Robustness of QTLs across germplasm pools using a model quantitative trait.

Knowledge of the inheritance of C-glycosyl flavone synthesis in maize (Zea mays L.) silk tissues has been acquired through detailed genetic studies involving primarily germplasm from the Corn Belt Dent race. To test the robustness of this genetic knowledge, we examined C-glycosyl flavone synthesis in a genetically distinct germplasm pool, popcorn. C-glycosyl flavone profiles and levels and the involvement of three specific genes/quantitative trait loci (p, pr1, and sm1) in C-glycosyl flavone synthesis were examined in popcorn germplasm representing at least two races and various diverse geographic regions. Twenty-four inbred lines and 23 hybrids involving these inbred lines and inbred line R17 were characterized for their flavone profiles and levels in silk tissues. Two F2 mapping populations were constructed to examine the involvement of p, pr1, and sm1 on C-glycosyl flavone synthesis. C-glycosyl flavone levels threefold higher than previously reported in Corn Dent Belt materials and a novel class of compounds were discovered. The gene action of sm1 was different, the functional p allele was not always dominant, and pr1 did not affect mays in synthesis. Based on this rather simplistic "model" quantitative trait, it appears that caution should be exercised when attempting to apply quantitative trait locus knowledge accumulated in one germplasm base to a germplasm base that is known to be distinctly unique.