【作者】 肖炎农；

【导师】 郑用琏； 张世煌；

【作者基本信息】 华中农业大学 ， 遗传学， 2005， 博士

【摘要】 玉米是重要的粮食、饲料和工业原料作物。在我国它是第二大作物,每年种植面积约2400万公顷,总产量约1.15亿吨,在国民经济特别是农业生产中占有举足轻重的地位。 干旱是玉米各生长发育期经常遇到的非生物逆境,也是当今世界玉米生产面临的首要问题。中国玉米主要分布在北方旱作区和南方山地,许多玉米产区缺少可靠的灌溉条件,每年因干旱造成玉米减产10%-15%左右,重者达20%-30%。干旱已成为我国玉米生产可持续发展的主要制约因素。选育优良的耐旱玉米杂交种是当前玉米遗传育种的重要目标之一。 玉米耐旱性是受多基因控制的数量性状,采用传统的育种方法进行玉米耐旱育种效率较低。本研究以我国推广面积最大,并具有广泛生态适应性和较强耐旱性的优良玉米自交系X178和美国玉米带坚杆综合种类型优良自交系B73为试材,配制F₂作图群体,在干旱胁迫与非胁迫条件下,于山西临汾和海南三亚两地,调查F₃家系田间抗旱相关性状的表型,对开花期、产量以及株高和穗位高与耐旱性相关的QTL进行了定位和遗传分析,讨论了不同遗传背景的作图群体所定位玉米耐旱QTL的一致性和QTL之间的互作对耐旱性的影响。旨在定位玉米成株期与耐旱性有关的数量性状位点（QTL）,分析它们的遗传效应,为玉米耐旱性状的分子标记辅助选择提供遗传学理论依据和分子标记。获得的主要结果如下: 1.利用121对SSR引物构建了覆盖玉米基因组1379.5cM的分子标记连锁图,平均图距11.4cM,最小图距1.3cM,最大图距35.7cM。其中第1染色体有15个标记,第2染色体13个,第3染色体13个,第4染色体14个,第5染色体9个,第6染色体12个,第7染色体11个,第8染色体14个,第9染色体13个,第10染色体7个。基于分子标记排列顺序和间距的比较,本实验构建的连锁图谱与目前国际上发表的高密度的SSR图谱非常一致。 2.多态性引物中有12.4%的引物在F₂群体中出现偏分离。找到了一些偏分离的热点区域,进一步讨论了偏分离对确定QTL的位置和效应的影响。 3.正常灌溉条件下检测到散粉期QTL 6个,共解释46.0%的性状变片,单个QTL的更多还原

【Abstract】 Maize is an important crop in china .Water availability is one of the major limiting factors for maize growth. In China, maize is grown mainly under drought conditions (Northern-Western China), there were about 10%-30% maize yield losses.It is a big challenge for breeders to improve and develop drought tolerance cultivars.Drought tolerance is a trait that is influenced by multiple genes. It is not very efficient to improve drought tolerance of maize hybrids by traditional methods. A population of 234 F2 plants, derived from the cross X178×B73, was used in this study. X178 is an elite inbred line widely utilized in China. Field experiments had been done in Linfen ,Shanxi and Sanya, Hainan. QTLs for flowering time, yield, plant height and ear height were identified by using SSR markers. The consensus in results of QTLs location among difference genetic background was discussed. The aim of current study was to explore genetics base on drought tolerance in maize and gain useful molecular markers for molecular-assisted slection. The results are as following.1. The linkage map including 121 SSR markers covered 1379.5 cM in length with an average marker interval of 11.4cM, minimal interval of 1.3 cM and maximal interval of 35.7cM. The order of markers in this map was identical to the order of corresponding markers in IBMmap and their bins on the chromosomes.2. Ratio of segregation distortion among SSR markers was 12.4% in F2 population. Several loci for segregation distortion were identified. Influence of segregation distortion on the result of QTL analysis.3. Under well-watered condition, Six QTLs for male flowering time, 6 QTLs for female flowering time, 4 QTLs for anthesis-silking interval, 3 QTLs for yield, 5 QTLs for one hundred kernel weight, 4 QTLs for kernel number per ear, 3 QTLs for kernel weight per ear. 3 QTLs for ear weight, 5 QTLs for ear number per plant, 16 QTLs for plant height and 11 QTLs for ear weight.4. Under water-stressed condition, 9 QTLs for male flowering time, 6 QTLs for female flowering time, 6 QTLs for anthesis-silking interval, 1 QTLs for yield, 5 QTLs for onehundred kernel weight, 2 QTLs for kernel number per ear, 1QTLs for kernel weight per ear, 4 QTLs for ear weight, 2 QTLs for ear number per plant, 17 QTLs for plant height and 10 QTLs for ear weight.5. It was revealed that thirty eight QTLs referred to drought tolerance in maize by comparing the difference between QTLs detected under both well-watered and water-stressed condition, of which 6 QTLs for male flowering time, 2 QTLs for female flowering time, 4 QTLs for anthesis-silking interval, 1 QTLs for yield, 4 QTLs for one hundred kernel weight, lQTLs for kernel number per ear, 1 QTLs for kernel weight per ear, 5 QTLs for cob weight per ear , 3 QTLs for ear weight, lQTLs for ear number per plant, 5 QTLs for plant height and 6 QTLs for ear weight.6. Two-way ANOVA showed that interaction between pair of marker loci contributed to phenotype of trait. It was suggested that the epistasis contributed to the phenotypic variation of plant height. 17 and 38 pairs of loci influenced significantly plant height under well-watered condition, according to field data from Linfen and Sanya respectively, 20 and 47 pairs of loci underwater-stressed condition, as well.7. It was suggested that heterozygocity played an important role in heterosis. The result showed that correlation coefficient between plant height and general heterozygocity was lower than that between plant height and specific heterozygocity.更多还原