尾叶桉多世代育种群体的遗传多样性及其改良性状的关联分析

发布时间：2018-05-12 05:50

本文选题：尾叶桉育种群体 + 微卫星标记　；参考：《中国林业科学研究院》2017年博士论文

【摘要】：尾叶桉是我国最重要的桉树改良树种之一,长期以来积累了丰富的尾叶桉优良种质资源。目前,我国的尾叶桉改良处于第三代改良阶段。尾叶桉第二代育种群体的构成材料是第一代育种群体中经高强度人工选择的自由授粉子代,第三代育种群体的构成材料同样经历高强度的人工选择,主要为尾叶桉前两个世代的自由授粉子代。因此,尾叶桉高世代育种群体的遗传多样性和遗传结构较之前的世代群体发生了很大的变化,但世代间的遗传物质又存在很大的继承关系。所以,在计划推进尾叶桉进入下一个世代的改良、选择构成下一代群体的遗传材料之前,了解现有世代育种群体的遗传多样性和遗传结构显得非常重要。本研究的主要内容包括:(1)借助微卫星标记分别对尾叶桉三个世代育种群体的遗传多样性和遗传结构进行分析,包括清楚了解第一代天然种源的遗传多样性水平和遗传结构特点,重点对比三个世代育种群体遗传多样性的变化规律。(2)评估尾叶桉三个世代育种群体改良性状的表型遗传变异水平。探索近红外光谱(NIRs)分析技术用于桉树改良性状快速预测的可行性。(3)挖掘与尾叶桉木材密度和生长性状显著关联的微卫星位点。本研究的主要结论如下:(1)基于微卫星的Hardy-Weinberg平衡检测显示,尾叶桉三代育种群体都表现出明显的杂合子缺失现象,且均偏离遗传平衡。(2)16个基因组微卫星位点分别在三代尾叶桉育种群体中检测到459、313和428个等位基因。Shannon信息指数(1.966、2.093和2.265)表明尾叶桉三代育种群体的遗传多样性较为一致。多态性信息含量(0.859、0.840和0.866)表明,三代尾叶桉育种群体具有高度多态性。期望杂合度(0.807、0.830和0.857)表明尾叶桉三代育种群体都具有很高的遗传多样性。(3)尾叶桉三个世代育种群体间的遗传距离距离分别为0.450、0.238和0.249,遗传一致度分别为0.645、0.788和0.781,遗传分化系数分别为0.044、0.021和0.018,基因流分别为6.387、11.506和14.393。这些数据说明,尾叶桉三代育种群体内的遗传分化水平很低且在逐代降低,群体内的基因流在逐代增加。(4)分子方差分析结果显示,尾叶桉三代育种群体的遗传变异主要来自种源或亚群体间的所有个体间(接近70%),群体内变异占30%以上,群体间的遗传变异最小。尾叶桉第一代群体的Structure亚群体分类和UPGMA聚类分析结果基本一致,但尾叶桉天然种源间的聚类结果与其地理分布并不一致。(5)尾叶桉木材密度和生长性状的表型变异分析表明,尾叶桉三代育种群体目标性状在种源和亚群体间都存在显著的遗传变异(0.05)。尾叶桉三个世代育种群体的木材密度和生长性状的多重聚类分析显示,从木材密度的差异来看,尾叶桉三代育种群体的表型分化相对较小,显著性不高。三代育种群体基于生长性状的表型分化水平相对较高(0.05)。(6)基于最小二乘法(PLS)建立的桉树木材密度、纤维长度和纤维宽度的NIRs模型的测量值和预测值间的决定系数(R2)分别为0.93、0.94和0.92。测量值与预测值间的平均均方根误差(RMSEC)分别为0.007、0.013和0.254。用独立的验证集样本对桉树木材密度和纤维形态NIRs校正模型的预测检验显示,木材密度、纤维长度和纤维宽度的NIRs模型的预测效果都很好。(7)关联位点的表型变异解释率(R2)显示,基于群体T164(木材密度43.8%、胸径67.6(一个位点)、树高40.1%)和群体T77(木材密度24.3%、胸径40.5%、树高55.4%(两个位点))所得到的所有关联位点的表型变异解释率都比较高,说明这些关联位点对目标性状的控制程度比较高。(8)在两个关联群体中,基于同样的微卫星位点没有发现同一个在两个群体中同时与相同的性状关联的标记。在两个群体中,与尾叶桉木材密度关联的位点数量都相对较多,与生长性状关联的位点较少。在群体T164中,位点EUceSSR900同时与木材密度和树高关联,位点EUceSSR425同时与尾叶桉木材密度和胸径关联。位点EUceSSR900在GLM模型和MLM模型的算法中被同时检测到,这在很大程度上排除了其假阳性的可能性。位点Embra100与木材密度的关联程度达到了极显著水平(P0.001),其对木材密度的表型变异解释率为75.8%,远高于木材密度关联位点的平均解释率。在群体T77中,与尾叶桉木材密度和胸径关联的位点数量相当,与树高关联的位点有2个。
[Abstract]:Eucalyptus urophylla is one of the most important improved eucalyptus tree species in China. It has accumulated rich germplasm resources of Eucalyptus urophylla for a long time. At present, the improvement of Eucalyptus urophylla in China is in the third generation improvement stage. The composition of the second generation breeding population of Eucalyptus taurophylla is the free Pollination Progeny of the first generation breeding population by high intensity artificial selection, and the third generation. The genetic diversity and genetic structure of the high generation breeding population of Eucalyptus urophylla were greatly changed in comparison with those of the previous generations, but there was a great inheritance of genetic material between generations. It is very important to understand the genetic diversity and genetic structure of the existing generation breeding population before entering the next generation of genetic material in the next generation of Eucalyptus urophylla. The main contents of this study include: (1) the genetic diversity of the three generations of Eucalyptus urophylla populations by microsatellite markers, respectively. Analysis of the pattern and genetic structure, including a clear understanding of the genetic diversity and genetic structure of the first generation natural provenance, focusing on the variation of genetic diversity in the three generations of breeding populations. (2) to assess the level of the genetic variation of the modified traits in the Oba Mi breeding population and to explore the near infrared spectroscopy (NIRs) score. The feasibility of rapid prediction of the improved traits of Eucalyptus was analyzed. (3) mining the microsatellite loci significantly associated with the wood density and growth traits of Eucalyptus urophylla. The main conclusions of this study are as follows: (1) the Hardy-Weinberg balance detection based on microsatellites showed that the three generation breeding populations of Eucalyptus urophylla showed obvious heterozygote deletion. (2) 16 genomic microsatellite loci have detected 459313 and 428 alleles.Shannon information index (1.966,2.093 and 2.265) in three generation of Eucalyptus urophylla populations (1.966,2.093 and 2.265), indicating that the genetic diversity of the three generation of Eucalyptus taurophylla is more consistent. Polymorphism information content (0.859,0.840 and 0.866) indicates that the three generation of Eucalyptus The expected heterozygosity (0.807,0.830 and 0.857) showed that the three generation breeding population of Eucalyptus taurophylla had high genetic diversity. (3) the genetic distance distance between three generations of Eucalyptus urophylla was 0.645,0.788 and 0.249 respectively, the genetic consistency was 0.645,0.788 and 0.781, and the genetic differentiation coefficient was 0.044, respectively. 0.021 and 0.018, the gene flow is 6.387,11.506 and 14.393., respectively. The genetic differentiation level in the three generation breeding population of Eucalyptus taurophylla is very low, and the gene flow in the population increases in generation by generation. (4) the results of the molecular variance analysis show that the genetic variation of the Oba Mi generation population is mainly from the provenance or subpopulation. Among all the individuals (close to 70%), the variation in the population was over 30% and the genetic variation among the groups was the smallest. The results of the Structure subgroup and the UPGMA cluster analysis of the first generation of Eucalyptus urophylla were basically the same, but the results of the cluster between the natural species of Eucalyptus urophylla and its geographical distribution were different. (5) the wood density and the phenotype of the growth traits of Eucalyptus urophylla. The variation analysis showed that there were significant genetic variations between the seed and subpopulations of the three generation breeding population of Eucalyptus urophylla (0.05). The multiple cluster analysis of wood density and growth traits of three generations of Eucalyptus urophylla showed that the phenotypic differentiation of the three generation breeding population of Eucalyptus urophylla was relatively small. The level of phenotypic differentiation based on growth traits of the three generation breeding population is relatively high (0.05). (6) the determining coefficient (R2) between the measured values and the predicted values of the NIRs model of Eucalyptus wood, fiber length and fiber width (R2) based on the least square method (R2) is divided into the average mean square between the 0.93,0.94 and 0.92. measured values and the predicted values. The root error (RMSEC) for 0.007,0.013 and 0.254. used independent validation set samples to predict the density of Eucalyptus wood and the NIRs correction model of fiber morphology. The prediction results of NIRs model of wood density, fiber length and fiber width were all good. (7) the phenotypic variation interpretation rate of association sites (R2) was based on population T164 (wood). Density 43.8%, DBH 67.6 (one site), tree height 40.1%) and population T77 (wood density 24.3%, DBH 40.5%, tree height 55.4% (two loci)) have high phenotypic variation in all associated loci, indicating that these associated sites have higher control over target traits. (8) in two related groups, based on the same microsatellite. In the two population, the number of loci associated with the wood density of Eucalyptus urophylla is relatively more, and the loci associated with the growth traits are less. In population T164, the site EUceSSR900 is associated with wood density and tree height, and the site EUceSSR425 is at the same time. The association with wood density and DBH of Eucalyptus urophylla. Site EUceSSR900 was detected at the same time in the GLM model and the MLM model algorithm, which largely eliminated the possibility of false positive. The correlation between the site Embra100 and the wood density reached a very significant level (P0.001), and the interpretation rate of phenotypic variation to wood density was 75.8%, far from that of wood density. In population T77, the number of loci associated with the wood density and DBH of Eucalyptus urophylla is equal, and there are 2 loci associated with tree height.

【学位授予单位】：中国林业科学研究院
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S792.39

【参考文献】