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Post by keen101 (Biolumo / Andrew B.) on Jun 12, 2011 5:02:16 GMT -5
okay, i have a question about sweet corn that still has me puzzled. So there are three different kinds of sweet corn from what i've read. SU, SE, and SH2. What is the difference between them? And how does one visually tell them apart. And why can't you breed them all together? I've read that if you breed Sh2 with the other two that you will get starchy corn and i'm confused as to why...
If anyone can provide a good explanation and pictures to go with it, that would be awesome. Thanks
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Post by raymondo on Jun 12, 2011 22:16:40 GMT -5
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Post by Joseph Lofthouse on Jun 13, 2011 0:38:06 GMT -5
okay, i have a question about sweet corn that still has me puzzled. So there are three different kinds of sweet corn from what i've read. SU, SE, and SH2. What is the difference between them? And how does one visually tell them apart. And why can't you breed them all together? I've read that if you breed Sh2 with the other two that you will get starchy corn and i'm confused as to why... su is old fashioned sweet corn. It has tough skin so it is chewy and contains around 9% to 11% sugar in my garden. se is extra sweet and contains around 21% to 24% sugar in my garden. It has very tender skin. sh sweet corn has tough skin and high sugar. People prefer sweeter corn so as a farmer I have to grow either se or sh. sh doesn't normally play nice with su or se, so I don't grow sh. Commercial se and sh require very warm soil to germinate reliably. I grow su as my earliest two crops of sweet corn because it is more reliable in cold soil. I am working on breeding a hardier se sweet corn, but it may take years. In dry corn sh can be distinguished from the others because the kernels are "shrunken". That is to say that they shrivel up to almost nothing when dry. That makes them notoriously unreliable to grow, (even more unreliable than se). In fresh corn, se can be distinguished from the others because of the very tender skin on the kernels. In dry corn su and se can be distinguished by soaking the kernels at room temperature for around 16 hours. The su kernels remain wrinkled, while the se kernels plump up fully.
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Post by keen101 (Biolumo / Andrew B.) on Jun 13, 2011 1:10:30 GMT -5
People prefer sweeter corn so as a farmer I have to grow either se or sh. sh doesn't normally play nice with su or se, so I don't grow sh. Commercial se and sh require very warm soil to germinate reliably. I grow su as my earliest two crops of sweet corn because it is more reliable in cold soil. I am working on breeding a hardier se sweet corn, but it may take years. In dry corn sh can be distinguished from the others because the kernels are "shrunken". That is to say that they shrivel up to almost nothing when dry. That makes them notoriously unreliable to grow, (even more unreliable than se). In fresh corn, se can be distinguished from the others because of the very tender skin on the kernels. In dry corn su and se can be distinguished by soaking the kernels at room temperature for around 16 hours. The su kernels remain wrinkled, while the se kernels plump up fully. Thanks, that helps a little. I found a nice pdf online that also explained it a bit. For some reason I'm finding it hard to visualize. Maybe i will just have to grow sweet corn next year to get hands on data. okay, yeah i would imagine that shrunken kernels in general would prove to be a problem both to cold tolerant seeds, but also perhaps easier rotting. The shrunken seeds almost to nothing sounds like a real hassle. Okay, so sh2 basically is the sweetest, but for many people it's not worth it to grow since it doesn't mix well with the other su and se sweet corns. okay, so the only major difference between su and se is the tender skin, and a slightly higher sweetness, but se and su sweet corn can be bred without problems? Ok, that's what i'll do then, i'll just make sure to grow only su or se and stay away from the sh2 gene.
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Post by raymondo on Jun 13, 2011 6:17:26 GMT -5
You can combine all three into one if you have the time, space and patience. There are already some varieties that have all three Su, SE, and Sh2.
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Post by Joseph Lofthouse on Jun 13, 2011 10:21:33 GMT -5
okay, so the only major difference between su and se is the tender skin, and a slightly higher sweetness, but se and su sweet corn can be bred without problems? Nothing slight about it. The difference in sugar content between su and se is dramatic to the taste. I have heard se corn described as "sickly sweet". se and su get along very well together. (To get a sugary enhanced cob you have to have both the su gene and the se gene.) I am evaluating several su/se F1 hybrids this year (su as the mother). They have the reliability of su corn in early spring, and 25% to 50% of the kernels can be sugary enhanced, (the later if pollinated with se).
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Post by DarJones on Jun 14, 2011 22:29:42 GMT -5
To answer your question above, the reason SU and SH2 don't work very well together is because they are on different chromosomes. So the typical SH2 corn happens to have a starchy gene on chromosome 4 which is dominant over the su gene. The result of crossing su and sh2 will always be a starchy kernel. Where it gets kinky is when you cross an se variety with an sh2. The se gene is on chromosome 2, sh2 is on chromosome 3, and su is on chromosome 4. A homozygous se variety has both se on chromosome 2 and su on chromosome 4. Crossing with SH2 gives starchy genes that override both se and su. In the next generation, segregation will give 1 in 8 kernels that will be se/se, su/su, sh2/sh2. These kernels will then breed true for all three traits.
If you want to try a very good long season se X su cross, grow some Merit beside some Silver King and de-tassel the Silver King so the pollen has to come from the Merit. The result is a very vigorous corn that has exceptional vigor, flavor, and sweetness.
There are other genes that can be used to enhance sweetness such as du and brittle. These genes are finding their way into a few hybrids that rival sh2 for sweetness without the negative effects of the sh2 gene on vigor.
DarJones
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Post by Darth Slater on Jun 14, 2011 23:01:01 GMT -5
Joeseph, the corn you sent me is really doing well..except i planted the blue hopi in the back 40 and the deer said to send them more....hehehe. Anyway, I planted the astronomy domine in the front of the property but it was mixed in with the other colored corn you sent it is really getting big fast, and the only water it has got is the rain we have gotten so far. I will post pics soon..I didnt plant the pink I will next year for sure. Thanks from me and the deer!!
Darth
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Post by Joseph Lofthouse on Jun 17, 2011 12:11:22 GMT -5
I didn't go to work on the farm this morning. Instead I stayed home and separated (reputedly) homozygous se+ sweet corn seed out of a segregated F2/BC1 population. Here's what the chosen seeds looked like after selection. I'm heading out to the garden to plant them this afternoon. My technique was as follows. To screen populations in which a small percentage of homozygous sugary enhanced kernels were expected I first separated the kernels by density by making a concentrated sugar water solution (1 cup of brown sugar and about 2/3 warm water, I just eyeballed it) The kernels were dumped in the sugar solution and anything that floated was skimmed off with a slotted spoon and composted. The sinking kernels were removed, rinsed, and soaked in room temperature water for about 20 hours. Populations that were expected to be 25% to 100% homozygous were soaked in water for about 20 hours. After soaking each kernel was inspected. Any damaged kernel was discarded. (Damage could be detected both visually, and by squeezing the kernel gently to see/hear if any bubbles emerged.) Any wrinkled kernel was discarded. The remaining fully plumped kernels were selected for planting. During selection I tasted kernels to make sure I was selecting for high sugar and thin skins. One variety failed the taste test: It had popcorn as a parent. One variety which I got from family and was allegedly se+ did not pass the soak test or the taste test. I'll plant those two in a separate patch, and let them segregate one more year. An interesting thing I noticed is that many of the non-yellow se+ kernels had blotchy/spotted coloration. (Here's one for blue)
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Post by Darth Slater on Jun 19, 2011 16:24:26 GMT -5
Here are some rows of corn with the se gene in an Indian corn type i got these from Joseph so I am sure he would have a better idea of the outcome!!
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Post by Joseph Lofthouse on Jul 27, 2011 13:18:21 GMT -5
Here's what my patch of Cherokee Squaw X Silver King (courtesy of DarJones) looked like today. There's some weeds for you Darrel! And since the garlic was ready to harvest today, I took my digging fork and pulled it out from amongst the 7 foot tall ground cover. By the way, does anyone have a name for that weed?
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Post by keen101 (Biolumo / Andrew B.) on Jul 27, 2011 18:53:08 GMT -5
By the way, does anyone have a name for that weed? no, but there is a field near here that i like to visit sometimes, and it has some of the tallest and largest weeds you have ever seen, and they all are incredible heat and desert tolerant. That plant looks similar to some i have seen out in that field. I believe many of the weeds are actually some sort of native herbs. lol, you should harvest them and make biofuel.. haha
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Post by DarJones on Jul 30, 2011 19:34:24 GMT -5
I have corn that is at the hard milk stage grown from the crossed seed of the Cherokee Squaw X Silver King. Another 2 weeks and it will be ready to harvest for seed. I expect 1/4 of the kernels to be wrinkled and therefore express the su gene and then 1/4 of those will be se+. In other words, 1 kernel in 16 will be the su:su and se:se genotype.
There are some outstanding traits in this corn. Germination was exceptional at 3 days from planting. Growth was very fast to the normal 8 feet tall. Ears average about 8 inches long and with 14 to 16 rows of kernels are just the right size to make good sweet corn.
DarJones
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Post by Darth Slater on Jul 30, 2011 20:10:45 GMT -5
hahaha Joseph and his blue ribbon weed!!
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Post by mnjrutherford on Aug 1, 2011 6:16:19 GMT -5
We have weeds that look a bit like that. They are all over the place... there is something else growing that looks kinda like okra. I'm waiting to see what it does...
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