Identification of quantitative trait loci controlling seed physical and nutrient traits in cotton

Cotton (Gossypium spp.) is an important source of edible oil and protein meals. Complex genetics and strong environmental effects hinder progress in seed quality trait breeding in this species. The use of molecular markers can improve an understanding of the genetic factors conditioning seed quality traits, and is expected to assist in selection of superior genotypes. This study was conducted to identify quantitative trail loci (QTL) associated with seed physical and nutrient traits in cotton. To achieve this objective, a population of 140 BC1S1 lines developed from a cross between'TM-1' and 'Hai7124' was evaluated in 2003 and 2004. A linkage map consisting of 918 markers from this population was used to identify QTL using QTLNetwork-2.0 software. Eleven single QTL were identified for kernel percentage, kernel oil percentage, kernel protein percentage and seven amino acids (Asp, Ser, Gly, Ile, Leu, Phe and Arg). Phenotypic variation explained by each individual QTL ranged from 10.89 to 46.28%. Two epistatic QTL for Cys and Leu were detected, explaining 9.55 and 4.43% of the phenotypic variation. These QTL detected for seed quality traits in cotton are expected to be useful for further breeding programmes targeting development of cotton with improved nutrient quality.