Saturday, 2 July 2016

dehybridizating hybrids

Here's a challenge for you: Save seeds from a hybridized vegetable variety, then use the power of selection to create your very own new cultivar.  It's way easier than it sounds as the commercial plant breeders have done the hard part for you.  I first posted the challenge on permies.com.  You can join in there, or if you like, feel free to tell me about your project in the comments below.

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?

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