| The knowledge of the allotetraploid Upland cotton (Gossypium hirsutum L.) genome is currently limited. For the cotton scientist to enhance yield, quality, and pest resistance performance, much time and labor is needed for significant progress. The identification of desirable genetic diversity in parental material, and efficient parent progeny selection will hasten the accumulation of desirable characteristics within cotton germplasm. With this in mind, a study to reveal more of the architecture of cotton chromosomes and the position of genes controlling desirable agronomic and fiber traits was undertaken.;A genetic molecular linkage map was constructed using restriction fragment length polymorphisms (RFLP) analyzed on a population of 96 F2-derived F3 bulk sampled families of HS46 x MARCABUCAG8US-1-88. A total of 137 probe/enzyme combinations unveiled 259 polymorphic fragments which were organized into 146 molecular loci. With the assistance of MAPMAKER;An analysis to find the location of quantitative trait loci (QTL) relative to this molecular linkage map and the unlinked loci, involving 19 agronomic and fiber traits measured from a 96-family, F2-derived F5 population, of HS46 x MARCABUCAG8US-1-88, was initiated. MAPMAKER;The Mixed Model Approach, authored by Jun Zhu and Bruce Weir, was also used to identify QTL. The Mixed Model Approach was concluded to be a better method than MMQTL. This method revealed 148 QTL among the 19 agronomic and fiber traits. Twelve of the 32 QTL suggested by MMQTL were in common with MMA, while the remainder were regarded as noise. At least one QTL was identified for each of the 19 traits, with several QTL associated with more than one trait. These 148 QTL were contained in 68 different locations positioned on 22 different linkage groups. These studies constitute the only molecular linkage map, and the first identification of QTL associated with desirable agronomic and fiber traits, in Upland cotton. |
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