两种标记方法对短枝木麻黄(Casuarina equisetifolia)无性系遗传多样性评价的差异分析

为了探究形态标记和分子标记对短枝木麻黄无性系遗传多样性评价的差异性,本研究分别利用形态标记和分子标记两种方法对109个短枝木麻黄无性系单株进行遗传多样性差异的比较分析。结果表明:12个形态性状的多样性指数(H’)范围在0.347~2.053之间,其中各质量性状差异较大,短枝木麻黄无性系的表型相似度较高。基于形态性状和分子标记的聚类分析结果,分别可将参试的109个短枝木麻黄无性系单株分别聚为13类和22类,而分子标记的聚类结果更为精确。12对EST-SSR标记引物共检测到等位基因50个,平均每个位点3.42个;无性系样本的观测杂合度Ho和期望杂合度He平均为0.867和0.641;群体的平均Shannon多样性信息指数为1.099,分子标记分析表明华南沿海地区短枝木麻黄无性系人工林遗传多样性较低。研究发现两种方法对短枝木麻黄无性系的遗传多样性评估结果的一致性较低,表明华南沿海林木形态性状标记易受环境影响,遗传多样性评价方法应以分子标记法为主。

Difference Analyses of Genetic Diversity Evaluation of Casuarina equisetifolia Clones by Two Marker Methods

In this study,morphological markers and molecular markers were used to compare the genetic diversity of 109 clonal samples of C.equisetifolia,aimed at exploring the differences between the two marker methods at evaluating genetic diversity of C.equisetifolia clones.Results showed that diversity index(H')of all morphological traits ranged from 0.347 to 2.053,the differences of qualitative traits were obvious,and the C.equisetifolia clones perform high phenotypic similarity.The 109 clonal samples were clustered as 13 and 22 groups respectively based on morphological and molecular marker methods,and the results obtained from molecular marker were found more precise than that of morphological marker.A total of 50 alleles were detected in 12 EST-SSR loci,with an average of 3.42 per locus.The average observed heterozygosity(Ho)and expected heterozygosity(He)were 0.867 and 0.641 respectively.The average Shannon diversity information index of the population was 1.099,indicating relatively low genetic diversity of C.equisetifolia clonal plantations in coastal areas of south China.Obviously different genetic diversity results of C.equisetifolia clones produced by two marker methods were found.The results indicated that the morphological marker method of C.equisetifolia in the south China coastal areas are less reliable due to its susceptibility to environmental influences,and molecular marker was recommended as main evaluation method of genetic diversity of clonal plantations of C.equisetifolia.