Host specificity among five species in the cowpea cross-inoculation group

Summary

In a cross-inoculation experiment using crushed nodules from cowpea (Vigna unguiculata), groundnut (Arachis hypogea), bambara groundnut (Voandzeia subterranea), lima bean (Phaseolus lunatus) and soybean (Glycine max.), it was found that soybean did not nodulate with Rhizobia from any of the other species whilst its Rhizobia nodulated with all species. Cowpea and lima bean, on the other hand, nodulated with Rhizobia from all species, but their Rhizobia nodulated only with each other. Groundnut and bambara groundnut nodulated with Rhizobia from all species except cowpea and lima bean, and their Rhizobia also nodulated with all species except soybean.