Mapping QTLs for rice ( Oryza sativa L.) grain protein content via chromosome segment substitution lines

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.