New research led by the University of Utah is shedding light on the agricultural history of the American Southwest, focusing on the domestication of the Four Corners Potato (Solanum jamesii). This wild tuber, a vital part of Indigenous diets for millennia, may have played a more significant role in early crop domestication than previously believed.

Discoveries from Ancient Tools

The study, published in PLOS One, analyzed 401 ground stone tools from 14 archaeological sites, spanning locations both within and beyond the potato's natural range. Researchers were searching for microscopic starch granules from S. jamesii embedded in the crevices of early food-processing tools such as large slabs (metates) and handheld grinding stones (manos).

Findings revealed that S. jamesii starch granules were present on tools at nine of the sites. Remarkably, four of these sites demonstrated consistent use of the tuber as early as 10,000 years ago, suggesting that early Indigenous peoples were processing and possibly cultivating the plant far beyond its natural range.

Building a Case for Domestication

According to Lisbeth Louderback, anthropologist at the University of Utah and the Natural History Museum of Utah, and senior author of the study, "By adding new archaeological data and ethnographic interviews, we are building a case for domestication of S. jamesii in the American Southwest."

Previous genetic studies have indicated that the tubers were transported and intentionally cultivated outside their native habitat. These findings, combined with nearly a decade of investigation, strongly support the hypothesis that Indigenous peoples initiated the domestication of S. jamesii across the Four Corners region, which includes parts of Colorado, Utah, Arizona, and New Mexico.

The study also marks the first effort to define the "anthropogenic range" of S. jamesii, shaped by extensive Indigenous trading networks across the Colorado Plateau. These networks facilitated the tuber's movement and cultivation, showcasing the resource's cultural and economic significance.

Implications for Agriculture and History

The findings challenge traditional narratives about the timeline and geography of crop domestication in North America. Most research has centered on maize and other staples introduced from Mesoamerica, but S. jamesii offers a homegrown story of agricultural innovation by Indigenous peoples of the Southwest.

Beyond its nutritional value, the Four Corners Potato has been used for medicinal purposes, demonstrating its multifaceted significance. Its continued use today reflects a deep cultural connection, and researchers hope their findings will inspire renewed interest in this ancient crop.