Mapping of quantitative trait loci associated with rice black-streaked dwarf virus disease and its insect vector in rice (Oryza sativa L.)

Rice black-streaked dwarf virus disease (RBSDVD), transmitted by small brown planthopper (SBPH, Laodelphax striatellus), causes serious loss in rice production. Breeding resistant cultivars are one of the most effective strategies to control the virus disease and its vector. By both natural inoculations in the field and modified seedling-box screening test in the glasshouse, an indica variety WR24 showed high resistance to RBSDVD and SBPH. An F-2:3 population consisting of 153 lines derived from a cross between WR24 and a susceptible japonica variety Suyunuo was used for quantitative trait loci (QTL) analysis of RBSDVD and SBPH resistance. The linkage map consisting of 130 SSR markers was constructed with an average marker interval of 13.90 cM, spanning a total of 1890.9 cM. Totally, five QTLs for RBSDV resistance, viz. qRBSDV3(WR24), qRBSDV6(WR24), qRBSDV7(WR24), qRBSDV9(WR24) and qRBSDV11(WR24), were detected on chromosomes 3, 6, 7, 9 and 11, with LOD scores of 2.7, 3.08, 3.13, 5.28 and 3.7, respectively. Meanwhile, three QTLs for SBPH resistance, including qSBPH5(WR24), qSBPH7(WR24) and qSBPH10(WR24), were mapped on chromosomes 5, 7 and 10, with LOD scores of 2.18, 3.5 and 3.57, respectively. All resistant alleles were from WR24. Among these QTLs, qRBSDV7(WR24), qSBPH5(WR24) and qSBPH10(WR24) were newly reported, and qSBPH10(WR24) showed major effect that explained 17.9% of total phenotypic variance. The RBSDVD and SBPH resistance QTLs and the tightly linked DNA markers can be utilized in RBSDV and SBPH resistance breeding in rice.