Submitted to: Helia
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/10/2009
Publication Date: 9/1/2009
Citation: Yue, B., Cai, X., Yuan, W., Vick, B.A., Hu, J. 2009. Mapping Quantitative Trait Loci (QTL) Controlling Seed Morphology and Disk Diameter in Sunflower (Helianthus annuus L.). Helia. 32(50):17-36. Interpretive Summary: In order to map the quantitative trait loci (QTL) underlying sunflower seed morphology and disk diameter, we constructed a linkage map containing 165 target region amplification polymorphism (TRAP) and 44 SSR markers from an F2 population of 120 plants derived from a cross between two sunflower breeding lines. Using this linkage map, we were able to map 55 QTL controlling seed morphology and disk diameter traits such as seed and kernel size, shape, stripe, asymmetry and disk diameter in both F2 and F3 generations. Most of the QTL were clustered in seven chromosomal regions and four of the regions were reported previously to harbor similar QTL. The information generated by this study will facilitate confection sunflower germplasm improvement.
Technical Abstract: Several seed morphological traits, along with disk diameter, differ greatly between oilseed and confection sunflower types, which are bred for different end-use purposes. This paper reports the results of analyzing the quantitative trait loci (QTL) underlying seed morphological traits and disk diameter in a segregating population derived from an oilseed by confection cross. A linkage map containing 165 target region amplification polymorphism (TRAP) and 44 simple sequence repeat (SSR) markers was constructed from 120 F2 plants. This map contained 17 linkage groups and spanned a total genetic distance of 1784.3 cM. The QTL for 12 seed morphological traits such as seed and kernel size, shape, stripe, asymmetry and disk diameter were analyzed in both F2 and F3 generations. A total of 55 QTL were detected and 33 of them were identified in both the generations. Each QTL explained 5.1-29.3% of the phenotypic variation, suggesting these traits were controlled by multiple genes. Most of the QTL were clustered in seven chromosomal regions and four of the regions were reported previously to harbor similar QTL. Two of the three QTL identified for disk diameter were also located in two of the seven regions. Moreover, alleles from the confection line at these QTL had positive effects on these traits. Both of QTL congruence and correlation analysis revealed that different genetic bases are responsible for seed shape, stripe and other confection traits. The information generated by this study will facilitate confection sunflower breeding.