Utility Assessment of Published Microsatellite Markers for Fiber Length and Bundle Strength QTL in a Cotton Breeding Program
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Crop Science Society of America | 5585 Guilford Rd., Madison, WI 53711 USA. All rights reserved. Numerous DNA markers associated with quantitative trait loci (QTL) for cotton (Gossypium spp.) fiber quality traits have been identified in the literature, but there are still significant challenges regarding the use of these QTL in marker-assisted selection. While one of the primary limitations to the application of marker-assisted selection for fiber quality traits has been the inconsistency of markertrait associations, more recent studies have reported numerous markertrait associations and colocating of QTL in different genetic backgrounds and environments. The objectives of this study were to assess the published microsatellite markers linked to upper-half mean fiber length (UHML) and fiber bundle strength (Str) QTL in different genetic backgrounds and to characterize the utility of stable markertrait associations in selection for improved fiber quality within the context of an applied breeding program. Using the results of 32 published QTL mapping studies, six stable markertrait associations each for UHML and Str were detected. For each trait, the mean of F3:4 progeny rows that were grouped based on the six marker genotypes was compared with the mean of F3:4 progeny rows that were grouped based on phenotype. In all but one case, the mean UHML and Str of F3:4 progeny rows with the majority of alleles (i.e., four to six alleles) in the desirable state was similar to the mean of F3:4 progeny rows derived from F3 plants in the top 20% for UHML and Str. Our results indicate that, after proper validation, published QTL for UHML and Str could be utilized in selection for improved fiber quality.