Rice (Oryza sativa L.) is a saline-alkali-sensitive crop. Saline-alkali environments can seriously affect the growth, development, and yield of rice. The mechanisms of salt tolerance and alkali tolerance in rice are different; thus, it is very important to study and explore the alkali-tolerant gene loci to improve the saline-alkali tolerance of rice varieties. In this study, the japonica rice varieties Dongnong 425 (DN425) and Changbai 10 (CB10) and a hybridized recombinant inbred line (RIL) population were used as materials to be irrigated with Na₂CO₃ solution under field test conditions. A resistant pool (R-pool) and a sensitive pool (S-pool) were constructed by selecting the lines with extremely high and extremely low 1000-grain weight (TGW), respectively, from the RIL population under alkali treatment. Four candidate TGW regions on chromosomes (Chr.) 2 and 3 were associated using the bulked segregant analysis (BSA) strategy assisted by next-generation sequencing (NGS) technology (NGS-assisted BSA). Using the linkage analysis, QTL-qATGW2-2 in the candidate region was mapped within a range of 116 Kb between the SSR marker RM13592 and the Indel marker Indel3 of Chr. 2, which contained 18 predictive genes. The BSA sequencing results showed that Os02g39884 contained a nonsynonymous substitution mutation SNP (nsSNP), leading to the transformation of a residue from arginine (cGg) to glutamine (cAg); thus, Os02g39884 was inferred to be the candidate gene of qATGW2-2. The results of the qRT-PCR analysis also confirmed this. This paper provides important information for the rapid and accurate identification of the alkali-tolerant gene loci in rice.

水稻( Oryza sativa L. )是一种对盐碱敏感的作物。盐碱环境严重影响水稻的生长发育和产量。水稻的耐盐和耐碱机制不同；因此，研究和探索耐碱基因位点对于提高水稻品种的耐盐碱能力具有重要意义。本研究以粳稻品种东农425（DN425）和长白10号（CB10）以及杂交重组自交系（RIL）群体为材料，在田间试验条件下用Na ₂ CO _{3溶液进行灌溉。}从碱处理的RIL群体中分别选择千粒重(TGW)极高和极低的品系构建抗性库(R-库)和敏感库(S-库)。使用下一代测序 (NGS) 技术（NGS 辅助 BSA）辅助的批量分离分析 (BSA) 策略将 2 号和 3 号染色体 (Chr.) 上的四个候选 TGW 区域关联起来。利用连锁分析，将候选区域中的QTL- qATGW2-2定位在SSR标记RM13592和Chr.的Indel标记Indel3之间116Kb的范围内。2，包含18个预测基因。BSA测序结果显示，Os02g39884含有非同义取代突变SNP（nsSNP），导致残基从精氨酸（cGg）转化为谷氨酰胺（cAg）；由此推测Os02g39884是qATGW2-2的候选基因。qRT-PCR分析的结果也证实了这一点。该文为快速、准确鉴定水稻耐碱基因位点提供重要信息。