Résumé
A total of 25 fast-growing rhizobium isolates from variety of legumiuous plants in Hainan Province, a tropical region of China, and 7 representative strains of genera Rhizobium, Sinorhizobium and Agrobacterium were characterized by numerical taxonomy. The results indicated that rhizobium isolates from Hainan were taxonomically heterogenous. At thesimilarity level of 70%, 13 strains from Hainan formed a distinct group which could use wider range of carbon and nitrogen sources, and were more resistent to antibiotics and chemicals than known rhizobium species. 2 strains could not fall into any group, and the others fell into different known species respectively. There were no correlations between hosts and the taxonomic positions of their symbionts. The rhizobium isolates from the same host genus or speceis could fall into different groups.