Actually, it does affect the kernels. It seems counterintuitive, but it does. What you say about the second generation of plants from crossing of corn is certainly true.
High-Sugar Sweet Corn
"Also, the sh2 types must be isolated from sugary enhanced, standard sweet corn, popcorn, and field corn. Cross-pollination between the sh2 types and the sugary enhanced and standard varieties will destroy the quality of both. The kernels will be tough and starchy. Pollen from field and popcorn will produce similar results. Isolation may be achieved by planting sh2 types at least 250 feet from other types of corn and by avoiding prevailing winds. Cross-pollination may also be avoided by planting the various types so they mature at different times. There should be a minimum 14 day difference between silking/tasseling dates."
