Genetic Linkage Map and QTL Analysis of Agronomic and Fiber Quality Traits in an Intraspecific Population

Molecular techniques have been developed that can enhance breeding efficiency for quantitatively inherited traits, many of which are economically important. Examples include yield, yield components, and fiber properties. Such traits do not consistently fall into discrete classes because environmental conditions greatly modify their performance. Molecular markers such as restriction fragment length polymorphisms (RFLPs) can aid in selecting for quantitative traits because they identify the segments of chromosomes that contain useful quantitative trait loci (QTL) or gene locations. Thus, once identified, breeders can select for desirable QTLs without interference from environmental effects. An RFLP genetic linkage map of cotton was developed from 119 F2.3 families derived from a cross of MD5678ne × 'Prema' and used for QTL analysis of yield, yield components, and fiber traits. Twenty-six QTLs were identified that were associated with agronomic and fiber quality traits. The identification of QTLs may indicate the presence of genes that influence expression of specific traits. Most QTLs contributed by the Prema parent conditioned low yield of fibers that were long, strong, and fine, while those from MD5678ne imparted high yield of short, weak, and coarse fibers. Analysis of these QTLs will identify specific chromosome regions that affect economic traits, and can allow breeders to search germplasm for useful genes and ultimately accelerate the breeding progress. ABSTRACT