17 Yingbao Wu Gaoyang Zhang Chao Zhang Weiqi Tang Ting Wang Huining Zhang Hongkai Wu Journal of Animal and Plant Sciences JAPS 20232023/12/15 33 6 1467-1473 1018-7081 https://doi.org/10.36899/JAPS.2023.6.0686 <p><span lang="EN-US">Drought is among the foremost constraints influencing global rice productivity. The drought tolerance nature of rice is complicated, depending on multiple components and having low heritability. Thus, breeding drought-tolerant varieties is a fundamental way which can be used to increase rice yield in drought. To investigate the genetic basis of seedling tolerance to drought stress of rice (<em>Oryza sativa&nbsp;</em>L.), we performed QTL mapping on a big F₂&nbsp;population of 2600 participants from a cross between the&nbsp;<em>japonica</em>&nbsp;rice variety Huaidao 5 (HD5) and the&nbsp;<em>indica&nbsp;</em>rice variety 1892S&nbsp;</span><span lang="EN-US">through performing bulked segregant analysis and whole-genome sequencing (BSA-seq).</span><span lang="EN-US">&nbsp;HD5 showed greater tolerance to prolonged drought stress compared with1892S</span><span lang="EN-US">at seedling stage. By analyzing a pair of opposite DNA pools made from 182 extremely-sensitive seedlings and 182 extremely-tolerant seedlings from the F₂&nbsp;population using the block regression mapping (BRM) method, we mapped a QTL on chromosome 1, of which the additive effect was estimated to explain 2.20% of the phenotypic variance. We named the QTL</span><em><span lang="EN-US">qSLDT1.1</span></em><span lang="EN-US">(<em>q</em>&nbsp;represents quantitative trait loci,&nbsp;<em>SL&nbsp;</em>represents seedling leaf,&nbsp;<em>DT&nbsp;</em>represents drought tolerance,&nbsp;<em>1.1</em></span><span lang="EN-US">representsthe first one found on chromosome 1</span><span lang="EN-US">), which must be a novel QTL, because no QTLs for rice seedling tolerance to drought stress have been mapped on chromosome 1 before. The information derived from the current research facilitates marker-assisted breeding of drought-resistant lines and positional cloning of the gene conferring drought tolerance in rice.</span></p> Rice, Drought tolerance, QTL mapping, Bulked segregant analysis, Whole-genome sequencing Pakistan Agricultural Scientists Forum https://thejaps.org.pk/AbstractView.aspx?mid=2022-JAPS-490