14233 10.30848/PJB2026-5(19) <p> <strong>QTL mapping and candidate gene analysis for drought tolerance at the seedling stage in sorghum using BSA-SEQ</strong></p> Lin Lin Yang, Jia Xu Wang, Ze Yang Zhao, Fei Zhang, Feng Lu, Kai Zhu, Zhipeng Zhang, Han Wu, You Hou Duan, Fu Lai Ke, Kuang Ye Zhang and Yan Qiu Wang <p> To elucidate the genetic basis of drought tolerance at the seedling stage in sorghum, we used the drought‑tolerant restorer line LNR‑6 and the drought‑sensitive restorer line LR‑2381 as parents to construct an F₂ segregating population. Drought stress was carefully applied at the six‑leaf seedling stage, and two extreme phenotype bulks (highly tolerant and highly sensitive) were established based on phenotypic evaluation. Bulked segregant analysis (BSA) combined with high‑throughput sequencing was then employed to map quantitative trait loci (QTL) associated with seedling drought tolerance. The results showed that two significantly associated genomic regions were detected on chromosomes 9 and 10, designated <em>qKH9</em> (29.677 kb) and <em>qKH10</em> (400.118 kb), respectively. The <em>qKH9</em> region contained 231 variant sites involving 17 transcripts, whereas <em>qKH10</em> harbored 4,039 variant sites involving 144 transcripts. Functional annotation indicated that <em>qKH9</em> includes candidate genes related to zinc finger proteins and protease‑mediated protein degradation, while <em>qKH10</em> contains putative drought‑responsive genes involved in peroxidase activity and kinase‑mediated signal transduction. These QTL provide key genomic intervals for dissecting the molecular mechanisms underlying seedling drought tolerance in sorghum and lay an important foundation for fine mapping, marker development and molecular breeding for drought tolerance</p> Published 2026 58 5 1104 1110