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Post by mickt on Oct 30, 2014 15:05:17 GMT -5
Hello!
I think this is my first thread on this forum! Been reading for years....
I have been breeding multiple vegetables for almost a decade now, but my question concerns carrots. I have a genetically diverse populations of orange storage carrots that are large and have little woodiness and hairyness.
I am wondering where to find genes for super carotene quality - super duper orange. Is it out there?
Also, I am wondering about CMS. If it is in my population (and it is), how do I breed it out? Does selection work?
Thanks all.
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Post by Joseph Lofthouse on Oct 30, 2014 15:27:21 GMT -5
mickt: Good to hear from you. I acquired genes for super-carotene carrots by buying a bunch at the grocery store and replanting them... That was decades ago, and I lost the seed due to an unfortunate series of bad judgements on my part: (A woman was involved...) CMS is easy to eliminate in carrots... Look closely at the flowers. If they don't have anthers chop the plant out. With careful selection you can eliminate CMS in carrots in a single growing season. Fertile carrot flowers have robust looking anthers and filaments.  Male sterile carrot flowers don't have anthers or filaments. There is another kind of CMS in carrot that has shriveled brown anthers, but that hasn't shown up in my garden. 
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Post by mickt on Oct 30, 2014 16:12:50 GMT -5
Thanks Joseph,
Bad judgements and women seem to go hand-in-hand..... good luck with that.
So what if the CMS carrot happens to contain the exact genes you are looking for? Thats what Im up against at the moment. DO I ditch it or save it and see if future generations have CMS. As far as my understanding goes, the female gamete holds the key to CMS, so basically by saving the seed you are propagating that gene... even if it is crossed with a male fertile variety. Or would you only save male fertile plants and hope the genes you are looking for will crop up in later years?
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Post by Joseph Lofthouse on Oct 30, 2014 16:39:41 GMT -5
The simplistic response is that CMS is carried by the mitochondria, which are inherited only from the mother, therefore it cannot be eliminated... The more nuanced response is that in some species there may be some pollen donors that have nuclear genes that disable the CMS in the mother plant. In that case it would be possible to get the desired traits out of the CMS background. (Onions are an example that works this way.)
I have made the decision in my garden that any CMS I notice in any species will be chopped out immediately. I used to grow carrots that were 70% CMS. They grew fine as long as there were some pollen donors in the patch. If the desired trait is only in the CMS line, then it gets diluted more and more with each generation.
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Post by samyaza on Oct 31, 2014 7:10:55 GMT -5
As Joseph said, you'd better get rid of that as you notice. There's few chances you need it for breeding purpose.
There's workarounds anyway. You have to know that a CMS gene given by the male must express ( it's often recessive ) AND match the cytoplasm given by the female AND a given restorer for that gene doesn't express, for it to express at all. What you can do if you have a 100% male sterile line, for example, is to give it a pollinator, then recursively backcross the male fertile progeny to the mother until you get all the characters you want and finally breed the CMS out. The best way to breed a recessive gene out is to verify none of the progeny expresses it. If done well you can get something very similar to the mother, with completly normal anthers, except heterosis from F1 lines will be lost during this process. Don't try it with corn or other inbreeding sensitive crops.
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Post by mickt on Oct 31, 2014 11:50:21 GMT -5
Ok I agree with both of you. Thanks for the input.
Joseph, I never thought that the CMS carrot wouldnt even be pollinating (duh!), so Im actually selecting more for undesireable characteristics, as the CMS lines are getting crossed with the male fertile plants, which dont have the desired genes. Thanks for the insight.
Samyaza, thats basically what Ive been doing...(without knowing it) as Ive been mass hybridizing... I just havent been selecting out the male infertile progeny yet.
Back to the drawing board!
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Post by Joseph Lofthouse on Oct 31, 2014 12:16:26 GMT -5
Joseph, I never thought that the CMS carrot wouldnt even be pollinating (duh!)... LOL! Yup. Male Sterile ==> No pollen: Genes check into a CMS line, but they don't check out... A fertility restorer gene exists in a carrot variety called W266D, but I'm unlikely to be able to gain access to lines with restorer genes, so I take the pragmatic approach of culling plants that don't produce pollen. |
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Post by nicollas on Dec 2, 2014 12:01:59 GMT -5
From "Carrots and related vegetable Umbelliferae"  |
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Post by 12540dumont on Dec 2, 2014 14:20:58 GMT -5
I have just given up buying any hybrid carrots. As I have seen CMS in every hybrid I trialed. Of the OP carrots I have recently grown, Autumn King, Berlicum and Flakey were all good.
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mick
gopher
Posts: 5
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Post by mick on Jun 30, 2015 15:36:42 GMT -5
Well let's see if anyone is still paying attention to this thread....
I'm looking over my carrot flowers this year and am getting mixed messages. Its not cut and dry as to whether the plant is fertile or not. For instance some plants have no pollen on one flower and low amounts on another flower. And some have the anthers sticking up with no pollen sacks... Some are very easy to spot with zero anthers. Where do we draw the line?
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Post by Joseph Lofthouse on Jun 30, 2015 15:43:27 GMT -5
In my garden I have only seen Petaloid type male sterility, so I'll write about that. If you have the brown anthers type of sterility then what I write may not apply... The age of the flower cluster makes a difference. It seems to me that the first day or so that the flowers are starting to open there aren't many filaments poking up... And, on older flowers I think the pollinators have knocked off many of the filaments and anthers. So there is a sweet spot where the flowers are really fuzzy. A little older or a little younger it's not so obvious.
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Post by mickt on Jun 30, 2015 17:10:21 GMT -5
So basically we are looking for filaments and ignoring whether anthers are there or not? Can cms varieties have filaments?
So far I have only noticed one filament per flower (if im lucky).
About 60% of my crop this year is obviously infertile. Found about 20 that definitely have filaments and pollen sacs. The rest I am having difficulty deciding... One stem will have maybe 4 anthers with wide open flowers and another stem on the same plant will have 40 filaments and another will have zero filaments while the individual flowers are obviously fully open...
I grew out about 150.
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Post by templeton on Jun 30, 2015 18:30:45 GMT -5
micktthere are some pics i took a few years ago on my blog on this page templetonsmedelania.blogspot.com.au/2012/12/male-sterility-in-carrots-some-photos.html . I think flower age is pretty important in determining whether you have useful anthers or not. Depending on what selection you have been doing, you could just reject anything that looks suspect, and hope there is sufficient diversity in the genes of the remaining population to escape inbreeding depression. Could you collect seed into 3 bags - known good ones, suspect ones and reject ones, and next season plant bag-to-patch? That way if when you inspect them next season and you have rejected any good ones, you can restore them to the population.
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Post by Joseph Lofthouse on Jun 30, 2015 21:58:07 GMT -5
Another way to tell... Normal carrot flowers have 5 petals. Flowers that are sterile due to Petaloid male sterility have about twice as many. Takes a jeweler's loupe for me to see details that small.
I found 2 sterile plants today out of about 100. So woo hoo! I finally got that issue resolved.
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Post by steev on Jul 1, 2015 0:22:18 GMT -5
Yes, jeweler's loupe; this getting old and "blind" shit is a bummer, but there it is. This is why we forge connections to the young: they can still see.
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