Many of the plants we cultivate and consume today are the result of hundreds or thousands of years of human selection. These long-term selective pressures have led to significant phenotypic and genetic changes in many plant species, ultimately enabling complex agricultural systems that feed billions of people. Even though the history of domestication impacts archaeology, biology, and agriculture, the process through which a wild plant becomes domesticated is relatively poorly understood. “Lost crops” represent one underappreciated component of the domestication process, wherein some species are utilized and genetically altered, only to be abandoned at later a later time. By exploring how and why some domesticated species are allowed to go extinct, we can gain insights into potentially useful plant resources and important events in human history. A recent interpretation of Polygonum erectum (erect knotweed) as a lost crop presents a new opportunity to consider how Native American agricultural systems changed around 1100 CE with a greater reliance on maize. The loss of P. erectum as a crop species must be contextualized within knotweed’s adaptive strategy of “evolutionary bet-hedging” using dimorphic seeds to survive unpredictable habitats in the wild.
--Nathan Wales