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Post by blueadzuki on Sept 2, 2014 14:57:30 GMT -5
Hi
This upcoming spring I have plans once again to try and grow out some of the mini non-pop I found 4-5 years ago ( I think I enough for ONE last shot before all of the seed is used up) On the assumption that THIS time I figure out so me way to take care of my critter problem so I actually have plants. I had one quick question about ear formation genetics.
Basically my question is as follow, how closely are the genes that control ear size/cupule distribution linked to the ones that control kernel size? I'm referring ONLY to the genetic factors controlling them, not the environmental I know that poor plant nutrition/pollination can result in cobs and kernels that are significantly smaller than they should be, but what I have is actually genetically small as far as I can tell, like miniature popcorn. In fact I'm working on the assumption that that is what these seeds are; the offspring of crosses between a mother plant that was a standard (if P gene free) miniature popcorn (possibly something like strawberry for most, since a lot [not all] of the ears shared its short, stubby, wide, Andean-like ear shape) and assorted normal sized non popcorn (though some of the seed indicates and astonishingly diverse group of non-pop papas. ) So I have to assume most or all of the pollen donors had ears and kernel sizes comparable to a standard flint/flour/dent.
So what I want to know is, in your collective experience, when a full size corn crosses with a miniature one, what happens. Do you get full split (some full size some mini). Mostly in between sized (I have another ear from a different collection that is sort of mid size range, smaller of ear and kernel that one would expect of a standard size corn but still bigger than most popcorns) a sort of bell curve of sizes.
More to the point do the ear and kernel genes have a tendency to disassociate, making corns that get cob instructions from one family and kernel instructions from the other. I'm sort of worried about losing a lot of space to things like this. Mini kernels on a full size cob are probably OK propagation wise (you'd simply wind up with an ear whose kernels were VERY widely spaced from each other. Potentially unsightly, but not a viability issue. But my concern is what happens if full sized kernels try and grow on a miniature cob; that they will squash themselves and end up killing themselves.
Actually I may have some evidence that this has already happened. Below is the one picture I have left of one of the original stock cobs (this one has a normal shape ear)
I you look carefully you will see that the dented kernels are very slightly larger than the undented ones. What you, wont see (because it was concealed until I actually shelled it, is how squashed they are; so squashed and malformed on their bases that, while I still have those seeds and am trying them in the spring I honest am not sure if any of them are actually going to be viable (most have deep folds and creases across their germ areas.)
So does anyone have experience here. Joseph , I'm especially looking to you since I presume that in your project to get Glass Gem colors into popcorn, you must have done a lot of pop/non pot crosses and at least some must have been with popcorns of less that non-pop size.
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Post by DarJones on Sept 2, 2014 19:59:52 GMT -5
Most of your speculation does not meet the smell test. Here is what I have seen.
1. Number of rows of kernels is highly heritable. There are genes for 2 rows, 4 rows, 8 rows (very common), 10, 12, 14, and 16 rows, and all the way up to 24 rows of kernels on a normal cob. I have not seen a normal cob with more than 24 rows, there was always some type of cob deformity. The general rule of thumb is that adding another pair of rows increases cob diameter to include the additional cupules.
2. The diameter of the core of the cob can be selected separate from the number of rows of kernels. Pencil Cob corn is a good example. It typically has 10 to 12 rows of kernels but the cob is severely reduced in size by squeezing cupules closer together and reducing the size of the core. These ears of corn tend to produce tapered flat "gourdseed" type kernels. The major change is in the shape of the kernel which becomes pointed and elongated.
3. The deformed kernels you are describing are linked to a particular variation in shape of the soft starch in the kernel. It is not associated with the cob traits in my experience.
4. Kernel size has a "doping" effect. Meaning that there is a difference because the endosperm is triploid. Two chromosome sets come from the mother, 1 set from the father. This means that endosperm traits and genetic traits of the plant grown from the seed may be dramatically different. For example, yellow color is highly affected by triploid interactions. If the female plant was heterozygous for yellow (one yellow gene, one white gene) and the male parent was also heterozygyous, you could get 4 different color variations (White, 1 gene pale yellow, 2 genes medium yellow, and 3 genes dark yellow). It is possible to have a yellow kernel that when grown produces a white seeded plant. For similar reasons, the kernels that are constricted now may produce normal shaped kernels next year.
5. I have grown some varieties of corn with elongated cupules. These varieties tend to produce kernels that are more square shaped than varieties with squeezed cupules such as Pencil Cob.
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Post by blueadzuki on Sept 2, 2014 20:32:46 GMT -5
So it sounds like I am OK, there won't be any self killing cobs. Good I can proceed.
Though if I DO manage to get any of it to grow, I may have to get back to you on #1 and post some pics, since I seem to recall that that "gourdseed micro" I have had more than 24 rows and seemed to have no cob deformity. I want to say 32-36, but it's been five years since I broke the cob apart and my mind may be getting hazy. I just remember it was a LOT (actually 24 is already probably a lot of rows for a mini corn, most of the ones around here tend to be in the 8-16 range)
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Post by Joseph Lofthouse on Sept 2, 2014 23:35:51 GMT -5
blueadzuki: I haven't paid specific attention to this. In a month or so I expect to pick a crop which is the F2 of a cross between popcorn and large seeded sweet corn. I intend to take photos and revisit this post. My best guess based on the corn I have grown is that the core size (of dried cobs) is fairly heritable at about 3/4 inches in diameter... Then if the kernels are small more rows are required to fill up the available space (about 24 rows in small seeded popcorn). If the kernels are large then fewer rows are formed (about 8 rows in large seeded flour corns). My popcorn averages about 16 rows. If the cob diameter is much larger or much smaller then I'd expect more/fewer rows of kernels as necessary to fit the cob. Once in a while I see cobs with space between rows, but mostly the kernels flatten out to take up all available space and the rows end up slightly interlocked. That is unrelated to the 'shoepeg' trait, which causes twice as many kernels to form in each row, so they end up crowding each other and thus developing all sorts of funky shapes. The shoepeg trait is heritable. The photo you shared looks like a shoepeg cob to me. I select against the shoepeg trait in my popcorn because the sharp angles interfere with the formation of a strong pressure vessel. I haven't done germination testing specifically on shoepeg cobs to get a sense of whether viability is harmed.
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Post by blueadzuki on Sept 3, 2014 5:22:28 GMT -5
Yes that one probably is a shoepeg. I really wish I had photos of some of the other cobs, but most of them pre date me having a phone that could take pictures (guess that means both f the dents are dent's + something else a shoepeg dent and a gourdseed dent. See what I meant about the potential pollen donor pool having to be unusually diverse. This is New York, commercial farmers don't usually grow gourdseed corns, or Southwestern type flours (some of the flours) and certainly not usually all in the same field.)And since they were so insect damaged when I got them, keeping them intact until I planted them was a no go (half of them fell apart in the bag on the way home from bug chewing).
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Post by blueadzuki on Sept 5, 2014 13:29:23 GMT -5
Just for kicks/curiosity. while trolling around SSE I found my old original thread about the mini corn (before I ever came here) and darned if there wasn't a second pic I took (isn't in my Photobucket account so I must have uploaded it directly from the computer. Posting below so you can see about the "short cob" thin I mentioned outer two are all flint, middle probably has a little flour in some kernels
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Post by blueadzuki on Sept 26, 2014 14:11:16 GMT -5
I had to take some pictures for someone else so here are the other corns I mentioned (with a penny for size comparison) 1. Jo-gee-oh/ Puckwudgie 2. The mini Gourdseed 3. That somewhere between mini and normal sized ones I mentioned with the stippled kernels and tan pericarp
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