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Post by Deleted on Dec 3, 2011 10:10:41 GMT -5
I just found an interesting article discussing anthocyanin production and insect resistance (it's only the abstract, unfortunately): www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=249695Has anyone else noticed less severe insect and / or animal feeding on corn foliage and seeds with high levels of the pigment? How about mold infection? Joseph, if there's something to this, then maybe that's a biological reason for people not liking purple-pericarp corn: it's a defensive chemical. Your thoughts? |
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Post by Joseph Lofthouse on Dec 3, 2011 12:08:51 GMT -5
Has anyone else noticed less severe insect and / or animal feeding on corn foliage and seeds with high levels of the pigment? How about mold infection? Joseph, if there's something to this, then maybe that's a biological reason for people not liking purple-pericarp corn: it's a defensive chemical. Your thoughts? The most significant thing I can do to avoid avian/mammal feeding on my corn is to get the cobs further from the ground. Any cob within 18" of the ground is much more susceptible to predation by small critters. I don't have a deer problem, so results might vary in other gardens. It's too dry here for me to have much experience with mold. Purple-pericarp corn can be very tasty. I think the objection is due more to texture (general toughness of the kernel) than to taste. There is also a normalcy bias going on... People tend to like what they have had before and to dislike unfamiliar things. In the coming growing season, I want to focus more effort on selecting for tender kernels in the purple-pericarp group. |
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Post by keen101 (Biolumo / Andrew B.) on Dec 3, 2011 13:05:53 GMT -5
Has anyone else noticed less severe insect and / or animal feeding on corn foliage and seeds with high levels of the pigment? How about mold infection? I have noticed that the grasshoppers do seem to prefer the green ones better than the purple ones. When i planted a row of Double Red sweet corn i noticed a much higher level of corn smut infection in the ears (and one near the pollen). I believe that chemically the anthocyanins are just basically a complex sugar, so the fact that it might feed the corn fungus more than yellow or white corn makes sense to me. But Double Red does have some Inca corn in it's heritage, so the higher smut infection isn't necessarily due to the pigment, and could just be the result of an old variety that has little smut resistance. |
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Post by Deleted on Dec 3, 2011 15:15:11 GMT -5
Speaking of smut, can the disease be spread by infected seeds? How about the leaf blights?
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Post by Andre on Jun 25, 2013 19:54:17 GMT -5
anyone have a clue at to how the sharp tight kernel specking I prize so highly is transmitted? I think you're talking about R1-nj (R1-Navajo or Red Crown), a dominant variant allele of the R1 locus, now widely used for the screening of haploids in kernels. R1-nj in combination with other dominant genes in the anthocyanin synthesis pathway (A1, A2, Bz1, Bz2, C1, and C2) causes deep pigmentation of the aleurone (endosperm tissue) in the crown (top) region of the kernel (Coe, 1994). In addition, it conditions purple pigmentation in the scutellum (embryo tissue). This phenotype is called the Navajo kernel phenotype. In haploid inducer lines that are commonly used now, the R1-nj allele is integrated along with other genes necessary for anthocyanin biosynthesis. Most of the maize germplasm used in breeding programs does not have R1-nj allele or anthocyanin biosynthetic genes that confer purple/red pigmentation in the kernel/plant tissues. When the inducer lines are crossed (as male parent) to the source germplasm (as female parent) not having the anthocyanin color markers, all the resulting hybrid kernels are expected to expressthe Navajo phenotype in the endosperm and in the scutellum (embryo) as R1-nj is dominant over the colorless r1 allele. Thus, the differential expression of R1-nj facilitates identification of maternal haploids from the diploid kernels. When haploid inducers with a high haploid induction rate (HIR) are used in the induction cross, maternal haploids usually occur at a frequency of 6–10%. In practice, three types of kernels may be obtained from the induction cross: (1) Normal diploid or hybrid kernels with purple coloration on the endosperm (aleurone) and the embryo (scutellum); (2) Haploid kernels with purple endosperm but no coloration on the embryo; and (3) Kernels without purple coloration on the embryo and endosperm, which could be due to pollen contamination. Source: CImmyt See also: www.maydica.org/articles/54_485.pdf |
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Post by Andre on Jun 25, 2013 20:27:14 GMT -5
Last year, I have grown strawberry pop corn (dark red) and it was definitely the most attacked by European corn borer (Ostrinia nubilalis) and smut ! |
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Post by Andre on Jun 25, 2013 20:34:26 GMT -5
Okay, I've finally gotten ahold of the tropical varieties I was interested in, and I have my composite's pedigree figured out. Here it is. (Please feel free to critique.) Group 1: Double Red Sweet Gigi Hill Painted Mountain (50%) Rhode Island White Cap Roy's Calais Group 2: Mayo Tuxpeno Pepitillo Tohono O'odham June Virginia White Gourdseed Group 3: Aztec Red Aztec White Giant Cherokee White Flour Jala Group 4: Cuzco Gigante Hickory King (50%) Maiz Morado (Cuzco Morado, I believe) So how did this worked  |
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Post by blueadzuki on Jun 25, 2013 20:34:52 GMT -5
Thanks for the help but what I was describing was something called stippling which is caused by a different mutation of the R gene (actually one of several The comment you are referring to is quite old, in the time since I posted it, someone sent me a link to a paper on the trait). The Navajo pehotype causes a colored "cap" on the kernel. What I was referring to causes deeply colored speckles to appear all over the surface of the kernel. It isn't all that common in Northern corns, but appears to be VERY common in the Andean populations. Ironically given the Navajo phenotype is different, one of the few northern corns I know of that is famous for the trait is Navajo Robin's egg.
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Post by Andre on Jun 25, 2013 20:38:14 GMT -5
Ironically given the Navajo phenotype is different, one of the few northern corns I know of that is famous for the trait is Navajo Robin's egg. That's probably why I thought of R1-nj gene ;-) I looked for a picture of this Navajo Robin's egg on Google images but there's no one... If someone could post one, I'll be happy to see how it looks. |
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Post by blueadzuki on Jun 25, 2013 21:19:37 GMT -5
I'm not sure there IS a pic or robin's egg on the web, it's not a hyper popular corn. Moreover, it's one of the ones that has been passed around so much there are really multiple strains out there, some of which have the stipple some don't. The version most commonly found is a small wrather sompressed blue and white corn with very poor indistinct stippling. The other version is a much larger, more inflated flour corn that is mostly true white with small sharp blue speckles. That is most likey the "true" rombins egg, both because of the stronger speckles and the fact that that kernel characteristics (being a "true" flour corn, with opaque kernels and an rounded shape far closer to the "concho" shape) looks more like a typical Southwestern Native corn, and, as such, far more along the lines of what one would expect a corn grown by the Navajo would look like. However that one's gotten a bit hard to find recently. My source dissapeared so long ago I've actually forgotten who it was (and I've long since run out of seed of my own) Native seeds Search probably had the orginal (since they specilize in Native American corns) but they also no longer carry it (though one of thier other offerings, Tanamura Rosari has the stipple gene, shop.nativeseeds.org/collections/corn-flour/products/zf011) Below is a quick scan I made of some of my own stippled dent (and no I don't have any to share at the moment, what you see is my whole current supply) for a clearer picture  |
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Post by Andre on Jun 25, 2013 21:37:55 GMT -5
Thank you ! Indeed, it looks like a transposon pattern. In a similar style I try this year a Peruvian corn which I ignore the name but it could be called "Dalmatian corn" (right on the picture).  |
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Post by blueadzuki on Jun 25, 2013 22:18:59 GMT -5
Ah yes, that is a version of the same thing. Back when I lucked into my bumper supply of Andean (I found a little bodega in NYC that was selling whole cobs of andean corn as "Indian corn" for hanging on doors and bought out ther supply) I had a lot of cobs with a similar pattern on the kernels.
BTW that seond red row on the left, is part Cuzco Gigante? I'm not sure I've seen a red version of that (I got a tiny number of CG with the same sort of purple splotches as the Dalmation, but those are really rare and I am almost sure they are due to contamination not intentional breeding)
Assuming you planted these (no insult to your language skills but I'm a little confused about whether you mean "I tried" or "I am going to try" these corns i.e, whether you planted them this year or are going to plant them next. I'd be interested to hear how they do/did. Andean corn can be difficult to grow outside the andes, since it needs that weird near year round early spring coolness.
Oh and you may have one more surpise in store with that all purple one second to the right. Based on my experiance, some of the ultra purple strains of cancha can have purple insides (i.e. the actual starch inside of the corn kernel is purple not just the thin aluerone layer.) and exceeding rare trait. It doesn't happen with all of them, but it does happen. That corn looks like it has a purple endosperm, which is another good sign for that trait.
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Post by Andre on Jun 26, 2013 1:54:42 GMT -5
Sorry for my bad english.
I did sow all these kernels one month ago. If it grows OK I'll create here a "Peruvian corn" topic to keep you informed. I don't know the names of these CV, all these kernels have been given to me by a friend who didnt know the names.
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Post by 12540dumont on Jun 26, 2013 11:16:51 GMT -5
Really beautiful. I love corn with distinctive markings. Attachments:
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Post by steev on Jun 26, 2013 22:57:58 GMT -5
Blue: that is gorgeous corn (I admit to being a slut for shallow appearance); please remember me when you have seed to share.
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