|
|
Post by oldmobie on Mar 30, 2014 21:41:49 GMT -5
Sounds like I have homework... Suppose you have a corn (of unknown pedigree) with a color you want to use, but you're kind of a noob and don't know how to tell if the color is in the aleurone or the pericarp. How do you determine the pigment of the individual parts? Can I learn to tell with the seed intact, or will this require disection?
|
|
|
|
Post by oldmobie on Mar 30, 2014 21:44:35 GMT -5
|
|
|
|
Post by Joseph Lofthouse on Mar 30, 2014 22:27:40 GMT -5
Suppose you have a corn (of unknown pedigree) with a color you want to use, but you're kind of a noob and don't know how to tell if the color is in the aleurone or the pericarp. How do you determine the pigment of the individual parts? Can I learn to tell with the seed intact, or will this require disection? I was going to describe how to tell the difference, but there are so many complicating factors and exceptions that dissection is probably easiest. I dissect dry corn seeds with a pair of pliers or loppers. Or I soak them for a day and then dissect with a knife. What I would have said - skipping exceptions... It's much easier to tell pericarp color using intact cobs. Pericarp is maternal tissue so therefore every kernel on the cob has the same tint (unless transposons are involved). The pericarp color can then be modified by underlying colors but it still carries the overlying tint. In genetically diverse varieties, aleurone coloring tends to be spotty. Different colors scattered across the cob. If there are white kernels on a cob then the other colors on the cob are due to aleurone coloring. A mother plant could have a double dose of the same aleurone coloring, so it's still possible for every kernel on a cob to have the same tint even when dealing with aleurone colors. |
|
|
|
Post by oldmobie on Mar 30, 2014 22:52:30 GMT -5
Is it fair, then, to say pericarp color is determined exclusively by the female, aleurone exclusively by the male (barring mutation)? Or do I over-simplify?
For example: I could detassle any white popcorn, and only let it be pollinated by a selected corn with the aleurone color I want, and the detassled mothers would produce the same color that was present in the father? (Perhaps muted, depending on whether the white popcorn had a white or a clear pericarp)
I may have to disect some indian corn seeds tomorrow...
|
|
|
|
Post by DarJones on Mar 31, 2014 1:07:51 GMT -5
You've forgotten something important Joseph. There are 3 crucial genes involved in the aleurone color pathway. The white popcorn chosen would be...crucial.
|
|
|
|
Post by Joseph Lofthouse on Mar 31, 2014 10:22:50 GMT -5
oldmobie: Definitely oversimplified... In following through with DarJones's comment, there are multiple genes responsible for every trait and the way the aleurone is colored depends on a complex interplay between the genes provided by the mother and the father. And since the aleurone is triploid tissue the way the aleurone looks might be different depending on whether the necessary genes are donated by the father (1 set of chromosomes) or by the mother (2 sets of chromosomes). And for the sake of simplicity I also didn't mention sap color, which pretty much colors all parts of the kernel. I tend to ignore the complexity, and select for the traits I want out of the blended conglomeration.
|
|
|
|
Post by oxbowfarm on Mar 31, 2014 11:02:41 GMT -5
Those photos of Joseph's popcorn demonstrate a corn that is showing different aleurone colors. Every cob in that photo has clear pericarp. Here's a picture of Bronze Beauty, a flint corn that shows a great diversity of pericarp colors. This is exactly the opposite of what you want. Notice how every cob is basically one color? That's the maternal tissue of the pericarp. If there was colored aleurone genetics in this corn they would show up on the white and light colored ears and be very hard to see/invisible on the darkest pericarp reds and browns (there actually is a very tiny amount of light blue speckled aleurone in BB, its hard to see in this picture). Even when transposons turn on or off a color in pericarp it will occur in distinct patches on the cob, not on individual kernels.  I would make sure you are dealing with clear pericarp corns exclusively. It is really hard to tell pericarp from aleurone color with shelled kernels. So know what your varieties look like on the cob. |
|
|
|
Post by Joseph Lofthouse on Mar 31, 2014 11:09:48 GMT -5
oxbowfarm: Great photo. A corn population that consisted of red, clear, and blue pericarp and no endosperm or aleurone coloring would look really clever.
|
|
|
|
Post by oxbowfarm on Mar 31, 2014 11:14:56 GMT -5
Also, the corn you are trying to create is really going to be primarily an ornamental corn. If you get the mix of red white and blue going it will likely look pretty spectacular on the cob. But once it's shelled off, it won't look like anything much. Glass Gem is a great example of this. A lot of cobs of Glass Gem look incredible, so much so that images of the corn started an idiotic viral craze. Shelled Glass Gem seed doesn't look like anything special however, you might even call it ugly and muddy looking compared to a similar sample of a standard yellow popcorn.
So your patriotic corn should be marketed with images of the intact cobs, and possibly even sold as intact cobs, for maximum effect.
|
|
|
|
Post by oxbowfarm on Mar 31, 2014 11:18:48 GMT -5
oxbowfarm: Great photo. A corn population that consisted of red, clear, and blue pericarp and no endosperm or aleurone coloring would look really clever. Are there blue pericarps? I've always thought of pericarp and aleurone as having pretty distinct color pallets. Aleurone is more diverse color-wise, Green, Blue, purple, etc. Pericarp I've always thought of as limited to various intensities of red or brown. Blue pericarp sounds cool, I didn't know it existed. |
|
|
|
Post by Joseph Lofthouse on Mar 31, 2014 12:09:00 GMT -5
Blue pericarp, if it exists on my farm, is very subtle. Not the typical bold reds, pinks, and browns that I associate with pericarp color. I've been thinking that there is a very lightly tinted blue pericarp on a few glass gem cobs, and on a few Cherokee popcorn. Cobs with this trait tend to look muddled/dirty. So I'd expect selection by humans to dis-favor the trait. I don't have any intact cobs left to do a closer analysis. I'm intending to plant some plants descended from glass gem this spring, so I'll watch for the trait intending to pull them out to isolate whether the trait is real or just a fancy. It'd take some screening to reduce the aleurone colors.
And I wonder about Oaxacan Green and whether some populations have a slightly blue pericarp.
|
|
|
|
Post by DarJones on Apr 1, 2014 13:21:01 GMT -5
Oaxacan Green is blue aleurone on top of yellow endosperm.
|
|
|
|
Post by oldmobie on Apr 2, 2014 2:35:23 GMT -5
 Having trouble inserting picture. If it doesn't imbed, here's a link. These kernels are from one ear. All the pericarps show the stripes. (You told me that's from the mother, so the whole cob's the same.) I think I skinned the aleurone off of all but the bottom one. It has blue. I would call the pericarp a transparent yellowish brown? (With stripes.) I guess this isn't educational for anyone here but me, but I think I'm starting to get it.  |
|
|
|
Post by raymondo on Apr 2, 2014 3:42:56 GMT -5
I don't want to complicate things but ... How thick is the aleurone layer? And how well is it attached to the pericarp? If, as many sources say, the aleurone layer is only one cell thick, how can you be certain that the layer peeled off is just pericarp?
|
|
|
|
Post by oxbowfarm on Apr 2, 2014 6:02:57 GMT -5
I don't want to complicate things but ... How thick is the aleurone layer? And how well is it attached to the pericarp? If, as many sources say, the aleurone layer is only one cell thick, how can you be certain that the layer peeled off is just pericarp? Aleurone is one cell thick in corn, except for in South American Coroico/Piricinco corns which have multiple layers of aleurone. On top of Ray's question of whether the aleurone would peel off with the pericarp, is whether anthocyanin aleurone pigments would leach in a soaked corn seed and stain the pericarp and give you a false color? |
|
