Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/8/2008
Publication Date: 6/1/2008
Citation: Yue, B., Vick, B.A., Miller, J.F., Cai, X., Hu, J. 2008. Construction of a linkage map with TRAP markers and identification of QTL for four morphological traits in sunflower (Helianthus annuus L.). 17th International Sunflower Conference, June 8-12, 2008, Cordoba, Spain. p. 655-660. Interpretive Summary: Quantitative trait loci (QTL) are defined as chromosomal regions that can be located by their statistical association between molecular markers and a measurable trait in a segregating population. In this study, we constructed a linkage map containing 202 target region amplification polymorphism (TRAP) and 24 SSR markers from an F2 population derived from a cross between two sunflower breeding lines. We used this linkage map to map the QTL underlying four agronomically important traits including plant height, chlorophyll content, leaf shape and head shape using both F2 and F3 generations. We identified 18 QTL for these traits. One major QTL for plant height and one major QTL for chlorophyll content could explain more than 30% and 40% of the phenotypic variation, respectively. These mapped QTL will be useful for sunflower improvement.
Technical Abstract: Genetic maps have been constructed using RFLP, AFLP, RAPD and SSR markers in sunflower, and quantitative trait loci (QTL) underlying agronomically important traits have been positioned on these maps. In this study, a linkage map containing 202 target region amplification polymorphism (TRAP) and 24 SSR markers was constructed in an F2 population derived from a cross between two sunflower breeding lines. This map spans a total distance of 1597.5 cM and contains 17 linkage groups, and 13 of them were aligned with the linkage groups of the published SSR map. QTL for plant height, chlorophyll content, leaf shape and head shape were identified and mapped in the F2 and F3 generations. A total of six, five, six, and one QTL were detected for plant height, chlorophyll content, leaf shape, and head shape, respectively. Among the QTL identified, two QTL for plant height and two QTL for chlorophyll content related traits were identified in both F2 and F3 generations. In addition, a QTL for plant height and a QTL for chlorophyll content explained more than 27.2% of the phenotypic variation. These QTL will be useful in molecular breeding. Each of the QTL for leaf shape and head shape had a small contribution to the phenotypic variation and was detected only in one of the two generations, suggesting a complex genetic basis for these two morphological traits. The results demonstrate the benefits of TRAP markers for genome mapping and QTL analysis.