Many Indiana gardeners are experiencing a new phenomenon in their potato patch. At least, it’s new to them. Potato plants appear to be producing little green fruit, about the size of a large cherry tomato.
These round, green berries are actually the fruits of the potato plant. It’s not surprising that they look like tomatoes, since both plants are in the nightshade family.
Most gardeners never see this fruit form on potatoes in Indiana. Cool temperatures during long days tend to promote fruiting in potatoes, which explains the increase in potato fruit this year. Until recently, most of Indiana experienced prolonged, cool springs. Also, some cultivars seem more prone to fruit formation than others. So some potatoes may be fruiting while others growing nearby may not.
Plant breeders tend to locate potato fields in cooler climates, such as Idaho and Wisconsin, to facilitate hybridization and fruit production. The seeds that form inside the fruit as it ripens are then grown out to evaluate the new plant.
For production of the tubers that we eat, a particular hybrid that has disease-resistance or high yields is propagated through pieces of the underground tubers. This type of propagation assures that those desired qualities of the hybrid are preserved, since hybrid plants rarely reproduce true from seed.
Gardeners could harvest the seed from the fruit as it matures and raise the seeds for next year’s garden as a novelty. But, in general, it is much easier to raise a crop from tubers than from true seed. Also, the resulting plants may not be as desirable as those grown from the tubers this year. Be prepared to start the seeds indoors in winter, as plants are much slower to develop from seed than from tubers.
Do keep in mind that potato fruits are likely to be high in solanine, a substance that is toxic to humans, particularly children. Potato fruits should not be eaten, no matter how much they look like tomatoes!