Lack of seed dormancy, a major cause of pre-harvest sprouting in rice and other cereal crops, causes significant reductions in grain yield and quality. Weedy rice is often strongly dormant; therefore, quantitative trait loci (QTLs) related to seed dormancy in weedy rice “Ludao” could be useful for improving pre-harvest sprouting resistance in the important japonica variety “Ninggeng 4.” To identify SD QTLs in variety Ludao, we constructed an advanced backcross population (BC₆F₂) of Ninggeng 4 with Ludao as the donor parent by marker-assisted backcrossing followed by SD phenotyping. The consistently detected QTL qSdr9 on chromosome 9L explained 18.09% of the phenotypic variance, and the Ludao allele decreased germination percentage by 10.78%. qSdr9 was fine-mapped to a 586.60 kb region between markers QNU9–10 and RM5777. Based on the closest linked marker for locus qSdr9, we developed near-isogenic lines with the qSdr9 allele from Ludao in Ninggeng 4 background. The qSdr9 near-isogenic lines with strong SD will be useful as parents in breeding for pre-harvest sprouting resistance.

缺乏种子休眠是稻米和其他谷类作物收获前发芽的主要原因，导致谷物产量和品质显着下降。杂草米经常休眠。因此，与杂种水稻“鲁道”的种子休眠有关的数量性状位点（QTLs）可能对提高重要粳稻品种“宁耕4号”的收获前发芽抗性有用。为了鉴定鲁道品种的SD QTL，我们通过标记辅助回交，然后进行SD表型构建了以鲁道为供体的宁gen4号先进回交群体（BC ₆ F ₂）。一致检测到的QTL qSdr99L染色体上的基因解释了18.09％的表型变异，而Ludao等位基因使发芽率降低了10.78％。qSdr9被精细映射到标记QNU9-10和RM5777之间的586.60 kb区域。基于qSdr9基因座的最紧密连锁标记，我们在宁gen4号背景下利用来自鹿岛的qSdr9等位基因开发了近等基因系。具有强SD的qSdr9近等基因系将作为亲本在收获前发芽抗性育种中有用。