大花序桉的遗传多样性分析

目的 揭示大花序桉的遗传多样性，为大花序桉群体资源的保存和育种潜力的评估提供理论基础。 方法 利用14个简单重复序列（SSR）标记对大花序桉4个主要分布地区进行变异检测，分析位点多态性和群体多样性，计算地区间的分化系数和遗传相似性以及地区间和地区内的分子方差分量，基于遗传相似性进行聚类分析。 结果 14个SSR标记共检测到249个等位片段，平均每个标记检测到18个等位片段。基于所有标记，大花序桉各地区的Shannon's信息指数平均为1.785 4，观测杂合度平均为0.510 0，期望杂合度平均为0.788 2，表明遗传多样性较高。地区间平均遗传分化系数为0.071 6，分子方差分析（AMOVA）中群体间方差分量仅为6.8%，表明遗传分化水平中等、遗传变异主要存在于群体内。非加权分组算术平均法（UPGMA）聚类分析将大花序桉4个主要分布地区划分为北部和南部2大类。 结论 种质资源保存要优先考虑多样性较高的地区。大花序桉遗传多样性较高，进一步选育的潜力较大。

Genetic Diversity of Eucalyptus cloeziana

Objective To study the genetic diversity of Eucalyptus cloeziana for the purposes of germplasm conservation and breeding potential evaluation. Method Fourteen simple sequence repeats (SSR) markers were used to detect the variation in four main distribution areas of E. cloeziana. The locus polymorphism and population diversity were analyzed, the differentiation coefficient and genetic similarity among regions and the molecular variance components inter-and intra-regions were calculated. Cluster analysis was conducted based on genetic similarity. Result A total of 249 alleles were detected in 14 SSR markers, with an average of 18 alleles per marker. Based on all the markers, the Shannon's information index was 1.785 4, the observed heterozygosity was 0.510 0, and the expected heterozygosity was 0.788 2, indicating a high genetic diversity. The average coefficient of genetic differentiation among regions was 0.071 6, and the component of variance among populations in analysis of molecular variance (AMOVA) was only 6.8%. This indicated that the level of genetic differentiation was moderate and genetic variation mainly exists in populations. Unweighted pair group method with arithmetic (UPGMA) clustering analysis divided the four main distribution areas of E. cloeziana into two major categories:north and south. Conclusion The germplasm resource conservation should give priority to the areas with high diversity. The genetic diversity of E. cloeziana is high, and it has great potential for breeding.