Identification and genetic characterization of new sources of betaand gamma-tocopherol in sunflower germplasm / identificación y caracterización genética de nuevas fuentes de beta- y gamma-tocoferol en germoplasma de girasol / identification et caractérisation génétique de nouvelles sources beta et gamma de tocophérol dans le germoplasme du tournesol
2014
Velasco, Leonardo | Fernández-Martínez, José M.
Sunflower seeds have more than 90% of the total tocopherols in the form of alpha-tocopherol, which exerts a weak antioxidant protection of the extracted oil. A partial substitution of alpha-tocopherol by another tocopherol derivative with greater antioxidant action would improve the oxidative stability of sunflower oil. The objective of the present research was to identify sources of modified tocopherol profile in sunflower germplasm. A total of 952 germplasm accessions were evaluated by analyzing the tocopherol profile of 12 half-seeds per accession by HPLC. The screening resulted in the identification of a source of increased beta-tocopherol content and a source of increased gamma-tocopherol content. In both cases the accessions corresponded to old populations of Peredovick. The line T589 presented a beta-tocopherol content from 30.4 to 48.5% of the total tocopherols, whereas the line T2100 had a gamma-tocopherol content from 87.9 to 93.9%. Genetic studies revealed that both traits were partially recessive in crosses with material with standard tocopherol profile. In both lines, the altered trait was determined by alleles at a single locus. Comparative studies with previously developed sunflower lines with similar levels of beta- and gamma-tocopherol will elucidate whether the new lines have the same or different genetic modifications within the tocopherol biosynthetic pathway.
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