Seed yield is one of the main limitations in hybrid rice production. The improvement of stigma exsertion rate (SER) of male sterility lines is essential for the higher seed yield in hybrid rice. Wild rice species are valuable germplasms with exserted stigma. It is worthy of mining-related genes for SER in wild rice species, as well as probing the way to use the beneficial genes in rice breeding. In the present study, we identified a total number of 36 stable QTLs for the SER distributing on 11 chromosomes by using a set of single-segment substitution lines (SSSLs) of 3 AA-genome wild rice species, O. barthii, O. meridionalis, and O. rufipogon. The mean genetic effects of these QTLs were ranged from 14.50 to 41.25% during 2016–2017. Twelve QTLs among them were novel by comparing the chromosome intervals with the reported QTLs. Besides, 7 homozygous 2-QTL pyramiding lines (PLs) were developed in BAR-SSSLs and MER-SSSLs to detect QTL interactions on the same background of HJX74. The epistatic effects in 3 out of 7 QTL pairs were positive, including qSERb3-1/qSERb6-1, qSERb3-1/qSERb8-1, and qSERb3-1/qSERb12-1, which mean epistatic effect was 13.56%, 4.76%, and 7.29% in 2018–2019, respectively. The PL of B6/B19 (qSERb3-1/qSERb12-1) had the highest mean SER of 80.59% and the largest pyramiding effect of 55.51%. The results in the present study demonstrated that SSSLs were the elite materials for SER QTL detection from wild rice species, and elite PLs could be developed among SSSLs for SER improvement in hybrid rice breeding.

种子产量是杂交水稻生产的主要限制之一。雄性不育系柱头外露率的提高对于杂交水稻更高的种子产量至关重要。野生稻种是柱头外露的有价值的种质。值得在野生稻种中挖掘与SER相关的基因，并探索在水稻育种中利用有益基因的方法。在本研究中，我们通过使用一组的3 AA-基因组野生稻，单段代换系（单片段代换系）的鉴定的36个QTL稳定为SER分配上11条染色体的总数O. barthii，O.鲇和O. rufipogon。在2016–2017年期间，这些QTL的平均遗传效应范围为14.50％至41.25％。通过比较染色体间隔和报道的QTL，其中的12个QTL是新颖的。此外，在BAR-SSSLs和MER-SSSLs中开发了7条纯合的2-QTL金字塔系（PL），以检测HJX74相同背景下的QTL相互作用。在7个QTL对中，有3个的上位性效应为阳性，包括qSERb3-1 / qSERb6-1，qSERb3-1 / qSERb8-1和qSERb3-1 / qSERb12-1，平均上位效应为13.56％，4.76％，在2018-2019年分别为7.29％和7.29％。B6 / B19的PL（qSERb3-1 / qSERb12-1）的平均SER最高，为80.59％，最大的金字塔效应为55.51％。本研究结果表明，SSSLs是用于检测野生稻种中SER QTL的优良材料，并且可以在SSSL中开发出优良PL，以改善杂交水稻育种中的SER。