Abstract：The genetic diversity of the diazotrophic population in the rhizosphere soil and the washed roots of rice was investigated using nifH PCR—RFLP. The PCR—RFLP profiles were compared and analyzed with UPGMA and by maximum parsimony clustering. The RFLP profiles with the restriction enzyme Mnl showed that there are eight the RFLP pairs of similar patterns (similarity>50%) and two pares of similar patterns with 100% similarity between the rhizosphere soil and the root surface/tissue; and three specific patterns generated from the rhizoshere soil, and the washed root respectively, implying high diversity of the diazotrophe presents in the rice rhizoshpere soil and the washed rice roots of rice.
