干旱区生态环境知识资源中心

Backgroud Populus euphratica Oliv., a long-lived woody perennial plant, is the only forest species naturally distributed in desert regions. Severe desertification has resulted in this species becoming endangered, and its populations are seriously fragmented in northwest China.

Objectives We investigated the within-population and long-distance separated population diversity in northwest China using eight pairs of simple sequence repeat markers.

Results Our results reveal that this species has high overall genetic diversity with a mean of 12.125 alleles per locus; its expected heterozygosity (H(e)) ranged from 0.713 to 0.878. However, there was a high level of genetic diversity within the species (when compared within congeneric species) and low genetic differentiation between populations (average F(st)= 0.093). Analyses of molecular variance suggested that 5.21% of the total molecular variance was attributable to between-population diversity (P< 0.001), while the remainder of the variance was associated with differences within populations. There was no distinct correlation between geographical distributions and genetic variation.

Conclusions We found no evidence to support our initial hypothesis of low genetic diversity within the species and high differentiation between populations separated by long distances. The recent fragmentations of this species due to anthropologic and environmental effects resulted in its endangered status.