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[目的]为探讨额河杨和银灰杨天然杂种的起源机制,[方法]应用18对SSR标记,从分子水平上对新疆额尔齐斯河流域杨属植物的种间关系进行分析研究。[结果]表明：（1）SSR系统发育树将整个流域天然杨属植物分为两大类群,即黑杨派和青杨派为一类,白杨派为一类;（2）白杨派派内系统聚类图显示,银白杨、欧洲山杨、银灰杨三个树种均有较大的遗传分化,特别是杂种银灰杨似乎更大;（3）黑杨派和青杨派的UPGMA分类图显示,青杨派和黑杨派分属于2个分支,其中,青杨派内部分化相对简单,分为2支,均为典型的苦杨;黑杨派内部的分化较为复杂,可分为4类,包括典型的欧洲黑杨、额河杨和回交子代。[结论]杂种额河杨具有更多的欧洲黑杨的遗传成分,因此,将额河杨放到黑杨派是正确的。

[目的]对分布于我国新疆地区欧洲山杨自然居群的遗传多样性与遗传分化进行研究。[方法]对4个欧洲山杨自然居群共72个个体的6个单拷贝核基因标记（sing-copy nuclear markers）进行扩增与测序,并计算相应的遗传多样性和遗传分化参数。[结果]表明：比对后6个基因的长度在459 bp到747 bp之间,平均多态核苷酸位点个数为14,遗传多样性指数π和θw分别达到了0.004 8和0.004 4,基因多样性指数为0.73,以上结果表明欧洲山杨表现出较高的遗传多样性水平。Tajima中性检验结果均不显著,表明所用6个单拷贝核基因均符合中性进化假设。AMOVA分析表明89.72%的遗传变异存在于居群内,居群间的平均遗传分化指数Fst为0.10,居群间平均基因流（Nm）为3.235。[结论]高度异交,高碱基突变率及超长距离的基因流机制能够很好的解释我国新疆地区欧洲山杨表现出的较高的遗传多样性水平与较低水平的遗传分化。

To explore the hybrid origin mechanism of Populus × jrtyschensis and P. canescens, the phylogenetic tree based on nuclear microsatellite markers (SSR) analysis was structured. The result show that the natural Populus populations can be classified into two groups, the one is Section Leuce, and the other is Section Aigeiros and Section Tacamahaca. In Section Leuce, significant genetic differentiation was found in the populations of Populus alba, P. canescens and P. tremula, especially the crossbreed Populus (P. canescens). A UPGMA phylogenetic tree shows that Section Aigeiros and Section Tacamahaca can be divided into two groups. Compared with Section Tacamahaca, the genetic differentiation in Section Aigeiros is more complex, and they can be further divided into four subgroups, including P. nigra, P. × jrtyschensis and their backcross progeny. It is confirmed that P. × jrtyschensis should be classified as Section Aigeiros based on their smaller genetic distance. [目的]为探讨额河杨和银灰杨天然杂种的起源机制,[方法]应用18对SSR标记,从分子水平上对新疆

[Objective]This paper aims at investigating the genetic diversity and genetic differentiation of Populus tremula distributed in Xinjiang, China. [Method]Six single-copy nuclear gene markers of 72 P. tremula individuals from 4 populations in Xinjiang were amplified and sequenced. The parameters of genetic diversity and genetic differentiation were calculated. [Result]After aligning, the length of the six genes ranged between 459 bp and 747 bp and the average number of polymorphism sites was 14. Diversity parameters, π and θw reached 0.004 8 and 0.004 4, respectively. The mean value of gene diversity was 0.73. These indicated high level of genetic diversity of P. tremula. The results of Neutral tests using Tajima's D were not significant, which indicated all the six genes did not violate from neutrality. The results of AMOVA analysis showed that 89.72% of the total variance existed within populations. The average genetic differentiation parameter Fst and gene flow among populations reached 0.10 and 3.235, respe

应用SSR标记技术,对新疆齐斯河流域河谷分布的白杨派树种银白杨、银灰杨和欧洲山杨天然居群的克隆结 构、克隆多样性和遗传多样性进行研究.结果表明：欧洲山杨、银白杨和银灰杨均有很强的克隆繁殖特性.欧洲山杨、银白杨居群的克隆多样性均比较高,Simpson指数分别为0.987和0.983.与欧洲山杨相比较,银白杨居群具有较低的遗传多样性,Shannon信息指数分别为1.068 9和0.324 9,Nei多样性指数平均为0.505 6和0.211 2.欧洲山杨和银白杨居群间的遗传一致度均较高,变幅分别为0.778 1～0.9544和0.975 1～0.9946,反映出其超长距离的基因流特性,超强的基因流阻止了银白杨和欧洲山杨居群的遗传分化.研究发现,银白杨和欧洲山杨分别有95％和89.98％的遗传变异存在于居群内.

Along the Erqis River, there are various natural Populus forests, which include Section Leuce in Populus, such as Populus alba, Populus canescens and Populus tremula. Clonal diversity and structure were studied using nuclear microsatellite markers. The results showed that clonal reproduction was the primary reproduction strategy of these Populus populations. The populations of P. alba and P. tremula had an abundant clonal diversity and the mean Simpson's index were 0.983 and 0.987, respectively. Compared with the P. tremula, Populus alba had lower genetic diversity and their Shannon' index were 1.068 9 and 0.324 9, Nei' index were 0.505 6 and 0.211 2, respectively. The genetic consistency was high among populations, and variation range were 0.778 1 0.954 4 in P. tremula, 0.975 1 0.994 6 in Populus alba. It suggested they had long-distance gene flow and prevented genetic differentiation among P. alba and P. tremula population. In addition, genetic diversity indicated that the genetic variation occurred within

应用SSR标记技术,对新疆额尔齐斯河流域河谷分布的苦杨（Populus laurifoli）和欧洲黑杨（Populus nigra）天然居群的遗传多样性和遗传分化进行了研究.结果显示：苦杨和欧洲黑杨的天然居群具有较高的遗传多样性,且苦杨明显高于欧洲黑杨.与苦杨居群相比,欧洲黑杨居群间基因流较高,居群间的遗传分化程度较小,变异主要源于居群内.苦杨和欧洲黑杨居群内的杂合度较高,各个居群的各项遗传参数都要小于物种水平.苦杨和欧洲黑杨均偏离Hardy-Weinberg平衡,表现为杂合子过量的现象.

The genetic diversity and population genetic differentiation of Populus laurifolia and P.nigra distributed along Erqis River were studied by using nuclear microsatellite markers (SSR). The results showed that the P. laurifolia and P. nigra populations had an abundant genetic diversity, especially P. laurifolia. Higher gene flow (Nm=10.0585) was found in P.nigra than in P.laurifolia, which prevented the genetic differentiation among populations. It was found that 97.57% genetic variation resulted from intra-populations. In addition, there existed a higher heterozygosity in P. laurifolia and P. nigra populations, and many genetic coefficients of populations were smaller than those of species. The inbreeding coefficients among populations were negative, indicating that all SSR loci investigated were deviated from Hardy-Weinberg equilibrium at the level of individuals and populations, which suggested that excess of heterozygotes was present in the population. 应用SSR标记技术，对新疆额尔齐斯河流域河谷分布的苦杨（Populus laurifoli）和欧洲黑杨（Po

利用SSR分子标记技术，对采自新疆额尔齐斯河流域阿尔泰市哈巴河及北屯地区的白杨派3个树种银白杨、银灰杨、欧洲山杨的半同胞家系子代进行遗传多样性分析。结果表明：筛选12对SSR引物在90个样本中共检测到58个等位基因（A）、112种基因型，多态位点百分率是100％，Nei遗传多样性指数（h）平均为0．6485，Shannon多样性指数平均为1.234。基因分化系数（Fst）为0.3371，即在总的遗传变异中有33.71％的变异来自于不同树种之间，绝大部分存在于子代个体问。白杨派内种间分化程度较高，种间遗传距离为0.3863～1.869；银灰杨的遗传变异最大，而银白杨的遗传变异最小。

新疆额尔齐斯河流域河谷的银白杨天然林分呈雌雄独立斑块状分布,为了解其成因及分布模式,利用SSR分子标记技术对根据2种采样策略采集的银白杨样本进行了克隆结构和克隆多样性研究。结果表明：（1）运用12对SSR引物对采自各雌雄独立斑块的所有样本进行分析,发现所有样本单株是同1个无性系克隆,斑块内只有1个基株,即斑块居群是单克隆结构;（2）整个流域不同斑块所采集的90个样本用12对SSR引物进行扩增分析,共检测到53个基因型（克隆基株）,银白杨居群克隆多样性水平较高,Simpson指数（D）平均为0.983,基因型比率PD平均为0.589。银白杨以根孽方式繁殖后代,其最初建群时由多个不同基因型克隆基株形成了较高的克隆多样性,现存植株是克隆后代或克隆后代的后代。