research

Publications

Growing the lost crops of eastern North America’s original agricultural system

Natalie G. Mueller, Gayle J. Fritz, Paul Patton, Stephen Carmody, and Elizabeth T. Horton - 2017

Abstract. Thousands of years before the maize-based agriculture practiced by many Native American societies in eastern North America at the time of contact with Europeans, there existed a unique crop system only known through archaeological evidence. There are no written or oral records of how these lost crops were cultivated, but several domesticated subspecies have been identified in the archaeological record. Growth experiments and observations of living progenitors of these crops can provide insights into the ancient agricultural system of eastern North America, the role of developmental plasticity in the process of domestication, and the creation and maintenance of diverse landraces under cultivation. In addition, experimental gardens are potent tools for public education, and can also be used to conserve remaining populations of lost crop progenitors and explore the possibility of re-domesticating these species.

Documenting domestication in a lost crop (Polygonum erectum L.): evolutionary bet-hedgers under cultivation

Natalie G. Mueller - 2017

Abstract. This study uses morphometrics and digital image analysis to document domestication syndrome in an annual seed crop, Polygonum erectum L. (erect knotweed), which was cultivated by Native Americans for c. 2,500 years in eastern North America. This plant is one of several seed crops referred to as the Eastern Agricultural Complex, a pre-maize agricultural system that supported societies in a core area centred on the central Mississippi valley for millennia. The extinct domesticated subspecies P. erectum ssp. watsoniae N. G. Muell. described here, exhibits some classic markers of domestication, including larger fruits and reduced germination inhibitors in comparison to its wild progenitor. Domesticated P. erectum also exhibits greatly reduced germination heteromorphism. Germination heteromorphism is the classic example of evolutionary bet-hedging in plants: wild P. erectum sacrifices maximum fitness per generation for a reduction in fitness variance over many generations. It does so by producing two different types of fruits: ones that germinate immediately in the spring after they are produced (smooth morphs), and ones that remain in the soil seed bank for one or more growing seasons before germinating (tubercled morphs). Tubercled morphs allow populations to recover after adverse events. Under cultivation, the selective pressures that maintained this strategy were relaxed as humans saved seeds and created predictable microenvironments for seedlings, resulting in homogenous harvests and reliable germination for ancient farmers.

Archaic Period Domesticated Plants in the Mid- Ohio Valley: Archaeobotanical Remains from the County Home Site (33at40), Southeastern Ohio

Paul E. Patton and Sabrina Curran - 2016

Abstract. Late Archaic archaeobotanical remains from the County Home site (33AT40), southeastern Ohio, are described. Measurements of chenopod (Chenopodium berlandieri) seed-coat thicknesses and marshelder (Iva annua) achene and kernel lengths from the site are indicative of domesticated types (ssp. jonesianum and var. macrocarpa, respectively) dating to ca. 3000 B.P. to 3600 B.P. Together, these specimens represent some of the earliest evidence of plant domestication outside the oak-hickory and oak-savannah forests of eastern North America. The recovery of these plants with other cultigens in hearths and earth ovens at the County Home site indicates that the timing for the arrival of the Initial Crop Complex in the Appalachian mixed forest of the middle Ohio Valley occurred earlier than previously documented. The results of this research contribute to the growing database of early plant domestication and a broader understanding of the origins of food production.

Ancient DNA confirms a local origin of domesticated chenopod in eastern North America

Logan Kistler and Beth Shapiro - 2011

Abstract. Domesticated chenopod was an important starchy seed crop in eastern North America before the rise of maize agriculture. Domesticated chenopod first appeared in North America during the fourth millennium B.P., however its wild progenitor and site of domestication remain unresolved. Archaeological evidence suggests a local domestication in the Eastern Woodlands, while morphological similarities with modern Mexican cultivars indicate a possible introduction from Mesoamerica. To distinguish between these two scenarios, we isolate chloroplast DNA (cpDNA) from modern and archaeological North American chenopods sampled from across their geographic range. Our results demonstrate that the chenopod grown in the Eastern Woodlands was locally-derived, indicating that independent domestication events gave rise to the ancient eastern North American and modern Mexican cultivars. These results strengthen the argument for an entirely native pre-maize crop complex with chenopod as a major component.