Aubrey Streit Krug, Emily B. M. Drummond, David L. Van Tassel, and Emily J. Warschefsky

Edited by Susan McCouch, Cornell University, Ithaca, New York; received June 21, 2022; accepted February 9, 2023

PNAS, March 27, 2023; 120 (14) e2205769120

Abstract

Current food systems are challenged by relying on a few input-intensive, staple crops. The prioritization of yield and the loss of diversity during the recent history of domestication has created contemporary crops and cropping systems that are ecologically unsustainable, vulnerable to climate change, nutrient poor, and socially inequitable. For decades, scientists have proposed diversity as a solution to address these challenges to global food security. Here, we outline the possibilities for a new era of crop domestication, focused on broadening the palette of crop diversity, that engages and benefits the three elements of domestication: crops, ecosystems, and humans. We explore how the suite of tools and technologies at hand can be applied to renew diversity in existing crops, improve underutilized crops, and domesticate new crops to bolster genetic, agroecosystem, and food system diversity. Implementing the new era of domestication requires that researchers, funders, and policymakers boldly invest in basic and translational research. Humans need more diverse food systems in the Anthropocene—the process of domestication can help build them.

See https://www.pnas.org/doi/10.1073/pnas.2205769120

Figure 1: The domestication triangle [sensu (2, 3)] provides a framework for describing the diversity of factors present within the process of domestication. The triangle is comprised of the genetic particularities of crop plants, ecological and geographical factors, human agronomic and cultural practices, and the interrelations between these three elements. Diversity within the domestication process is hierarchical (4). Crop diversity encompasses diversity within lines/varieties, within the crop as a whole, and across the entire crop genepool, which includes crop wild relatives. Ecological diversity spans from the level of a single field, to agroecosystems, which incorporate multiple fields and their surrounding areas, to regions and landscapes. Human diversity includes the tools and interventions used in domestication, agricultural practices and forms of labor, and culture and cuisine that drive domestication. The domestication triangle acknowledges that genetic diversity and biodiversity at the species level interacts with diversity in human systems to shape diversity in domesticates and agroecosystems. For example, the agricultural practice of polyculture increases ecological diversity within a field and can drive the demand for new crop diversity that maximizes yield under this cultivation scheme. Alternatively, cultural demands for specific nutrient content in food such as “complete proteins” or vitamin A can drive breeding programs for underutilized crops that fill these gaps, thereby increasing the species richness of ecological systems. This depiction of domestication makes it clear that the challenges facing modern food systems–creating crops that are resilient, sustainable, nutritional, and equitable–lie at the intersection of the three elements of domestication, and can only be overcome by engaging factors from across each of these elements to improve whole system diversity in domestication.