|SMITH, C. WAYNE - Texas A&M University|
|HAGUE, STEVE - Texas A&M University|
|JONES, DON - Cotton, Inc|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/4/2016
Publication Date: 9/22/2016
Citation: Hugie, K.L., Fang, D.D., Smith, C., Li, P., Hinze, L.L., Hague, S.S., Jones, D. 2016. Utility assessment of published microsatellite markers for fiber length and bundle strength QTL in a cotton breeding program. Crop Science. 56:2983-2995 doi:10.2135/cropsci2016.02.0093.
Interpretive Summary: Demand for longer, stronger, and more uniform fibers for the production of higher-quality yarns has led to an increased emphasis on the genetic improvement of cotton fiber quality. To date, cotton breeders have predominantly relied on conventional breeding methods for the improvement of fiber quality by making crosses between elite cultivars and selecting progeny based on measurable fiber properties. However, DNA marker-assisted selection has the potential to increase the efficiency of selection, particularly concerning the simultaneous improvement of fiber quality and lint yield. Over the past few decades, hundreds of DNA markers linked to fiber quality traits have been identified, yet their utility in an applied cotton breeding program has not been well documented. In this study, we compared the efficiency of selection based on previously reported DNA markers for fiber quality traits to selection based on direct measures of fiber properties. We found that selection for both fiber length and strength based on six DNA markers was comparable to direct selection for plants in the top 20%. Although DNA markers are not likely to substitute for the physical measurement of fiber properties, our results suggest that DNA marker-assisted selection could improve the efficiency of selection for cotton fiber quality traits.
Technical Abstract: Marker-assisted selection (MAS) may help mitigate some of the current challenges regarding the genetic improvement of cotton fiber quality, such as low genetic diversity and the negative association between fiber quality and lint yield. A multitude of quantitative trait loci (QTL) for fiber length and bundle strength have been identified in the literature, but the use of MAS for the improvement of fiber quality is still rare in public cotton breeding programs. Validation studies are necessary to develop portable genetic markers and to identify QTL with stable effects on trait expression across environments and genetic backgrounds. The effects of previously reported microsatellite markers (SSRs) linked to QTL for fiber length and bundle strength were evaluated in three genetic backgrounds, and the efficiency of MAS for fiber quality utilizing SSRs linked to robust QTL was investigated. Using the results of 32 published QTL mapping studies, six SSRs linked to robust QTL for upper-half mean fiber length (UHML) and six SSRs linked to robust QTL for fiber bundle strength (Str) were identified. In all but one case, the genetic gain achieved through marker-based selection of F3 plants having four-to-six alleles in the desirable state for UHML and Str was similar to that achieved by phenotypic selection of the top 20%.