北京市华北落叶松优树群体遗传多样性分析

Genetic Diversity and Population Structure of Elite Larix principis-rupprechtii Mayr in Beijing

利用SSR分子标记对北京市华北落叶松人工林5个群体的220棵优树进行遗传多样性和群体结构分析。20对SSR引物共检测到81个等位基因,每个位点等位基因数2~8个不等,平均4.05个。群体观测和期望杂合度平均值分别为0.429和0.440,Shannon信息指数和多态性信息含量分别为0.756和0.380。5个群体中,百花山和云蒙山遗传多样性水平最高,雾灵山遗传多样性水平最低。AMOVA分析结果显示,2.65%的遗传变异来自于群体间,剩余97.35%的遗传变异来自于群体内。遗传分化系数仅为0.023,表明北京市华北落叶松优树群体遗传分化程度很低。基于Nei＇s遗传距离可以将5个群体划分为3个类群,四海镇和雾灵山归为第Ⅰ类,松山归为第Ⅱ类,百花山和云蒙山归为第Ⅲ类。STRUCTURE群体结构分析结果与上述聚类分析结果大体一致。以上研究为华北落叶松人工林遗传多样性评价和优良种质资源收集、保护和利用提供理论依据。

SSR markers were used to describe the genetic diversity and population structure of 220 elite genotypes in five populations of Larix principis-rupprechtii Mayr plantation in Beijing. A total of 81 alleles were amplified using 20 SSR markers while 4. 05 alleles were detected on average per locus with the range of 2-8. The means of observed and expected heterozygosities were 0. 429 and 0. 440,respectively. Shannon＇s information index and polymorphic information content for these populations were 0. 756 and 0. 380,respectively. Among the five populations,BHS and YMS populations had the highest level of genetic diversity,while WLS populations had the lowest one. The analysis of molecular variance exhibited that 2. 65% of genetic variation was observed among populations,while the remaining 97. 35% of genetic variation was within the populations. The coefficient of genetic differentiation was only0. 023,elucidating that the extent of genetic differentiation was quite low. The five populations could be divided into three groups based on the Nei＇s genetic distances between populations,group Ⅰincluded SH and WLS,group Ⅱ included SS,and group Ⅲ contained BHS and YMS. The result of population structure analysis based on STRUCTURE software was roughly consistent with cluster analysis. The results of this study will provide the theoreticalfoundation for the collection,conservation and utilization of excellent germplasm resources and evaluation of genetic diversity in the man-made forest.