Study on population genetic structure in Toona ciliata var. pubescens with SSR.

Population genetic structure of seven natural populations of Toona ciliata var.pubescens was studied with simple sequence repeat(SSR) markers.The results showed that a low level genetic diversity was detected in the populations of T.ciliata var.pubescens.Average number of alleles and effective number of alleles(Ne) were 6.1 and 2.7 respectively.The mean expected heterozygosity was 0.600 6.The major of genetic genetic variation occurred within populations,which could be concluded from the coefficient of genetic differentiation(FST =0.185 4).The level of gene flow(Nm) was 1.098 3.Dendrogram based Nei's(1978) genetic distance was analyzed with UPGMA.Significant correlation was found between geographical distance and genetic distance.The reasons that result in endangered status were analyzed,and some conservation strategies were put forward.