Corn kernels have different colors because of genes that control color. Each kernel is an individual with its own set of genes, like an embryo. Kernels are siblings housed on the same ear and so naturally have many different colors. By naturally, I mean, through the course of natural selection. One-color ears are unnatural products of human selection.
It’s worth heading over to Nicola Twilley’s Edible Geography to read the full post about how this corn came to be, if you can tear your eyes away from the beautiful corn above.
p.s. The seeds for the corn are sold out at present, but you can head to Seeds Trust’s Facebook page if you want to be added to their mailing list.