Abstract: In this study,the factors affecting the ISSR reaction system of Astragalus membranaceus were optimized,and the genetic diversity of A. membranaceus was analyzed.The initial ISSR reaction system of A. membranaceus was established,and the ISSR reaction system was optimized by single factor experiment.Then,the ISSR system was finally established.Genetic diversity and cluster analysis of 8 batches of  A. membranaceus was analyzed by unweighted pairgroup method arithmetic averages (UPGMA).The ISSRPCR reaction system in this experiment (20 μL) contained 10×PCR Buffer 2.0 μL、0.5 mmol/L dNTPs、1.0 U Taq DNA polymerase、3.5 mmol/L MgCl₂、0.25 μmol/L primer、and 50 ng template DNA.A total of 118 polymorphic bands were amplified by 14 primers.Genetic consistency ranged from 0.492 1 to 0.730 2 and the genetic distance ranged from 0.314 5 to 0.709 1.The results of UPGMA clustering showed that Xinghe County of Inner Mongolia,and Guaner Township of Hunyuan country,Shanxi Province belonged to one class,respectively,while the rest of Shanxi different areas were clustered into other class.This experiment showed that the establishment of the A. membranaceus ISSR system was stable.The genetic diversity of A. membranaceus in two producing areas in Shanxi and Inner Mongolia was rich,which laid a foundation for breeding and germplasm protection of A. membranaceus.

Key words: Astragalus membranaceus, ISSR system optimization, genetic diversity, germplasm resources