Phenotypic and genotypic characterization of purple kernel streak in white food corn
Purple kernel streaking (PKS) in white food corn (Zea mays L.) is characterized by the accumulation of purple-pigmented streaks (anthocyanins) in an otherwise colorless pericarp. This paper is the first published report documenting PKS, the prevalence of the trait in commercial white food corn germplasm, and the genetics underlying it. Entries from the Early White Food Corn Performance Trials were grown in Ontario over a three-year period and rated for incidence of PKS and days to flower. All commercial hybrids entered were genetically predisposed to PKS with severity varying across years and entries, and not consistently related to hybrid maturity. Quantitative trait locus (QTL) mapping was used to identify the genomic regions influencing PKS expression in an F2:3 population derived from the cross of two white food corn inbred lines, SD79 and SD80. PKS exhibited significant genotype x year interaction. QTLs were identified for each year explaining 64 and 46% of the phenotypic variation, with only one single-effect and one two-way interaction common across the two years. Linkage of the main single-effect QTL with the y1 gene, coupled with the GxE effects, may explain the prevalence of PKS in commercial white food corn hybrids.