论文标题:滇杨遗传多样性与杨属派间遗传分化研究
Study on Genetic Diversity in Populus Yunnanensis and Differentiation among Sections in Populus
论文作者
论文导师 张志毅,论文学位 硕士,论文专业 林木遗传育种
论文单位 北京林业大学,点击次数 525,论文页数 81页File Size4121K
2006-05-01论文网 http://www.lw23.com/lunwen_1104852/
Populus L; Populus yunnanensis; Allozyme; AFLP marker; Genetic diversity; Genetic differentiation
杨树是杨柳科( Salicaceae )杨属( Populus L. )树种的统称,由于其生长快、适应性强、用途广而被世界许多国家和地区广泛进行栽培,是当今世界中纬度地区栽培面积最广、木材产量最多的一个树种。我国具有丰富的杨树种质资源,占世界杨树种类的50 %以上,特别是在白杨派、青杨派中,有许多种为中国所特有,并且分布非常广泛,充分挖掘、开发和利用这些杨树基因资源,对培育更新换代的杨树优良新品种具有重要意义。本研究以滇杨主要分布区的4个种源的120个个体为试材,从等位酶水平和DNA水平测定了滇杨的遗传多样性,分析了其遗传结构,比较了4个种源间遗传多样性的高低。同时,以杨属中的白杨派、青杨派、黑杨派、胡杨派四个派内共54个个体为试材,应用AFLP分子标记技术对其派间遗传分化进行了研究,为今后开展派间及派内种间杂交育种,提供了科学依据。通过以上研究,得出以下主要结论: 1.以滇杨4个种源的120个个体为试材,应用水平淀粉凝胶电泳技术,对8个酶系统进行检测,共产生13个清晰位点,其中多态位点12个,多态位点百分数P = 92.31 %。共检测出等位基因数29个,平均每个位点的有效等位基因数Ae = 1.8858个,期望杂合度He = 0.4461,Shannon信息指数I = 0.6416。各遗传多样性参数值在滇杨种源内的表现为P = 92.31 %,A = 2.231,Ae = 1.934,He = 0.4518,I = 0.6619。4个种源间的遗传一致度变幅为0.9566 ~ 0.9964,遗传距离的变幅为0.0036 ~ 0.0443。遗传分化系数Fst = 0.0254,表明滇杨各种源间相似性很高,也即有97.45 %的遗传多样性存在于滇杨各种源内个体间。利用种源间的遗传距离进行了UPGMA聚类分析,结果发现滇杨4个种源聚成两类,地理位置近的种源聚在一起,即丽江种源和大理种源聚为一类,昆明种源和宣威种源聚为一类。从等位酶水平看,滇杨种源内个体间存在着丰富的遗传变异。 2.以滇杨4个种源的120个个体为试材,应用AFLP标记技术对11对AFLP引物进行研究,分离出清晰的AFLP标记1006个,其中692个标记具有多态性,多态位点百分数P = 68.79 %,平均每位点等位基因数A = 1.418个,平均每个位点有效等位基因数Ae = 1.174个,Nei’s基因多样性指数H = 0.105,Shannon信息指数I = 0.162。种源间遗传分化系数GST = 0.2591,即有25.91 %的变异存在于滇杨4个种源间,74.09 %的变异存在于种源内个体间。基于遗传距离的聚类结果可将4个种源聚为两类,大理种源、宣威种源和昆明种源聚为一类,丽江种源单独聚为一类。在DNA水平,滇
Poplar is a general name of all tree species in genus Populus L. of family Salicaceae and is characterized by rapid growth, high adaptability and wide employment. It has been cultivated in many countries and become one of the tree species with the broadest distribution and the highest timber production in the mid-latitude areas. Poplars are abundant in China, accounting for over 50% of the total resources. Many species in section Leuce and Tacamahaca are indigenous and widely distributed in China. Full employment of these genetic resources is of significance for the improvement and the breeding of new varieties or cultivars. In this study, 120 clones of P. yunnanensis from four provenances were used for the analyses of genetic diversity and genetic structure and for the comparison of diversity level on both allozyme and DNA levels. Meanwhile, 54 poplar clones from section Leuce, Tacamahaca, Aigeiros and Turanga were studied using AFLP analysis for identification of inter-section differentiation. This study laid a scientific foundation for both the inter- and intra-section cross breeding. The main results are described as follows: 1. A total of 120 clones of P. yunnanensis from four natural populations were used for the horizontal starch-gel electrophoresis with eight enzyme systems. 13 clear bands were observed in the gel, of which 12 bands demonstrated polymorphism, thus the polymorphic index (P) is up to 92.31%. 29 alleles were detected, average effective alleles (Ae) was 1.8858. The expected heterozygosity (He) was 0.4461, and Shannon’s information index (I) was 0.6416. At inter-population level, the estimates were P=92.31%,A=2.231,Ae=1.934,He=0.4518,I=0.6619. The genetic similarity among populations ranged from 0.9566 to 0.9964, and genetic distance from 0.0036 to 0.0443. The genetic differentiation coefficient (Fst) was only 0.0254, indicating the high similarity among different populations of P. yunnanensis. 97.45% of genetic diversity originates from the differences of individuals within population. A UPGMA dendrogram, based on the genetic distances, were constructed in four populations of P. yunnanensis. Four populations were separated into two groups according to their geographic distances, the population LIJIANG and population DALI in the first group, and population KUNMING and population XUANWEI in the second group. The allozyme analyses showed that there were rich genetic variations among individuals within populations of P. yunnanensis. 2. AFLP analysis was carried out in a total of 120 individuals from four populations of P. yunnanensis with 11 primer combinations. 1,006 AFLP bands were observed, of which 692 makers showed polymorphism. The percentage of polymorphism (P) is 68.79%. 1.418 alleles and 1.174 effective alleles were detected in each locus. The Nei’s index (H) and Shannon informative index are 0.105 and 0.162, respectively. According to genetic divergence of populations, GST=0.2591, the variation among population contributes 25.91% of the total variation and the other 74.09% exists among
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