中文摘要：

利用RFLP和序列测定方法，对分离自西北地区的67株天蓝苜蓿根瘤菌16S rDNA进行了分析研究。结果表明：所有供试菌株分别归属于中华根瘤菌属（Sinorhizobium）、根瘤菌属（Rhizobium）和土壤杆菌属（Agrobacterium）。以CCNWNX0042—2为代表的大部分天蓝苜蓿根瘤菌属于草木樨中华根瘤菌（Sinorhizobium meliloti），其余菌株在分群上表现出了较为明显的地域特征。

英文摘要：

67 rhizobia isolated from Medicago lupulina in northwestern China were studied by 16S rDNA RFLP and sequencing analysis. The result revealed that all the tested strains belonged to Sinorhizobium, Rhizobium,Agrobacterium respectively. The most strains representated by CCNWNX0042-2 belonged to Sinorhizobium meliloti. The other strains show obvious geographical character on genetic diversity.