Analysis of QTLs for Resistance to Small Brown Planthopper in Rice Using an F2 Population from a Cross Between Mudgo and Wuyujing 3

To map quantitative trait loci (QTLs) associated with rice (Oryza sativa L.) resistance to small brown planthopper (SBPH), this study constructed a genetic linkage map with an F2 population derived from the cross between indica cultivar Mudgo (high resistance to SBPH) and japonica cultivar Wuyujing 3. The linkage map comprised of 104 simple sequence repeat (SSR) and 3 Indel markers and covered 1409.9 cM of rice genome with an average marker interval of 13.2 cM. One hundred and seventy-seven plants from the F2:3 families were identified for resistance to SBPH by the modified seedbox screening test. QTL analysis of SBPH resistance was conducted using composite interval mapping implemented in Windows QTL Cartographer 2.5. A total of 3 QTLs conferring resistance to SBPH, Qsbph2b, Qsbph3d, and Qsbph12a, were detected in the regions of RM5791–RM29, RM3199–RM5442, and I12-17–RM3331 on chromosomes 2, 3, and 12, with the LOD scores of 3.25, 3.11, and 6.82, respectively. The resistant alleles of Qsbph2b, Qsbph3d, and Qsbph12a were all from Mudgo and explained 17.3, 15.6, and 35.8% of the total phenotypic variance, respectively. The QTL Qsbph12a tightly linking to markers RM3331 and I12-17 has a potential in breeding for SBPH resistance by marker-assisted selection.