小麦AR_z抗纹枯病的QTL定位研究

Study on QTL Mapping of Sharp Eyespot Resistance (Rhizoctonia cerealis) in wheat AR_Z

纹枯病在我国已成为影响小麦高产、稳产的主要病害之一。为了确定小麦纹枯病抗性基因的位点和数量,本文以单粒传(SSD)方法构建了ARz和扬麦158杂交的F6代重组自交系(RIL)的遗传群体共137个单株,分别在2002和2003年用牙签法和沟带接菌法进行了3次纹枯病抗性鉴定。初步研究结果表明,小麦纹枯病抗性是由主效基因和微效多基因共同控制的。在2D、3A、3B、3D、7D等5条染色体上分析了42个SSR引物,共49个位点,结合回归分析找到10个SSR分子标记。综合本项目组先前分析的48个SSR标记位点,分别对2、3、7同源群使用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6个QTLs,位于2D、3D、3B和7D上,单个位点可分别解释表型变异方差的9.0%、7.0%、7.0%、9.0%、14.0%和8.0%。初步认为在7D上有一个抗小麦纹枯病的主效QTL。

Sharp eyespot caused by Rhizoctonia cerealis is a widespread wheat disease and resulted in severe yield and quality losses. A F_6 RILs population (containing) 137 lines was developed from a cross ARz × yangmai 158 through the method SSD. Resistance (evaluation) was carried out three times, once in 2002 employing a (toothpick) with Rhizoctonia cerealis inoculation and twice in 2003 using both (toothpick) and seed inoculation method. The result indicated that two pairs of major genes plus many minor ones governed the inheritance of resistance to sharp eyespot in the RIL. 42 SSR primers with 49 loci on 5 (chromosomes): 2D, 3A, 3B, 3D and 7D showed polymorphic bands when (segregating) among the population. Using marker regression analysis, 10 SSR markers linked to resistant QTLs were found based on the disease index from two years. With 48 loci from (previous) research, 14 linkage groups were (constructed) on 2, 3, 7 homological (chromosomes) by Map Manager QTXb17; 6 resistance QTLs (LOD>2.0) were detected on 2D (2 QTLs), 3D, 3B and 7D (2 QTLs) (chromosomes) by interval mapping, each would explain 9.0%, 7.0%, 7.0%, 9.0%, 14.0% and 8.0% of the phenotypic variance, respectively. We (consider) one major QTL resistant to wheat sharp eyespot was located on 7D chromosome.