短枝木麻黄种子散布模式及子代群体的遗传多样性分析

目的 利用短枝木麻黄(Casuarina equisetifolia L.)实生人工林群体及其自由落种长成的天然更新群体，开展短枝木麻黄种子散布规律研究，比较天然更新群体(子代群体)与其母本群体以及30年生实生人工林群体的遗传多样性差异，为人工促进木麻黄天然更新提供理论依据。 方法 利用木麻黄11个SSR标记位点的遗传分型数据，通过亲本分析软件Cervus 3.0对天然更新群体植株的母本进行确定，分析短枝木麻黄种子散布的距离和模式，并利用遗传多样性参数对这3个群体的遗传多样性进行比较。 结果 （1）子代和母本群体共367个个体样本在11个SSR位点共检测出137个等位基因，每个位点的等位基因数为6～24，平均有效等位基因数为4.95，平均期望杂合度、观测杂合度和多态性信息量分别为0.75、0.77和0.72，所有位点均属于中或高度多态性位点。（2）在80%的置信区间下，利用11个标记位点的分型数据，可为148株子代确定它们的母本，占鉴定子代总数的72.20%；种子的有效散布距离为10～130 m，平均散布距离为71 m，属于短距离传播；天然更新群体的母本主要集中在样地的东北和东部，2个方向的母本对子代的贡献率为75.00%。（3）从3个群体中各选择84株个体的DNA样品进行遗传多样性比较，结果显示：天然更新群体在各个遗传多样性参数上均低于母本群体和实生人工林群体，但其参数表明该群体仍具有较高的遗传多样性。 结论 短枝木麻黄种子散布属于短距离传播，天然更新群体可以保持较高的遗传多样性，这为人工促进木麻黄实生林的天然更新提供了理论基础。

Seed Dispersal Pattern and Progeny Genetic Diversity of Casuarina equisetifolia

Objective To reveal the seed dispersal pattern and compare the genetic diversity differences among natural regeneration population (progeny population), maternal population and seedling plantation population of Casuarina equisetifolia, and to provide reference data for artificially promoting natural regeneration of C. equisetifolia seedling plantation. Method Paternity analysis software Cervus 3.0 was used to determine the maternal parents of individuals in regeneration population, and to compare the genetic diversity of the three kinds of C. equisetifolia populations based on genotype data of progeny and candidate maternal parents obtained from 11 polymorphic SSR loci. Result (1) Totally 137 alleles (Na) were detected from 367 individual samples of maternal and progeny populations using 11 SSR markers, and the number of alleles per SSR locus varied from 6 to 24, with an average effective alleles (Ne) number of 4.95. The average expected heterozygosity (He), observed heterozygosity (Ho) and polymorphism information (PIC) were 0.75, 0.77 and 0.72 respectively. All the loci were categorized as moderate-high polymorphic loci. (2) At 80% confidence interval, the female parents of 148 progeny which accounted for 72.20% of the total progeny number were identified using genotype data obtained from 11 SSR markers. The seed effective dispersal distance of C. equisetifolia ranged from 10 m to130 m, with the mean dispersal distance of 71 m, which belongs to short-distance dispersal. The female parents were mainly concentrated in the northeast and east of the sampling plots, and their contribution to progeny reached up to 75.00%. (3) For the purpose of determining an even sample number, the genotype data of 84 individual samples were extracted respectively from the three populations for genetic diversity comparison. The results showed that the natural regeneration population presented slightly lower genetic diversity than the other two populations, but it still possessed relatively high genetic diversity based on its genetic parameters. Conclusion The seed dispersal of C. equisetifolia is of a short-distance dispersal, and the natural regeneration population can also maintain a high genetic diversity, which provides reference data for artificially promoting the natural regeneration of the seedling plantation of C. equisetifolia in coastal shelterbelts of Southern China.