【作者】 周连第；

【导师】 韩振海；

【作者基本信息】 中国农业大学 ， 果树学， 2005， 博士

【摘要】 中国板栗（Castanea mollissima）居群分布,按照群体分布及其生态梯度进行（随机）分组取样,研究了板栗9个种群群体的表型多样性及DNA水平多样性,并对表型与DNA二个不同层次的遗传多样性研究进行了比较和评价;应用AFLP分子标记技术,进行供试板栗品种的分子鉴定。主要结果如下: （1） 板栗种群表型性状在群体间和群体内都存在极显著差异。群体间表型分化系数为V_ST=0.2426;群体内为V_ST=0.7574,Shannon信息指数群体内Ⅰ=0.0705,群体间为Ⅰ=9413;板栗群体内的平均表型变异占75.74%,种群内变异是表型变异的主要来源,种群内的多样性大于种群间的多样性。板栗表型性状与EGA（生态梯度）相关显著,随着纬度的南移,坚果逐渐增大,果实由半圆形、圆形向长圆形变化,叶形由长倒卵形向宽倒卵形变化,随着海拔升高,坚果逐渐变小。利用群体间欧氏距离进行UPGMA聚类分析,可将供试群体划分为两大类组,4个亚类。 （2） 利用筛选出的9对荧光引物,对6个群体共90个品种进行了AFLP标记分析,共得到806条带,其中多态性条带695条,平均多态位点百分率为86.23%。AFLP标记测定的扩增谱带频率的差异,反映了群体间遗传结构的差异,揭示了基因频率在群体间差异显著;群体特异带及群体间共有带的差异与分布揭示了各群体的遗传差异及相似性;板栗遗传多样性在群体间存在真实遗传差异,但遗传多样性52.47%分布于群体内,群体内分化比较严重。群体间的遗传多样性（Dst）为0.0728,群体内遗传多样性（Hs）为0.0804,基因流Nm为0.4529。 （3） 用AFLP荧光法技术对板栗90个优良品种进行了DNA鉴定,为其中20个品种找到了独一无二的AFLP指纹。其余的品种用2条或3条带完全可以分开。供试板栗品种之间的相似系数均大于0.56,品种间的亲缘关系比较接近。UPGMA聚类分析可以初步将板栗供试品种分为14类,板栗自然群体间的遗传距离有随地理距离跨度递增趋势。 （4） 表型与DNA分子标记揭示的板栗遗传多样性水平有差异,表型性状比DNA具有更大的变异性,对环境更敏感。二种方法揭示的群体聚类结果较一致,表明这二种方法在评价板栗（同一套试材）遗传多样性中的耦合性较好。本研究为板栗及其它栗属植物种质保存、评价和利用研究提供了可信赖的实验依据。更多还原

【Abstract】 Based on field investigations and analysis of the natural distribution of Castanea mollissima in P. R. China, 90 varieties of 9 populations of C.Mollissima (Beijing, Hebei, Shandong, Zhejiang, Shanxi, Hubei, Henan, Jiangsu, and Anhui) were selected and investigated. Genetic diversities were evaluated and compared at two levels of morphology(i.e., leaf and nut for 9 populations) and DNA fingerprint(AFLP analysis on 6 populations) . The study was undertaken to identify chestnut(Castanea mollissima) material of varieties in China by Amplified Fragment Length Polymorphism(AFLP) The main results as following:(1) Morphological diversities among/within populations were discussed by analyzing characters such as leaf and nut. Analysis of variance for all characteristics were significantly different among populations and among individuals within population. The mean phenotypic differentiation coefficient (Vst) shows that the variation within population (24.26%) is extremely higher than that among populations(75.74%) which revealed that variation within population were the more important. The nut becomes larger, the shape of the nut changes from spherical, and leaf shape of the longitude and latitude, upon increasing of the lonitude and latitude. The nut gets smaller as the altitude becomes higher. According to the correlation analysis, the populations of C.Mollissima investigated may be divided into two groups and four sub-groups.(2) The AFLP system was built and used for the amplification reaction in the experiment. There were totally 90 individuals were selected and analyzed by amplifications using 9 pairs of AFLP primers screened, 806 bands were obtained, 695 bands (86.23% ) of them were found to be polymorphic. The difference of frequency reflected the differences of genetic structure. The polymorphic bands and common bands showed variation diversity and genetic intercommunity of chestnut germplasm resources. As for C. Mollissima, genetic differentiation coefficient among 6 populations (Gst) is 0.4753. Genetic identities within the 6 populations were 0.0804 , this indicated that the genetic diversity of C. Mollissima were mainly existed within population at molecular level. According to the UPGMA cluster analysis.(3) To obtain AFLP markers in chestnut germplasm resources, the polymophic primers were used. It was found that 20 varieties had unique AFLP fingerprinting. The others could be identified by 2-3 bands. The similar coefficient of materials tested was 0.56. The UPGMA cluster based on AFLP wasundertaken and a total of 90 chestnut varieties were distinctly classified into 14 types. The genetic distance increased with the enhancing of geographic distance.(4)The diversity levels are different between pheuotype or DNA markers and the former was more sensitive to environment. Genetic cluster analysis is similar based on the results of phenotype and DNA markers which means the coincidence of this two methods applied for evaluating genetic diversity was better. The study is a meaningful approach for evaluating genetic diversity, sampling strategy, conservation and utilization of genetic resources of Castanea.更多还原