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Post by Joseph Lofthouse on Feb 25, 2010 15:59:14 GMT -5
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Post by Joseph Lofthouse on Feb 26, 2010 4:14:15 GMT -5
And now that I may understand meiosis and mitosis and when they occur, in relation to pollination I also repent of all that stuff about genes hidden within the embryo and not expressing themselves in the endosperm. (The two haploids that fertilize the egg are identical, and the three haploids that are provided by the mother are identical.)
Might as well do plain old fashioned selection based on kernel shape or brix readings for the cob in general.
If there was a magic for corn breeding you all would have found it a long time ago.
Blushingly, Joseph
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Post by raymondo on Feb 26, 2010 5:36:51 GMT -5
I think I learned something from your little journey. Not sure I fully grasp it all though.
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Post by spero on Feb 26, 2010 11:04:01 GMT -5
I, too, am working on multi - colored sugary enhanced corn varieties. I am working with Painted Mtn/Painted Hills and with Wilda's Pride as colored varieties in crosses. I am curious what varieties you are working with.
I have a different method of teasing out the se. Since my main "sweet" parents are se/su and not se/se, I will have a smaller percentage of homozygous se, but by the f3 should have some. I learned from Carol Deppe that se kernels dry slower. I harvest the corn patch when some percentage of the cobs have kernels that are starting to shrivel. I go through the pile, peeling back, and husking the ripest ones. A few hours later, the kernels are in shrinking mode. Some kernels (with su) will be shrinking, others (se) will still be full and smooth. I paint or magic marker the slower drying kernels and put the cobs up to dry. The next day I go back through my pile of unhusked cobs and again pick the ripest to "work"
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Post by Joseph Lofthouse on Feb 26, 2010 12:36:09 GMT -5
Here's the current list of candidates for inclusion in my multi-colored sweet corn breeding project. These will be detassled, so it they don't grow well for me it will be easy to cull them.
I'm hoping to add a few others if I obtain seed.
Painted Mountain, soft flour Long Island Seed Project, Fiesta, su/se (sad that I didn't save a copy of the pedigree for Fiesta) Long Island Seed Project, Ashworth, su/se Anasazi, soft flour Earthtones, dent Taos Blue, flour Mandan Red, hard flint Apache Red, hard flint (looks the same as mandan red) Rainbow Inca Hopi Blue, flour Hopi Pink, flour Black Aztec, sweet, grown for years in Nevada Black Aztec, different source White dent Red dent Purple leafed flint Black very soft flour corn from native in Oaxacan Oaxacan Green Sweet Indian corn grown for years in Missouri F1 hybrid of Indian X sweet, source unknown Triple Play (Hookers) Waxy corn from Asia
And perhaps others...
Pollen donors are generic se+ varieties, maturing in 65, 75 and 85 days.
I'm planting about 1000 mother plants, and as many pollen donors.
I like the idea of opening the husk and selecting right on the cob... Seems better than trying to sort them out by how wrinkled they are after they dry. I figure that down the road I may open the husk to select for kernels that are more colored in the milk stage.
I got a degree in Chemistry, and worked 20 years as a scientist... and the only exposure to genetics I ever had was to talk about Mendels peas for a day in 7th grade. Sheesh!!!!
And for what it's worth... I am so horrified at the thought of mixing varieties!!! I never realized how strong the indoctrination is: Don't save seed!!! You'll destroy your farm if you save seed. Only Hybrids will grow good for you. An F2 will taste bad. Your customers will hate you... They won't buy your crop unless you plant F1 hybrids from The Company. The Government will get you if your variety is not pure. Yield will suffer. Pollen from other gardens will contaminate your seed. The Company will sue you if their pollen gets into your seeds. Wild relatives will sneak their pollen into your garden and wreck it or poison you. Once a variety has been inbred it is useless to the home gardener or seed breeder.
It never stops -- the propaganda. I figure that I'll plant a small patch of F2 corn this year right next to it's F1 parent, and take photos all along so that I can publish a web page that says, "looks like corn, tastes like corn, must be corn".
Regards, Joseph
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Post by canadamike on Feb 26, 2010 13:34:05 GMT -5
I am with you Joseph! F...them all. There is a reason why there is not much OP se in the network....and much more Sh2...it ia apparently hard to SEE the se gene in the kernels. I like the idea of doing it on the cob. It takes fields to get a good number of kernels, then there is all the work...Fiewwwwww.....
But with regards to identifying the colored kernels at milk stage, I have done that 2 years ago. I had diminutive 2 feet high PICKANNINY SWEET CORN growing besides Argent. They were not (and by far) supposed to shed pollen at the same time but in 2008, all my cornsw, early or not, transplanted or not had the same dtm, it had been so frigging cold at night AND during the day the weather became a great equalizer.
As I was planning to pick the first ears of Argent, I partially husked one to see if it was ready and VOILĂ€, some blue kernels at milk stage. I slit the neighbours open with an exacto to identify the desirable ones and closed the husks, put a few elastics against bugs and it worked, I was coming back from time to time to check progression. Just that it was so late a darn hard frost killed the ears before they were dry enough.
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Post by spero on Feb 26, 2010 15:59:15 GMT -5
As far as I can tell, it is not possible to see se as opposed to su once the kernel has dried. My experience is you have a window of some hours as the kernels start to dry and that is it for visual methods.
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Post by canadamike on Feb 26, 2010 21:54:44 GMT -5
What are the other methods that are available to us ordinary folks..?
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Post by spero on Feb 27, 2010 10:56:32 GMT -5
Joseph - quite a list. I have some others. I did something similar a few years ago. The male was se/su so the seeds may be only 1/4 se.
Mike - this kernel selection method I outlined is the best method for those of us out wandering in the fields. I understand that the two other common (but more intensive) methods are: 1. carefully nick each dried kernel and take a brix reading on the sample. 2. locate a genetic marker gene an do genetic analysis.
those methods make the slower-drying method seem easy by comparison. Hopefully it only needs to be done once or twice to establish a pretty good se population.
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Post by Joseph Lofthouse on Feb 27, 2010 16:25:30 GMT -5
Any chance of selecting like we would if it was a squash? By measuring the average sugar in a sample of kernels on the fresh cob?
Mothers that are se/se aught to have a higher average sugar content than mothers that have one or no se genes...
I wonder if such a strategy would avoid the tedium of trying to select individual kernels from the cob?
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Post by Joseph Lofthouse on Feb 27, 2010 19:41:01 GMT -5
I did something similar a few years ago. How did that work out for you? What would you do different if you were doing it today? Thanks, Joseph
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Post by Alan on Mar 1, 2010 23:19:06 GMT -5
I've been away for a couple days, reading but hadn't had a chance to post and this has been a fantastic conversation.
I'm going to do a few SE crosses this year.
Astronomy Domine to SE+ F1 populations
And SE+ F1 populations x SE+F1
as well as SE inbreds crossed to one another to yeild a new F1 and then segregation.
And Alan Kapulers idea of crossing chires baby to sweet corns including Astronomy Domine as well as some various SE+ populations.
I am familiar with the idea of selecting from drying down kernels due to sperro and deppe, which works really well for my purposes in drying down in the greenhouse and is relatively quick, easy, and cheap. I had never even though of identifying the SE triat by the shape of the kernel as described on your site Joseph, but I'm thinking it would actually be possible and makes sense considering SE+ don't convert as much sugar to starch as do SU varieties and as such it should be at least theoretically identifiable by phenotype of seed.
You could think of it as the difference between the seed of Golden Bantam types and Kandy Korn types, there certainly is a difference in the way the seed "crinkles".
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Post by canadamike on Mar 2, 2010 0:18:51 GMT -5
Is it only me or only the corns I have grown or did anybody noticed that se tend to be more contorted and difformed when drying?
As an exemple, I have my white midget that is incredibly shrunken ( 3900 seeds/pound) but it tend to stay flat, keeping its general shape, and it is a corn way more shrunken than Golden Bantam.
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Post by spero on Mar 2, 2010 10:52:17 GMT -5
As far as different kernel shape between se & su when dry - I have been doing this individual kernel selection on a population that should be 1/4 sese. After letting the cobs dry, I looked for any visible characteristics that went along with the chosen versus unchosen kernels. I was not able to see any difference.
As far as testing a representative sample of the whole cob to find cobs that are generally sweeter, and thus the female 1/2 is likely se - it seems it should work. I bought a brix meter for this purpose. However the juice squeezed from the kernels was too milky to get a decent brix reading. Any suggestions on how to remedy this to try again next year are welcome.
As far as what I might have done differently, I did about 18 crosses that first year. I found myself with too many to trial in any serious manner. Joseph - I sent you one cross (51-B) that seemed to have some potential, but I just couldn't follow through due to too many to work on. I settled on 2 multi-coloreds to continue to work with, and abandoned some promising possibilities because it was just too many. Joseph - I still have 20 or more colored flour or flint varieties, some from the GRIN, some from SSE, some from friends, some from commercial catalogs . I could make you a package deal and send the whole set if you want more choices. - JS
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Post by Joseph Lofthouse on Mar 2, 2010 17:05:51 GMT -5
In the chemistry lab we had several methods of dealing with milky solutions.
1- Let it sit for a few minutes and let the solids settle out.
2- Filter the solution through a filter that has poor sizes smaller than the particles.
3- Centrifuge the sample.
4- Dilute the sample enough that the test results can be read in spite of the interference.
I've just been experimenting on some fresh corn... (Definitely not sugary enhanced, and the store might be liable for fraud if they had called it "fresh" since it is barely palatable, but it works for testing.)
First I squeezed out some juice and filtered it through a coffee filter. That is too coarse the starch came right through. This might be workable in the field if I found the right filter and a suitable press (pair of pliers?)
Then I checked centrifuge prices on eBay, about $50 for a Brinkman Eppendorf 5415 Micro Centrifuge which is my favorite type of centrifuge for these kinds of tests... Doesn't work in the field, but they sure are slick to use.
Then I checked again on the sample, and in the time it took me to write this message the starch had settled to the bottom of the glass leaving clear liquid on top. I think this method would work great in the field if I collected the samples and then did some weeding while they settled. It's not instant results, but they are near-real-time, inexpensive, and super simple.
spero, thanks for the seeds. I'll treat them with the honor and respect that they deserve.... And I'll think seriously about the consequences of including too many varieties. It doesn't seem bad until the F2 starts segregating.
Regards, Joseph
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