【作者】 魏昕；

【导师】 潘光堂；

【作者基本信息】 四川农业大学 ， 生物化学与分子生物学， 2007， 博士

【摘要】 玉米丝裂病的发生严重影响了种子的发芽率及出苗率，由于病粒感染真菌后又大大影响了商品玉米的品质。四川农业大学玉米研究所选育的“高配合力、大穗、多抗、广适玉米自交系08-641”已组配了近20个经国家、省审定的玉米新品种，已成为西南、特别是四川玉米育种的骨干自交系，但正是由于玉米丝裂病对该自交系的危害，使得在我国西北地区配制的以该自交系为亲本的新杂交种的丝裂病发病率高达30～40％，严重影响了杂交一代种的发芽率，这在一定程度上影响了该自交系在西南地区玉米育种和生产上应用。本研究为探讨其遗传规律并为做进一步深入的研究打下基础，对玉米的这个性状进行了遗传研究。利用植物数量遗传学的方法对普通玉米自交系R08与975-12杂交组合的P₁、P₂、F₁、F_2：3、B_1：2和B_2：2六个世代群体的种子丝裂病进行了研究，同时利用R08与Es40组合和R08与99s2052-3-2-1组合的F₂群体和F_2：4家系采用复合区间作图法对玉米丝裂病QTL进行了检测。主要研究结果如下：1、R08×975-12组合种子玉米丝裂病的遗传符合1对加性主基因+加性-显性多基因模型。在F_2：3、B_1：2和B_2：23个家系世代，主基因方差分别为201.4525，31.9877和31.9877；多基因方差依次为11.0397和81.1362。主基因加性效应值为11.3116；多基因加性效应值为-4.4719，显性效应值为10.8496。主基因遗传率在F_2：3和B_1：2两个分离家系群体中为81.31％和21.56％，多基因遗传率为4.46％与54.68％。其中，主基因遗传率在F_2：3世代中最大，为81.31％。2．R08×Es40组合中，利用115对SSR标记构建了覆盖玉米全基因组的分子标记遗传连锁图谱，该图谱覆盖玉米10条染色体，遗传图谱总长2178.6cM，平均间距18.9cM，标记偏分离分析结果表明，有19对标记（0.05水平）存在偏分离，标记偏分离比例为16.5％，能满足QTLs初级定位的要求。各连锁群上的SSR引物相对顺序大多数与玉米基因组数据库中提供的SSR染色体节点（bin）位置一致。采用复合区间作图法进行QTL定位及遗传效应分析，共检测到12个QTLs，分别位于1、2、4、5、7染色体上，分别命名为qSC-1-1、qSC-1-2、qSC-1-3、qSC-2-1、qSC-2-2、qSC-3-1、qSC-4-1、qSC-4-2、qSC-4-3、qSC-5-1、qSC-7-1、qSC-7-2。其位置分别为130.81、272.41、292.81、81.01、100.01、20.01、140.41、158.91、180.91，临近的连锁标记分别为bnlg1564、umc1144、umc2189、umc1004、umc1003、bnlg2047、mmc0371、mmc0371、umc2280、umc1815、phi328175、phi328175。其中在第1和第3染色体上分别检测到了一个主效QTL qSC-1-1和qSC-3-1，贡献率分别为36.91％和37.95％，其余的10个QTL贡献率在从4.22％到18.61％不等。基因作用方式分析表明，所检测到的12个QTL中，qSC-1-1、qSC-3-1、qSC-7-1为显性，qSC-1-2、qSC-1-3、qSC-2-2为加性，qSC-7-2为超显性，其余为部分显性。3．R08×99s2052-3-2-1组合中，利用86对SSR标记构建了覆盖玉米全基因组的分子标记遗传连锁图谱，该图谱覆盖玉米10条染色体，遗传图谱总长1706.1cM，平均间距19.8cM，标记偏分离分析结果表明，有12对标记（0.05水平）存在偏分离，标记偏分离比例为13.95％，能满足QTLs初级定位的要求。各连锁群上的SSR引物相对顺序大多数与玉米基因组数据库中提供的SSR染色体节点（bin）位置基本一致。采用复合区间作图法进行QTL定位及遗传效应分析，共检测到4个QTLs，分别位于2、3、5、6染色体上，分别命名为qSC-2-1、qSC-3-1、qSC-5-1、qSC-6-1。其位置分别为296.31、24.01、114.41、48.51，临近的连锁标记分别为umc1080、bnlg1754、umc1019、umc1006。其中在第3和第5染色体上分别检测到了一个主效QTL qSC-3-1和qSC-5-1，贡献率分别为39.42％和43.11％，其余的2个QTL贡献率分别为5.04％和7.29％。基因作用方式分析表明，所检测到的4个QTL中，qSC-3-1、qSC-5-1为显性，qSC-2-1、qSC-6-1为部分显性。4．在两个具有不同遗传背景的组合中均在第3条染色体相近位置上检测到了一主效QTL位点，位置分别为20.01cM与24.01cM，贡献率均大于30％，且加性效应与显性效应的值和方向都基本一致，这极可能说明在第3染色体上的确有真实存在有一个控制丝裂病性状的主效QTL；另外，在两个组合第2和第5染色体上也都检测到了QTL位点。5．通过对不同的组合的研究，不管是数量遗传的方法还是QTL的分析方法均表明丝裂病是由主基因加多基因控制的一种遗传性病害，可以互相印证和补充。更多还原

【Abstract】 The ratio of germination and seedling was effected badly due to silk-cut, and thequality of commercial maize was impacted greatly after infection by epiphyte. Inbreedline 08-641 with the agronomy characters of high combining ability、big ear、multipleresist and wide adaptability, which was combinated abort 20 new maize varietiesauthorized by province or nation, has become main inbreed lines in southwestchina, especially in SiChuan province. As a result of harm by Silk-cut, the germinationrate of F1 combinated by 08-641 was relatively low. The incidence of the disease achieved30-40% for F1 combineted by 08-641 in northwest china, so its implication was impactedin a certain extent. Some genetic studies were developed in order to investigatethe genetic basis of the character and make preparation for the studyafterwards. In this study, inheritance of silk-cut of the crossR08×975-12（Zea mays L.） was detected by applying the major gene pluspoly-gene model of quantitative traits to a joint analysis ofmulti-generations (P₁, P₂, F₁, B_1:2, B_2:2 and F_2:4). And silk-cut QTL of maize weredetected by CIM method, using F₂ population and F_2:4 family.1. The results indicated that silk-cut in the cross R08×975-12 wascontrolled by one major gene with additive major gene effects plus polygenewith additive-dominance effects（the D-2 model）. Genetic variance values ofthe major gene in B_1:2, B_2:2 and F_2:3 populations were estimated as 201.4525,31.9877 and 31.9877, while those of polygene were 11.0397 and 81.1362,respectively. And the additive effects values of major geneand polygene wereestimated as 11.3116 and -4.4719, while the dominance effects value ofpolygene was 10.8496. Heritability values of the major gene in B_1:2 and F_2:3populations were estimated as 21.56% and 81.31%, while those of polygene were4.46% and 54.68%, respectively.2. A genetic linkage map containing 115 SSR markers was constructed, whichcovered 2178.6cM totally, with an average of 18.9cM, in cross R08×Es40. Allthe markers were analyzed for the genetic segregation distortion, 19markers（at 0.05 level） were segregation distortion, and the ratio was 16.5%. By compared analyse, the SSR linkage map can be used for QTL mapping. Therelative order of SSR bin on the genetic linkage map was consistent with maizeGDB.In cross R08×Es40, 12 QTLs of silk-cut were detected by CIM method. TheseQTLs distributed on the chromosome 1、2、4、5 and 7, were named as qSC-1-1、qSC-1-2、qSC-1-3、qSC-2-1、qSC-2-2、qSC-3-1、qSC-4-1、qSC-4-2、qSC-4-3、qSC-5-1、qSC-7-1、qSC-7-2, respectively. Their position was 130.81、272.41、292.81、81.01、100.01、20.01、140.41、158.91、180.91, respectively, and their nearerlinkage marker was bnlg1564、umc1144、umc2189、umc1004、umc1003、bnlg2047、mmc0371、mmc0371、umc2280、umc1815、phi328175、phi328175、respectively.Two major QTLs, qSC-1-1 and qSC-3-1, were detected on the chromosome1 and 3, its contribution to phenotypic variations was 36.91% and 37.95%. Thecontributions to phenotypic variations for other 10 QTL varied from 4.22% to18.61%. The indication for the way of gene action was that among all the 12QTL, qSC-7-2 with overdominance effects, qSC-1-2、qSC-1-3 and qSC-2-2 withadditive effects, qSC-1-1、qSC-3-1 and qSC-7-1 with dominance, the others withpartial dominance effect on the character.3. A genetic-linkage map containing 86 SSR markers was constructed, whichcovered 1706.1cM totally, with an average of 19.8cM, in crossR08×99s2052-3-2-1. All the markers were analyzed for the genetic segregationdistortion, 12 markers（at 0.05 level） were segregation distortion, and theratio was 13.95%. By compared analyse, the SSR linkage map can be used forQTL mapping. The relative order of SSR bin on the genetic linkage map wasconsistent basically with maize GDB.In cross R08×99s2052-3-2-1, 4 QTLs of silk-cut were detected by CIMmethod. These QTLs distributed on the chromosome 2、3、5 and 6, were namedas qSC-2-1、qSC-3-1、qSC-5-1、qSC-6-1, respectively. Their position was 296.31、24.01、114.41、48.51, respectively, and their nearer linkage marker wasumc1080、bnlg1754、umc1019、umc1006, respectively.Two major QTLs, qSC-3-1 and qSC-5-1, were detected on the chromosome 3 and 5, its contribution to phenotypic variations was 39.42% and 43.11%. Thecontributions to phenotypic variations for other two QTL were 5.04% and 7.29%.The indication for the way of gene action was that among all the 4 QTL,qSC-3-1and qSC-5-1 with dominance effects, qSC-2-1 and qSC-6-1 with partialdominance effect on the character.4. QTL was detected on chromosome 3 in different combinations withdifferent genetic background. Its position were close, and the contributionrates were greater than 30%. The value and direction of gene action wereconsistent basically. All of these showed a major QTL which controlledcharacter of silk-cut for maize was true being on chromosome3. In addition,QTLs were also detected on chromosome3, 5.5. Silk-cut was abiotic disease which controlled by major gene plus minorgene by research of different genetic background and different methods. Thejoint segregation analysis and QTL method all have their superiority and theycould be confirmed and supplemented by each other.更多还原