Mapping Genomic Regions for Grain Protein Content and Quality Traits in Milled Rice (Oryza sativa L.)

Grain protein content (GPC) is gaining attention due to increasing consumer demand for nutritious foods. The present study carried out at ICAR-IIRR, Hyderabad, focused on the identification of quantitative trait loci (QTLs) linked with GPC and other quality traits. We utilized a population of 188 F₂ individuals developed from BPT 5204 (low GPC) X JAK 686 (high GPC) for QTL analysis. QTL analysis yielded four significant QTLs for GPC, three for amylose content, and multiple QTLs for other quality traits. <i>qPC1.2</i>, a major QTL in milled rice, was located in the marker interval RM562-RM11307 on chromosome 1 with an LOD value of 4.4. <i>qPC1.2</i> explained 15.71% of the phenotypic variance (PVE). Additionally, the Interval Mapping for Epistatic QTLs (IM-EPI) method detected 332 pairs of di-genic epistatic QTLs. Fifteen QTLs exhibited a positive additive effect, indicating that the contributing allele(s) was from JAK 686. Five F₂ plants, <i>viz</i>., F₂-140, F₂-12, F₂-7, F₂-147, and F₂-41, exhibited a high GPC of 14.67%, 14.36%, 14.32%, 13.60%, and 13.36%, respectively. Additionally, these plants also exhibited high per-plant grain yield (~17.0-29.0 g) with desirable agronomic traits. The QTLs identified are valuable resources for developing high-grain-protein varieties with high grain yield and desirable quality traits.