Abstract:Clonal diversity,growth structure,and genetic diversity of 8 natural Syringa pinnatifolia var.alanshanica populations were assessed by ISSR molecular markers.Results showed that 16 ramets of 3 individual genets shared the same genotype,whereas 136 genotypes were differentiated among the other 239 samples from 7 populations.Clonal diversity revealed that S.pinnatifolia var.alanshanica was a phalanx clonal species and each population was composed of several clones.Most genets contained one ramet and the highest quantity of one genet consisted of 8 ramets.A relatively high clonal diversity of genotype Simpson’s index (D=0.994) and distributional uniformity of genotype Fager’s index (E= 0.985) was detected.Individuals per genotype (NC) and mean genotype proportion (PD) were 1.729 and 0.578,respectively,at the species level.In addition,high genetic diversity was detected at both population and species level.The coefficient gene differentiation (GST) was 0.320,indicating less differentiation among populations than within populations.