中国引种桉树种质资源的遗传多样性分析

Genetic Diversity among the Introduced Germplasms of Eucalyptus in China

该研究从110对SSR引物中,选用47个扩增稳定、条带特异的SSR多态位点,对42种159份桉树种质材料进行PCR扩增,通过统计条带构建二维数据库的方法,进行遗传多样性分析和聚类分析。结果显示:(1)共检测到137个等位基因,平均每个位点等位基因数为2.915个,各位点等位基因变异范围为2~7个。(2)遗传多样性分析结果表明,平均Shannon’s信息指数为0.181,平均观察杂合度Ho为0.068,平均多态信息含量PIC为0.182。综合各指标分析发现,位点eSSR-GR018、eSSR-GR083和eSSR-GR109的多态性程度最高,反映的遗传信息量更大,能够在桉树种质资源的遗传多样性分析和种质鉴定等方面发挥更大的作用。(3)非加权类平均法(UPGMA法)和主坐标分析法(PCoA法)聚类分析均表明,159份桉树种质材料分为两大类群,且昆士兰桉和少花桉间具有较高的遗传相似度,很可能产生杂交种;聚类结果与基于形态学的Hill&Johnson分类系统基本一致。研究表明,中国引种的桉树种质资源具有较高水平的遗传多样性,该研究所选用的47对SSR引物可有效地应用于桉树种质资源的鉴定分析。

In the study,47SSR polymorphic sites which have steady and specificity amplification were selected.PCR using159Eucalyptus germplasms accessions including42species of eucalyptus were applied to the genetic diversity analysis and clustering analysis,through the method of constructing a two dimensional database composed of the numbers of bands.(1)A total of137alleles obtained from the analysis of PCR results among all159accessions by47pairs of SSR primers with an average of2.915alleles per pairs of primers ranging from2to7.(2)The results of genetic diversity showed that the average Shannon s information index(I)was0.181.The average observed heterozygosity(H o)was0.068,and the average value of polymorphism information content(PIC)was0.182.The highest genetic diversity level was found in the three loci eSSR-GR018,eSSR-GR083and eSSR-GR109by comprehensive comparison.These three SSR loci would play an important role in genetic diversity and germplasm identification among Eucalyptus germplasm resources.(3)The results of UPGMA analysis and principal coordinate analysis(PCoA method)were consistently indicated that159accessions were divided into two groups,and this classification agreed with the taxonomy of Hill&Johnson(1995)that based on morphology.Two cluster results showed that the relationship between Eucalyptus cloeziana and E.pauciflora was relatively higher genetic similarity and they were more likely to produce hybrids.The results in present research revealed high level of genetic diversity among the159Eucalyptus germplasms accessions including42species of Eucalyptus introduction in China.The110pairs of SSR primers could be applied to analyze Eucalyptus germplasm identification,effectively.