Host Specificity Among Certain Plants in the Cowpea Cross‐inoculation Group

Abstract

AbstractThe objectives of this study were (a) to determine the extent of host‐plant specificity among various agriculturally important members of the cowpea cross‐inoculation group and if possible (b) to select rhizobial strains adapted to a wide variety of hosts in this group.In greenhouse tests 15 strains of rhizobia which were effective on their parent hosts were used as inocula for the cowpea, asparagus bean, peanut, indigo (4 species) crotalaria (3 species), velvet bean, partridge pea, jack bean and lima bean. Nodules were present on all inoculated plants. Growth of the cowpea and asparagus bean was improved with each of the rhizobial strains tested, whereas the other test plants showed a greater degree of selectivity. Growth of the lima bean, jackbean, peanut and velvet bean was improved by only two rhizobial strains. Only 7 of the 15 plant species tested gave effective response to 50% or more of the rhizobial strains used. None of the rhizobial strains were effective on all of the test plants.