【作者】 郑洪建；

【导师】 吴爱忠； 董树亭； 蔡润；

【作者基本信息】 上海交通大学 ， 生物化学与分子生物学， 2008， 博士

【摘要】 玉米（Zea mays L.）是世界上重要的粮食和饲料作物,近年来由于种质资源匮乏,玉米生产出现徘徊,在产量、品质和抗性育种上进展缓慢,育种家一直致力于优异基因资源发掘利用,以求在种质创新和品种选育上取得突破。玉米叶片保绿性指生长后期叶片衰老或黄化延缓而保持绿色的特性,是与产量、饲用品质、抗性具有直接联系的重要性状。保绿型玉米品种是当今最有价值的玉米品种,代表了玉米品种演进的方向,深入研究保绿性的遗传基础对玉米种质创新和品种选育具有重要意义。本文从玉米保绿性资源鉴定、玉米保绿性遗传分析和QTL定位三个方面开展研究。主要结果如下:1.通过对我国30份骨干玉米自交系保绿性进行鉴定表明,大部分自交系保绿性一般或较差,筛选出4份保绿性较强的玉米自交系,它们是沈3195、沈137、齐319和178。利用SSR标记将30份自交系划分为6个类群,其中4份保绿性自交系分布在B（旅大红骨）和E（PB种质）群,可用于改良类群内其它材料的保绿性;保绿型自交系沈137、齐319、178皆来自于PB种质,可用来组建保绿群体。2.对保绿（齐319、178）×非保绿（Mo17、BM）四套组合六个世代的保绿鉴定结果进行数量遗传分析表明,玉米叶片保绿基因的加性、显性和互作效应普遍存在。玉米保绿性状广义遗传力变化范围59.93～76.82%,加性方差占遗传方差的比值变化范围为40.70～60.10%。以齐319为保绿亲本的组合至少存在2对保绿基因,而以178为保绿亲本的组合至少由1对基因控制。3.利用115对SSR标记引物构建了覆盖玉米基因组1431.0cM含10个连锁群的分子标记连锁图谱,平均图距为12.44cM,基于分子标记排列顺序和位点比较,该连锁图谱与玉米基因组数据库所公布的玉米整合图谱有较高的一致性,可以用于进一步的QTL定位研究。4.对166个F_2:3家系的叶片保绿度、绿叶数、叶绿素含量、抽雄期、散粉期、吐丝期、雌雄间隔期、株高、穗位高、穗长、穗粗、秃尖长、穗行数、行粒数、出籽率、千粒重和单株产量等保绿相关性状进行测定和统计分析表明,各性状的平均数在家系间差异显著,存在超亲分离现象;玉米叶片保绿度与千粒重、穗粗和产量呈极显著正相关。5.以复合区间作图法（LOD≥2.5）,对保绿相关性状进行QTL检测,总计检测出80个保绿相关性状的QTLs,其中31个为主效QTL（sR2≥10%）。每个性状检测到的QTLs数目在1～8个,单个QTL所能解释的表型变异4.68～24.75%之间,QTL位点基因作用方式以部分显性和超显性为主。6.发现保绿相关性状的QTL在染色体上有成簇分布的特点,初步找出保绿性QTL在染色体上的6个关键区域,包括第1染色体上的115.0～125.0cM区段和140.0～155.0cM区段;在第2染色体上的95.0～110.0cM区段;在第5染色体上的50.0～55.0cM区段;第8染色体上的0～10.0cM区段;第9染色体上的50.0～60.0cM区段。7.通过与前人研究比较,本研究不仅检测到与前人相近的保绿QTL位点,同时检测出了较多新的位点,为全面了解玉米保绿性状的遗传背景提供新的信息,也为玉米保绿性分子标记辅助育种奠定基础。更多还原

【Abstract】 Maize （Zea mays L.） is an important food and forage crop. Recently, steps towards high yield, good quality and resistance in maize breeding programs have been limited due to a reduced genetic background in the maize germplasm. Maize breeders have been exploring different maize germplasm varieties for suitable genes to further enhance maize yield and in doing so, anticipate a breakthrough in maize breeding advancements. Stay-green is a generalterm applied to a variant in which senescence is delayed, compared to a standard reference genotype, and is regarded as a desirable character closely related to yield, forage character and resisitance. The stay-green maize varieties is the most valuable one nowadays. The inheritance of stay-green were studied focused on stay-green germplasm certification, genetic analysis and quantitative trait loci （QTL） mapping. The main results were as follows:1. Thirty elite maize inbred lines were evaluated for stay-green. The results showed that 4 lines （Shen3195, Shen137, Q319 and 178 ） had good stay-green trait, and others had normal or bad stay-green trait. The cluster analysis by SSR markers showed that 30 inbreds could be classified into 6 distinct groups. The 4 stay-green inbreds were found in 2 sources （B and E）, respectively and could be used to improve the bad stay-green lines in the same group.2. The inheritance of stay-green was studied in progenies derived from four crosses between two stay-green lines, Q319 or 178, and two non-stay-green lines, Mo17 and BM. The results showed that additive and dominant gene effect as well as gene interactions could be found in the inheritance of stay-green. The broad heritability for stay-green ranged from 59.93% to 76.82% and the ratio of narrow heritability to genetic heritability ranged from 40.70% to 60.10%. Q319 and 178 were estimated to contain at least two and one stay-green genes, respectively.3. A genetic linkage map containing 115 SSR markers and 10 linkage groups was constructed, which spanned a total of 1431.0 cM with an average maker interval of 12.44 cM. Compared with other published maize linkage map in chromosome bin locus, the linkage map established in this study was consistent with them. The SSR linkage map can be used for QTL mapping.4. The major traits（stay-green degree, number of green leaf, chlorophyll content of leaf, emergence-anthesis interval, emergence-pollination interval, emergence-pollination interval, antheisis-silking interval, plant height, ear height, ear length, bald tip length, ear diameter, ear rows, row grains, percent grain, 1000-grain weight, individual plant yield） related to stay-green of 166 F_2:3 family lines were surveyed an analysed. The results showed that the average values of all traits are significant among family lines. Correlation analysis showed significant correlations between stay-green traits at different days after flowering （DAF） and some yield-related traits such as ear diameter, 1000-grain weight and plant yield.5. By composite interval mapping（LOD≥2.5）, 80 QTLs were detected for traits related to stay-green, in wich 31 QTLs were major effect QTLs（R2≥10%）. Each traits have been identified 1–8 QTLs, which were responsible interpreting 4.68–24.75% of phenotypic variance individually, and showed partial dominant effect and over dominant.6. This results also showed that some QTLs trend to cluster the same chromosome region. The six key chromosome regions for stay-green mostly lie on following chromosome: chromosome 1, 115.0–125.0 cM and 140.0– 155.0 cM; chromosome 2, 95.0–110.0 cM; chromosome 5, 50.0–55.0 cM; chromosome 8, 0–10.0 cM; chromosome 9, 50.0–60.0 cM.7. Compared with the results of previous study, our study not only detected the similar stay-green QTLs reported previously, but also found out many new QTLs. The QTLs got in this study not only offered new information for understanding stay-greeen traits of maize, but also provided a potential starting point for marker assisted selection of maize stay-green .更多还原