A major quantitative trait locus qSBR11 from Oryza sativa 'Milyang 44' confers resistance to rice stink bugs

Stink bugs are major insect pests that damage rice after heading, causing pecky rice and sterility, which significantly reduce grain quality and yield. We identified a major quantitative trait locus (QTL) for stink bug resistance derived from the resistant donor variety 'Milyang 44' and explored DNA markers useful for marker-assisted selection in rice breeding. QTL analysis using an F₅ population (n = 94) identified a major QTL, qSBR11, on chromosome 11, which explained 28.46% of phenotypic variance in Pecky Rice Index. Fine mapping of the BC₁F₃ and BC₅F₃ populations narrowed the candidate region of qSBR11 to approximately 616 kbp. In the validation experiments, individuals selected using the marker C5_indel9205 located within this candidate region showed significantly reduced pecky rice rate. Additionally, the marker genotype was highly consistent with phenotypes of 22 tested varieties, and genomic analysis of 685 accessions from TASUKE+ in the Rice Annotation Project Database showed that the resistant allele was rare in japonica cultivars. Therefore, that qSBR11 is a promising target for breeding japonica rice. This study identified a major QTL for stink bug-induced pecky rice resistance and demonstrated the utility of a reliable DNA marker for practical breeding.