Identification and characterization of QTLs for brown planthopper resistance from wild rice, Oryza rufipogon

The brown planthopper (Nilaparvata lugens (Stål); BPH) is a serious pest of rice (Oryza sativa L.). Host plant resistance is an effective means of controlling it; at least 46 BPH resistance genes have been identified. However, BPH can overcome resistance genes, so we need to detect more genes. To find new BPH resistance genes in Oryza rufipogon, we analysed quantitative trait loci (QTLs) associated with BPH resistance. Using 161 backcross recombinant inbred lines derived from O. rufipogon accession W0630, we identified eight loci associated with resistance. qBPH5 and qBPH6, on chromosomes 5 and 6, were validated in F₂ and F_2:3 populations derived from crosses between O. sativa japonica variety 'Nipponbare' and the inbred lines. BPH resistance of a line carrying both QTLs was higher than that of lines carrying just one. Pyramiding improved resistance and can be used in breeding BPH-resistant rice.