SYMBIOTIC PROPERTIES AND RHIZOBIUM REQUIREMENTS FOR EFFECTIVE NODULATION OF 5 TROPICAL DRY ZONE ACACIAS

Five tropical dry zone acacias were inoculated with three fast-growing Rhizobium strains and four slow-growing Bradyrhizobium strains. After two months of growth in the greenhouse, the plants were harvested and their shoot height and dry weight, nodule number and dry weight, acet ylene reduction activity, and total shoot nitrogen were determined. Th e results showed that: (1) Acacia polyacantha (being evaluated for the first time) was promiscuous, nodulating indiscriminately with Rhizobi um and Bradyrhizobium strains. (2) Faidherbia albida and Acacia holose ricea (that were previously known to nodulate with Bradyhizobium strai ns only) nodulated with Rhizobium strains as well and (3) Acacia seneg al and Acacia nilotica that were previously known to be nodulated excl usively by Rhizobium strains only were nodulated with both genera.