Potato Breeding

Breeding potatoes for resistance to blight and Colorado potato beetle is the first project of the Open Plant Breeding Foundation. OPBF maintains a bank of true potato seeds, which you are welcome to plant out in a field trial. Even a small plot of potato plants can help our breeding efforts to progress. In simplest terms, the method is as follows:

  1. Plant the potato seeds with about a 2" spacing.
  2. As the potato plants grow, they can be thinned to around one per foot.
  3. Allow any pests and diseases that may be present in your garden to do their worst.
  4. Rescue the last few plants before they are killed off, and allow them to be cross-pollinated.
  5. Save the seed-balls from these plants, and send them back to us. If the plants do not set seed, you can send us a few tubers from each plant.
  6. These become the parents of the next breeding generation, and will be crossed with the results from the other participants in the project.

Potato Breeding Instructions

Once you volunteer to help the potato breeding project, you will be sent a packet of seeds. A few of these seeds will be the parents of a new blight & beetle resistant variety of potato, and your work will help by selecting which seeds are the best. Unlike seed potatoes, which are identical clones of their variety, each one of these seeds is genetically unique. After you’ve selected the best plants from this batch of seeds, we’ll cross them with the results of our other test plots to produce another generation of seed. Every generation gets better than the last, and we hope to have a new disease-resistant variety within the fewest possible number of generations. When we do, we will happily share the results with you.

Seed Germination

You can treat these seeds the same way as tomato seeds. They can be planted in flats or in a seed bed, and then transplanted into the garden. If you are short of time, you can also sow them directly in the garden – this will save transplanting, but they will need careful attention for the first few weeks while they are very delicate. The soil for germination should have a fine tilth which is neither too wet nor too rich in organic matter, otherwise the seedlings may die of stem rot. The young seedlings should be shaded, but mature plants like full sun. Germination time will be 1-2 weeks, and you can expect a germination rate of about 50%.


Because we actually want pests and diseases in this plot of potato plants, it’s best to plant them as far as possible from any potatoes that you are growing for food. Plant or thin them to about a 2-inch spacing – they will get thinned out more during the selection process. The more seedlings you’re able to plant, the better your chances of finding something really good.

The Selection Process

There are two stages to the selection process once the plants are in the garden. The first stage is to let pests and diseases destroy the most susceptible plants. Water them if needed, and remove the plants that are obviously dying, until there are only five to ten plants left. The second stage is to rescue the survivors, and keep them alive as long as possible to collect their tubers. Beetles can be picked off; and blight can be minimized with a clear sheet-plastic roof, and/or organically-approved copper salts such as Bordeaux mixture. As soon as they are in danger of dying, dig up the tubers and keep them, no matter how small they are, in a dry place with subdued light. Don’t expect to see any large tubers from these plants, since they are grown from seed. It’s very important to keep the tubers from each plant separate, to prevent genetic mixing. If possible, we’d like to have five tubers from each plant; you’re welcome to keep any others for your own investigations if you’d like to plant them out next year. Please pack the tubers carefully in a box, and mail it to us at: 445 Provost Lane, Fergus, Ontario, N1M 2N3. We’ll refund the cost of the postage.