利用分子标记研究小麦遗传群体的赤霉病抗性鉴定方法

针对小麦赤霉病抗源苏麦3号构建的两个小麦重组自交系遗传群体苏麦3号／Alondra和苏麦3号／安农8455，采用单花接种、表土接种及自然发病3种不同的接种方法进行小麦赤霉病抗性接种鉴定，并根据苏麦3号赤霉病抗性主效QTL的连锁分子标记Xgwm 493和Xgwm 533．1分别对群体进行抗性连锁分析．检测结果表明，在温室单花接种所获得的鉴定数据中，标记的赤霉病抗性连锁效应最高，P值分别小于0．0001，抗性鉴定结果最为准确．研究表明，对小麦赤霉病这种由数量性状控制，受外界环境影响较大的真菌病害进行抗扩展性的遗传研究，应采用控温控湿条件下的单花滴注接种鉴定方法最为合适．

Evaluation Method of Wheat Fusarium Head Blight Resistance for Genetic Populations Based on Molecular Markers

Fusarium head blight (FHB) is a destructive disease of wheat worldwide. Exploring new FHB resistance gene and breeding wheat cultivars resistant to FHB is the preferable approach to minimize FHB damage. However, progress in breeding FHB resistant cultivars has been hindered by the complex nature of wheat resistance and by the confounding environment effects. Furthermore, variable resistance gene from the same resistance resource has been reported with different evaluation method. Accuracy in phenotyping of FHB resistance directly affects the power of resistance gene detection. In this study, wheat cultivar Sumai 3 was selected as FHB resistance resource and was crossed with susceptible cultivar Alondra and Annong 8 455 respectively to construct recombinant inbred lines (RILs) populations. To search for appropriate evaluation method of wheat FHB Type II resistance, 218 F6- and F7-derived RILs of Sumai 3/Alondra population and 118 F6-derived RILs of Sumai 3/Annong 8 455 population, were inoculated by Fusarium graminearum through three methods including single floret inoculation (SFI), soil surface inoculation and natural infection in this study. SSR markers Xgwm 493 and Xgwm 533.1, which had been universally approved associating with FHB resistance of Sumai 3, were assayed in these two populations to test the resistance linkage effect. Results indicated that significant variation in FHB severity of each line was observed in testing years or testing locations and it can not be determined the most accurate inoculation method from phenotypic evaluation data. Regression results showed that associations of these two markers with FHB resistance were extremely distinct (P<0.000 1) in evaluation data obtained from SFI in greenhouse indicating the accuracy of evaluation data from SFI. The present study demonstrated that wheat FHB resistance evaluated by SFI method with controlled temperature and humidity was the most precise one for genetic analysis and QTL characterization for Type II resistance.