Participatory Plant Breeding Projects

There will be no new projects in 2021. I just didn’t have the time this year.

Participatory plant breeding is a way to increase the footprint of a breeding project by collaborating with the public.  There are a variety of reasons why this can be helpful.  More plants means more chances to produce valuable trait combinations.  More observers means more chances to notice when unusual traits appear.  Access to different climate conditions can help to produce a more widely adapted variety.  Participatory breeding can range in complexity, from selection among plants produced elsewhere to multi-generational breeding with complex criteria.  I have learned that simple works best for most people.  That means that I make and choose the crosses and then I send them out to collaborators to grow them, observe them, and make selections.  This is a great way to get some experience with plant breeding without having to do everything on your own.  With some plants, I can make a lot more crosses than I have the space to grow or time to observe, so distributing these to people who have some time, space, and interest can be a big help.

The ultimate goal of this project is to select varieties that I will offer in the catalog or that I can use for further breeding. I will send you seeds of species and crosses that I choose.  Each seed will produce a plant with a different phenotype.  You will select perhaps one to three plants that represent the best of what you grew.  In some cases, you might not get any plants worth further evaluation.  That’s plant breeding – there is a lot of uncertainty.  I will test and evaluate your top selections. If they perform sufficiently well, we will name them, OSSI pledge them, and sell them. You will be named co-breeder and will receive a 5% royalty on sales of the variety.  (I will not share your name or any personal details on the web site without getting your permission first.  You are welcome to to remain publicly anonymous or pseudonymous if you prefer.)

I’ve had some questions about the odds that one of your selections might make it into the catalog.  The stats vary by crop, but on average, I tend to keep about 1 in 500 plants.  So, all else being equal, there is probably something on the order of a 10% chance that you will pick one that can run the gauntlet all the way to release.  That said, all else isn’t equal.  I grow my surest bets myself.  For these projects, I send crosses that I think are very interesting, but not top bets.  I also probably have more experience selecting these plants than you do. There is the further complication that I need to test anything that is returned for diseases and I would be most likely to just discard anything that turns out to be infected. So, the odds are something less than 10%.  Maybe a lot less, but I’m not really sure.  If this project goes well, we’ll have better numbers to work with in a couple of years.  Regardless of how your selections perform, we will collect important information about the crosses that I send.  For example, total failure in your climate, while not a particularly fun result, is still a valuable result that will help to inform my future breeding strategy.

2020 Projects

There are seven projects this year.  I have added three since this was originally posted.  Oca and dahlia will probably run out fairly quickly.  It is unlikely that I will run short on either potato project though.

Andean Potato Selection

I will send you seeds of a genebank accession that has been bulk pollinated from a group of varieties with similar phenotype.  For example, one of the first batches I send out will be PI 243416 x red fleshed tetraploids.  I hope that you will find plants that produce tubers with bicolor blue and red skin and some red flesh.  I have plenty of other similar crosses, depending on response.  Odds that you will find something useful are fairly high in this project.  50 plant minimum.  Seedlings must be grown under lights.  Andean potato information

Wild Potato Selection

I will send you seeds of a particular species of wild potato.  There are about 30 different species that I might send.  You will be looking for plants with shorter stolons, tubers larger than jelly beans, interesting ornamental traits, and maybe even palatable tubers if you are willing to taste them, but I will not require that you taste them.  Odds that you will find something useful are fairly high in this project.  Plants should be grown in pots.  20 plant minimum.  Seedlings must be grown under lights.  Wild potato information

Oca Selection

Oca mostly tuberizes in the fall, but I have been selecting for earlier tuberization.  It is not a common trait.  To screen for it, you will dig all of your plants in the last week of September.  There is a very good chance that none of them will have tubers at that point.  Any that do will be kept for further trial.  This project has the worst odds of the four.  50 plant minimum.  Seedlings must be grown under lights.  Oca information

Edible Dahlia Selection

Dahlia tubers are edible, but plants that have really good tasting tubers are hard to find.  I will be sending a mix of seeds collected from the reciprocal crosses between palatable selections of D. variabilis and D. coccinea.  You will dig them and taste test them for tubers with good flavor.  We are looking for tubers with either a sweet or neutral flavor that is not overly radishy or piney tasting.  Flower appearance is only considered if the plants also have good flavor.  Odds that you will find something useful are moderate with this project.  50 plant minimum.  Seedlings are best started under lights, but could be started under natural light in a greenhouse or direct seeded if you have warm spring weather.  If you don’t have experience, I would prefer that you start them under lights.  Edible dahlia information

Potato Onion

I will send seeds of a mass cross between potato onion varieties.  You will be looking for plants that have unusual colors (red/purple tubers), large bulb size, or top set bulblets.  Odds that you will find something useful are moderate.  50 plant minimum.  Start seeds as you would any other onion.

Smallanthus connatus

I attempted to pollinate the wild yacon relative S. connatus with yacon pollen in 2018 and 2019.  I haven’t seen much evidence that those crosses worked, but I also can’t really grow enough seedlings to find the successes if the crossing rate was really low.  You will be looking for plants that make anything that looks remotely like yacon storage tubers.  I’m not sure what the odds of success are, but they are probably pretty low.  Plants should be started under lights.  20 plant minimum.


I was given some horseradish seed this year and I will be growing a lot of it, but will still have some extra.  I can’t give any guidance about growing it since I have never grown horseradish from seed before.  I figure I might as well spread around the excess and hopefully increase my odds of getting something good.  I have no idea what you should select for, but it will probably be obvious when you see it.  Plants should be started under lights.  20 plant minimum.

Rules and Qualifications

  • You must be in the USA.  Even if I could send you seeds outside the USA, I would not be able to receive roots/tubers/plants back.
  • You must be a member of either the Cultivariable Facebook group or the Open Source Plant Breeding forum.
  • You can participate in any of these projects that you like, but you must be able to grow a minimum of 20 or 50 plants in 2020 for each project in which you participate.  The project descriptions above specify the minimum amount.
  • You must be equipped to grow the seedlings under lights.
  • I will send you the seeds for free, but that doesn’t mean that there is no expense involved. I expect you to send me back tubers from your three best selections for each project and you are on the hook to pay for the shipping.
  • I will send suggestions about what to look for, but you pick what you think was best from what you grew.  If you aren’t sure, I will be happy to advise.
  • If you participate in the wild potato project, you must agree to grow the plants in pots. I don’t want to be responsible for leaving you with an invasive weed.
  • If you participate in the Andean potato or oca projects, you must harvest the plants the last week of September. That means that the harvest is likely to be disappointing, but we are looking exclusively for plants that can tuberize under long days.
  • If you participate in the dahlia project, you must taste test them in the two weeks following harvest. Taste tests after overwintering or long storage are not useful.
  • All material is derived from OSSI pledged varieties and must be offered under those terms. Other than that, anything that you grow belongs to you and you can do what you like with it.
  • Posting progress and harvest pictures in one or both groups would be great.

Sign Up Instructions

To join, send me an email at  Include the following information:

I will accept new participants through the end of April.


3 thoughts on “Cultivariable Participatory Plant Breeding Projects

    • bill says:

      It is hard to say right now. It has been unusually busy and it is possible that I won’t have time for it this year. If I haven’t updated it by April, it probably isn’t going to happen.

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