Quantitative trait loci for seed tocopherol content in sunflower

Tocopherols are natural antioxidants with vitamin E activity. Sunflower seeds contain predominantly α-tocopherol (>950 g kg -1 tocopherols), which is the tocopherol form exhibiting the highest vitamin E activity. The objective of this research was to study the genetic basis of total seed tocopherol content in sunflower (Helianthus annuus L.). Quantitative trait loci (QTL) analysis was conducted in two mapping populations derived from crosses between lines with increased (IAST-413) and reduced (IAST- 522) tocopherol content and the conventional sunflower line HA-89. Tocopherol content was measured in the F 2 and the F 3 generations. Linkage maps were constructed using simple sequence repeat and insertion-deletion polymorphism markers. Seven and six QTL determining increased and reduced seed tocopherol content, respectively, were identified. Of these, a major QTL on linkage group (LG) 10 was responsible for more than half the explained phenotypic variation for increased tocopherol content in the IAST-413 × HA-89 population, whereas a major QTL on LG 11 was responsible for more than half the explained phenotypic variation for reduced seed tocopherol content in the IAST-522 × HA-89 population. Three QTLs on LG 2, 4, and 17 were found in both mapping populations at overlapping support intervals. A 2-methyl-6-phytyl-1,4-benzoquinone/2-methyl- 6-solanyl-1,4-benzoquinonone methyltransferase (MT-2) locus was found co-locating with the QTL on LG 4. Quantitative trait loci information from this research will contribute to the development of marker-assisted selection tools for total tocopherol content in sunflower seeds. © Crop Science Society of America.

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