Abstract: Ginkgo biloba L., a unique species in Ginkgopside and known as the “living fossil”, has high value on economic and scientific research due to its wide usage with fruit, leaf, wood and ornament. In this study, 21 polymorphic SSR primers were used to analyze the genetic diversity and population genetic structure of G. biloba distributed in seven regions of China, with 137 alleles being detected in 214 individuals from seven ancient G. biloba populations. We observed high levels of genetic diversity (H_e=0.764) in the G. biloba populations, and the populations with highest level of genetic diversity came from Anlu (AL), Jingshan (JS) and Suizhou (SZ). The genetic differentiation coefficient (F_st=0.094) indicated that the most of the genetic variation were within population because of the high gene flow among populations (N_m=2.405). The seven populations were clustered into three major groups by STRUCTURE, PCA and phylogenetic analysis, with the population from Zhuji (ZJ) being significantly different from the others. The genotype frequencies of 21 SSR loci significantly deviated from the Hardy-Weinberg equilibrium within all populations. The imbalance of sex ratio caused by human interference might be the main reason. The abundant resources of ancientG. biloba in genetic diversity provided material basis for its use, and should be given priority in protection, especially for the male individuals of ancient G. biloba.

Key words: Ulva prolifera, 24-epibrassinolide, salinity, chlorophyll fluorescence parameters, antioxidant.