小麦抗纹枯病种质创新及QTL定位的初步研究

Germplasm Development and Mapping of Resistance to Sharp Eyespot(Rhizoctonia cerealis)in Wheat

目的纹枯病已成为影响中国小麦高产、稳产的主要病害之一,创造抗纹枯病小麦种质,并探讨其抗性遗传特点,是启动小麦抗纹枯病遗传育种研究的基础。方法以中国育种中很少利用的ARz和Niavt14为纹枯病抗源,以大面积推广品种扬麦158等为受体亲本,通过复交组合,聚合抗病基因;用单粒传法构建含137个重组自交系ARz/扬麦158遗传群体为材料,以致病力较强的R-46菌株为纹枯病病原,分别用沟带接菌法和牙签接菌法进行抗纹枯病的接菌鉴定。结果创造出02P12、02P315等兼抗纹枯病、赤霉病或白粉病的新种质;ARz/扬麦158群体在牙签接菌法中,病情指数介于29.8%～64.4%之间,在沟带接菌法中,病情指数介于25%～75%之间,病情指数均呈正态分布,具数量遗传的特点;单标记分析法对97个在抗感池或亲本间呈多态性的位点进行回归分析,获得Xgdm67等11个与纹枯病抗性极显著相关的SSR标记,能解释群体纹枯病病情指数变异的5.0%～13.0%,其中Xgwm247、Xgdm67、Xwmc94和Xgwm437在牙签接菌法和沟带接菌法的抗性资料中都能检测到;用MapManagerQTXb17建立了14条连锁区段,并用区间作图法检测到与小麦纹枯病抗病相关的2个QTL位点,其中,Xgdm67～Xbarc172之间的QTL在两种接种条件下都能检测到,LOD值分别为4.0和3.63,能够解释表型变异14.36%和12.3%;Xwmc94～Xwmc273.2之间的QTL只能在牙签法中检测到,其LOD值和贡献率分别为2.3和14.68%。结论初步认为在7D上存在抗小麦纹枯病的主效QTL。

[ Objective] Sharp eyespot （Rhizoctonia cerealis） is one of the important diseases in wheat production in China. Due to lack of knowledge on the inheritance of resistance, little progress has been made in wheat breeding for sharp eyespot resistance. [ Method] In this study, the newly evaluated ARz and Niavt 14 were used as sharp eyespot resistant donors, and crossed with widely released cultivars such as Yangmai 158, respectively. At the meantime, ARz/Yangmai 158 genetic population was developed using SSD method with 137 F6 RILs. The 137 RILs and the parents were inoculated with the fungi culture R-46 in F6 using cultured toothpick method and seedbed method, respectively, in 2003. [Result] Novel germplasms, such as 02P12 and 02P315, with multiple resistance and promising agronomic traits were developed. The RIL population showed normal distribution of disease Index, with disease index 29.8%-64.4% in cultured toothpick method and 25%-75% in seedbed method, indicating the resistance is a quantitative trait. By using marker regression analysis, 11 SSR markers associated with resistant QTL were found based on the disease index data, explaining 5.0%-13% of phenotypic variance. Among them, Xgwm247, Xgdm67, Xwmc94, and Xgwm437 were datectable in both inoculating methods. QTL mapping of resistance to sharp eyespot was conducted using MapManager QTXb17, 14 linkage groups were established. Two QTLs on chromosome 7D related to the resistance were found by composite interval mapping analysis. One QTL between Xgdm67 and Xbarc172 could been detected, explaining 14.36% and 12.3% of the phenotypic variance, in cultured toothpick and seedbed inoculation conditions respectively. Whereas the another QTL between Xwmc94 and Xwmc273.2 was only been found under the toothpick inoculation, explaining 14.68% of the phenotypic variance. [Conclusion] It was deduced that there is a major QTL conferring to resistance to sharp eyespot on 7D in wheat.