Antitative Trait Loci(QTL) For Resistance Gene Of Gray Leaf Spot In Maize

Maize (Zea mays L) is an important food, forage and energy crop as well as a model plant for genetics in the world. According to the latest statistics by Ministry of Agriculture latest statistics, in2011, the maize yiele has achieved19.17million ton and plays an important role in the national economy. Yet, the Gray Leaf Spot (GLS) is a world main disease caused by Gercospora zeae-maydis Tehon&Daniels, were one of serious restricted factors to maize industry of our country. It is well-known that development and cultivation of resistant hybrids are the effective strategys to control the disease, which greatly depended on the understanding of resistant resources and heredity for this desease. In this page, the preliminary study quantitative trait loci (QTL) for resistance gene of gray leaf spot in Maize by composite interval mapping (CIM) method using F2population. Which will provide useful information for breeding maize resistance to GLS. The main results are as following.1. A mapping population consisting of206F2individuals from the cross between maize inbred lines YML32(resistant line) and Ye478(susceptible line) were used in this study. The polymorphisms between the parental lines were detected with760pairs of SSR markers,167(21.9%) of which showed polymorphisms and used to construct genetic map. The integrated molecular generic lingage map was constructed by the128SSR markers, which spanned the genome of about1653.7cM with an average of12.9cM between two markers. The relative order of most SSR bin on genetic linkage map coincident with MaizeGDB, indicating that the population and its corresponding genetic map are suitable for QTLs mapping.2. The206F2:3families and two parental lines were evaluated for resistance under natural infection in Baoshan and Dehong, which are the key locations for severe disease pressure in Yunnan. There were two replications at each location. This paper we used composite interval mapping (CIM) method to analys resistant QTL locis.The mapping results showed that, in Baoshan, four QTLs on chromosome3,4and5were identified which explained0.24-18.89%of phenotypic variation; In Dehong, six QTLs on chromosome1to4were identified which explained7.29-11.01%of the phenotypic variation.2QTLs on chromosome3and4coincided in both environments, explaining11.48%and11.01%of the phenotypic variation in chromosome3;18.89%and10.19%in chromosome4respectively. The additive, partial dominant and overdominant effects were in genetic effects of maize gray leaf spot.