利用MR1523/苏御糯F_(2:3)群体定位水稻抗灰飞虱QTL

灰飞虱是我国水稻生产的主要害虫之一,不仅直接取食危害水稻,还是水稻主要病毒病的传播介体,严重制约水稻生产。籼稻品种MR1523对灰飞虱表现较强的排趋性。为发掘抗灰飞虱新基因,本研究利用MR1523与感虫粳稻品种苏御糯构建了一个包含200个家系的F2:3分离群体,进行灰飞虱抗性鉴定。并利用120对均匀分布在水稻12条染色体的多态性SSR标记,构建了全基因组连锁图谱,进行抗灰飞虱QTL定位。结果分别在水稻第2、第5和第6染色体上检测到Qsbph2、Qsbph5a、Qsbph5b和Qsbph6 4个抗灰飞虱QTLs,分别位于分子标记RM526–RM3763、RM17804–RM13、RM574–RM169和RM190–RM510之间,LOD值分别为2.14、3.13、3.23和2.35,贡献率分别为12.0%、14.7%、17.4%和14.1%,各QTL的抗性等位基因效应均来自抗虫亲本MR1523。该结果为后续抗灰飞虱基因的精细定位及通过分子标记辅助选择培育抗灰飞虱水稻新品种奠定了基础。

Identification of QTLs Conferring Small Brown Planthopper Resistance in Rice (Oryza sativa L.) Using MR1523/Suyunuo F2:3 Population

The small brown planthopper (SBPH), Laodelphax striatellus Fallén (Homoptera: Delphacide), is one of the most destructive insect pests in rice (Oryza sativa L.) production. SBPH not only causes direct damage by sucking plant sap but also transmits the main viral diseases, which seriously threatens the safety of rice production. An indica cultivar MR1523 displayed strong antixenosis against SBPH. In order to identify SBPH resistance genes, a F2:3 population derived from a cross between MR1523 and susceptible japonica cultivar Suyunuo was constructed, and then evaluated for SBPH resistance. Moreover, 120 polymorphic SSR markers between the parents uniformly distributed on 12 chromosomes of rice were used to construct the molecular linkage map, and then conducted the QTL assay for SBPH resistance. A total of four QTLs on chromosome 2, 5, and 6, Qsbph2, Qsbph5a, Qsbph5b, and Qsbph6 were detected in the interval of RM526–RM3763, RM17804–RM13, RM574–RM169, and RM190–RM510, with LOD score of 2.14, 3.13, 3.23, and 2.35, and explained the phenotypic variance of 12.0%, 14.7%, 17.4%, and 14.1% , respectively. All of the QTLs came from the resistance parent MR1523. The results in this study lay a foundation for furtherly fine mapping SBPH resistance and developing new cultivars by molecular marker assisted selection in the future.