a problem with landrace breeding

[gilbert]

I know there are a lot of supporters of landrace breeding here. And part of me thinks it is a great idea. Also, I don't know that much about these things. But at least I realize that!

So, my question is; if you have a diverse landrace of squash, and an extremely bitter gourd that a neighbor is growing crosses in, what happens? By the time that you gag on the first horrible tasting fruit, the pollen from that plant could have contaminated your whole patch. (In other words, it only needs one bitter pollen grain from someone three miles away. The crossed fruit tastes good, the contaminated seed is planted, and only in the fall of that year do you have a problem.)

Similarly, how to does one keep carrots from becoming queen ann's lace? There are many plants like this.

And Carol Deppe says that selection based on one parent is good, but selection based on both is much better and more powerful.

Couldn't you just cross two varieties of squash, and keep hand crossing those varieties back and forth down the generations to keep genetic diversity high, and contamination and reversion low? 

And what about GMOs infiltrating corn and beets?

I will eagerly await your answers. 

[gilbert]

Also, you can create landraces by mixing together heirloom varieties. But if nobody had ever saved these pure varieties, that would not be possible.

If all varieties were mixed up, would not some of the rarer genetics be lost? At least with inbreeding plants, each generation tends to reduce the amount of genetic variability in the seeds.

[Joseph Lofthouse]

Gilbert: Great topic for conversation. Welcome to the forum.

Pollination is a highly localized event... Mathematically it follows an inverse square law:



A plant is very likely to be pollinated by itself or it's closest neighbor. The odds of being pollinated by a plant from a mile away or from 3 miles away is extremely unlikely. Pollination is quadratic in nature. That means that doubling the distance between two plants results in a 4 times lower chance of cross pollination. Dilution happens extremely quickly with distance and it adds up fast. To put real world numbers on the odds. A plant is 28 million times more likely to be pollinated by a neighbor plant growing a foot away than it is to be pollinated by a plant growing a mile away. And by 3 miles the chances become 1 in 205 million less likely. Sure cross pollination from far away can happen, but the odds are so incredibly rare that I don't worry about it. I have never observed cross pollination between my popcorn and sweet corn fields which are located 3000 feet apart. I accidentally planted one kernel of yellow popcorn within my white popcorn patch last spring. Only 2 cobs were highly pollinated by the plant with yellow kernels. Corn pollen falls at a rate of 0.8 feet per second. Most times in my fields it falls approximately straight down. Even on those rare occasions when the wind does blow at an average speed of 10 mph the pollen falls below silk level after 25 feet. It doesn't even cross the grassy strip between the edge of my field and the road pavement.

Squash are highly outcrossing. On my farm, pepo squash cross pollinate at less than 5% when separated by 100 feet. I've never had a bitter squash show up in my garden. I taste every fruit before saving seed from it. If a fruit is bitter then I don't allow it's offspring in my garden. If a bitter gene was introduced into a squash patch, it would still be easy to taste the fruits from every squash plant before allowing the patch to go to seed. The bitter gene could be eliminated in a single growing season. I grew some bitter wild melons one year, but they didn't transfer the trait to the cantaloupes.

I prefer promiscuous pollination: Because in order to know who's the daddy I have to do manual manipulations, and that doesn't work for me as a day-to-day activity.

As long as Queen Anne's lace is weeded out of the carrot patch and the area immediately surrounding it, there isn't much contribution of pollen from wild plants. Here's what the odds look like if Queen Anne's lace is weeded to a distance of 15 feet from the carrot patch. There is a little bit of crossing that occurs along the outer edge of the patch.



If you have one queen anne's lace plant inside the carrot patch, and you have a patch containing 100 carrots, then the cross pollination rate will be around 1%. Easy to live with in a home garden: Just don't replant any carrot root with wild traits. I use this sort of local dilution to my advantage. Even though my neighbor plants a garden that touches my garden I don't worry about it, because I am planting 10,000 corn plants and he is only planting 50 corn plants. That's a 200:1 dilution factor in my favor.

There are two kinds of genetic engineering that are common in plants. The roundup ready type which is part of the nuclear DNA is not typically detectable in the home garden, but could be tested for in a laboratory or via meticulous chemical tests at home. This type is only grown by large commercial farms that sign contracts with the mega-seed companies. Not much that can be done about contamination by that type of GMO. If I am growing sweet corn, and some of the kernels end up the wrong color or end up being dent or flour kernels then I don't replant them.

The other type of genetic engineering is common in plants in home gardens. It is called cell fusion cytoplasmic male sterility. This type of GMO produces plants that are visibly defective: That don't produce pollen. I routinely screen my plants for this type of GMO and chop out any I find that have abnormal looking flowers.

GMO beets, carrots, broccoli, and onions do not produce pollen, therefore they cannot contaminate home gardens by pollen drift. Home gardens can be contaminated by planting roots from the grocery store or farmer's market.

[Joseph Lofthouse]

Genes come into my landraces and genes get lost from my landraces. I don't care. The genetics and traits change somewhat from year to year. I don't care.

I am not a historian. I am not a preservationist. I don't want a story about some strangers great aunt Polly. I don't care that someone grew a plant with a particular combination of genetics before I was born. I only care about reliability today and about the ability to adapt as growing conditions and my habits change from year to year and decade to decade. I don't require named heirlooms as a seed source. Any open pollinated or promiscuously pollinated variety is as good as any other. Many types of hybrids are perfectly acceptable starting points. Doesn't matter to me. I'll throw away any genes that don't work for me.

[philagardener]

Joseph, thanks for sharing your knowledge! I'm learning a lot here so hope you or someone else might answer a few simple questions that your first response raised for me.

"The bitter gene could be eliminated in a single growing season." Is bitterness is a dominant trait in squashes? (I have been concerned about bitterness in Delicata lines, and that would make it easy to eliminate.)

"one queen anne's lace plant inside the carrot patch, and you have a patch containing 100 carrots, then the cross pollination rate will be around 1%. Easy to live with in a home garden: Just don't replant any carrot root with wild traits." CMS in many carrot strains could mean that the QAL contribution could go as high as 100% (if it were the only pollen source) - I know you and others are working to get that out of your strains. What are the wild traits to look for, and are they generally dominant to selected traits like colored, large, non-hairy rooted, sweet carrot roots?

Thanks for helping me understand these things!

[Joseph Lofthouse]

Philagardener: You're right on about those carrots. If the variety being grown for seed doesn't produce pollen then any seed that gets pollinated will be from something else like Queen Anne's Lace. Carrots pollinated by Queen Anne's Lace typically grow skinny white (or light colored) roots that are very fibrous. They often bolt in the first growing season.

I think that this growing season I finally eliminated CMS from my carrots.

Since I have never found a bitter squash I haven't studied whether the bitterness trait is dominant or recessive. I'm leaning towards dominant. For the most part in most species traits that are highly valued by humans in food crops are recessive traits. Recessive traits are glorious to work with as a plant breeder, because once you select for them they are fixed. Dominant traits are easy to eliminate but hard to stabilize because they can mask recessives for generations making dominant traits difficult to clean up without meticulous selfing procedures.

What I typically do with squash is to allow them to flower. Shortly after every plant has a fruit on it then I go into the patch and chop out any plant that doesn't conform to specifications. That might mean that the fruit is the wrong color, or shape, or in this case that it is bitter. Then I go through the patch and pick every fruit. That means that the only pollen available in the patch for the rest of the growing season is from plants that conformed to specifications. If bitterness is a dominant trait then it would be gone in one growing season. If bitterness is due to recessive genes then I have reduced it's probability of showing up next year.

[Joseph Lofthouse]

I don't mean to sound ungrateful to the illiterate plant breeders that created most of the varieties that we use today. I live in awe at what they accomplished without the ability to read or write and without the detailed understanding of plant genetics that we have today.

[diane]

Last weekend I watched some of the Organic Seedgrowers Conference talks available by webinar, and archived at www.extension.org/pages/25242

One talk about encouraging native pollinators was very much on this topic. These native bees are usually solitary ground-nesting ones. They just pop up and pollinate near-by squash - not at all like far-flying honeybees that could bring pollen from as much as a mile away.

[gilbert]

Hello Joseph,

Thanks for clarifying that for me. I had been wondering if the isolation distances listed in Seed to Seed and other sources are a little overstated. Do you suppose pollinator pressure on your land is stronger or weaker than average?

I have been reading some more about your work, and it sounds interesting. I may try to do some of that for my own location.

As far as varieties; I admit to being sentimental. And I have an uncomfortable feeling every time I hear of some variety going extinct; who knows what locks we just lost the key to. But I realize that this is not equally important to everyone, and that two hundred years ago, nobody was worried about it. And yet those same people created the diversity we are loosing today.

Would it be possible to get a variety which is stable in fruit appearance and taste, but wildly variable in all the others, thus getting the best of both worlds?

[Joseph Lofthouse]

The isolation distances listed in most publications are aimed more towards creating "foundation seed", which is grown out to produce seed for huge farm conglomerates who harvest the entire crop by machine on the same day. A little error in the foundation seed gets magnified and can mean the difference between making a profit or breaking even. I harvest only by hand so that type of uniformity is not important to me.

I don't know how to judge pollination pressure in my garden compared to far away places. I live in an extremely arid environment. Insects don't thrive here. I see a mosquito every few years while working in my garden. There are something like 50 colonies of honey bees within easy flight distance of my fields. I use no -cides of any type, and I cultivate many species of bees and wasps which are known pollinators. Locally that means that pollinators are much more common in my garden than in those of my neighbors.

This summer I grew 10,000 genetically unique varieties of sweet corn that have never been grown before anywhere in the world. I grew 1000 unique varieties of squash that have never been grown before. Any one of them could be selected and inbred to become a new named cultivar that might be considered an heirloom in 2063. I am preserving many of the alleles from something like 300 varieties of sweet corn in Astronomy Domine. The genes might be rearranged, but much of the biodiversity is still there. And it continues to increase as I convert flint, flour, dent, and popcorns into sweet corn and add those genetics to Astronomy Domine.

It is very easy to select for specific traits: My sweet peppers are always sweet peppers. My sweet corn is always sweet corn. My crookneck are always yellow and always have a pronounced crook. Other traits in these species can vary all over. I don't care what color or size or shape my peppers are as long as they are not hot. I don't care what color my sweet corn is as long as it is sweet and tender. On a different sweet corn I have established a criteria that it can only be yellow corn. No other color allowed.

[oxbowfarm]

A core issue with the Heirloom preservation movement and books like Seed to Seed by Ashworth (which is a great book) is that they cribbed all their seed-saving information and recommendations pretty much straight from the commercial seed industry in Oregon and the Ag Universities. Which is absolutely NOT the way the heirlooms were preserved and maintained when they were actively used by the "ancient ones". Additionally, the seed industry in Oregon and the PNW has developed very good data on isolation distances etc for the conditions in the PNW necessary to produce a seed product acceptable to commercial agricultural needs. Those data and those standards are completely inappropriate for the rest of continental North America and for folks truly interested in saving varieties that are at the same time useful to us in the present.

The bitter delicata thing is actually a great case for landrace plant breeding on a wider scale. The problem with the bitter genes from ornamental pepo gourds getting into commercial delicata squash was that it occurred at the foundation seed level. The wholesale grower in Colorado then took this foundation seed and grew it out in an enormous field to produce a very large wholesale seed lot. This seed was contaminated with the bitterness genes at a significant percentage. That seed lot was huge and supplied most of the seed industry for a few years. Clearly there was very lax quality control, no one was tasting their squash.

I do think Joseph is wrong in that it would be difficult to eliminate the bitterness contamination in one generation. F1 seeds contaminated with bitterness genetics would be surrounded by non-bitter maternal squash. Tasting the crossed fruit would tell you nothing. You wouldn't taste the bitterness till you grew out those F1s. After finding the bitter F1 plants you'd prolly need to do a hard purge of that seed generation and go back to an earlier seed lot.

If plenty of folks are saving their own delicata, any one seed lot that gets contaminated is irrelevant.

[oxbowfarm]

Also, it demonstrates the need to keep earlier seed lots as an archive of that crop in case something goes wrong. Which quickly will make your house like ours filled with seeds everywhere, rooms of seed, random jars of seed laying around, seeds rolling around on the floor. It's not very Martha Stewart but its very very comforting.

[Leenstar]

As a small time gardener (backyard, not for market) and seed saver. My biggest concern has been that I might be bottlenecking the genetics of what I save from year to year. I love the idea of the landrace and like the idea of intentional stable hybridization that allows adapting to a local micro environment. I have the opposite situation of the larger scale growers in that I don't have the space to allow 100 plants to go to seed for any particular variety. I have to be very selective about what I allow to go to seed as it takes up valuable real estate in my limited garden.

Any opinions about the Seed to Seed cribbed notes about number of plants to save from year to year?

I have been trying to save some seed from prior years so that I might keep genetics a little more diverse by spreading out the genetics chronologically.

[gilbert]

Hello Joseph (and oxbowfarm),

I value your work of mashing together varieties, and I intend to try it myself. And I also value the work of Sand Hill preservation society, where one determined individual preserves thousands of varieties. I am sure that Glenn Drows has reasons for not mashing them all up. (It would certainly make things easier for him!) But I now see that there are also reasons to mash some of them up some of the time.

Thanks so much for clarifying the isolation distances. It will make things much easier for me.

I will be doing some grand scale mashing in my brassica project this spring. And I will start a new thread about it.

[blackox]

What I do is preserve those historic varieties native to my region. I see it as the responsibility of the locals to keep their natural treasures safe. Most of all that I grow has to earn it's keep. I then use the foreign varieties for breeding projects if they have some desirable characteristics, but I won't do this if I find that they already preform well enough.