flowering

Here’s something I haven’t seen before in my, uh, six years of growing potatoes: green, tomato-like, walnut-sized potato fruit. Bob hadn’t seen ’em either, in 40 plus years of farming. I hit the web for education.

These are genuine fruit (also called berries), but not that common. Usually, potato flowers just drop off. Pollination can be an issue, but even when pollinated, little details of the season’s growing conditions can make the the difference. When fruit do form, they’re more likely found on certain varieties, like Yukon Gold. This year, there were fruit on just about every Chieftain plant, here and there on the Kennebec, and none that I noticed on the Yukon Gold. Since they suddenly appeared this year on two varieties I regularly grow, I’d guess it was about the weather!

Each fruit contains 300-500 seeds that don’t come true: planting them doesn’t result in the same potatoes as the parent plant or each other, there’s lots of genetic variation, each seed will produce a genetically different plant! Potato breeders plant out thousands of seeds, check out the results, then keep replanting the most desirable potatoes for many years or generations to get new commercial varieties—this is the traditional way new potatoes are bred.

Meanwhile, it takes only two seasons and one generation to breed a new potato, so for the small farm or home garden, as opposed to the big potato breeder, this seems worth a try. At least as an experiment. Harvest seed one season—you can hand-pollinate to cross two varieties—plant out the next and select the best-looking plants. The tubers (potatoes) from each individual plant are ready to go: planting out the tubers will produce genetically identical plants.

But there’s a kinda big BUT: even though a potato grown from a tuber is genetically the same, you can’t be sure how its genetic makeup will react to different growing conditions. For example, it may be the perfect potato after a wet summer, and quite different after a dry one. (That’s why professional breeders check over several generations, and now there’s also high tech genetic analysis, to make sure it will be the same potato in the full range of growing conditions.) Still, at the very least, fun to see what happens!

And, the fruit are poisonous, rich in solanine, not for eating. Potatoes, tomatoes, peppers, eggplant and tobacco are all members of the “deadly nightshade” family, all prone to having toxic parts (potato fruit are somewhat similar to little, hard green tomatoes). Interesting!

Since this is such a popular post, being dug up over and over via Google, I’ve started to update the article as I discover more. I’m not marking the changes. This is unusual. In general, I don’t edit old blog posts, and clearly mark the updates when I do!