Not Your Usual Potatoes

Jeremy’s latest newsletter discusses a very humble wild potato species, which we have actually blogged about here on a number of previous occasions. Do subscribe, there’s other cool stuff in there.

Indigenous people in the southwest of North America had more of a hand in crop domestication than is often thought, according to a new paper on the Four Corners potato, Solanum jamesii. So much so, according to the press release I read, that the results “support the [uncited] assertion that the tuber is a ‘lost sister,’ joining maize, beans and squash—commonly known as the three sisters—as a staple of crops ingeniously grown across the arid landscape”.

The release explains that populations of Four Corners potato, found, naturally enough, in the areas where Arizona, Utah, Colorado and New Mexico meet, fall into two distinct types. Some — archeological populations — grow within 300 metres of an archaeological site and are relatively small. The rest are non-archaeological and widely spread throughout the species’ range. Sampling the DNA of both types, the researchers discovered much more diversity in the non-archaeological populations than in those associated with settlements, which suggests domestication by local people.

Researchers were also able to show that specific archaeological populations were most like non-archaeological populations quite some distance away, which means that transport networks among the indigenous people were well developed. Settlement sites in the southwest of Utah were around 500 km from the nearest natural populations from which they might have been derived.

S. jamesii contains double the protein, calcium, magnesium, and iron of more familiar potatoes (S. tuberosum). The archeological populations were, however, not within the species’ central range, where the wild populations are much larger and more productive. So did people transport and grow the tubers simply to have a nourishing source of food close at hand in winter? That would be cultivation. Or were they, as seems likely, also actively selecting for things like taste, size and frost tolerance, which would put them well on the way to domestication? More detailed DNA might studies provide an answer.

A further thought. Four Corners potato, which is still grown by some Diné people (and probably others), copes well with drought and heat. Might it also have a wider market?