QTL Associated with Accumulation of Tocopherols in Maize
2003
Wong, Jeffrey C. | Lambert, Robert J. | Tadmor, Yaakov | Rocheford, Torbert R.
Tocopherols are a class of fat soluble antioxidant vitamin compounds present in maize (Zea mays L.) that provide health and economic benefits, which potentially could be captured by both producers and consumers to add value to the grain. α-Tocopherol, δ-tocopherol, and γ-tocopherol are the most abundant isomers present in maize. α-Tocopherol has the highest biological activity for the tocopherols; however, γ-tocopherol is generally present in much higher concentrations than the other tocopherols in maize kernels. The objectives of this research were to determine levels of tocopherol isomers in maize kernels from two related maize mapping populations and to map quantitative trait loci (QTL) controlling accumulation of tocopherol isomers. Two sets of materials were assayed in this research, a (W64a × A632) F₂:₄ mapping population and testcross progeny with AE335. Molecular markers were evaluated on the F₂:₄ mapping population and a linkage map created. Each population was analyzed by high performance liquid chromatography (HPLC) for α-, δ-, and γ-tocopherol. Composite interval mapping (CIM) identified QTL for individual tocopherols and total tocopherols, notably on chromosomes 1 and 5. The ratio of α-/γ-tocopherol was analyzed to identify QTL influencing the conversion of γ-tocopherol to α-tocopherol. The QTL associated with the largest percentage of phenotypic variation in the study was detected on chromosome 5 for ratio (α/γ) tocopherol. The QTL identified in this study have potential for use in a marker assisted selection program to facilitate increasing levels and ratios of tocopherols in maize grain.
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