籽粒容重是国际上对玉米品种进行等级划分的主要标准,培育籽粒容重较高的玉米品种是玉米育种的一个重要目标。本研究利用玉米优良自交系农系531和X178 杂交构建的200份RIL群体,基于GBS技术获得SNP标记构建高密度的重组bin遗传连锁图谱,定位控制玉米籽粒容重相关QTL。结果表明：构建的物理图谱和遗传图谱的总长度分别为2017.03 Mb和2568.99cM,相邻两个bin标记之间的平均物理距离和平均遗传距离分别为0.27 Mb和 0.35cM。运用所构建的遗传连锁图谱对RIL群体获得的所有目标性状进行连锁作图,2年共定位到了4个与籽粒容重相关的QTL位点,分别位于chr1、chr7和chr8上；穗部性状穗长、穗粗、穗行数、行粒数和出籽率两年分别共定位到了6、5、5、1和2个QTL位点,位点分布于chr1、chr2、chr3、chr4、chr5、chr7和chr8。研究结果为玉米籽粒容重QTL精细定位、候选基因发掘和分子标记开发提供基础。
英文摘要:
As kernel test weight is the main international standard that ranks the maize hybrids, it is an important goal to cultivate excellent maize variety with high test weight to improve the international competitiveness of Chinese exported maize. In this study, we constructed a recombination inbred line (RIL) mapping population crossed from two elite inbred lines of maize, X178 and NX531, consisting of 200 individuals. The library building and high- throughput sequencing of RIL population were conducted by genotype by sequencing method (GBS). Besides, the depth re-sequencing was applied for the two parents of the recombinant inbred lines, and the high throughput SNP markers of the populations were obtained. Bin markers were employed to construct genetic linkage map for RIL population. The overall length of genetic linkage map and physical map were 2017.03 Mb and 2568.99cM respectively, and the average genetic and physical distance between every pair of adjacent bin markers were0.27 Mb and 0.35cM. By means of mapping the whole interested traits obtained from RIL on the genetic linkage map, 4 QTL distributed on chr1, chr7 and chr8 were found for test weight.6,5,5,1 and 2 QTL distributed on chr1, chr2, chr3, chr4, chr5, chr7and chr8 were respectively found for ear length, ear diameter, row number, kernel number per row and kernel percentage. The results provided a basis for the fine mapping QTLs of kernel test weight related traits, the discovery of candidate genes and the development of molecular markers.
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