关键词: 珙桐, 遗传多样性, ISSR, 保护策略

Abstract:

Davidia involucrata is an endemic plant species native to Southwest China. The genetic diversity of 11 natural populations of this plant was assessed using inter-simple sequence repeat(ISSR) markers. Of the 100 primers screened, 5 primers were generated stable, distinct and highly polymorphic bands. Of 77 total ISSR discernible bands, 74 were polymorphic. The percentage of polymorphic bands was 96.10%. At the population level the percent of polymorphic bands ranged from 37.66% to 63.64%, and the average value was 54.07%. The Shannon's information index within species(H_SP) was 0.484 9, while the values within population(H_POP) were from 0.188 6 to 0.327 4 and the mean value was 0.277 4. The result showed there existed high level genetic diversity both at population and species level. Analysis of molecular variance(AMOVA) revealed that among and within population genetic variation accounted for 46.22% and 53.78% of the total genetic variation, respectively. A high degree of genetic differentiation was also found among populations. Population genetic differentiation was significantly positive correlated with geographical distances(r=0.546,P<0.01). These 11 populations were divided into 3 major groups based on the UPGMA cluster analysis. These results would provide a valuable basis for developing conservation strategies.

Key words: Davidia involucrata, genetic diversity, ISSR, conservation strategy