Biodiv Sci ›› 2008, Vol. 16 ›› Issue (6): 562-569.DOI: 10.3724/SP.J.1003.2008.08201

• Original Papers • Previous Articles     Next Articles

Genetic diversity in natural populations of Sorbus pohuashanensis

Jian Zheng1,2, Yongqi Zheng1,*(), Chuanhong Zhang1, Yichen Zong1, Bojing Li1, Chao Wu3   

  1. 1 Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091
    2 Research Institute of Tropic Forestry, Chinese Academy of Forestry, Guangzhou 510520
    3 Afforestation Management Office of Hedong District, Tianjin 300176
  • Received:2008-08-19 Accepted:2008-10-29 Online:2008-11-20 Published:2008-11-20
  • Contact: Yongqi Zheng
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Sorbus pohuashanensis is a tree species native to northern China with high potential for ornamental use. The genetic structure and diversity of eight natural populations of Sorbus pohuashanensis were studied at ten loci encoding four isozymes using horizontal starch gel electrophoresis. Genetic diversity was high at the species level with the mean number of alleles per locus Na= 2.2000, the percentage of polymorphic loci P = 100%, and the mean expected heterozygosity He= 0.4240. Values of the three parameters of He, Ne, and Shannon′s information index indicated a random pattern of genetic diversity among the eight populations. A low level of genetic differentiation among populations (Fst= 0.0758) and a high estimate of gene flow (Nm= 3.0472) were detected together with a high level of genetic identity (I) among the populations (from 0.8585 to 0.9872). Wright’sF-statistics analysis indicated an excess of heterozygotes both at the individual population level (Fis= -0.4180) and at the total population level (Fit= -0.3105). χ2-tests (P<0.05) indicated that 73.62% of the assayed loci departed from the Hardy-Weinberg equilibrium. The UPGMA cluster analysis suggested that the genetic distances among populations were weakly correlated with their geographic distances.

Key words: Sorbus pohuashanensis, isozyme, genetic diversity, genetic structure, genetic differentiation