• Post Reply
  • Bookmark Topic Watch Topic
  • New Topic

dehybridizing hybrids - I invite you to join me

 
R Ranson
master steward
Pie
Posts: 3418
Location: Left Coast Canada
371
books chicken tiny house toxin-ectomy
  • Likes 3
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Dehybridizing the hybrids - saving seeds from hybrid varieties, with a view to creating a new cultivar. 

Amateur seed savers so often forget that every seed saved is an act of plant breeding.  We are taught the myth of preserving the varieties we are growing.  Not realizing that living things cannot be preserved from one generation to the next, but they can be maintained.  And that's what we do when we save seeds.  We select qualities that we value (be it big seeds, tall plants, short plants, purple leaves, early/late harvest) and we also unintentionally select for qualities depending on our location (bug tolerance in an organic setting, thriving with our planting schedule, weather patterns, &c).  When we look at seed saving this way, it only takes a tiny nudge to arrive at international plant breeding. 

As seed savers, we are also taught to avoid hybrid seeds (labeled F1 on seed packets).  Instead, we must always grow Open Pollinated (OP) seeds as these are the only ones that will grow 'true' to type.  A hybrid is a cross between two different cultivars/varieties.  The first generation of hybrids has predictable characteristics, which for us gardeners means that just about every plant looks and acts the same in this first generation, or F1 generation.  The second generation after the cross (F2) has a lot of variation.  Some are tall, some early, some plants slow to develop, some may be more drought tolerant, some less... F2 generation expresses all sorts of possibilities.  It is from these expressions of the genes that the plant breeder selects the traits they like best and begins the journey to creating  a new variety. 

A plant breeder can choose two OP varieties, and make the cross themselves, or they could start with a commercial hybrid variety and save a year's work.  It is for that reason, that I suspect starting with hybrid seeds is the perfect introduction to plant breeding.  Quicker results from a cross that we know has good genetics.

In Breed Your Own Vegetables, Deppe writes about dehybridizing the hybrids.  I've gotten into the habit of growing OP or landrace plants, but the other day I saw this beautiful hybrid komatsuna (mustard green) that I instantly fell in love with.





I'm going to plant some this week and eat the smallest plants that grow, leaving about 2 dozen widely spaced plants.  Then I'll take out the first 3rd that bolt.  The rest I'll save seed from and plant next spring to see what variation I can get. 

It is possible these are not a true hybrid - seed companies sometimes label OP varieties as F1 to discourage seed savers.  In that case, my F2 generation will already be stable.

If they are a hybrid, then my F2 generation will have plenty of variation to choose from.  My garden will do a lot of selecting for me, including bug and drought tolerance.  I can also choose if I want green or coloured leaves, or leaf shape, or last to bolt, &c.  I can also choose how I select: do I mass select, or backcross, or something else?  I have so many choices.  What's more, a different person, growing the same seeds in different conditions could create a whole different variety.  There are so many possibilities. 


The great thing about komatsuna is that I can grow and save seeds from at least two generations in a year.  This will speed things up tremendously. 



Would anyone else like to embark on a journey of dehybridizing a hybrid? It doesn't have to be komatsuna.  Any hybrid seed will do. 

Here's my proposed method:
  • Tell us which hybrid you are starting with and where you got it. 
  • Find out how many plants you need for seed saving (this first generation isn't that many)
  • Grow the plants and tell us how it goes
  • Save the seeds
  • Grow F2 generation and tell us how it goes
  • Observe and interact - look, smell, and taste your plants, then choose the qualities you like best and we can brainstorm how best to select for them.
  • Keep growing.  Keep selecting.   Keep saving seeds.
  • When happy with the variety, maybe we can set up a dehybridization seed exchange?


  • According to Deppe, depending on the characteristics we are breeding for, the selection method and the breeding method (self pollinating with squash, back breeding, &c), we can have a stable variety by the third generation, but sometimes it takes longer. 

    Anyone up for the challenge?
     
    R Ranson
    master steward
    Pie
    Posts: 3418
    Location: Left Coast Canada
    371
    books chicken tiny house toxin-ectomy
    • Mark post as helpful
    • send pies
    • Quote
    • Report post to moderator
    Carol Deppe on Dehybridization methods

    The link has some good stuff, but here's the relevant bit for this project:

    A few general approaches and ideas:

    1) If I wanted a variety mostly similar to a hybrid, except just an op version, after the initial cross (to something as similar as possible) I would usually backcross at least once to the hybrid before starting to select. That way I would have material that was genetically ¾ like the hybrid, and that would be already segregating for and expressing most of the genes in the hybrid including the recessives.

    2) I especially tend to backcross at least once to whatever variety that has the flavor I want, since that’s hardest to select for, and is usually influenced by many genes. A delicious distinctive flavor may not reappear even in thousands of F2 or F3 plants if many genes are required to make it. The odds go up considerable if you enrich preferentially for the genes involved. Also, it’s considerably easier to select for visible traits than flavor and cooking characteristics; so when a particular flavor or cooking characteristic is a major desired characteristic of the new variety, I generally backcross at least once to the variety with the magic flavor and start selecting from there.

    3) If I want one or more new varieties that are thorough combinations of characteristics from two or more parents, I generally proceed by going to the F2, then selecting gently from the F3 on.

    4) You can’t afford to eliminate all but the best plant in any generation, because the incompatibility system means you’ll get little or no seed from that one plant. However, you can afford to cull to, say, your favorite six plants and save seed from just your favorite, if that favorite is uniquely worthy, and if it’s close enough to the others so as to cross with them, and if this is in the early generations of selection after outcrossing. Generally, keeping the numbers up in later generations really matters in or to avoid inbreeding depression and end up with a vigorous variety.

    5) I often select very gently only one characteristic at a time. So if I’ve crossed a blue, tender-veined kale to one that is broad-leaved and very sweet, and I ultimately want a blue tender-veined broad very sweet kale, in the F2 and F3 generations I might eliminate all the greens and keep the blues, whatever their other characteristics. My reason for choosing color first is partly that is is easiest and obvious, and likely to express fully early. I once crossed a sweet mustard to a very cold hardy one, and it was 5 generations before I got anything sweet. I selected first based upon cold hardiness and leaf breadth and didn’t worry about the fact that everything tasted awful for the first 4 generations. I could select for cold hardiness automatically by just planting thousands of seeds in a few square feet each year, letting winter cull most of them, then weeding out all but the biggest in spring.

    By “gentle selection” I mean eliminating, say, half the plants, the half with the narrowest leaves, for example. And leaving dozens of plants. I try to move the frequencies of characteristics I want gently gradually in the desired direction, while maintaining a representation of most of the other genes (until later generations when it is their turn for attention).

    6) You don’t start selecting in the F1, and sometimes not even the F2, because you’re mostly seeing a reflection of dominance relationships among the genes at that point, and many genes you want in your final line are recessives that are hidden until later generations.

    7) Don’t select arbitrarily. There is no reason to select for green versus brown brassica seed, for example. Various genes and characteristics are linked genetically and physiologically. So you might accidentally throw away the gene that could have conferred something important because it was linked to the seed color you selected against for no reason. I was tempted once to select the deep green plants that were segregating out of a squash cross. I could argue that such plants had more chlorophyll, so might well be better at growing. But I didn’t select arbitrarily like that, based upon just my speculations. Good thing, too. Those deep green plants attracted such huge numbers of cucumber beetles that the plants were badly stunted. And the fruit was somewhat bitter, too. Apparently, the segregation had uncovered some genetic combination, probably, that made more cucurbitacin, and that was linked to the deep green color, somehow.

    Be curious. Be flexible. Notice things. Ask the plants what is happening as it happens. If I’m unsure what I want, or want two different things, I might cull the greens at one end of the row and the blues at the other, so that greens interbreed mostly among themselves, and blues also. I might have “wanted” blue to start with, but almost never would I be so rigid as to just eliminate all the green without exploring further. So I save two batches of seeds, one from the greens, one from the blues, and plant them at two different ends of the row or plot the next year, and see how each does, and taste them, and use them different ways, including different ways than I was initially intending. The blue might all turn out to have a delicious flavor cooked, but the green to be more delicious raw, for example. Before I eliminated the green, I would give it a chance to show what it can do, even if that wasn’t quite what I had in mind to start with. I wasn’t quite what my parents had in mind either.

    There is an almost supernatural relationship between the plants and the plant breeder as they talk with each other about future possibilities. You will get more ideas about what could be by looking at and listening to the plants and walking through the patch and tasting everything than you ever will sitting indoors designing a plant breeding project.

    9) With respect to the cytoplasm: When doing the initial cross, it matters what direction you do it, that is, which variety is the mother. Keep in mind that mitochondria and chloroplasts are integral to energy metabolism, photosynthesis, etc. And they have some of their own genes. And those genes come only from the mother plant. Most plant breeders make their crosses in whatever direction is the most convenient (usually, the direction that makes it easiest to recognize hybrids). I think this is a mistake. I am guessing that ability to grow in cold or hot weather are going to be partly genetically determined by cytoplasmic genes. So I usually do the initial crosses in the direction that preserves the cytoplasm of the cold resistant or drought resistant, or disease resistant variety, or more vigorous variety. I can make good arguments as to why genes in the chloroplasts and mitochondria might sometimes be involved in those characteristics, and they are known to be involved in some cases of disease resistance. I think the role of cytoplasmic genes is going to turn out to be very much more important than is currently realized.

    10) If one cytoplasm is unusual and another is overused, I might deliberately retain the cytoplasm of the underused variety so as to increase the diversity of cytoplasms in the agricultural environment. So, if I were crossing a widely grown hybrid and a (rare) op, I might keep the cytoplasm of the op.
     
    Joseph Lofthouse
    pollinator
    Pie
    Posts: 1708
    Location: Cache Valley, zone 4b, Irrigated, 9" rain in badlands
    314
    bee chicken food preservation fungi greening the desert
    • Likes 3
    • Mark post as helpful
    • send pies
    • Quote
    • Report post to moderator
    Looks good. My only quibble is:

    The F2 generation *may* have a lot of variation. Sometimes, it's really hard to tell.

    The hybrid mustard might have been created by cytoplasmic male sterility, in which
    case it may not make seeds. Look at the flowers. If they don't have anthers, then they
    are male sterile.
     
    Dan Boone
    gardener
    Pie
    Posts: 1686
    Location: Central Oklahoma (zone 7a) ~39" rain/year
    179
    forest garden trees woodworking
    • Likes 1
    • Mark post as helpful
    • send pies
    • Quote
    • Report post to moderator
    You're way ahead of me when it comes to methodology (and, probably, follow-through).  But I did buy a SuperSweet 100 cherry tomato start this year that's now almost as tall as my house and producing a prodigious volume of really tasty cherry tomatoes.  Out of curiousity and hope, I am planting some of the fresh seed from it to see what I get in subsequent generations.
     
    Joseph Lofthouse
    pollinator
    Pie
    Posts: 1708
    Location: Cache Valley, zone 4b, Irrigated, 9" rain in badlands
    314
    bee chicken food preservation fungi greening the desert
    • Likes 2
    • Mark post as helpful
    • send pies
    • Quote
    • Report post to moderator
    I really like dehybridizing: tomatoes, corn, spinach, squash, and melons. Not so much for brassicas, onions, and carrots because of cytoplasmic male sterility.

    Here's photos of a few tomatoes that are descended from the same ancestor a few generations ago... The number of fruits represents the productivity of each plant.








     
    R Ranson
    master steward
    Pie
    Posts: 3418
    Location: Left Coast Canada
    371
    books chicken tiny house toxin-ectomy
    • Likes 2
    • Mark post as helpful
    • send pies
    • Quote
    • Report post to moderator
    The hybrid mustard might have been created by cytoplasmic male sterility, in which
    case it may not make seeds. Look at the flowers. If they don't have anthers, then they
    are male sterile.


    That's good to know.  I'll keep a close eye on that.
     
    Tracy Wandling
    pollinator
    Pie
    Posts: 339
    Location: Cortes Island, British Columbia. Zone: 8ish Lat: 50; Rainfall: 50" ish; sand and rocks; well water
    27
    bee books chicken forest garden fungi hugelkultur trees
    • Likes 2
    • Mark post as helpful
    • send pies
    • Quote
    • Report post to moderator
    I'm in! This subject has fascinated me for some time now, and I think it's time to jump on the wagon and see what I can conjure up on my little plot.

    I foresee many interesting mistakes and wrong turns in my future    - but I think that it will be worth the time and effort to learn how to do this, and start to breed and save seed for the plants that we like to eat, and the things that grow well here. (And maybe some things that don't usually grow well here!)

    I'll read through the thread again, and then post the parameters of my own breeding 'experiments' soon. Should be fun!

    Cheers
    Tracy
     
    Shawn Harper
    Posts: 360
    Location: Portlandia, Oregon
    7
    • Mark post as helpful
    • send pies
    • Quote
    • Report post to moderator
    I am currently in the process of mixing together the genetics I want. Then I am going to use landrace techniques to shift the phenotype towards what I want before dehybriding.
     
    R Ranson
    master steward
    Pie
    Posts: 3418
    Location: Left Coast Canada
    371
    books chicken tiny house toxin-ectomy
    • Likes 1
    • Mark post as helpful
    • send pies
    • Quote
    • Report post to moderator
    I planted my seeds this week and the weather turned nice and cool with a light drizzle.  Should be perfect for the komatsuna to germinate and grow. 

     
    Tracy Wandling
    pollinator
    Pie
    Posts: 339
    Location: Cortes Island, British Columbia. Zone: 8ish Lat: 50; Rainfall: 50" ish; sand and rocks; well water
    27
    bee books chicken forest garden fungi hugelkultur trees
    • Mark post as helpful
    • send pies
    • Quote
    • Report post to moderator
    Looking forward to watching your experiment. What is the time to maturity for this mustard?
     
    R Ranson
    master steward
    Pie
    Posts: 3418
    Location: Left Coast Canada
    371
    books chicken tiny house toxin-ectomy
    • Mark post as helpful
    • send pies
    • Quote
    • Report post to moderator
    I can eat komatsuna after about three weeks (from germination) but seed saving time depends on the weather.  In cold and hot conditions it usually bolts quickly and can be in flower in as little as 6 weeks.  This variety claims it is "slightly prone to bolting in heat."

     
    Ali Brassie
    Posts: 1
    • Likes 1
    • Mark post as helpful
    • send pies
    • Quote
    • Report post to moderator
    I'm brand new to this website, but it looks so interesting and I'm going to learn so much!  Thank you all.  I've been gardening for about 30 years...question:  some seedlings came up in my early spring garden that looked like squash seedlings.  Probably in the spot I tossed butternut or some other squash seeds last fall.  It might have even been an unknown variety of winter squash from the organic grower at our farmers mkt. Anyway, I babied the seedlings along, separated a few out and Amy faithfully guarding them against squash bugs and their seeds on the underside of leaves.  I have had many baby squash yellow and wither, but that is not my question so much as why are each of my growing, surviving squashed different colors and shapes?  If I can figure out how to post pics I will.  One is a light green cucumber color and round.  About 4 inches in diameter right now.  Another is the color of watermelon skin and round with light stripes.  The 3rd is taking on the shape of a butternut squash but is watermelon green.  ARE THESE SQUASH GOING TO BE SAFE TO EAT?  I read one online comment (not this website) saying he and family ate a green looking crook necked squash and had terrible stomach issues that night.  Please help!  I will try saving these if they are safe, otherwise I'm ripping them out to make room for something like another tomato plant.  Thanks so much!
     
    Joseph Lofthouse
    pollinator
    Pie
    Posts: 1708
    Location: Cache Valley, zone 4b, Irrigated, 9" rain in badlands
    314
    bee chicken food preservation fungi greening the desert
    • Likes 3
    • Mark post as helpful
    • send pies
    • Quote
    • Report post to moderator

    Ali: Have fun with those volunteer squash!

    Squash poison is well behaved. It tastes horrid bitter. It makes me want to puke. I'm not going to be accidentally ingesting poisonous squash. If I bite into a poisonous squash, I'm going to be spitting, gagging, and retching.

    You know the bitterness that sometimes develops on the stem end of a cucumber? That's what squash poison tastes like. To avoid squash poison, don't eat squash that taste bitter, or make you feel like barfing!

    One year, I threw out the entire year's worth of seed from my melon crop, because I had went far out into the wild-side and included a plant that had poisonous fruit.  I wasn't willing to take the risk that pollen from it had gotten into the general muskmelon patch. From a pragmatic standpoint, during domestication, clever illiterate plant breeders eliminated the poison genes from most of the crops we grow.  There are still some wild relatives floating around with lots of poisons, and some domesticated species (cucumbers, potatoes) still have small residues of poisons in them, but for the most part, if you start out with current domesticated varieties, their offspring are not going to spontaneously become poisonous.
     
    R Ranson
    master steward
    Pie
    Posts: 3418
    Location: Left Coast Canada
    371
    books chicken tiny house toxin-ectomy
    • Likes 2
    • Mark post as helpful
    • send pies
    • Quote
    • Report post to moderator
    Seedlings are up and happy.  A bit of bird and bug damage, but not as much as I would expect for a mustard this time of year.  This is why I chose a red-ish komatsuna instead of a green one, because plants with a red-ish tinge seem to be bothered by fewer bugs in my garden.

    ops, edit to add photo
    IMG_1363.JPG
    [Thumbnail for IMG_1363.JPG]
     
    • Post Reply
    • Bookmark Topic Watch Topic
    • New Topic