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Post by Edgar López on Feb 24, 2015 3:27:40 GMT -5
Good day everyone! This year I will start a new breeding project, I want to breed a landrace corn for my climate. I managed to gather several local varieties as well as some teosintes including Zea diploperennis. What I've seen so far is that most of what I have is dent corn. Is it possible to select for flour or flint corn from mostly dent corn? I understand that flour corn is homozygous recessive for the gene fl, and that dent corn has both hard and floury endosperm. Any suggestions or comments?
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Post by reed on Feb 24, 2015 7:17:32 GMT -5
Hello Edgar, I imagine some of the more knowledgeable folks here can give you better info but I think you can do that. I hope so cause I also want to eliminate any dent in my corn. I'm starting out with mostly flour / flint / sweet types and plan to discard any dent. I'm not very knowledgeable on the genetics of it but if I understand it right it is better not to select by kernel but rather by cob. If a cob has some kernels with traits you don't like you shouldn't even use the good looking ones from that cob.
Starting with mostly dent you might not have a choice but I bet you can still do it, it will just take longer.
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Post by darrenabbey on Feb 24, 2015 15:57:30 GMT -5
I'm not very knowledgeable on the genetics of it but if I understand it right it is better not to select by kernel but rather by cob. If a cob has some kernels with traits you don't like you shouldn't even use the good looking ones from that cob. If a trait of interest is recessive then there is no problem using kernels from a cob that has the dominant version of the trait. If you want the dominant version, then this is a good rule for excluding the recessive alleles. |
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Post by DarJones on Feb 24, 2015 21:18:12 GMT -5
The answer to this question is more complex than just asking if a trait is dominant or recessive. Floury is dominant over flint, but that is not the entire story, there is more than one floury gene. I can point out at least 5 more genes that affect the starch type, protein content, and kernel size each of which would influence the breeding program. In my experience, if you start with a pure dent corn, it is nearly impossible to select a flint corn out of the mix. I suggest starting by identifying any flint kernels in the seed you have and if little or none are found, then deliberately introduce a flint variety to the mix so you have something to work with. Note that zea diploperennis tends to be a flint type so you might be able to pull the hard kernel trait from it.
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Post by Carol Deppe on Feb 26, 2015 22:26:15 GMT -5
I agree with fusionpower that stable dent varieties don't segregate out flinty or floury types. But lots of varieties are of mixed type for kernel type, and you can select out material that has largely flint or largely floury character. If your mostly dent corn is showing variability from ear to ear and kernel to kernel for kernel type, you can probably select out a flint. If it isn't, you may need to add a good flint to the mix. I wouldn't depend upon the teosinte for flint, because my guess is that is going to introduce a whole lot weird stuff you may need to get rid of that will be linked to genes for kernel type.
You will probably need to start by selecting out the kernels that are most flinty, taking such kernels from as many ears as possible to get the numbers up. Once you have mostly flinty ears, you can get fussier an discard the entire ear if it shows very many dent kernels. The situation is exacerbated by the fact that endosperm is triploid tissue, with 2/3 the contribution coming from the mother plant. So the genes in the baby plant (germ) in the kernel are not quite the same as those in the endosperm of the kernel. In addition, I think genes affecting flint:flour ratio are often codominant and often variable in expression. In addition, you only get the obvious dent if the flint is arranged around the flour just right; otherwise you get a dentless dent. So theoretically it is quite a mess. But practically, it's actually pretty easy. Just keep the glassy kernels and plant those. You will see a huge shift toward more flinty type in even just one generation of selecting.
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