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[目的]由于过度采伐和天然更新能力较差等原因,红椿天然林分和林木的数量日益减少。深入研究红椿不同种源的遗传多样性,揭示其群体结构分布,可为其种质资源保护和选择育种提供理论依据。[方法]利用相关序列多态性分子标记(SRAP)对来自中国的29个种源及1个澳大利亚种源进行遗传多样性分析。各种源地选取母树30株,株距50 m以上。澳大利亚种源取自华南农业大学红椿资源收集圃。利用POPGENE1.32,NTSYSpc2.1,Gen AIEx 6.5和STRUCTRUE 2.3进行遗传参数估计、聚类图构建、主坐标分析、地理隔离模式构建及遗传结构分析。[结果]24对SRAP引物组合共扩增出505条多态性条带,引物的多态信息含量(PIC)均值为0.41;30个红椿种源间的Nei’s基因多样性指数平均为0.377 0;种源内Shannon’s信息指数(I)变动幅度为0.157 5~0.467 5,种源间均值为0.556 9。分子方差分析(AMOVA)得出,在总的遗传变异中,79.26%的遗传分化存在于种源间,种源内分化仅占20.74%,表明红椿的遗传分化主要来源于种源间,红椿良种选育应首先开展种源选择。STRUCTURE分析将30个红椿种源分成2大组群,趋势呈现为华东与华中种源为一组,西南、华南与澳大利亚的种源为另一组;Mantel检测显示,中国红椿种源存在地理隔离模式(IBD)。非加权平均法(UPGMA)聚类分析将红椿30个种源划分为4大类:第Ⅰ类包括14个种源,主要是来自华中和华东地区的种源;广东乐昌种源独立成为一类,形成第Ⅱ类;第Ⅲ类包括13个种源,主要是来自西南和华南的种源;广东云浮种源和澳大利亚多瑞格的种源组成第Ⅳ类。主坐标分析(PCo A)得到的结果与聚类分析结果相似。[结论]红椿分布地区生境片段化,使各群体在空间上相对隔离、基因交换频率低、流动程度小,从而导致地理变异。聚类分析与主坐标分析的结果与地理分布格局基本吻合。在红椿保护和管理的过程中,在对原有生境进行保护的同时,要加强人工繁育技术研究,并注意最大限度地保护红椿的遗传多样性。
[Objective] Due to over-harvesting and poor natural regeneration, the natural forest and forest trees of Red-crowned Manila are decreasing day by day. Studying the genetic diversity of different provenances of Toona sinensis and revealing their population structure distribution may provide a theoretical basis for conservation and selective breeding of germplasm resources. [Method] The genetic diversity of 29 provenances and 1 Australian provenance from China were analyzed by using the related sequence polymorphism molecular markers (SRAP). 30 kinds of mother trees were selected from all kinds of sources, with a plant spacing of more than 50 m. Australian provenance from South China Agricultural University Red Spring Resources collection garden. Genetic parameters estimation, clustering map construction, principal coordinate analysis, geographic isolation pattern construction and genetic structure analysis were carried out using POPGENE1.32, NTSYSpc2.1, Gen AIEx 6.5 and STRUCTRUE 2.3. [Result] A total of 505 polymorphic bands were amplified by 24 pairs of SRAP primers. The average polymorphic information content (PIC) of the primers was 0.41. The average Nei’s gene diversity index of 30 Populus tomentosa populations was 0.377 0 Shannon’s information index (I) within provenances ranged from 0.157 5 to 0.467 5, and the mean between provenances was 0.556 9. According to the analysis of molecular variance (AMOVA), 79.26% of the total genetic variation existed between provenances, with only 20.74% of total germplasm within provenances, indicating that the genetic differentiation of Toona ciliata mainly came from provenances, Breeding should first carry out provenance selection. STRUCTURE analysis of 30 Toonae provenances were divided into two groups, the trend showed that the East China and Central China provenance as a group, Southwest China and Australia, the provenance for the other group; Mantel test showed that the provenance of Chinese Toon Geographical Segregation Mode (IBD). The UPGMA cluster analysis divided the 30 provenances of Toona sinensis into four major groups: the first group consisted of 14 provenances, mainly from the provenance of central and eastern China; the independent source of Guangdong Lechang became Class III, forming Class II; Class III includes 13 provenances, mainly from Southwest China and South China provenance; provenance of Yunfu, Guangdong and Australia Doric composition Class IV. The result of PCo A is similar to that of cluster analysis. [Conclusion] The fragmentation of Habitat in the areas where T. mandshurica distributed, so that each population was relatively isolated in space, gene exchange frequency is low, the degree of mobility is small, resulting in geographical variation. The results of cluster analysis and principal coordinate analysis basically coincide with the geographical distribution pattern. In the process of conservation and management of red cedar, while protecting original habitats, we must strengthen the research on artificial breeding technology and pay attention to the maximum protection of the genetic diversity of red cedar.