Analysis of Quantitative Trait Loci for Resistance to Brown Planthopper in Dongxiang Wild Rice (<I>Oryza rufipogon</I> Griff.)

Abstract

Wild species of Oryza is an important resource of the genes for resistance to brown planthopper (BPH). In this study, two populations were developed from an interspecific cross between Dongxiang wild rice (Oryza rufipogon Griff.) and cultivated rice Xieqingzao B (Oryza sativa L.) and used to determine quantitative trait loci (QTLs) for BPH resistance. A BC 1 F 5 population derived from Xieqingzao B//Xieqingzao B/Dongxiang wild rice was infested with BPH collected from the paddy field. Two QTLs were detected, of which qBph2 was located in the interval RM29-RG157 on chromosome 2 and qBph7 in the interval RM11-RM234 on chromosome 7, and the Dongxiang wild rice allele decreased seedling mortality by 22.2% and 43.7%, respectively. Validation of the two QTLs was followed by testing a BC 3 F 3 population with BPH biotypes I, II, and III, respectively. QTL analysis showed that qBph2 confers resistance to biotypes I and II, while qBph7 to biotypes I and III. The two QTLs have a great potential in the improvement of BPH resistance of rice varieties.