Genetic Structure And Genetic Diversity Research Of Clonal Seed Orchard Of Masson Pine

Pinus massoniana is one of the most important material trees for nursing, which can be used to built architecture, to make paper and veneer etc. Selecting good gene to improve wood's growth and quality is become one of the important research way in our country. Because of complicated geography condition , natural selection and breeding separation in its distributing area, abundant heredity variation is observed which offers a rich substance base for establishment the clonal seed orchard of masson pine and improving the growth character of tree, timber character on genetic degree. With the growing of trees, it becomes necessary to cut down the inferior trees in order to keep the rational genetic structure and high genetic diversity of seed orchard.The clonal seed orchard of masson pine located in Jingshan of Hubei province and it was founded in 1993, DNA of needling leaves for 123 superior trees in this seed orchard was extracted respectively and examined by RAPD technology. All samples were clustered from four different factors of latitude, longitude, geography distance and provinces. The parameters of Gene flow (Nm), gene differentiation (Gst), genetic distance and genetic identity were calculated and genetic structure and diversity of the seed orchard were analyzed based on the results of the different cluster analysis. The results indicated the cluster analysis from different factors has a big influence to the analyzing result. The gene flows (Nm) of cluster analysis for the four factors are 2.880,5.219,2.437, and 1.528 in order and the gene differentiations (Gst) are 0.148, 0.087, 0.170 and 0.247, respectively. Similarly the average Nei's genetic distances are 0.061, 0.028, 0.060 and 0.133. According to the cluster dendrogram, it was found the correlation between genetic distance and latitude was more significant than that between genetic distance and geography distance. Usually the method of the superior tree collection in constructing seed orchard of trees by province can be accepted for its smaller Gene flow, bigger gene differentiation and bigger in average Nei's genetic distance.The result indicated the clonal seed orchard of Masson Pine had higher genetic diversity. The average genetic diversity of clonal seed orchard was 0.317, the Shannon's Information index was 0.481 and the percentage of polymorphic loci was 71.01%, which is similar with the result of natural population researched by isozyme analyses. Average genetic distance among population was 0.107. The smallest was between Jiangxi provenance and Hunan provenance (D=0.023) ; however the next was between Zhejiang provenance and Jiangxi provenance (D=0.023) . The largest was between Guangdong provenance and Jiangxi provenance (D=0.218) .