Abstract: The genomic DNA polymorph on 13 isolator of Melampsora larici－populina Kleb. from Shaanxi and Qinghai were analyzed using random amplified polymorphism DNA markers (RAPD). 81 RAPD bands were amplified with 13 decanucleotide random primers, 69 bands of them were polymorphic(85.2%).Similarity coefficient of isolates was 0.608～1.000 and difference among isolates was 0～33 1%. The tested 13 isolates of the group were divided into 4 clusters with the similarities and genetic distances among them. Two isolates from Huoditang C in Qingling were placed in one group(group I) and one isolate from Huoditang B in another group(group II). Six isolates from Xining, Huzhu in Qinghai and Taibeibaotailu, Tiantaishan, Houzhengzi(Hza) in Shaanxi were placed in the third group(group III). Last two isolates from Houzhengzi(Hza,HZb) were placed in the fourth group(group IV).However, the DNA polymorphic of isolations were not obviously related to the collecting places or hosts and pathogenicity.

Key words: Poplar, %Melampsora larici-populina, RAPD, Pathogenicity