Abstract: Invasive plant have caused serious harm to crop production, orchards, lawns, natural environments and biodiversity in China. Solidago canadensis, a perennial plant originating from North America, was introduced into China in the 1970s. Studies on the genetic diversity of invasive plant are of practical significance in the predication of their potential distribution areas and their habitats.Three methods were adopted to extract genomic DNA from the invasive plant Solidago canadensis. Population genetic differences of Solidago canadensis from Shanghai and Zhejiang province were analysised using random amplified polymorphic DNA (RAPD).The results showed: (1) the method of 2×CTAB had better effects than that of the improved high-salt method and the SDS method to extract genomic DNA from Solidago canadensis. The DNA samples extracted by the 2×CTAB method had better integrality and lower content of protein, phenol and polysaccharide; (2) Genetic polymorphism of Solidago canadensis populations was high. Amplification of 13 random primers revealed 102 amplified fragments of which 84 (82.35%) were polymorphic and 41 (40.20%) unique. polymorphic percentage among 4 populations followed as Shanghai(SH) (73.13%) > Jiaxing(JX) (68.97%) > Hangzhou(HZ) (68.42%) > Jinhua(JH) (57.14%); (3) The average homozygosity(J) (0.38) and average heterozygosity(H) (0.62) were computed; (4) Based on the presence/absence bands, Nei's genotypessimilary, cluster and principal components analysis(PCA) were analyzed. The results showed that higher genetic diversity existed within Solidago canadensis populations, and the population genetic differentiation had corresponding relation with the geographical position; (5)The adaptive evolution of Solidago canadensis population was closely linked with the characteristic of the weeds.

Key words: invasive plant, Solidago canadensis, total DNA extraction, RAPD, genetic diversity