【作者】 高世斌；

【导师】 荣廷昭； 李晚忱；

【作者基本信息】 四川农业大学 ， 作物遗传育种， 2004， 博士

【摘要】 干旱是影响玉米生产的最主要非生物胁迫因素，解决这一问题的有效策略是选育并推广耐早性品种。但是，耐旱性是一复杂的数量性状且需要特殊的环境才能被鉴定，因此传统育种方法进行耐旱性遗传改良的效率不高。随着分子标的应用与发展，可以作为一种有效辅助手段，提高传统育种效率，为玉米耐早性育种带来新的途径。本研究利用SSR标记构建基于组合N87-1（耐旱）×9526（敏感）的分子标记连锁图谱，并对该组合的183个F_2：3家系在对照与干旱胁迫两种环境下进行耐旱性鉴定，分析控制玉米耐旱相关性状QTL位点与遗传效应，探索玉米耐旱性的分子遗传机制，为玉米耐旱性的遗传改良提供理论和参考。取得了以下结果： 1．在对照与干旱胁迫两种环境下，对183个F_2：3家系的12个耐旱相关性状（单株产量、抽雄期、吐丝期、雌雄开花间隔、株高、穗高、根数、根重、穗叶长、穗叶宽、雄穗分枝数和雄穗主轴长）进行了鉴定与统计分析。结果表明：在两种环境下，各性状的平均数在家系间存在显著差异；除雌雄开花间隔（ASI）与产量呈显著的负相关以外，多数性状与产量呈显著的正相关；在干旱胁迫环境下，除ASI以外，其余各性状的变异系数比对照增加；与产量相关系数较大的ASI、根重和雄穗主轴长等性状，可作为耐旱性鉴定的重要次级性状。 2．利用103个共显性的SSR标记构建了覆盖玉米全基因组的分子标记连锁图谱。图谱的总长度为1512.9cM，平均间距为16.27cM。基于分子标记排列顺序与位点比较，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。 3．以复合区间作图法（LOD≥2.0），对两种环境下的12个耐旱相关性状和产量耐旱系数（DTI）进行QTL检测。总计检测到89个QTL位点，其中对照环境下43个、干旱胁迫环境下39个以及7个DTI的QTL。每个性状所检测到的QTL数目在1～7个之间，单个QTL所能解释的表型变异在4.68～34.1％之间，基因的作用方式以部分显性和超显性为主。产量、ASI、根重、穗位叶宽、穗位叶长及穗位高性状的部分QTL位点在两种环境下有较好的重复性。 4．发现耐旱相关性状的QTL在染色体上有成簇分布的特点；初步找出了耐旱性QTL存在的重点区域。这些区域主要集中在第1连锁群上的标记bnlg2086（binl．04）与标记bnlgl347（binl.10）临近区域，第4连锁群上的标记区f日J umClll7一ne0OS（bin4.O4一bin4.05）与标记区间bnlg2126一umex573（bin4.os一bin4.og），第5连锁群上标一记区间bnlg 1 006一ume 1416（bins.0），第6连锁群上标记umel296（bin6.o6一bin6.07）临近区域，第7连锁群上标记区间phi034一bnlgl792（bin7.02）与bnlgl8OS一ume1O15(bin7.03李。 5.与国外相关研究的结果比较表明，本研究所检测的耐旱相关性状QTL在第4连锁群上的分布频率相对偏高，可能与母本N87一1的特殊遗传背景有关。更多还原

【Abstract】 Drought is the most important abiotic factors limiting maize production. The effective approach to solve this problem is breeding and popularizing variety for drought tolerance. However, conventional selection for drought tolerance is inefficient because that drought tolerance is a complicated quantitative trait and required special environment to identify. With the development and application of molecular markers, MAS(molecular assistant selection) supply a useful tool to the breeding for drought tolerance. In order to investigate the molecular genetic basis of drought tolerance and find useful information for genetic improvement to drought tolerance further, molecular marker linkage map was construct with F2 population derived from N87-l(drought tolerance) 9526 (drought sensitive ) by 103 SSR markers; then 183 F2:3 family lines were identified for drought tolerance under two water regimes(normal control and water stressed); in the end, quantitative trait locus(QTL) associated traits related to drought tolerance were identified and analyzed in this study. The major results are as follows.1. The major traits(grain yield , male flowering, female flowering, anthesis-silking interval, plant height, ear height, ear leaf length, ear leaf width, root number, root weight, tassel branch number, tassel main axis length ) related to drought tolerance of 183 F2:3 family lines were surveyed and analysed under two water regimes. Under two water regimes , the average values of all traits are significant difference among family lines,which may be used for QTL mapping; most of these traits are significant positive correlation with yield ,but ASI has significant negative correlation with yield, under water stressed condition, yield and ASI, root weight and tassel main axis length may be used for important second drought tolerance indexes.2. A genetic linkage map containing 103 SSR markers was constructed, which spanned a total of 1512.9 cM with an average interval of 16.9 cM. Compared with other published maize linkage maps in chromosome bin locus, the linkage map established in this study was consistent with them. The SSR linkage can be used for QTL mapping.3.By composite interval mapping(LOD 2.0),82 QTL were detected for 12 traits under two water regime and 7 QTL were detected for DTI. Under water stress environment,39 QTLwere detected; and under normal environment 43 QTL were detected. Each traits have been identified 1~7 QTL which were responsible for interpreting 4.68-34.1% of the phenotypic variance individually, and showed partial dominant effect and over dominant .QTLs of grain yield and anthesis-silking interval, ear height, ear leaf length, ear leaf width and root weight are relatively consistence across two environments4. This result also show that some QTLs trend to cluster the same chromosome region. The key chromosome regions for drought tolerance mostly lie on following chromosome: chromosome 1, bnlg2086(binl.04) and bnlgl347(binl.lO);chromosome4, umc 1117~nc005(bin4.04~bin4.05) and bnlg2126~umcl573(bin4.08~4.09);chromosome5, bnlgl 006~umcl416(bin5.0);chromosome6,umcl296(bin6.06~bin6.07);chromosome7,phi034~bnlg 1792(bin7.02)and bnlgl805~umc1015 (bin7.03) .5. Compared the results with other researchers’ reports, the chromosome 4 of N87-1 genomic have higher frequency of QTLs associated drought tolerance.更多还原