利用连锁-连锁不平衡联合作图挖掘玉米抗粗缩病优异等位基因的研究

Maize yield reduced significantly because of maize rough dwarf virus(MRDV)disease. Using natural population and linkage population, genome-wide association mapping, marker-trait association analysis will be carry out to develop MRDV resistant gene.Inbred lines(n=230) will be planted in three regions during two years. After artificial inoculation of MRDV, phenotype data, genetic diversity and level of linkage disequilibrium will be analyzed. Relationship between genotype and phenotype will be explanied by the way of DNA chip and statistics to get related SNPs and anti-MRDV genes on a large scale. Linkage-linkage disequilibrium mapping will be investigated by combining natural population with linkage population to mining MRDV resistant gene. The significance of the project lies in: 1)Identification of the ralated proteins and genes against MRDV,which will provide key genes for further developing and cultivating resistant hybrids. 2) Results will provide important scientific basis for analyzing molecular mechanism of MRDV, improving the MRDV resistance of inbred lines and breeding new MRDV-resistant varieties.

针对玉米粗缩病胁迫下玉米受灾面积逐年加重并导致大量减产甚至绝产的问题，以关联分析群体结合连锁群体为研究对象，进行结构分析、标记/性状关联分析，挖掘玉米粗缩病抗病基因。以230份玉米骨干自交系为自然群体，经过两年多地种植，田间调查性状结合人工接种,获得粗缩病表现型；利用SNP等标记对群体进行遗传多样性、连锁不平衡结构及水平的分析；采用芯片技术获得高通量SNP基因型数据，通过统计学手段进行LD作图；结合F2代群体的连锁作图构建连锁-连锁不平衡联合图谱，挖掘玉米粗缩病抗病基因。本项目的研究意义在于：1） 挖掘玉米粗缩病抗病基因，为候选基因的克隆及抗病育种提供重要的理论依据及关键基因；2）为深层次阐明粗缩病抗病机理，培育有突破性抗病新品种提供重要的科学依据。

玉米粗缩病是影响玉米高产稳产的重要病害之一。为获得玉米粗缩病抗性基因的QTL区域，本项目以292份玉米自交系及F6、F2连锁群体为研究材料，经过三年五点的玉米粗缩病抗病鉴定，分析了自然群体的遗传多样性和结构特性；利用Maize chip50K 基因芯片获得基因型数据，结合Farm CPU、Tassel和GAPIT软件，进行了标记/性状关联分析，在玉米1号、2号、4号、6号、7号和8号染色体获得抗粗缩病初步QTL区域，获得6个紧密连锁SNP标记；经F6和F2代连锁群体的验证，8号染色体区域与前人研究结果吻合，1号染色体QTL区域的验证达到显著水平。该研究为精细定位新的玉米粗缩病抗病基因及克隆提供了科学数据，并为阐明粗缩病的抗病机理及新品种选育提供了理论依据。