Questions about GMO, Corn Genetics and some Corn Pictures

[reed]

Carol Deppe, flowerweaver, Joseph Lofthouse, blueadzuki, steev, I'm starting to think that in a sense there is no such thing as dent corn. When I first started researching and reading I came on a lot of resources that talked about and diagrammed the difference between flint and dent, leading me to believe they were the major types. There are also sweet and pop which I guess are variations of flint. And I came across gourd seed and waxy which I haven't completely identified yet.  

Back to flint / dent, in my research on those I never encountered information on flour corn, I learned about it here on the forum. When I cut open a kernel of my corn or a kernel of the local grown Indian corn including the ones that taste good I find a combination of soft white material and a layer of hard colored material. If I cut open a dented kernel I find the same thing but in different proportions, more (I expected less) of the hard material especially on the sides. These kernels are also generally flatter and smaller the the good ones.

When I cut open a kernel of Painted Mountain or Cherokee White Flour I find very small amounts of the hard material or none at all that I can identify. Based on this I'm thinking that some of the university and other material I found is kinda of misleading in a way. Sure the dented kernels and the non dented kernels look different inside and out but the real types are flint and flour. Dent is just a common mix of the two where the proportions and configuration causes the dent. Perhaps there is really just one kind and flint and flour are just variations of it and perhaps I'm just splitting hairs or rather kernels. 

If I understand it right, flint, dent and flour are not different distinct genes. These properties can just mix up and come out in varying proportions. This is different than a sweet gene where a kernel either has it or not. That's why I can't I can't mix a little sweetness into a corn I want mostly for corn bread. 

[blueadzuki]

Your essentially right in that there is no specific gene that makes "dent" corn. "Dent" is simply a term used for a specific shape of kernel where the sort starch reaches the end of the kernel, causing a "dent" or dimple in the top (soft starch shrinks more than hard as it dries thus making the dimple).

Most of the "dents" that make up the majority of industrial corn production are what is know as the "corn belt" dents. Allegedly they resulted from a farmer around the middle of the east coast. According to the story, he planted his field with a northern flint corn. Then a story knocked down a lot of his plants, and since it was early he decided to re plant in the spaces. However the seed store was out of that northern flint so he had to replant with a southern gourdseed (gourdseeds are another group of corns notes for having kernels that are very tall and flattish (that miniature pink white and purple corn I took the picture of is a gourdseed). the two crossed and created a dent corn which was more productive than either of the parents and formed the basis of the dents of the corn belt.)

I have my own scale for floury/flinty. On the far of the hard end is what I think of as Crystal or Glassy Flints, which have only a tiny "lick" of soft starch in the center (while theoretically there probably is some kind of corn that has absolutely NO soft starch (besides sweet corn) I have never actually seen one. Glass Gem is a Crystal flint. Then you get increasing amounts of soft until you reach what I call "cap" or "tip" flint, still mostly hard but with a soft floury cap with a hard cover (basically this is dent corn without the dent in terms of how it will grind) Dent comes next, where the soft reaches the tip of the kernel. After that in soft increase (by now your pretty firmly into what most people would think of as "four" corn) you get to what I think off as "pillar" which is nearly all soft starch but with traces of hard (I call it pillar because the hard starch usually forms two bands on the sides of the kernel (hard to see directly, but if you put the kernel on a light source, they become visible) Next is "shell" basically a soft starch core that nearly fills the kernel surrounded by a thin hard starch shell\. Finally you get to something like some of the Andean corns which basically are PURE soft starch, and so light they will actually float (to make things a bit more confusing the Andeans can have dents too, but in this case the dents are due to collapse due to the kernels being hollow inside.)

Waxy or Glutinous corn is another thing entirely. You don't see it around here much but it is popular in China. That has a mutation that changes the kind of starch the corn makes into a different form (Amylose, I think) so the corn is gummy.

There's actually one more kind you may bump into called Pod corn. This is basically like flint except each kernel has it's own little private under husk. Not eaten much but used ritually in some parts of South America.

[flowerweaver]

Here's a couple of photos of some of the corn you sent me Reed, perhaps Blue could comment on where these fall in his descriptive continuum. For reference, the first one is from #32 and the second from #14.  The first one is very rounded and glassy, and the starch is contained within a central column. The second one is more narrow and square, a little bit less glassy, and the starch umbrellas out towards the top of the kernel as seen by the shadow (I should have picked one without pericarp coloration for better comparison).

[blueadzuki]

By that description, #32 is lick going on cap and #14 is cap.

One other note if you want to assess, it's usually better to use the BACK of the kernel, the germ makes things hard to see clearly .)

[Joseph Lofthouse]

reed: University researchers get paid to write about things that can make them more money next year. The crops grown by people on the fringes are not much interest to them. It's much harder to get funding to study a very minor crop like the flour corns grown in Hopiland or by a farmer in Montana. Dent corn is industrialized corn. It is what factories use to make flour, and oil, and alcohol, and just about anything else that ends up getting made from corn. Something like 90% of corn grown in industrialized agriculture is GMO corn. People outside of industrialized agriculture tend to not grow GMO crops, therefore they are marginalized to the fringes of agriculture, and thus outside the area of study that is likely to attract funding for a university.

The selection of dent characteristics for the food processing industry strikes me as purely pragmatic... Hard flints cause a lot of wear and tear on equipment, and are hard to work with culinarily because they stay hard rather than absorbing water readily. Soft flour corns are easy to work with, but quite susceptible to damage by mold, insects, and processing equipment. The dents are the perfect compromise: They have a hard flinty layer right under the skin to prevent damage by pests and processing equipment, but then they are soft inside.

I think that the education system has done a disservice to all of us by teaching Mendelian genetics the way they do: In isolation, as simple one gene interactions, without acknowledging the complexity that exists in the real world, where there are multiple genes that affect the structure of the kernels. Additionally, in the kernel there is triploid tissue, and diploid tissue, and tissue derived only from the mother. And I suspect that there is a lot more penetrance going on than the school system would be comfortable admitting.


There is a gene for flint Fl, and a gene for floury fl. Then I suppose that there are modifier genes that affect how they express. With the corn genome being so thoroughly sequenced, Isuppose that those modifier genes are known: Just not to me because I made a socially-oriented decision to not grow dents: (Dents are for feeding factories, not people.)

[Carol Deppe]

Reed--I class corns as flint, flour, or dent based on the proportions of flinty and floury endosperm, not on the shape of the kernel. It's a practical classification, because that proportion is what determines how I can use the corn. As you note, some varieties with a generous mix of both types of endosperm have a dent in them and some don't. As best I can tell, it has to do with how the flint is arranged. If it is arranged in a tube around the central floury core with the floury core running all the way to the top of the kernel, you end up with a dent. This is because the floury endosperm contracts more than the flint as they dry out. If, however, a good bit of the flint runs across the top of the kernel, the kernel is not going to show a dent.

I like pure flints because only very pure flints can be used to make fast cooking polenta that actually tastes cooked. Or johnny cakes that taste cooked. I also like pure flour types because I can use them to make cakes, sweetbreads, gravy, (and if they are the right colors) for parching. The dents only make good polenta if you use very laborious methods (for example, simmer with stirring 45 minutes, then pour in pan and bake an hour). Or if you mechanically separate out the flinty part and use just that. (Sifting. But you never get rid of all the flour.) The Italian "flint" polenta corns I've examined are all dents according to my classification.

Blueadzuki--I've also read that story about the origin of dents. Maybe that is the history of the midwestern cornbelt dents. However, Indians have had their own dents for a long time before that. Oaxacan Green Dent, for example, which traditionally supposedly was used to make green tortillas. (And has a distinctie dent. It has a yellow endosperm and black/blue aleurone. The most vivid green kernels are heterozygous black (blue) aleurone over yellow endosperm.) And many SW corns native American corns were dents, at least by my classification of having a good bit of both flint and flour endosperms. In most of them, the arrangement of the two types doesn't give you a dent most of the time. Most corns used to make tortillas seem to be these dent types. There is both a good bit of flour and some grit to a good tortilla. Of course, the SW Indians also had lots of pure flour corns. As best I can figure out from Buffalo Bird Woman's garden, she grew flint corns and flour corns, but not dents. At least she referred to them as "hard" and "soft", and praised the flavor of the "hard" but said it was a lot more difficult to grind.

Joseph--I agree that what is taught students as Mendelian genetics is simplistic. In breeding plants, so many of the characteristics we care about are influences by so many genes we never see anything resembling Mendel when we do crosses. Size of fruit, yield, and vigor are virtually always multigenic characteristics in crosses and don't show classical segregation. For quantitative characteristics, the old model of "blood" works better than the Mendelian model with the exception that it doesn't account for dominance, especially in the first generation. That is presumably why humans were very effective deliberate plant breeders long before any knowledge of Mendelian genetics. They had a concept of genetics that was all wrong, but practically speaking, it mostly worked most of the time when it came to plant and animal breeding. I'm talking about the ancient belief that what was inherited from parent to offspring was in the blood, and just mixed together in all possible proportions in offspring. (As opposed to be unitary.) (This mistaken concept is where the expressions "pure blood", "half blood" etc. come from.) If you have dozens of genes affecting a trait, beyond the F1, that's more or less what things look like. If you cross a squash with big fruits to one with small fruits and go to the F2, you see a smear of every possible size, with most being between the two parents.

In the lab you actually have to work pretty hard to find a mutation with a consistent enough expression to give you clean "Mendelian" segregation classes. Most mutations are "leaky". (Geneticists use the words "variable penetrance" and "variable expressivity" when talking about it in print, and "leaky" when talking informally, especially about biochemical mutants.) Then even if you have some simple Mendelian genes that have complete penetrance, they may not segregate normally in crosses to another variety unless the two varieties are closely related and share the same genetic background. (So all the Drosophila genetics is done with one particular highly inbred line. If you go and cross it to some line from the wild, you might see messed up segregation ratios. In practical plant breeding most of our crosses are between lines that are not very closely related. So even when we are dealing with completely penetrant mutant genes, there can be all kinds of genetic anomilies that screw up segregation patterns. Chromosomal inversions in gene order between the two varieties, for example. And segregation distorters can crop up in crosses. ie genes that actually influence the segregation or recovering of chromosomes in their own favor. But basically, if we want the characteristics of two different varieties in a new variety, we just cross them. Then either backcross or go to an F2 and start selecting what we want. Practically speaking, it's pretty straightforward. Sometimes we know something about the genetics of some of the characteristics we care about; often we don't.

I think the cornbelt dents were selected above all for yield for animal feeds and factories. And the European settlers who started doing that were basically just using corn to make wet batter cornbread (which works with any corn) and for animal feed. They didn't really have the sophistication the Indians had with respect to many different corns types and flavors and many different uses. Indians used mostly true flints and true flours, because they were eating the corn themselves, and the flavors and cooking characteristics mattered more than just yield.

Flints aren't so hard that they damage metal equipment. Flours definitely are more vulnerable to insects.

[Carol Deppe]

Interesting corns, Blueadzuki! But I think all those tiny grains would drive me nuts. I wonder what they would be like nixtamalized and just served whole. Sort of like rice-sized hominy.

Reed--Actually, everything that is heritable is coming from both sides of the cross except characteristics that might be associated with the cytoplasm. but those actually sometimes can matter. If one variety is more vigorous or cold hardy or disease resistant, I like to use that as the female parents since the mitochondria could be involved in it. (Some mitochondrial genes are located in the nucleus, but some are actually in the mitochondriaal DNA and are maternally inherited.) Sometimes I start a corn project by detasseling one variety with alternating rows of varieties. But more often I don't. I just plant alternating rows and keep everything, and let the genes all mix together over the generations, with both cytoplasms represented. If one is better in my situation it will end up being selected for automatically. The second generation of my project I plant densely, then just keep all the biggest plants when thinning. Those are likely to be nearly all hybrids. So I can pretty much get nearly all hybrids to plant the second year without the mess of detasseling. If any plant that is purely one variety is so vigorous it matches the hybrids, it deserves to be overrepresented in the new variety anyway, I figure.

With respect to the varieties mentioned in my article--That 'Parching Red Supai' sold by Seeds of Change has apparently been all crossed up. The pics in their catalog actually show one in the three ears as seriously dent, meaning that nobody involved seems to realize what the corn is supposed to be like. And elsewhere on this forum are some pics of 'Parching Red Supai' that show multicolored ears. So I wouldn't bother getting that corn from them. However, that variety is just too good to not have available. And I put a couple quarts into long-term frozen storage when I gave Seeds of Change the parching-reselected material they introduced. Accordingly, I've arranged with with a grower to grow the corn out in isolation next year. If all goes well I should be able to make a good line of 'Parching Red Supai' available again in 2016.

I think any corn that is growing 6-8' isn't pure Painted Mountain. Beside the point, though, if it is the kind of corn you want and it does well for you.

[blueadzuki]

You also might want to take a look at the other thread I started for this year. Some of what has shown up at the FM stand this year (starting last week) has quite a bit of what seems to be floury endosperm as well (there's some on the first 3-4 cobs in the top row) And the mostly white cob seems to have those "bread slice" shaped kernels that the first floury stuff did alanbishop.proboards.com/thread/8162/wierdo-corn-stand-again

And I agree wholeheartedly with the definition. As far as I'm concerned a "cap" flint is functionally a dent. In fact, for some circumstances (like mine) a "cap flint" works better as a dent than an actual dent does. The extra hard starch veneer over the top means you get most to all of flint corns supposed resistance to mold and pests while still getting a kernel that has a lot of soft starch. And the "shell" kind has even more.

In the below (three cobs I picked up at the farmers market two weeks ago) you can sort of see the spread. The bottom cob is a "cap" flint the middle a pretty pure flint, and the top is a mix of cap, pillar and shell.

I never claimed that ALL dents came from that cross. It was always said to be the origin of the corn belt dents, and just those. Certainly the corn belt dents show a certain amount of Gourdseed ancestry. The kernel shape shows that (they may not be as wide as a full gourdseed, but the are a lot flatter than most of the northern flints).

I'd nixamatize some and find out, but, I don't have all that much of it at this moment. Maybe some day, if I can get the stuff to increase and get a strain that is mostly floury. As I mentioned all of the floury stuff (including this years) is actually flour-flint, with flinty kernels still the majority. The flinty stuff is still basically pop, so it's probably too hard to be edible as whole grains, even cooked. But when most are soft, maybe. Not sure how good it would be as a side, but it might be good in some of those Latin stews where you add whole posole. Though since, proportionally, most small grains have a larger percentage of germ in the kernel versus endosperm, I imagine it might make hominy that was a bit too greasy (or does niximatizaion also purge out all the oil in the germ?)

[Carol Deppe]

I don't think nixtamalizing would remove much oil from the germ. It's boiling in alkali, which I wouldn't expect to dissolve oil. different varieties have different amounts of oil, too. And more oil might make the hominy actually taste better. After all, we invariably add some fat or oil of some sort to cornbread and/or slather some on top because it tastes better with more fat/oil than is found in most corns naturally.

[Carol Deppe]

Can some of you oldtimers on this forum tell me how I post pictures?

[flowerweaver]

Carol Deppe I'd wondered about that photo after you told me about the Parching Red Supai. I'd certainly be interested in purchasing it from you when you have your stock rebuilt.

[flowerweaver]

Carol Deppe to post photos you will need a photo hosting site like Flickr or Picasa. In Flickr there is a button on each photo page that takes me to a BBC code that I copy and paste into the forum post body. This must be done using the 'Reply' format on the upper right of the post instead of the default 'Quick Reply'. Once in the Reply there are code and preview mode tabs at the bottom you can use to view the post before publishing it.

[blueadzuki]

I use either snapfish or photobucket (depending on whether the picture I'm using came from my phone or my scanner). For the former, I go to the site go to the picture link, left click, go to "properties", copy the URL there, close that link then come over here. I go into "Reply mode (since quick reply doesn't really allow you to do any modifications, hit the image icon and paste the link. Photobucket is more or less the same except I use the bar marked "direct" instead of the properties button.

Oh and I just got these less than an hour ago (there was a farmers market stand next to the place I went to pick up lunch) 1 and 2 is the picture are obviously mostly strawberry popcorn (though probably not pure, they're a little long and large for that) but 3 seems to have some dent in it)

Actually a thought just occurred to me. When you boil an alkali and a fat together, don't you wind up with soap? Obviously there isn't a lot of it (or every pot of homily would be covered by greasy slippery foam. But I wonder if that is part of what makes masa taste like masa. Part of the masa flavor IS a slight bitter note, which I suppose could be tiny amounts of saponified oil.

[Joseph Lofthouse]

An image may be included from anywhere on the Internet. For example from CarolDeppe.com



I use both an image hosting service, and my own web site to host images. garden.lofthouse.com/images/ Sometimes one or the other is more convenient depending on where I am posting from. Once I upload an image I am careful not to rename or delete it because I might have linked to it in a forum post.

Then to link the image into a post, there is an icon on the (advanced) reply page.

[reed]

Carol Deppe, Joseph Lofthouse, blueadzuki, flowerweaver, These are the ears I'v selected for seed next year. They are all a mix of flour / flint and (some colors) on all of them taste good parched in the skillet. Generally the pink, red, chinmark and lavender kernels taste best. Other traits of the tasty ones is that they are large rounded kernels, the cobs are sort of flexible and easy to shell and in a couple cases are hollow. I discarded some other cobs because they were predominately yellow or had dented kernels. Only the tasty colored kernels will be planted. 

Those large ears originally failed the parch / taste test but it was because they were not completely dry yet. I'm glad I tested them again because 1, 2, and 3 are the best of all, with #8 (original #36) coming in fourth. They crack open when cooked and some even try to pop (maybe not a good thing but I'll take it for the flavor). There is no unpleasant grit or hard bits when cooked, I'm a little surprised by that. 

It's disappointing that #s 9 & 10 don't rate higher (but still good) they will be included regardless for sentimental reasons and because I know they grow well here and because they are wonderful for sweet corn if picked before the kernels get too big or turn color. 

I am worried about season length on those big ears but hope I can work it out in future generations. I don't have a real short season but I like short season things because I figure the sooner you can harvest something the less chance something will happen to it. 



I'm going to mix them up with Painted Mountain (from Sustainable Seed Co.) and perhaps some other flour corns and see what I get. I'll detassel the PM at one end and these at the other end. If I plant 12 inches apart with rows three feet apart I have room for about 1000 plants. Three hundred of those at one end will be all those sweet corns I'v accumulated and the other 700 will be this project. 

I hope to get the general hardiness, diversity, drought resistance and earliness of Painted Mountain and the flavors (with a little flint still there) from these into my own locally adapted new variety. If successful I might call it "Dazed & Confused".