Xu Shan, Fei Yuexin, Wang Yue, Zhao Wenjia, Hou Luyan, Cao Yujie, Wu Min, Wu Hongkai
College of Advanced Agricultural Sciences, Zhejiang A & F University, Hangzhou, 311300, Zhejiang, China.
Rice (N Y). 2023 Oct 13;16(1):45. doi: 10.1186/s12284-023-00664-x.
Direct seeding of rice (Oryza sativa L.) is a low-labor and sustainable cultivation method that is used worldwide. Seed vigor and early vigor are important traits associated with seedling stand density (SSD) and weed competitive ability (WCA), which are key factors in direct-seeded rice (DSR) cultivation systems. Here, we developed a set of chromosome segment substitution lines with Xiushui134 as receptor parent and Yangdao6 as donor parent and used these lines as a mapping population to identify quantitative trait loci (QTLs) for seed vigor, which we evaluated based on germinability-related indicators (germination percentage (GP), germination energy (GE), and germination index (GI)) and seedling vigor-related indicators (root number (RN), root length (RL), and shoot length (SL) at 14 days after imbibition) under controlled conditions in an incubator. Ten QTLs were detected across four chromosomes, of which a cluster of QTLs (qGP11, qGE11, qGI11, and qRL11) co-localized on Chr. 11 with high LOD values (12.03, 8.13, 7.14, and 8.75, respectively). Fine mapping narrowed down the QTL cluster to a 0.7-Mb interval between RM26797 and RM6680. Further analysis showed that the QTL cluster has a significant effect (p < 0.01) on early vigor under hydroponic culture (root length, total dry weight) and direct seeding conditions (tiller number, aboveground dry weight). Thus, our combined analysis revealed that the QTL cluster influenced both seed vigor and early vigor. Identifying favorable alleles at this QTL cluster could facilitate the improvement of SSD and WCA, thereby addressing both major factors in DSR cultivation systems.
水稻直播是一种低劳动强度且可持续的种植方法，在全球范围内广泛应用。种子活力和早期活力是与秧苗密度（SSD）和杂草竞争能力（WCA）相关的重要性状，而SSD和WCA是直播稻（DSR）种植系统中的关键因素。在此，我们以秀水134为受体亲本、扬稻6号为供体亲本，构建了一套染色体片段代换系，并将这些代换系作为定位群体，以鉴定种子活力的数量性状位点（QTL）。我们在培养箱的可控条件下，基于与发芽能力相关的指标（发芽率（GP）、发芽势（GE）和发芽指数（GI））以及与幼苗活力相关的指标（吸胀14天后的根数（RN）、根长（RL）和苗长（SL））来评估种子活力。在四条染色体上共检测到10个QTL，其中一个QTL簇（qGP11、qGE11、qGI11和qRL11）共定位于第11染色体上，其LOD值较高（分别为12.03、8.13、7.14和8.75）。精细定位将该QTL簇缩小到RM26797和RM6680之间0.7-Mb的区间。进一步分析表明，该QTL簇对水培条件下的早期活力（根长、总干重）和直播条件下的早期活力（分蘖数、地上部干重）具有显著影响（p < 0.01）。因此，我们的综合分析表明，该QTL簇同时影响种子活力和早期活力。在这个QTL簇中鉴定有利等位基因有助于改善秧苗密度和杂草竞争能力，从而解决直播稻种植系统中的这两个主要因素。
