If I have understood correctly, it’s possible to pick sweet corn crosses in grain corn by looking for wrinkly kernels. I have seen these before, but haven’t concidered using them. Now I thought it might be good way of increasing the genetic pool of my sweet corn population. However, as it’s the first time I’m not sure how they behave genetically and thus I have a few questions. Maybe someone can confirm if my assumptions are right.
First, are those likely to be crosses? They look very much like sweetcorn kernels, but not exactly which I assume comes from the fact that they grew in a grain corn and not all features are affected in this generation. There were about 70 kernels in total out of 10k or something like that. That would make sense as grain corn allele for sweetness is dominant in pollination, but by luck some have not been pollinated by grain corn. I’m not sure where that sweetcorn pollen would have come as there were very few sweet corn grown within the field and all a bit futher away. I speculate that there might have been a cross within my grain corn from previous generations that grew as sweetcorn as one cob had well over 10 wrinkly kernels whereas others usually had at most 2-3.
Secondly, if I grow them out they will behave like sweetcorn if they are pollinated within these crosses or other sweetcorn? I did plan to grow them in (semi) isolation, but still I’m curious to know before hand where I’m sticking my hands into. Probably I’ll grow them together with some from my own population and yukon chief to cross them already next year, but how much of those I’ll have depends how they affect when being cross-pollinated or cross-pollinating others. If they become inedible like when cross-pollinated with grain corn, I don’t want too many of those. This could occur at least if there is a change than some of the wrinkly kernels aren’t actually crosses.
Don’t have any more questions, but if someone has experience in the matter it would be nice to hear.
In general, genes for sweet corn are recessive, and hard starch genes for grain corn are dominant. Wrinkly kernels, such as you show in your photo, are sweet corn phenotypes resulting from the mother and the father corn parents containing recessive sweet genes. When pollination occurs, there is a chance for homozygous recessive genes to dominate and produce sweet corn.
There is a lot more nuance to this, as there exists heterozygous sweet corn, and sometimes corn kernels contain a mix of different starch-type phenotypes, but this is the main idea behind why you have a few sweet kernels showing up in a grain-dominant population.
Adding some of these kernels to your sweet corn population will unlikely hurt the sweetness if you aim to increase diversity.
Ok, so it doesn’t fully go the way I was thinking. But isn’t it that allele that causes the change of spoiling the taste. I don’t mean just being less sweet. I have previously had sweetcorn too close to grain corn and some sweet corn became horribly bitter. Being less sweet isn’t that big of a concern as my population is mostly from painted hill which originally was made by using painted mountain grain corn and thus isn’t always the sweetest, but well sweet enough. I’m now adding some “normal” sweet corns that would balance out possible less sweet genetics. Only thing I’m unsure is that do they have se/su allele in those wrinkled kernels or do I need that some other way. I could definetely grow them out and cut off tassels to make sure they cross with those that for sure have se/su allele. Maybe keep a few years as a separate population before merging it with the main project. Might be an idiot proof approach and wouldn’t have to think too much about peculiarities of corn genetics.
I am uncertain about the bitterness. I don’t find grain corn to be bitter at any stage, even green. Often at the young, milky stage it can be relatively sweet.
It is hard to be certain about which genes are influencing which phenotypes and how they are doing it in this case since we’re dealing with a diverse population. If it seems like a risk, I suggest not incorporating it into your main sweet corn population, or creating a separate population with it.
It’s not bitterness in grain corn per se. It comes when sweet corn is pollinated with grain corn and that pollination makes the sweet corn bitter. I don’t know how exactly it works, but it’s not heredidary, just concerns the kernels pollinated. I have only read about it and experienced the effects when I got a little lazy with the distances.
