华北落叶松种子园控制授粉子代遗传多样性分析

Genetic Diversity of Control-pollinated Progenies in Seed Orchard of Larix gmelinii var.principis-rupprechtii Mayr

以华北落叶松控制授粉群体的全部子代为材料,母本相同的个体视为同一家系,利用18对SSR分子标记对7个家系257个个体进行扩增,分析其遗传多样性及其遗传分化水平。结果表明：（1）18个SSR位点共检测到72个等位基因,平均等位基因数4个,有效等位基因数（Ne）为1.247~3.411。（2）7个家系的平均有效等位基因数为2.135个,观测杂合度（Ho）为0.518,期望杂合度（He）为0.502,Shannon信息指数0.846,其中55号家系遗传多样性水平最高,56号的遗传多样性水平最低。（3）遗传分化系数（GST）为0.113,各家系群体处于中等遗传分化水平,AMOVA分析结果显示82%的遗传变异存在于家系内,18%的遗传变异存在于家系间。（4）聚类分析结果表明,55号与59号家系的遗传距离最近,具有较近的亲缘关系,49号家系与其他家系的遗传距离最远。（5）结合遗传多样性及遗传分化水平结果,估算获得选择核心家系数及核心个体数,选择5个家系均可获得96%以上的遗传多样性,对于个体数较少的家系,选择15~20个个体;对于个体数较多的家系,选择35个个体,即可获得96%以上的遗传多样性。该研究结果对华北落叶松种子园育种群体的选择及其遗传多样性的保护具有重要意义。

In order to further understand the genetic diversity and genetic divergence of control-pollinated progenies of Larix gmelinii var.principis-rupprechtii,we utilized 18 pairs of SSR primers in 257 samples from 7families.（1）A total of 72 alleles were detected with a mean of 4alleles per primer and effective number of alleles of each SSR marker ranged from 1.247-3.411.（2）The number of effective alleles was equally 2.135 in each family.The observed heterozygosity（Ho）,expected heterozygosity（He）and Shannon information index（I）were 0.518,0.502 and 0.846,respectively.Among the 7families,the family of55 had the richest genetic diversity,while the family of 56 had the lowest one.（3）Gene differentiation coefficient was 0.113,illustrating the intermediate-level of genetic differentiation.The result of AMOVAshowed that 82% of genetic variation was within the populations（families）,while the remaining 18% was among populations（families）.（4）49family was far from others in the clustering analysis;55family was the nearest to 59 family so that they had the closest relationship.（5）According to the results of the genetic diversity and genetic divergence,the core of families and individuals were estimated.The 5families selected was accounting for 96% of genetic diversity.In addition,15-20 individuals can be selected in a family with less number of individuals,35 individuals can be selected when a family had more individuals.The result of this study has important theoretical and practical significance in elected populations for breeding and protected genetic diversity in seed orchard of Larix gmelinii var.principis-rupprechtii.