Bothered by Cytoplasmic Male Sterility

[Joseph Lofthouse]

Oct 15, 2011 12:21:53 GMT -5 mnjrutherford said:

That's amazing.... They actually look ... well... "male". So.... are the female flowers in the same flower head? Will you get any viable seed from that head at all?

How concerned should we be? What can we do to battle back?

I haven't noticed any problems with pollination, even though only 30% of the flowers are providing all of the pollen.

I modified the last photo in the previous post by adding a magenta colored pentagon around one carrot flower. As far as I can tell without a dissecting microscope, they are normal five petaled flowers with male and female parts, just tiny, and a whole bunch of them massed together.



I'll eliminate the male sterile carrots from my garden next summer. Then whenever new carrot seeds or roots come into my garden they will be screened before getting added to my carrot landrace.

I had some onions go to seed that I wasn't planning on. Pollination percentage was abysmal. They are obviously male sterile.

I'll learn how to identify male sterility in every crop that I grow, and weed out any affected plants. I'll screen all new germplasm that comes into my garden. I'll grow my own seed. I'm hereby adapting the same philosophy towards seeds that I have towards canning... It is not cost effective to can my own food, it is less expensive to buy it. But if I bottle it myself I know what went into it and where it came from, and I'm not contributing financially to organizations that are harming me.

I'll modify my web sites to eliminate the recommendation that F1 hybrids or grocery store varieties be used to create landraces. I'll write an article about how to identify and eliminate male cytoplasmic sterility for many species.

[12540dumont]

Joseph, I too am happy to stay out of the grocery store. If I don't grow it, I get it from another farmer and skip the middleman. I love trading and buying seeds here as I feel that I've purchased seed directly from the farmer.

I buy most of my meat from a farmer in Montana, Highmont Beef. I could find meat locally, but, I love this guy. He's a hard working rancher and his wife works at it too. They never saw a ripe tomato this year.

I do a lot of canning and freezing and drying. There's no sadder day for me than when we run out of our own potatoes and onions. It always happens in March...and then we eat rice. I'm so sick of rice by the time potatoes come again.

I sometimes think that there's two costs here. The cheapest food is not the best bargain. Not for your body and not for your soul. There's a lot to be said for the simple things that keep skills alive. Planting, canning, sewing, knitting, spinning, washing and cleaning, cooking, fixing the broken, making new things out of old. Leo and I both laugh because every time we have to leave the farm, we look at each other and say, "we better change our clothes."

Good thing we clean up good, or we'd never get any service.

So, talk to me about onions and CMS. I got half the trial planted.

[Joseph Lofthouse]

As far as I know onions are the only crop in which it is possible for amateur plant breeders to reverse cytoplasmic male sterility, because in onions cytoplasmic male sterility has both a nuclear DNA component and a organelle DNA component, and both have to be present in order for it to manifest itself... So if you have a male fertile onion shedding pollen in the patch, it will pollinate the male sterile plants and may also counteract the male sterility for some of the plants in the next generation.

The gene that causes male sterility expresses only as homogenous recessive, so in the F1 something like 50% to 100% of the offspring would be expected to be male fertile. In later generations the sterility/fertility of the offspring would segregate according to normal Mendelian genetics. So, if you identify mother-lines in which the cytoplasmic sterility factor is not present, you could grab the nuclear DNA out of any segregating population. Every plant in a segregating cross that lacks the cytoplasmic sterility factor would produce normal viable pollen.

But if you don't have any male fertile domesticated onions shedding pollen in your garden when the male sterile blossoms are blooming, then they are going to scavenge pollen from wherever they can get it: wild alliums, interspecific crosses, intergeneric crosses, etc...

I really like this article as a general overview of CMS. There is a specific section on onions as well.
ddr.nal.usda.gov/bitstream/10113/16824/1/IND43905141.pdf

Of the onions that I sent you, the red burgermaster has the cytoplasmic sterility factor, and presumably the nuclear sterility factor as well. I think the yellow sets are male fertile (I don't know if this is due to lacking the cytoplasmic sterility factor or if it's due to having at least one copy of the sterility-negating gene). Up to 5% of the seeds definitely contain the cytoplasmic sterility.

I have some onions blooming in my garden. I think they are male sterile. I'll take my magnifying glass out with me to see if I can determine how male sterility manifests itself in onions.

An onion landrace that wasn't bothersome to me would have eliminated both the cytoplasmic sterility factor, and the nuclear sterility factor. If I had to focus on eliminating one or the other, I'd work on eliminating the cytoplasmic factor.

[Joseph Lofthouse]

Another proposed page for my web site.
garden.lofthouse.com/cytoplasmic-male-sterility.phtml

Critiques welcomed.


Cytoplasmic Male Sterility


Summary

Modern commercial seeds are commonly grown using plants with cytoplasmic male sterility (CMS). Male sterile plants reduce the labor required to make hybrids, but they can cause problems for seed savers because the plants are male sterile in all succeeding generations. Even heirlooms and open pollinated seeds can be back-crossed onto plants with CMS making them male sterile as well.

Discussion

Cytoplasmic Male Sterility is used extensively by commercial seed companies as the simplest method of protecting their seed lines. No lawyers or courts are needed to prevent people from saving the seeds of a variety that has sterility built into it by design.

I believe that the widespread use of CMS by commercial seed companies is severely damaging the world's genetic legacy. CMS is inherited from the mother along with the mitochondria and other organelles. In most species, once CMS has been incorporated into a variety it cannot be reversed. As an example: I get queries from people about why their carrots go wild when they try saving carrot seeds. I believe it is due to CMS. All hybrid carrots, and just about all carrots from the grocery store have CMS. So when a gardener plants carrot roots hoping to get seed there may not be any domestic carrot pollen to fertilize the plants. The only available
pollen may be Queen Ann's Lace, which is the wild ancestor of carrots. So the carrots go wild in the first generation. For species without a nearby wild ancestor or close relative, no seeds will be produced.

Affected Species

Potatoes are so extensively damaged by CMS that nearly every heirloom and every modern variety would need to be eliminated in order to develop a healthy open pollinated population.

CMS is common in broccoli, cabbage, and radish. The brassicas are not as heavily contaminated as other crops due to a self-incompatibility mechanism which makes hybrids possible by other means than CMS.

Nearly all commercial carrots use CMS. Even open pollinated and heirloom lines have been converted to CMS versions.

Open pollinated corn is somewhat contaminated with CMS due to the widespread use of CMS in making hybrids prior to 1970 and the continuing use of other CMS varieties since then.

Nearly all sugar beets use CMS. About half of red beets are contaminated with CMS.

Nearly all commercial sunflowers are CMS.

All hybrid onions are male sterile and many open pollinated populations of onions are severely contaminated. The vast majority of commercial onions are male sterile. Onion sterility is due to an interaction between cytoplasmic DNA and nuclear DNA, so it can be reversed with the use of proper pollen donors.

Spinach and the cucurbits are not severely affected due to their monoecious or dioecious reproductive strategies. Peas and Beans are such radical inbreeders that they are not commonly hybridized. CMS is not widely available for tomato, but that is subject to change
in the near future.

What to do about it

I am actively eliminating male sterile plants from my farm by examining each plant in my seed producing beds and weeding out any with CMS.

Potatoes: Over the next couple of years, I am transitioning my farm to using only male fertile potatoes. The transition will involve trashing 95% of my current potato genome, but I think that in the long term it will be well worth it. The male fertile plants can be identified by two methods: Tapping a male fertile flower releases a cloud of pollen. Male fertile plants tend to be abundantly fruitful. One advantage of converting to using only male fertile potatoes is that I will have volunteer potato seedlings in my garden so I won't have to spend time and effort on a formal potato breeding program. I can save seeds and tubers from the best growing of the volunteer seedlings.

Carrots: Carrot flowers with CMS are easy to identify: They don't have filaments or anthers, or the filaments/anthers are brown and shriveled up. When seen from a distance a male fertile carrot flower looks fuzzy due to so many filaments poking up. Male sterile carrot flowers look smoother. Testing of my open pollinated carrot landrace in 2011 showed that 70% of the plants were male sterile. In the coming growing season the male sterile carrots will be weeded out of my seed patch after inspecting each flower to make sure it has anthers. Any new carrot varieties will be screened prior to incorporation into my carrot landrace.

Male Fertile Carrot

Male Sterile Carrot

Onion: There is both an organelle DNA factor and a nuclear DNA factor responsible for male sterility in onions. Cytoplasmic Male Sterility manifested itself in onions in my garden as topsetting onions and/or as umbels with a low percentage of pollinated flowers. Dispose of any flower heads from bulbing onion Allium cepa that have low seed set or that have bulbils.

Garlic: Remove bulbils from hard-necked garlic so that flowers have a better chance of setting seed. Specialized techniques may allow soft-necked garlic to flower.

Other Varieties: Please send feedback to me regarding how to identify CMS in other crops.

[mnjrutherford]

Something that occurred to me last night driving home from a friends business:

1. I'm blaming "seed companies" for creating the disproportionate male sterility, but what are my facts? Are the flowers proof in and of themselves?

2. If it is the seed companies, are they really doing something efarious or are they responding to consumer demands... i.e. "I don't want seeds falling around and making a big mess that I'll have to clean up."

3. What if it isn't the seed companies? What if this is happening as a result of some human activity?

[Joseph Lofthouse]

I've been stewing for days about how to remove cytoplasmic male sterility from my onion landrace. (I don't have an onion landrace yet, but I'll be developing one or importing one in coming years.) It's certainly possible to do a perfect job of eliminating both the undesired nuclear and cytoplasmic DNA: It would involve back-crossing, and creating special lines who's only purpose it to provide pollen or cytoplasm to be used in evaluating other lines. And there would be tedious grow outs, and self pollinations, and bulb-to-row plantings. And the paperwork. Argh! All those pedigrees!!!

But perhaps I don't have to do a perfect elimination of both components. Do I really care what the underlying genetics are as long as male sterility is not manifesting itself in my garden? Couldn't I achieve my goal by doing plain old mass selection?

So my protocol might look like this:

Start with enough diversity to get some non-CMS cytoplasm. This may mean including heirlooms, or landrace seed from far away places where CMS is not so prevalent.

For the main landrace:

Examine each plant at flowering time and chop out any that are not producing pollen normally.

When adding new varieties:

Grow them as a seed crop a row away from a known pollen producing population. If they produce normal pollen the first year add them to the landrace immediately. If they do not produce normal pollen, (and I really want the trait), then grow a seed crop from the F1, but only incorporate the pollen from them into my landrace.

I'd probably maintain two landraces:

One in which male sterility is almost non-existent, and a second called "A segregating Population".

This scheme depends on being able to determine with my limited tools and observation skills whether a plant is producing normal looking pollen. I'm headed to the farm now to look at onion blossoms.

[jonnyyuma]

Oct 16, 2011 13:19:25 GMT -5 mnjrutherford said:

Something that occurred to me last night driving home from a friends business:

1. I'm blaming "seed companies" for creating the disproportionate male sterility, but what are my facts? Are the flowers proof in and of themselves?

2. If it is the seed companies, are they really doing something efarious or are they responding to consumer demands... i.e. "I don't want seeds falling around and making a big mess that I'll have to clean up."

3. What if it isn't the seed companies? What if this is happening as a result of some human activity?

I'm not sure I understand your questions 1 and 3. As for #2, there is a demand for high level of hybridity and high levels of uniformity in large commercial productions. CMS is the cheaper alternative to hand pollination/hand rouging/throwing away low hybridity seed. There are laws that regulate the hybridity percentage that is legally allowed to be called hybrid seed. If it falls below this level they have to label it as "non-hybrid variety x" and if they can sale the seed it is at a very low price.

Thanks
Jonny

[12540dumont]

Joseph,

The biggest problem with CMS as I see it, is that the bees don't like it. Onions that don't make pollen, only make nectar. Bees are hard to entice into the onions to pollinate them if there is no pollen.

The purpose for me growing sunflowers is for the bees. Sunflowers without pollen are useless. Onions without pollen don't bring bees, don't make onions...

The French are worrying if organic onions can be derived from the breeding material we have available.

I sent a note to my perennial field crop adviser. Perhaps, he will come up with something.

[Joseph Lofthouse]

I have been looking closely at every onion blossom I can find... It seems to me like male-sterile onion blossoms look just like male-fertile blossoms, except that there is no pollen on the sterile anthers. If I rub my finger across a normal onion anther, it leaves a streak of yellow pollen on my finger. If I rub my finger across a male-sterile anther it doesn't leave a streak of pollen.

[turtleheart]

when they decided to destroy the diversity of native languages here and teach us indians all a monoculture of english, it came to bite them in the butt, cuz we were all talking to each other!

i think that this system designed to fail, will, and give us the advantage when that time comes. the thing is, how do we survive until then?

i try to keep completely free of these corporate influences on my gene pools. i have alot of landraces and endangered native lines. they are healthier and tastier and dont go sterile.

[Joseph Lofthouse]

Sometimes I wonder if every line I grow is endangered? Who would carry on my work if I croaked? I swap seeds with one local lady... That's not exactly a thriving locally adapted seed bank.

[keen101 (Biolumo / Andrew B.)]

Oct 24, 2011 15:00:29 GMT -5 Joseph Lofthouse said:

Good choice. Sometimes I wonder if every line I grow is endangered? Who would carry on my work if I croaked? I swap seeds with one local lady... That's not exactly a thriving locally adapted seed bank.

Joseph, i often wonder about the same thing. Not necessarily for the stuff i'm growing (although maybe in the future that will be the case), but for all the people out there who have a few varieties of something that is just barely hanging on.

A possible solution would be to donate samples of seeds to certain seed companies or seed banks. Just send some seeds in an envelope to their address without even telling them your going to send some. Maybe send some to Peace Seedlings, Adaptive seeds, Baker creek, native seeds, seed savers, seeds of change, ect...

That way, at least a few more places have some seeds, and if they get curious they might grow some out, and if they find they like whatever rare variety you sent them, then maybe they would even start selling some. But, it's just a crazy idea i came up with.

[Joseph Lofthouse]

I get seeds all the time from anonymous sources.... A packet shows up in the mail. Sometimes I can read the label on it, sometimes I can't. I used to save all the packets and might not get around to planting them. These days I keep a seed bottle or two for each species: When I get new seeds, I frequently open the packet and dump them into the appropriate bottle with other seeds from that species. Then at planting time, I plant some of my own locally adapted seeds, and some of the incoming seeds. No telling when something really clever is going to show up in the mail. Anything that is great, or even good enough, gets incorporated into one of my landraces.

Sometimes I donate seeds to the food pantry. Figure I'll do that again this spring. I guess technically that has the potential of preserving the germ-plasm after I'm gone, I just loose track of it.

[turtleheart]

im young and in it for the long haul. in coming years i will be expanding what i do. if we keep in touch we can help eachother. you do hybrid swarm breeding ennit? we do the same thing without talking to eachother. hehe.

[spacecase0]

I guess it is hard to find someone that will actually bother growing and preserving what has been done,
kind of seems like there needs to be a seed bank for all the plant breeders,
or is there one that I don't know about ?