海南普通野生稻抗白叶枯病新基因精细定位及育种利用

Bacterial blight (BB), caused by Xanthomonas oryzae pv. oryzae, is one of the most widespread diseases of rice, limiting rice production. The use of resistant rice varieties continues to be the most economical and effective way to combat this disease. Exploitation and utilization of major resistance genes is the basis of breeding for resistance.Wild rice carries abundant genetic variations and has formed a potential gene reservoir for rice improvement.A novel resistance gene to BB from common wild rice(Oryza rufipogon Griff) was identified based on the resistance spectrum evaluated, comparison of resistance type and inheritance analysis. The results indicated that it is a new complete dominance overall resistance gene with the wide spectrum resistance and high resistance,which was highly resistant to PXO86, PXO99, PXO145、PXO280 and PXO339, and moderately resistant to PXO61, PXO79, PXO71, PXO112 and PXO124. It was located on the short arm of rice chromosome 6 within a genetic interval of 4.9 cM, flanked by markers RM584 and RM1163. We are going to develop near-isogenic lines and separate populations for fine mapping the novel gene. Molecular tagging of disease-resistant genes will be obtained simultaneously by using molecular marker methods, SSR(Simple sequence repeat) and STS(Sequence-tagged sites). We are going to develop new varieties through molecular marker-assisted selection and traditional breeding methods, hybridization and selfcross. The novel disease-resistant gene will be tracked and detected from hybrid descent materials by using tightly linked molecular markers, and provides the new gene source for the rice disease-resistant breeding.

白叶枯病是水稻的主要病害，培育抗病品种是防治病害最经济有效的手段，挖掘与利用抗病新基因是抗病育种的基础。野生稻蕴含丰富的抗病基因。挖掘海南普通野生稻抗白叶枯病新基因，培育抗病新品种，保障水稻生产安全。我们从海南普通野生稻中发现了1个显性抗白叶枯病新基因，在海南白叶枯病重灾区多年多点的抗性鉴定中均表现抗病，对一套国际水稻白叶枯病抗性鉴别菌种P1-P10表现抵抗，初步将其定位在水稻第6染色体短臂上，位于标记RM584和RM1163之间4.9cM的范围内，暂命名为hn515。本研究以抗源5-15与感病材料9311杂交、回交构建的近等基因系为作图群体，利用SSR和STS等分子标记技术，对其进行精细定位，获得与该基因紧密连锁分子标记，结合常规育种，利用标记辅助选择培育抗病新品种。同时创新出一批抗病中间育种材料，明确该基因与主要农艺性状的关系，为消除育种中基因与不良性状连锁提供理论依据和指导。