Dynamic mapping of quantitative trait loci for brown planthopper resistance in rice

Brown planthopper (Nilaparvata lugens Stål, BPH) is one of the most serious pests of rice. Quantitative trait loci (QTLs) analysis was performed using a population of recombinant inbred lines (RILs) derived from a cross between the susceptible variety MH63 and the resistant accession B5. Damage scores of the parents and RILs were evaluated every five days from 12th day after infestation by the insects. Six QTLs contributing to BPH resistance were detected and mapped by using either conditional or unconditional mapping. Five BPH resistant QTLs are derived from B5, and one was derived from MH63. The contributions to BPH resistance of the QTLs displayed different dynamic curves, and most of them were active in early stage of BPH infestation. Our results are valuable to development of resistant rice variety and understanding the genetics of BPH-resistance in rice.