A Brief History of Maize
Maize (Zea mays ssp. mays), known in the United States as corn, is a grass, along with other important crops such as rice, wheat, and barley.
Because of its distinctive morphology, the origins of maize and its closest wild relatives were the subject of more than a century of debate, but thanks to the confluence of evidence from both genetics and archaeology we now know the broad brushstrokes of the evolution of maize in the Americas.
Archaeological evidence shows people living in what is today SW Mexico, began domesticating maize as early as 9000 years ago from a wild annual grass known as teosinte (Zea mays ssp. parviglumis). Why people domesticated maize remains poorly understood, and whether people initially used the grains for flour or for popcorn, or perhaps the sweet stems, is still unknown. In either case, domestication left maize completely dependent on people for its spread and reproduction. Quickly after domestication, early farmers moved maize with them and traded it with other communities. Within 1500 years maize reached S. America, but moved somewhat more slowly north, arriving in the US SW nearly 5000 years after domestication began. Although it is now a global staple, maize was introduced to other continents only after European colonization beginning in the early 16th century.
By the time of European colonization, Indigenous groups throughout the Americas had bred and adapted maize to a wide variety of environments and a vast number of cultural and culinary uses. Even today, traditional maize farming practices continue over tens of millions of hectares of farmland, playing an important role in local economies and food supplies but also contributing to the continued evolution of maize.
The Cultural and Culinary Importance of Maize
Maize holds incredible cultural importance to many peoples. Here we focus on a few examples. For many cultures in the Americas, maize fulfills not just nutritional requirements, but also important religious, spiritual, and ceremonial roles. For example, the central protagonists in the Popul Vuh, the origin story of the K’iche and Yucatec Mayans, are twins born from the god of maize from two types of maize (white and yellow). Deities of maize, such as the Aztec gods Centeotl and Chicomecoatl, were central to many societies. Maize was served as sacred food and drink throughout the Americas – in the Incan empire, for example, ajha (chicha de jora) made from fermented maize was often used as a ritual beverage.
Fueled by the agronomic ingenuity of indigenous farmers, maize evolved to become a staple crop throughout the Americas. Of the many processing techniques developed by indigenous groups, nixtamalization is of particular importance. Nixtamalization of maize is a chemical process where kernels are cooked in alkaline solutions of lime or wood ash to allow for nutrients in maize to be more easily accessible. Agricultural innovations also allowed maize to dominate food production systems, such as the “three sisters” co-cropping method of farming, involving a planting system of maize, beans, and squash. Regional selection for specific traits reflecting cultivation techniques, environmental differences, and cultural and culinary preferences have contributed to the diversity we see in maize today. Examples include “palomero” maize selected for popcorn production, “ancho” and “cacahuazintle” maize for pozole soups, and “pepitilla” for tortilla masa.
With the introduction of improved modern maize varieties into Mexico, the diversity of these culturally and culinarily significant traditional varieties has eroded. However, smallholder farmers today still consider traditional maize varieties to have relative benefits, especially women farmers who readily acknowledge the importance of grain flavor and cooking volume over yield. Today, contemporary farmers of traditional maize varieties – the most marginalized participants in the broader maize economy – nonetheless remain crucial to the selection and maintenance of culturally and environmentally relevant maize diversity.
Collection and Use of Maize Germplasm
Continued maize breeding and research heavily utilize germplasm collections of maize. Much of this material was collected during the 20th century as part of private and government initiatives, many motivated by concerns of population growth rooted in eugenics ideology. These trips extracted seed from indigenous communities, where maize had been bred for millenia, and placed them in long-term ex situ germplasm repositories. The International Maize and Wheat Improvement Center, CIMMYT, which grew in part out of these programs, maintains an extensive germplasm collection. Germplasm collections have directly contributed to advances such as genetic transformation and continue to be used by researchers and breeders today.
Geneticists leading many of these historical collection projects used the term ‘race’ or ‘landrace’ to describe maize populations, arguing that “the problem of races and their recognition is indeed almost the same in Zea Mays [sic] as in mankind” (Anderson & Cutler 1942). The idea of race as a biological category is unfounded and stems from a history of scientific racism. In maize, as in humans, ‘race’ is a social construct; while maize ‘races’ often share some morphological features, this sharing is imperfect and not representative of wider underlying genetic similarities. We advocate instead using the term ‘traditional varieties’.
Indigenous communities have historically not benefited from the use of germplasm collections or the economic windfalls of modern maize production. To combat extractive research practices and the denial of Indigenous data rights, we recommend the CARE Principles for Indigenous Data Governance, which presents guidelines for protecting Indigenous data rights in current and future scientific research. Another important avenue to address historic and ongoing extractive scientific practices is seed rematriation efforts, where seeds are returned to the original community from which they were collected. Ongoing efforts, including at CIMMYT, recognize the integral role of rematriation in building a more integrative, collaborative, and respectful partnership with the communities who maintain agricultural biodiversity.
Bibliography
Websites
Sustaining Lifeways and Anishinaabe Partners
Rockefeller Philanthropy and Population-Related Fields
The Rockefeller Foundation’s Mexican Agriculture Program, 1943-1965
CIMMYT - What is nixtamalization?
CIMMYT recognized for support in restoring Guatemalan seed systems after hurricane
Biographical Memoir, Elvin Charles Stakman
About the Races of Maize Collection
Searching for the Origins of Maize in Latin America, 1957-1981
The Teacher-Friendly Guide to the Evolution of Maize
Corn Tastes Better on the Honor System, Robin Wall Kimmerer
Maize: The most important crop for The Mayan Culture
The Three Sisters of Indigenous American Agriculture
Academic articles and books
Anderson, E., & Cutler, H. C. (1942). Races of Zea mays: I. Their recognition and classification. Annals of the Missouri Botanical Garden, 29(2), 69-88.
Bellon, M. R., Mastretta-Yanes, A., Ponce-Mendoza, A., Ortiz-Santamaría, D., Oliveros-Galindo, O., Perales, H., … & Sarukhán, J. (2018). Evolutionary and food supply implications of ongoing maize domestication by Mexican campesinos. Proceedings of the Royal Society B, 285(1885), 20181049.
Casañas, F., Simó, J., Casals, J., & Prohens, J. (2017). Toward an evolved concept of landrace. Frontiers in plant science, 8, 145.
Curry, H. A. (2021). Taxonomy, race science, and Mexican maize. Isis, 112(1), 1-21.
Eddens, A. (2019). White science and indigenous maize: The racial logics of the green revolution. The Journal of Peasant Studies, 46(3), 653-673.
Hellin, J., Keleman, A., & Bellon, M. (2010). Maize diversity and gender: research from Mexico. Gender & Development, 18(3), 427-437.
Kausch, A. P., Wang, K., Kaeppler, H. F., & Gordon-Kamm, W. (2021). Maize transformation: history, progress, and perspectives. Molecular Breeding, 41, 1-36.
Matsuoka, Y., Vigouroux, Y., Goodman, M. M., Sanchez G, J., Buckler, E., & Doebley, J. (2002). A single domestication for maize shown by multilocus microsatellite genotyping. Proceedings of the National Academy of Sciences, 99(9), 6080-6084.
Ocampo-Giraldo, V., Camacho-Villa, C., Costich, D. E., Vidal Martínez, V. A., Smale, M., & Jamora, N. (2020). Dynamic conservation of genetic resources: Rematriation of the maize landrace Jala. Food Security, 12, 945-958.
Piperno, D. R., Ranere, A. J., Holst, I., Iriarte, J., & Dickau, R. (2009). Starch grain and phytolith evidence for early ninth millennium BP maize from the Central Balsas River Valley, Mexico. Proceedings of the National Academy of Sciences, 106(13), 5019-5024.
Staller, J., Tykot, R., & Benz, B. (Eds.). (2006). Histories of maize: multidisciplinary approaches to the prehistory, linguistics, biogeography, domestication, and evolution of maize. Left Coast Press.
Willcox, M. C., Castillo-Gonzalez, F., Aragón-Cuevas, F., & Garcia, F. H. C. (2019). Native maize in Mexico: Participatory breeding and connections to culinary markets. In Farmers and Plant Breeding (pp. 80-90). Routledge.