玉米GY220×1145组合粗缩病抗性的QTL定位分析

QTL Mapping for resistance to rough dwarf disease with GY220/1145 combination in maize(Zea mays L.)

玉米粗缩病是近年严重影响中国玉米生产的病害,研究其QTL定位有助于利用分子标记辅助选择提高玉米粗缩病抗性育种效率。该研究调查了GY220×1145杂交衍生的重组自交系(RIL)群体109个家系(F10∶11)在2个环境下粗缩病的抗感表型值,结合该组合由272个DNA分子标记构建的遗传连锁图谱,分别采用基于多元回归模型的Win QTL Cartographer 2.5软件的复合区间作图法(CIM)和基于混合线性模型的QTL Network 2.0软件中CIM方法,检测了玉米粗缩病的抗性位点。结果表明:(1)运用Win QTL Cartographer 2.5软件中CIM法,检测到5个抗玉米粗缩病的QTL,解释表型变异的6.9%～17.6%,其中有3个QTL在2个环境下都检测到。5个QTL的加性效应变异幅度为-8.57～11.94。(2)用QTL Network 2.0软件中CIM法,检测到1个控制玉米粗缩病的位点MRDD2-22,解释表型变异的9.0%,加性效应为6.93。在第5连锁群与13连锁群之间存在1对非主效QTL间的互作,解释表型变异的7.4%,互作效应为-7.70。运用多元回归模型和混合线性模型都检测到的位点是MRDD2-22,位于第4染色体长臂g7M7806～n142标记区间,抗性等位基因来自自交系1145,平均加性效应为9.3。MRDD2-22位点可用于分子标记辅助选择进行玉米自交系粗缩病抗性的改良。

Maize rough dwarf disease（MRDD） is one of the most serious diseases caused by rice black-streaked dwarf virus（RBSDV） in maize-growing area in China.In order to enhance breeding efficiency of cultivars resistant to MRDD through molecular assisted selection,QTL mapping was carried out for the trait of MRDD by using a recombinant inbred line（RIL） population（109 lines,F10∶11） derived from a single cross hybrid of GY220/1145.Phenotypic values of resistantce/susceptibility to the MRDD in the RIL population were investigated in two environments,and a genetic linkage map containing 272 DNA molecular markers was used for QTL mapping in this study.Five QTLs controlling MRDD were detected using the composite interval mapping method in Win QTL Cartographer 2.5 software,explaining 6.9%-17.6% of phenotypic variation,and three of them were stably detected in both environments.The additive effects of five QTLs were from-8.57 to 11.94.By the QTL Network 2.0 software,one QTL,MRDD2-22,was detected and explained 9.0% of phenotypic variation.Additive effect of MRDD2-22 was 6.93.Inbred line 1145 carried resistance allele at this locus.An interaction between one non-major QTL located in linkage group 5 and one non-major QTL located in linkage group 13 was also detected,explaining the phenotypic variation of 7.4%.Interactive effect of the epistatic loci was-7.70.The locus MRDD2-22,detected by both of the models,located on marker interval g7M7806-n142 of long arm of chromosome 4 and had an average additive effect of 9.3.MRDD2-22 was a reliable locus and could be used for marker-assisted selection to improve breeding efficiency of maize cultivars resistant to MRDD.