| This thesis is an investigation of high carotenoid maize, an ideal source of high value dietary carotenoids, especially lutein and zeaxanthin, in human and animal feed, , which has been proposed as a feedstock for high carotenoid egg production. The presented work is divided in three major parts: First, an investigation into the handling and storage necessary for accurate quantification of maize carotenoids is described. A modified analytical method was demonstrated to have reliability, reproducibility, and improved run-time and separation of xanthophylls. Carotenoid profiles remained stable during storage, but carotenoid concentrations decreased significantly from initial levels between 3 and 6 months of storage, and then remained stable for another year. Extreme caution was needed to maintain carotenoid concentrations in maize during handling and storage, but in situations where freeze drying was not used, high heat drying was no more detrimental than low heat drying.;In the final section, the inheritance of carotenoid profile and concentration in hybrid crossing was examined. While most crosses examined did not exhibit any heterotic effect on either carotenoid concentration or profile, the cross of A619 with CG102 exhibited strong heterosis for both traits. The genetics underlying this phenomenon was further examined by crossing the two inbreds with other lines and by QTL analysis on F2 lines derived from A619 x CG102. Exploiting an overdominant heterotic response for lutein and total carotenoids should be given strong consideration as the most viable option to achieve high lutein and high-carotenoid maize.;In the second part, the development and characterization of novel maize inbred lines exhibiting uniquely high concentrations of carotenoids is described. Thirty-four high carotenoid (HiC) lines resulting from allele mining of the 'Orange Flint' race using traditional breeding techniques and visual selection for deep orange endospenn color were characterized for carotenoid concentrations and profiles, and genetically at three loci that are key to the carotenoid biosynthetic pathway. The HiC lines illustrated the utility of mining allelic variation from exotic sources, the power of simple visual selection, and the potential limitations of diagnostic polymorphisms. |
