouse than in the field. A strain-cultivar interaction on nodulation was significant in cultivar CC 25-9, in which some plant factor, possibly related to seed colour, limited nodulation since black seeded beans nodulated significantly less with Rhizobium leguminosarum bv phaseoli CFI than segregants having red or white seeds. Another strain-cultivar interaction affected nodule function since BAT 482 had a significantly lower specific nodule activity than other cultivars in symbiosis with strain CFI.