Abstract: One hundred and thrityfive samples of nine natural Populus pruinosa populations in Xinjiang Uygur Autonomous Region of Northwest China were taken, and twelve pairs of SSR primers were utilized to study the genetic diversity and genetic structure of these populations. A total of 136 alleles were detected, with a mean of 11 bands per primer. The mean percentage of the polymorphic loci of all the populations (P) was 97.2%, the mean Shannon’s information index (I) and Nei’s gene diversity (h) at population level were 1.185 and 0.541, and the observed heterozygosity and expected heterozygosity were 0.321 and 0.560, respectively. These data suggested that the genetic diversity of P. pruinosa was quite high. Among the nine populations, ZP population had the richest genetic diversity, while 14T population had the poorest one. The AMOVA analysis showed that the percentage variation among the populations was 12%, while the percentage variation within the populations was 88%, illustrating that the genetic differentiation of P. pruinosa was quite low. According to the genetic differentiation coefficient, the gene flow between the populations was 2.424. The average genetic distance of the 9 populations was 0.244, and the 14T population and XML population were the closest in genetic distance and the highest in genetic identity. Using unweighted pair group method arithmetic average (UPGMA), the 48T population, 14T population, MGT population, MY population, and SY population were clustered into one group, the AWT population and ALE population were clustered into another group, and the ZP population and XML population were clustered into two independent groups, respectively. The Mantel test also indicated that the genetic distances among the populations had no significant correlations with their geographic distances. In sum, the ZP population had the richest genetic diversity, and thus, should be given a high priority consideration in the P. pruinosa population’s in situ germplasm conservation.

Key words: jellyfish, zooplankton, isotope, food source, ecological niche.