Molecular mapping and characterization of traits controlling fiber qualityin cotton

Cotton (Gossypium spp) is the world's leading natural fiber crop. Genetic m anipulation continues to play a key role in the improvement of fiber qualit y properties. By use of DNA-based molecular markers and a polymorphic mappi ng population derived from an interspecific cross between TM-1 (G. hirsutum ) and 3-79 (G. barbadense), thirteen quantitative trait loci (QTLs) control ling fiber quality properties were identified in 3-79, an extra long staple (ELS) cotton. Four QTLs influenced bundle fiber strength, three influenced fiber length, and six influenced fiber fineness. These QTLs were located o n different chromosomes or linkage groups and collectively explained 30% to 60% of the total phenotypic variance for each fiber quality property in th e F-2 population. The effects and modes of action for the individual QTLs w ere characterized with 3-79 alleles in TM-1 genetic background. The results indicated more recessive than dominant, with much less additive effect in the gene mode. Transgressive segregation was observed for fiber fineness th at could be beneficial to improvement of this trait. Molecular markers link ed to fiber quality QTLs would be most effective in marker-assisted selecti on (MAS) of these recessive alleles in cotton breeding programs.