小粒野生稻抗白背飞虱新基因的精细定位与育种利用

Whitebacked planthopper (WBPH) is an important pest in rice production, not only harms rice directly, but also intermediates other pathogen or virus during feeding process, and causes serious threat to the safe production of rice in China. Identification of resistance genes and development of WBPH-resistant varieties is an economical and effective way to control this pest. In our preliminary study, a set of chromosome segment introgression lines was constructed by using Oryza minuta, a tetraploid wild rice, highly resistant to WBPH, as donor, and Oryza sativa as receptor. Through insect-feeding screen and field test, two introgression lines with ideal agronomic traits and highly resistance to WBPH were developed, and the genetic characteristics of their new resistance genes had been analyzed. In this project, these 2 materials will be used to construct mapping populations by crossing and back crossing with 9311. Through insect resistance identification and marker-assisted selection, new resistant genes conferring resistance to WBPH from Oryza minuta will be fine-mapped and ready for map-based cloning. At the same time, the new resistant genes will be pyramided to the main hybrid rice parents through marker-assisted selection and hence provide genetic resources and technical support for durable resistant rice breeding.

白背飞虱是水稻生产上的一种重要害虫，不仅直接危害水稻，还在取食过程中传播其他病害和病毒，严重威胁我国水稻的安全生产。发掘和鉴定新的抗虫基因，选育抗虫品种是最经济有效的防治手段。我们在前期研究中已利用高抗白背飞虱的四倍体小粒野生稻（Oryza minuta）为供体，栽培稻为受体，构建了一套染色体片段导入系，从中筛选出了2份农艺性状优良、高抗白背飞虱的材料，并对它们拥有的新抗性基因进行了遗传分析。本研究就是利用这2份高抗白背飞虱的材料与9311杂交和回交构建作图群体，通过抗虫性鉴定和分子标记筛选，对来自于小粒野生稻的抗白背飞虱基因进行鉴定与精细定位，为图位克隆基因做准备；同时开发其便于进行标记辅助育种的分子标记，通过标记辅助选择培育多个当前主栽杂交稻亲本的抗性基因导入系和抗白背飞虱多基因聚合系，为持久抗性水稻新品种培育提供基因来源和技术支持。

白背飞虱是水稻生产上的一种重要害虫，严重威胁我国水稻的安全生产。发掘和鉴定新的抗虫基因，选育抗虫品种是最经济有效的防治手段。在前期研究中，我们已从小粒野生稻基因渗入系中筛选出了2 份农艺性状优良、高抗白背飞虱的材料，并对它们拥有的新抗性基因进行了遗传分析。本研究就是利用这2 份高抗白背飞虱的材料与桂1025杂交和回交构建作图群体，通过抗虫性鉴定和分子标记筛选，从P114和K41中分别鉴定出2个和4个抗白背飞虱的QTL。来自于P114和K41中等位基因降低幼苗死亡率。在K41中，qWbph3位于第3染色体RM570-RM85之间，表型贡献率为15.3%，qWbph4位于第4染色体RM335-RM518之间，表型贡献率为34.3%，qWbph7位于第7染色体RM505-RM234之间，表型贡献率为7.3%， qWbph12位于第12染色体RM309-RM17之间，表型贡献率为5.2%。进一步利用BC2F2:3家系的苗期抗虫鉴定，分别将qWbph3和qWbph4定位于第3号染色体上长臂末端RM2187-RM3585间3.8 cM的区域内和第4号染色体上短臂RM3471-RM3536间2.5 cM的区域内。同时应用分子标记辅助选择，已开始将新抗虫基因聚合于6个优质恢复系中，目前已获得抗白背飞虱的株系材料121份。这项研究不仅鉴定了4个抗白背飞虱的新QTL，而且也为持久抗性水稻新品种培育提供了基因来源和技术支持。