I really don't know that much about corn genetics. Just that it is complicated, as
@Pulsegleaner said.
I read (in the last 10 years) that sweet corn pollen can be blown by wind up to 5 miles from the field. Which means living in the Willamette Valley here in Oregon means there is no way to be sure (unless you bag your ears and tassels) that your corn didn't get crossed with something. Dr. Alan Kapuler told me once, when I was worried about keeping a corn variety pure, why worry? Just select the best from what you grow and don't worry about it was his paraphrased remark.
Sorry for hijacking your thread
@heirloomgal Mea culpa.
I've sometimes wondered if, in places where EVERYONE if growing corn (i.e. The Corn Belt) everyone has to meet up in advance of planting season with a map and a list of what variety(s) they are growing, work out where everyone has to put and orient their fields to make sure there isn't cross contamination, and agree to hold by the decisions made (basically, a Corn Covenant). With most of the commercial strains patented, and many of them having GMO proprietary genes, after the whole Monsanto contamination incident lawsuits a few years back, I'd imagine farmers are willing to go to great lengths to make sure their crop stays pure and salable.)
Most of my stuff, on the other hand, comes from a total LACK of any sort of regulation. At least 70-80% of the seed I hold all came from a single farmers market stand, which was semi famous for two things 1. getting most of their seed for a given year by extracting it from whatever didn't sell the previous year (i.e. when a tomato got squished or went rotten, into the seed bin it went) and 2. planting whatever types they wanted, an not caring in the least about what crossed with what. This meant that the produce there was always a wild array of God knows what, where you could never be TOTALLY sure if what you were buying was actually the variety you thought it was, and odd mixes abounded. I found MANY odd looking tomatoes there I extracted seed from (unfortunately, no matter what their tomatoes LOOKED like, they all tended to TASTE the same (pretty awful) so trying to get ones that might be WORTH keeping up was a matter of buying saving the seed, and hoping that the progeny tasted OK when grown under your own watch.)
One Wednesday in fall, many years ago (probably almost twenty now). I was at their booth and I started looking at their miniature corn bunches (for ornaments) I noticed that a lot of them looked odd, in that they were much shorter and fatter than such ears usually are. And since, at that time, the only short stubby eared mini-corn I knew of was Strawberry, I started taking a closer look. The more I looked, the more odd this corn looked. It was small, but the kernel shapes on many were those of full sized ears, and the color palette was also much wider than I was used to seeing. Then I started finding ears with kernels that had the kind of mottling I was looking for at the time, plus cobs with kernels that appeared floury or dented.
Over that season I bought a TON of that corn, and picked the most interesting kernels to save (the only downside is that, apparently the corn must have been somewhat old and poorly stored when I found it, so most ears were infested with granary moths. I managed to eradicate them, but that means I could keep no ears intact for reference.) And then it was back the next year, so I repeated the process. By year three, there was a change, in that most of the ears now had normal carrot shapes, but there were still a few colorful, floury and dented (plus, between the seasons, three ears that actually had some sweet corn kernels mixed in.) By year four, it was all over, and their corn looked exactly like everyone else's. What happened there to let those corns cross like that, I'll never know, but it left me with a lot of miniature non-pop corn to play around with.
