Construction Of Molecular Marker Genetic Linkage Map And Localization Of QTLs For Some Important Economic Traits Of Allotetraploid Cotton

Cotton is one of the most important economic crops in the world. Cotton fiber is the most important material for textile industry, and takes an important strategic status in the world economy.During the past several decade years, the yield and quality of cotton fiber has always been steadily improved. However, in the recent ten years, the yield-improvement proceeded slow and was likely to reach a platform and stagnation. On the other hand, due to the development of textile industry and increased consumption demands on cotton fiber commodity, it is urgent to improve the fiber quality. Consequently, much effort of cotton breeder should been directed toward improving cotton fiber characteristics and yield. Along with the development of biology, the phenotypic markers (morphological markers, cytogenetical markers, and iso-enzyme markers) used in the selection of desirable alleles at a target locus from within any genetic material during traditional breeding program have been substituted by molecular markers based on DNA polymorphism. Due to the advantage of high through-put ratio, no interferer from expression and environment, and displaying difference of DNA sequence, the DNA-based molecular markers facilitated the construction of genetic linkage map and the detection of quantitative trait loci (QTL) controlling our interested quantitative traits. Based on a detailed genetic map, the QTL detection could be conducted, and thus it is easy to dissect comprehensively the genetic basis of quantitative traits into Mendelian factors, and the genetic basis of quantitative traits could be better understood. So the technique could lay a foundation for the acceleration of improvement on cotton yield and quality through molecular breeding.In this study, genetic linkage maps for tetraploid cotton were constructed by means of DNA-based markers based on two segregation populations. Cotton yield components and fiber quality were investigated in the population of F₂ individuals and corresponding F_2:3 families. On the basis of genetic map constructed, quantitative traits analysis and QTLs detection was performed. The purpose of this study was to find the genetic loci associated significantly with fiber yield and quality, so the further research and application (such as marker-aided selection, map-based cloning) could be conducted. The results obtained in this study were as follows:Dissection of genetic basis of fiber quality in Gossypium hirsutum with molecular markers:...