Abstract: In order to explore mechanisms of the successful invasion of Solidago cannadensis,inter-simple sequence repeat(ISSR)markers were used to analyse genetic diversity of the invansive species S.canadensis and the native species S.decurrens for comparison.Out of 100 primers,12 were chosen for PCR amplification showing good diversity and clear bands.On such a basis,genetic diversities of the two plants were analyzed with the POPGEN32 software.For Solidago canadensis,the percentage of polymorphic loci at the species level,Nei's gene diversity and Shannon's information index was found to be 95.19%,0.3085 and 0.4158,respectively,whereas for the native species(S.decurrens)the three indices were found to be 89.80%,0.2491 and 0.3834,separately,all lower than the former,respectively.For S.canadensis,the coefficient of genetic differentiation among populations was 0.1182 and the coefficient of genetic variation within the population was 0.8818,while for S.demurrers,it was 0.1313 and 0.8687,respectively,suggestiong insignificant genetic differentiation among the populations and highly consistent heredity of the two species.However,the main genetic variations exist within the populations,so the invasive species is higher than the native species S.decurrens in genetic diversity,which might be responsible for the successful invasion of S.canadensis.

Key words: invasive species, native species, Solidago canadensis, S.decurrens, genetic diversity, inter-simple sequence repeat(ISSR)