一个水稻苗期耐冷性的主效QTL精细定位研究

Study on Fine Mapping of A Major QTL for Cold Tolerance at Seedling Stage of Rice

苗期耐冷性是影响水稻生长发育的重要因素之一。此实验以低温导致叶片卷曲的卷曲度作为水稻苗期耐冷性指标,采用182个越光(粳型)/kasalath(籼型)//越光回交重组自交系(backcross recombinant inbred lines,BILs)和162个RFLP分子标记,对苗期耐冷性进行QTL(quantitative trait loci,QTL)定位分析。结果表明,BIL群体中苗期耐冷性均呈连续分布,属于数量性状遗传,并检测到4个控制苗期耐冷性的QTL,分布在第1、3、11、12染色体上,其贡献率为7.4%～21.9%,所有能增强耐冷性等位基因均来自越光;并在其目标区域内进一步设计分子引物把位于第12染色体上的主效qCTS-12定位在约77kb区域内。此研究结果及其检测到的QTLs两侧的连锁分子标记可为水稻苗期耐冷性分子育种以及相关基因克隆提供理论依据。

Cold tolerances at the seedling stage （CTS） are one of important factors affecting the development of growth in rice. In this study, we analyzed and located quantitative trait loci （QTL） for cold tolerance to cold tolerance at the seedling stage （CTS） using a backcross inbred lines （BILs） derived from a backcross of Koshihikari （japonica）/Kasalath （indica）//Koshihikari through 162 RFLP markers. Resultantly, a continuous phenotypic variation for CTS was observed, indicating that CTS was quantitatively inherited traits. Four QTLs for CTS were located on chromosome 1,3, 11,12, which explained 7.4%-21.9% of the phenotypic variance, respectively, all alleles increasing CTS come from the Koshihikari parent. Through fine mapping, a major QTL （qCTS-12） on chromosome 12 was narrowed to the physical distance of 77kb between RM28596 and R1709. These results and molecular markers tightly linked to QTLs detected in this study can provide useful information for molecular breeding and cloning of of cold tolerance genes in rice.