【作者】 刘鹏飞；

【导师】 王汉宁； 王晓明；

【作者基本信息】 甘肃农业大学 ， 作物遗传育种， 2013， 博士

【摘要】 高产是玉米育种的首要目标。种植密度的增加、株型的改善和穗部性状的优化是玉米产量提高的主要措施。利用玉米耐密型品种，依靠群体产量来提高单产是实现玉米再高产的保障，是满足未来玉米需求最经济最有效的增产途径，也是玉米品种选育及产业化发展的必然趋势和方向。本研究选用自交系郑58、PH6WC、豫87-1、自330构建一个四交（郑58/豫87-1//PH6WC/自330）作图群体，通过SSR标记分析，构建了玉米的四交遗传连锁图谱，在高、低两种密度下，对玉米耐密性及相关性状的QTL进行了定位分析。主要研究结果如下：1.利用耐密系数对我国15份骨干玉米自交系在高低2种密度下，进行耐密性鉴定表明，15份自交系的耐密系数变幅较大。耐密系数前5位的自交系依次为PH6WC＞郑58＞K12＞掖478＞沈137，这些自交系耐密性较强；耐密系数最后5位的依次为：自330＜87–1＜许178＜综3＜丹9046，这些自交系对密度反应比较敏感。对广州和三亚两个试验点下四交F2:3家系的耐密系数进行相关分析表明，两个环境的耐密系数呈极显著正相关（0.342**），表明基于产量计算的耐密系数衡量玉米耐密性是可行、可靠的。在两个试验点的高密度下，株高（0.131*，0.156*）、茎粗（0.1488*，0.152*）和叶向值（0.141*，0.132*）性状与耐密系数均达到显著性正相关；穗长（0.245**，0.161*）、行粒数（0.243**，0.237**）及百粒重（0.224**，0.168*）与耐密系数呈显著或极显著正相关，秃尖长（-0.138*，-0.143*）与耐密系数成显著负相关。因此，这些性状可以做为评价耐密性的重要次级指标。2.以郑58/豫87-1//PH6WC/自330的228个四交F1单株为作图群体，筛选出231对SSR引物基本符合所期望的1:1、1:2:1和1:1:1:1的各种分离比例，利用225个SSR标记在10对染色体上构建了覆盖玉米全基因组的分子标记遗传图谱，整个连锁图谱总长度1387.2cM，平均间距为6.19cM，10对染色体上标记平均间距在4.05～9.29cM之间，该图谱满足QTL初步定位的要求。3.基于四交群体以耐密系数作为评价耐密性的指标，应用区间作图法分析广州和三亚两个试验点的QTL，共检测到9个QTL，分别位于第3、4、7和8染色体上，单个QTL可解释的表型变异为5.2%~28.9%。发现1个在2个环境表现稳定的主效QTL位于第7染色体，落在同一标记区间，位于连锁群bin7.02-bin7.03位点；2个环境下检测到的第3染色体上的2个QTL，qDTC-E1-1和qDTC-E2-2都临近标记umc1399，而且连锁图上QTL位置非常接近，分别位于连锁群bin3.07-bin3.09和bin3.05-bin3.07位点。4.对耐密性相关的14个性状在两个试验点两个密度下进行QTL定位检测，共定位到184个QTL，单个QTL可以解释的表型变异范围为3.3％～28.9％。株型性状主要分布在第1、4、7、9染色体上；抗倒伏株型性状QTL主要分布在第1、3、8染色体上；穗部性状QTL主要分布在第4、6、7、8染色体上。部分染色体上部分区域出现QTL成簇分布，而有些区域检测到不同性状在同一位点存在重叠的QTL。检测到的QTL中有26个QTL至少在2种环境下被同时检测到。其中，同一试验点不同密度下共检测到7个稳定的QTL；同一密度下不同试验点下共检测到19个稳定的QTL。3个环境钝感QTL在3个环境下均被稳定检测到，第1染色体上检测到1个控制叶向值的环境钝感QTL qLO-E1-1（bin1.02）；第5染色体上检测到1个控制雄穗分枝数的环境钝感QTL qTBN-E1-3(bin5.00-bin5.01）；第3染色体上检测1个茎粗系数环境钝感QTL qSDC-E1-3（bin3.01-bin3.02）。本研究的结果有望为玉米耐密型育种及分子辅助选择提供一定的理论依据。更多还原

【Abstract】 Yield still was the main target of corn breeding in China. Using density tolerance varietiesand relying on population production to improve yields was the most economical and effectiveway to complete higher yield. It was the inevitable trend and development direction of cornbreeding and industrialization in future. In this study, a four-way cross population was built withfour inbred lines (Zheng58, PH6WC,Yu87-1, Zi330).The genetic linkage map was constructed bySSR markers. The density tolerance and related traits QTL was detected in both high and lowdensity in two test point. The major results were as follows:1. The density tolerance of15inbred lines was indentified in the high and low density withdensity tolerant coefficient (DTC).The results showed the DTC of the15inbred lines have alarge amplitude value. The top5inbred lines with high density tolerant ranked as: PH6WC>Zheng58> K12> Ye478> Shen137，these inbred lines have strong density tolerance. The last5inbred lines with high density tolerant ranked as: Zi330<87-<Zong3<1<Xu178Dan9046，these inbred lines sensitive to the density. Correlation analysis of the F2:3families in Guang zhouand San ya two test points showed that DTC has a significant positive correlation (0.342**) in thetwo environment. It indicated that the DTC calculated based on the individual production as ameasure of corn density tolerance is feasible and reliable. In the high density of the two test points,PH (0.131*,0.156*)，SD (0.1488*,0.152*) and LO (0.141*,0.132*) had a significant positiverelated between DTC; EL (0.245**,0.161*)，KRE (0.243**,0.237**) and HGW (0.224**,0.168*) had a significant or very significant positive related between DTC;there was a significantnegative correlation between BTL and DTC. Therefore, these traits can be used as an importantsubindicators for evaluating the density tolerance.2. A genetic linkage map containing231SSR markers was constructed based on an four-waycross F1population with228individuals. The map spanned a total of1387.2cM with an averageinterval of6.19cM, the average interval from4.05to9.29on the10chromosome. For the study of231markers, there are225markers in accordance with the rate of1:1or1:1:1:1or1:2:1in thesegregation population. A linkage groups were established, covering the whole10chromosomes.The map can meet the preliminary requirements for the QTL mapping.3. The DTC from the population of the four-way cross F2:3families were evaluated for QTL analysis, with the method of interval mapping,9QTL were indentified for DTC on chromosome3,4,7,8, and the phenotypic variance explained by each QTL ranged from5.2%to28.9%. A majorQTL was found on chromosome7fall on the same marker interval, located in bin7.02-bin7.03site, were detected in both Guang zhou and San ya environment stability. Two QTL detected onchromosome3in the two environment, qDTC-E1-1and qDTC-E2-2near the markerumc1399,these position in the linkage map is very close, located in bin3.07-3.09andbin3.05-bin3.07site of the linkage map, respectively.4. Hundred and eighty-four QTL for14traits related to the density tolerance were detectedin the two density and two test points. There were screened mainly distributed in4,6,7and8chromosome. The phenotypic variance explained by each QTL ranged from3.32%to28.9%.Planttype QTL were mainly located on chromosome1,4,7,9. Lodging resistance QTL were mainlydetected on chromosome1,3,8. Ear traits QTL were mainly distributed in4,6,7,8chromosome.Part of QTL clusters on the part of the region on partial region on chromosome.Twenty-six QTL were detected in at least two environment, in which7were detected underdifferent density,19stable QTL were detected under different test points,22major QTL hasphenotypic contribution rate greater than10%simultaneously detected in two or moreenvironment. Three environmental insensitive QTL were detected in4environments. Oneenvironmental insensitive QTL qLO-E1-1was found on chromosome1located bin1.02site,controlling the leaf orientation; environmental insensitive QTL qTBN-E1-3was detected onchromosome5located bin5.00-bin5.01site; environmental insensitive QTL qSDC-E1-3wasdetected on chromosome3located bin3.01-bin3.02site.The result of this study may provideuseful information for compact breeding and marker-assisted selection for maize．更多还原