corn needs time, not distance.
if you want different varieties, look for their maturity days. You''ll want to get varieties with at least 20 days difference.
There's all kinds of corn: dent (for corn meal), flint, sweet, pop...
its an american original.

corn likes to be in blocks at least 16 plants strong (I've read) to get good pollination. I've hand pollinated smaller patches, but it didn't worky too good.