Genetic Diversity of Allozymes of Quercus mongolica in China

A gel electrophoresis method was used to study the genetic diversity of eight Quercus mongolica populations located at Daxing′anling, Jiayin, Shuangyashan, Xiaoxing′anling Mountains of Heilongjiang Province, Jiaohe of Jilin Province, Kuandian of Liaoning Province,Daqinggou of Inner Mongolia Autonomous Region, Wulingshan, Zanhuang of Hebei Province, and one Quercus liaotungensis (a variety of Q. mongolica) population at Donglingshan of Beijing. Twelve of 22 loci from 13 enzymes assayed were polymorphic. Quercus mongolica maintained low level of genetic variation as compared with the average Quercus species. At species level, the mean number of alleles per locus A was 1.905, thepercentage of polymorphic loci P was 52.38%, and the observed heterozygosity Ho was 0.092 At population level, the estimates were A=1.421, P=28.976%,and Ho=0.088 Genetic differentiation Gst was high among populations, Gst was 0.107, and the means of genetic distance 0.012 1 The Nei' s genetic identity ranged from 0.974～1.00 The gene flow was 2.079 9 In contrast, the estimates for Quercus liaotungensis were almost the same (A=1.5, P=36.36%, Ho=0.070).According to the UPGMA cluster analysis based on the genetic distance, 4 populations located in northeast and 2 populations in southwest of the geographical distribution are classified into 2 sub groups in separate, there was no clear relationship between genetic distance and geographic distance among populations. The low level of genetic diversity of Quercus mongolica might related to the long term utilization as economic tree species in history, comparatively serious disturbance and damage by human beings, and secondary forests of most the existed stands.