Molecular Makers Associated With QTL For Plant Height And Yield Components In Winter Wheat

Wheat (Triticum aestivum L. em Thell.) is one of the most important crop plants in the world. The plant height and yield are two important agronomic traits. It is of great value to understand their molecular genetic information and select them effectively for genetic and plant breeding purpose. These traits are quantitative and controlled by multiple genes. With conventional breeding methods, the selection efficiency of these traits is low. The advent of molecular markers and QTL (Quantitative trait loci) mapping has made it possible to localize individual genes for this type of trait. Among all molecular maker systems, simple sequence repeats (SSR) show a much higher level of polymorphism in wheat than any other markers. In this study, a F2 population with 122 individuals, derived from a cross of Nongda 015xFuzhuang 30, was used to construct a genetic map and locate QTL of plant height and yield. The results are summarized as follows:1. Analysis the variance of differences between the parental groups on seven traits in the experiments showed significant difference between the plant height, ear length, ear number per plant, spikelet number per ear .2. In the F2 population, analysis the allele frequency of 14 loci. Chi-square test indicated that all allele ratio approximates to the expected 1:1. Analysis the frequency distribution of each phenotype trait in F23 population by SAS, the test showed that all traits approximately fit normal distributions.3. The software package MAPMAKER/EXP was used for constructing a genetic linkage map. Nine loci were located on 2A and the map covered 121.9cM with an average of one marker each 13.5cM.4. Single-marker QTL analysis using linear regression was conducted by SAS and QTL Cartographer, three QTLs were detected at P<0.05. One identified for plant height close to locus Xgwm339, one QTL identified for grain number per ear close to locus Xgwml82, the QTL identified for spikelet number per ear close to locus Xgwm294.5. The QTL interval mapping analysis was carried out with MAPMAKER/QTL and QTL Cartographer. The most important QTL was on 2A which close to locus Xgwm294 and identified for plant height accounted for 8.2% or 13.52% of the phenotypic variance.6. The correlation coefficients among all traits including plant height, ear length, ear number per plant, sterile spikelet number, spikelet number per ear, grain number per ear, 500-grain weight are detect by SAS. Ear length, spikelet number44per ear, grain number per ear were significantly correlated with sterile spikelet number o...