【作者】 徐郑；

【导师】 胡庭兴；

【作者基本信息】 四川农业大学 ， 森林培育， 2008， 硕士

【摘要】 核桃是果材兼用的优良经济树种,它作为四大干果之一,有极显著的经济效益和生态效益。本试验以川西高原和秦巴山区收集的35份核桃种质资源为研究对象,运用AFLP和RAPD两种分子标记,结合种群生态、形态学特征分析,运用系统聚类分析方法,对35份核桃种质材料的遗传多样性进行了研究。主要结果如下:(1)从引物筛选、酶切连接、扩增条件、检测方案等几个方面进行优化,建立了核桃RAPD和AFLP最适反映体系,在此优化体系下,可以得到重复性好、稳定且多态性高的核桃RAPD、AFLP条带。(2)对核桃遗传多样性研究表明:32条RAPD随机引物在核桃群体中共扩增出324条带,平均每个引物扩增出10.1条带。其中,呈多态性的条带有279条,多态性比率为86.11%;而10对AFLP引物组合在核桃群体中共扩增出769条带,平均每个引物扩增出76.9条。其中,呈多态性的条带有440条,多态性比率为57.2%,表明核桃类群遗传结构复杂,遗传多样性丰富。(3)聚类分析表明:秦巴山区由于相互引种,基因交流频繁,导致当地核桃种质的基因型趋于一致,其遗传差异不大,群内和类群间遗传距离相对较小,从而表现出较亲的亲缘关系;而川西高原由于地理上的隔离,交通不便,基因交流较少,当地丰富的基因资源得以保存,具有良好的遗传多样性,对核桃种质资源的保护和开发有十分积极的意义。(4)通过对两种分子标记的比较研究表明,RAPD所发现的基因位点数量上要少于AFLP。尽管每对AFLP引物组合的多态率要低于RAPD单个引物的多态率,但是每对AFLP引物组合揭示的有效多态性带数要明显高于RAPD引物,另外AFLP标记的假阳性低。更多还原

【Abstract】 China is a major area for origin and genetic variation of walnut, which has abundant nutrimental material, vitamin, and it has a long planting history. It is an important fruit and woody species. The genetic diversities of 35 walnuts samples derived from 7 different regions in Plateau of Western Sichuan Province and Qinba mountainous regions were investigated using AFLP and RAPD methods. To combine with morphological and agronomical traits, the results were as follows:1、Based on the genomic DNA extracted from Walnut, essential factors affecting the result of RAPD and AFLP assay were tested and compared. The research approved that an optimal reaction system was suitable for the assay and usage of RAPD and AFLP in Walnut.2、In the research, 324 RAPD fragments were produced, 279(86.1%) of total bands showed polymorphic with the size ranging from 180 to 2000bp, and 10.1 fragments per primer were amplified on average; 769 AFLP fragments were showed by twenty eight primers, and 440 polymorphic bands were generated, the percentage of polymorphic bands was 57.2%.3、Walnut in Plateau of Western Sichuan Province showed highest polymorphism detected by both RAPD and AFLP markers. The high number of alleles and the high expected genetic diversity detected with RAPD and AFLP markers make them a suitable tool for walnut cultivar identification, confirming these markers transportability among general in the walnut family.4、In the study, RAPD markers detect a few genetic loci than AFLP per primer. Although the level of polymorphism offered by AFLP was lower than RAPD, AFLP was efficient to reveal more polymorphic bands in a single lane than RAPD. Additionally, false positive products were easily recognized in AFLP, and sequence gel with high resolution and adaptor techniques used in AFLP analyzing that allows a more precise identification of similar and dissimilar AFLP allele. The study indicated that AFLP marker were much more reliable and provided a more coverage throughout the genome than RAPD.更多还原