水稻RIL群体高密度遗传图谱构建及粒型QTL定位

[目的]水稻粒型是与产量直接相关的重要农艺性状,影响稻米的外观品质和商品价值.挖掘新的水稻粒型相关基因,对揭示水稻粒型调控的遗传机理研究有重要意义,同时可为水稻粒型分子育种提供新的基因资源.[方法]以极端粒型差异的粳稻TD70和籼稻Kasalath,以及杂交构建的186个家系的重组自交系群体为研究材料,利用高通量测序技...

Construction of High-Density Genetic Map and QTL Analysis of Grain Shape in Rice RIL Population

【Objective】Rice grain shape is an important agronomic trait directly related to yield, which affects the appearance quality and commercial value of rice. Research on new rice grain shape genes is of great value for revealing the genetic mechanism of rice grain shape, and it can provide some new genetic resources for molecular breeding. 【Method】In the present study, a RIL population which constructed by an extra-large grain japonica rice variety TD70 and a small-grain indica rice variety Kasalath was used as the research material. The phenotypic data of grain shape, such as grain length, grain width, grain thickness and thousand grain weight were investigated. Using the Genotyping-By-Sequencing approach to re-sequence the parents and RILs to obtain SNP information. The sliding window method (the number of SNP/InDel is 15) was used for genotype calling and recombination breakpoint determination. Based on these results, a high-density Bin map was constructed. Meanwhile, the compound interval mapping method of QTL IciMapping software was used to map the QTLs related to grain shape. 【Result】A high-density genetic map containing 12 328 Bin markers was constructed. The number of Bin markers on each chromosome is 763 to 1367, and the average physical distance between markers was 30.26 kb. The frequency distribution of each trait for RIL population was continuous, which were consistent with the characteristics of quantitative characters, so it was suitable for the detection of QTL. QTL analysis of RIL population in 2018 showed that 40 grain-shape QTL were detected, including 12 grain length QTL, 9 grain width QTL, 8 grain thickness QTL, and 11 thousand-grain weight QTL. QTL analysis was performed of RIL population in 2019, and 56 grain-related QTL were detected, including 15 grain length QTL, 11 grain width QTL, 13 grain thickness QTL, and 17 thousand-grain weight QTL. Based on the two-year mapping results, we have mapped a total of 96 grain shape QTL. We found that 11 QTL could be detected for two consecutive years; among them, 7 QTL have been cloned and 4 new QTL were distributed on 1, 3, 4 and 5 chromosomes. Among the 4 new QTL, qGL-1-2 and qGL-5-2 was related to grain length, qGT-3-2 related grain thickness and qGW-4-1 related to grain width. 【Conclusion】We constructed a molecular genetic linkage map containing 12 328 Bin markers and used the map to analyze the grain shape loci of extra-large grain rice resources. Four new QTLs related to grain shape were obtained, which can be used for subsequent fine mapping, cloning and functional studies.