Genetic diversity of Salsola passerina populations in northwestern China based on inter-simple sequence repeat(ISSR)

Genetic diversity and differentiation among seven populations of Salsola passerina in northwestern China were investigated using ISSR markers.15 ISSR primers gave rise to 196 discernible DNA fragments,of which 153(78.06%)were polymorphic.However,the polymorphism at the population level was relatively low,with an average of 45.60%.The mean expected heterozygosity and Shannon's information index were 0.1759 and 0.2811 at the species level,0.1251 and 0.1977 at the population level, respectively.Based on Nei's Gst value,a large proportion of genetic variance(70.96%)resided among individuals within populations;however,only 29.04%genetic variance resided among populations.Pairwise genetic identity values among populations had a mean of 0.9320.AMOVA analysis also indicated a similar genetic structure.UPGMA cluster analysis based on Nei's genetic distance divided the populations into three main groups:QHDLH,LZXJS and the rest five populations(NXZN,NMWH,MQHLY, JTDX,and AXTS).The mantel test showed that genetic distance was significantly correlated with vertical geographical distribution(P0.001).A means of preserving genetic variation of this endemic species in those regions is to stop deforestation and to protect its suitable habitats in view of the lower genetic diversity within populations.