The quantitative trait locus SD1-2 for seed dormancy (SD) is identical to the semi-dawrf1 (sd1) gene prevailing in high-yield varieties of rice. However, sd1 alone appeared not sufficient to overcome the preharvest sprouting (PHS) problem in crop (or hybrid seed) production. This research aimed to address some genetic issues that may impact pyramiding of SD genes to improve semi-dwarf varieties for the PHS resistance. The isolated SD1-2, SD8, and SD10 loci were also associated with plant height (PH), awn or flowering time (FT), with the dormancy-enhancing alleles reducing stem elongation, increasing awned seeds, and promoting flowering, respectively. Allelic variants at SD1-2 and SD8 or SD10 were assembled in the same background as two digenic systems, each consisting of all the nine digenic genotypes. The two systems of plants were evaluated for the four traits and phenotypic data used to model trait correlations and the component additive, dominance, and epistatic effects of the two loci. FT was correlated with PH and germinability, but the correlations were opposite in direction between the two systems. Both additive and non-additive effects contributed to the variation for SD. All the three loci had effects on FT and PH in the digenic system(s). The SD10 alleles altered directions for effect on SD, with the late-flowering allele reducing germinability in the SD1-2 and SD10 system. This research demonstrated that genetic improvement of semi-dwarf cultivars for the PHS resistance involves proper selections for dormancy genes, recipient’s genetic backgrounds, and agronomic traits.

种子休眠（SD）的数量性状基因座SD1-2与水稻高产品种中普遍存在的semi-dawrf1（sd1）基因相同。但是，仅sd1似乎不足以克服作物（或杂种种子）生产中的收获前发芽（PHS）问题。这项研究旨在解决一些遗传问题，这些问题可能会影响SD基因的金字塔效应，从而改善对PHS抗性的半矮变种。隔离的SD1-2，SD8和SD10基因座还与植物高度（PH），芒或开花时间（FT）相关，增强休眠的等位基因分别降低茎伸长，增加芒的种子和促进开花。SD1-2和SD8或SD10的等位基因变体它们在与两个双基因系统相同的背景下进行组装，每个系统均由所有九种双基因基因型组成。对两个植物系统的四个性状和表型数据进行了评估，这些数据用于建模性状相关性以及两个基因座的成分加性，优势和上位性效应。FT与PH和可发芽性相关，但是在两个系统之间的相关方向相反。加性效应和非加性效应都有助于SD的变化。这三个基因座均对双基因系统中的FT和PH有影响。该SD10等位基因改变了效果的方向上SD，与晚花等位基因在降低发芽SD1-2和SD10系统。这项研究表明，半矮型品种对PHS抗性的遗传改良涉及对休眠基因，受体的遗传背景和农艺性状的正确选择。