High-resolution mapping of two rice brown planthopper resistance genes, Bph20(t) and Bph21(t), originating from Oryza minuta

Brown planthopper (BPH) is one of the most destructive insect pests of rice. Wild species of rice are a valuable source of resistance genes for developing resistant cultivars. A molecular marker-based genetic analysis of BPH resistance was conducted using an F(2) population derived from a cross between an introgression line, 'IR71033-121-15', from Oryza minuta (Accession number 101141) and a susceptible Korean japonica variety, 'Junambyeo'. Resistance to BPH (biotype 1) was evaluated using 190 F(3) families. Two major quantitative trait loci (QTLs) and two significant digenic epistatic interactions between marker intervals were identified for BPH resistance. One QTL was mapped to 193.4-kb region located on the short arm of chromosome 4, and the other QTL was mapped to a 194.0-kb region…