The Segregation And QTL Analysis Of Grain Quality Traits In Maize DH Populations

Maize is an important crop for both grain and silage.To improve grain guality is one of the major breeding goals of maize.However,conventional selection for grain quality is inefficient because that it is a complicated quantitative trait.With the development and application of molecular markers,MAS(molecular assistant selection)supply a useful tool to the breeding for grain quality.In order to investigate the molecular genetic basis of grain qulity and find useful information for genetic improvement to grain quality, molecular maker linkage map was construct with DH population derived from "Nong xi110×Nong xi531","DH8×DH40"and"DH86×Shen 137"by SSR markers;then 83,38 and 44 DH lines were analysised and identified for grain quality;in the end quantitative trait loci(QTL)associated traits related grain quality were identified and analyzed in this study.The major results are as follows:1.A genetic linkage map of Nong-dan 5 population containing 160 SSR markers was constructed,which spanned a total of 1523.8cM with an average interval of 9.53cM.A genetic linkage map of A population containing 88 SSR markers was constructed,which spanned a total of 1434.7cM with an average interval of 17.7cM.A genetic linkage map of B population containing 106 SSR markers was constructed,which spanned a total of 1165.4cM with an average interval of 11.9cM.Compared with other published maize linkage maps in chromosome bin locus the linkage map established in this study was consistent with them.The SSR linkage can be used for QTL mapping.2.25 QTLs were detected for 3 grain quality traits of Nong-dan 5 population.Each traits have been identified 1-8 QTLs which were responsible for interpreting 3.11%-38.99%of the phenotypic variance individually,and showed additive effect and additive-additive epistatic.11 QTLs were detected for 3 grain quality traits of A population.Each traits have been identified 2-4 QTLs which were responsible for interpreting 1.38%-58.81%of the phenotypic variance individually,but protein content have been not detected additive QTL,and oil content have been not detected epistatic QTL;and showed additive effect and additive-additive epistatic,18 QTLs were detected for 3 grain quality traits of B population.Each traits have been identified 1-5 QTLs which were responsible for interpreting 1.74%-38.59%of the phenotypic variance individually, and showed additive effect and additive-additive epistatic.But QTLs were detected for 3 grain quality are different in 3 population.3.It which are oil content,starch content and protein content has bidirectional super-parents segregation in maize population.The over- parent hereosis range is different in 3 DH population.The over- parent hereosis range of oil content is the greatest,the over- parent hereosis range of protein content is in the next place,and the over- parent hereosis range of starch content is the smallest.