Mapping of QTL controlling tocopherol content in winter oilseed rape
2005
Marwede, V. | Gul, M.K. | Becker, H.C. | Ecke, W.
Tocopherols are natural antioxidants in vegetable oils and are important dietary nutrients. Enhanced tocopherol content has become an important objective in oilseed rape breeding. A segregating DH population was tested for 2 years at two locations in replicated field trials. Genotypic differences occurred for alpha-, gamma- and total tocopherol content as well as alpha/gamma-tocopherol ratio, but highly significant genotype x environment interactions resulted in low heritabilities. Using a mixed-model composite interval mapping approach between one and five QTL with additive and/or additive x environment interaction effects could be mapped for alpha-, gamma- and total tocopherol content and alpha/gamma-tocopherol ratio. In addition, one to six locus pairs with epistatic interaction effects were identified, indicating a strong contribution of epistasis to trait variation. In total, the additive and epistatic effects explained between 28% (alpha-tocopherol content) and 73% (total tocopherol content) of the genotypic variance in the population, with individual QTL and locus pairs contributing between 7.5 and 29.2% of variance. Considering the low heritabilities of the tocopherol traits, the results of this study indicate that marker-assisted selection may be an efficient strategy in a breeding program for enhanced tocopherol content in rapeseed.
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