Grain protein content (GPC) is an important component of rice nutritional quality and influences the physical–chemical properties and taste of cooked rice. Quantitative trait loci (QTLs) for GPC in rice (Oryza sativa L.) were analyzed using chromosome segment substitution lines (CSSLs) developed from 9311 (used as the recipient) and Nipponbare (used as the donor). Using the substitution map strategy, we detected a total of 22 QTLs across all twelve chromosomes except chromosome 1. In addition, 13 QTLs were detected in both years, and 17 QTLs were consistent with previously reported GPC QTLs. Among them, qGPC4, which located between RM6748 and RM348 within the boundary of 30.45–33.95 Mb, was at the same position or flanked by several previous QTLs. qGPC6-1 was mapped to a QTL cluster where the Waxy gene is located. With the same Waxy^b alleles of 9311 and Nipponbare, the effect of Waxy on GPC could be removed, and there should exist a true stable GPC QTL near Waxy. Four novel and stable QTLs for GPC were identified in this research. These stable and novel QTLs could serve as candidate genes for future research, and CSSLs are suitable for mapping GPC QTLs in rice note.

谷物蛋白质含量（GPC）是大米营养品质的重要组成部分，影响着米饭的理化性质和口感。使用从 9311（用作受体）和日本晴（用作供体）开发的染色体片段替换系 (CSSL) 分析水稻 ( Oryza sativa L.) 中GPC 的数量性状基因座 (QTL )。使用替代图谱策略，我们在除 1 号染色体外的所有 12 条染色体上共检测到 22 个 QTL。此外，在这两年中检测到 13 个 QTL，其中 17 个 QTL 与先前报道的 GPC QTL 一致。其中，qGPC4位于RM6748 和RM348 之间，30.45-33.95 Mb 边界内，位于同一位置或两侧有几个先前的QTL。qGPC6-1 被映射到Waxy基因所在的 QTL 簇。9311和日本晴相同的Waxy ^b等位基因，可以去除Waxy对GPC的影响，在Waxy附近应该存在一个真正稳定的GPC QTL 。本研究确定了四个新的、稳定的 GPC QTL。这些稳定且新颖的QTLs可以作为未来研究的候选基因，CSSLs适用于定位水稻音符中的GPC QTLs。