马尾松种子园无性系遗传结构的地理变异

Geographical Variance of Genetic Structure of Clonal Seed Orchard of Masson Pine

运用RAPD技术,对湖北京山马尾松无性系种子园123株优树针叶的DNA进行测定,将样品按纬度、经度、空间实际距离及省份进行聚类分析,计算基因流、基因分化系数、遗传距离及遗传相似度等参数,分析该种子园的遗传结构地理变异及遗传多样性。结果表明:不同角度的聚类对马尾松无性系种子园遗传结构和遗传多样性的分析结果有较大的影响。按纬度、经度、空间实际距离及省份进行聚类的基因流(Nm)分别为2.8796、5.2186、2.4371、1.5282;基因分化系数(Gst)依次为0.1479、0.0874、0.1702、0.2465;遗传距离平均值分别为0.0607、0.0280、0.0595、0.1330。群体之间的聚类分析(UPGMA法)表明,各群体之间亲缘关系的远近与纬度的相关性明显,与地理距离的相关性较明显,而与经度的相关性不明显。传统的以行政区划即按省份采集优树建立马尾松无性系种子园的方法是可取的,其基因流动性小,基因分化系数、遗传距离平均值大,种子园遗传多样性丰富。

DNA of needling leaves of 123 superior trees from a clonal seed orchard of Masson pine located in Jingshan of Hubei Provenance was extracted and examined by RAPD technique. All samples were clustered in terms of four different factors such as latitude, longitude, spatial distance, and province. 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 analysed based on the results of different cluster analyses. Results showed that the cluster analysis with respect to different factors has a big influence on the analytical result. The gene flows （Nm） for the cluster analysis of the four factors were 2.8796, 5.218 6, 2.437 1 and 1.528 2 in order and the gene differentiations （Gst） were 0.147 9, 0.087 4, 0.1702 and 0.246 5, respectively. Similarly the average Nei＇s genetic distances were 0.060 7, 0.028 0, 0.059 5 and 0.133 0. According to the cluster dendrogram, it was found that the correlation between genetic distance and latitude is 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 provinces can be accepted for its lower gene flow, larger gene differentiation and higher average Nei＇s genetic distance. The genetic diversity of this clonal seed orchard is also at a high level in genetic structure.