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Genetically Modified Maize: Understanding the Debate in Mexico

By Victoria Boyd-

Marcos Castillo/Shutterstock

Just over a year ago, on the 1st of January 2021, by presidential decree, the Mexican government banned the use of Genetically Modified (GM) maize seeds and vowed to phase out the importation of GM maize by 2024, following years of controversy. By altering the genetic material of the crop, GM maize seeds are used to produce crops that are resistant to certain diseases, produce higher yields, and require less water.

In its statement, the government said it aimed to become self-sufficient and replace the 16 million tonnes of yellow maize that is imported each year, principally from the USA, with new national maize production. Due to its importance to the Mexican diet and indeed national identity, the issue of GM maize has been thrown into the spotlight by campaigners on both sides of the debate.

In Mexico, maize features heavily in the traditional and staple diet, with flour tortillas and tacos made from white corn and yellow corn being central to feed livestock. In contrast to the USA, where maize is mainly used for feeding for livestock, 82% of white maize produced in Mexico is for human consumption. The country produces 59 distinct varieties of the crop, suited to the conditions of the various regions and different landscapes and climates. It is grown in forests, deserts and jungles, from sea level to more than 3000 metres in altitude.

The origin and importance of Maize in Mexico

Maize originated in Mexico, centuries before the arrival of Europeans to the region, and has become the most widely produced crop in the world due to its biodiversity and resilience in a wide range of climates. Using methods of selective breeding, ancient Mesoamerican farmers cultivated maize so that it would thrive in any specific local environment, be that dry, rocky, mountainous, fertile or wetter conditions. In this way, through traditional methods, indigenous peoples farmed the crop to be resistant to disease and resilient to the varying regional climate.

Sculpture of the Mayan Maize God. © The Trustees of the British Museum. Source:

Proof of the importance maize held for indigenous peoples and ways of life can be seen through its symbolic and spiritual role. For example, in the Mayan creation story, Popol Vuh, the first humans were made by the deities from white maize. The deities accessed the maize seed using a bolt of lightning to break the rock under which it was hidden, and in the process burned some of the grain, creating the other maize colours, red, black and yellow. Maize features in artefacts and murals across Mesoamerica, Mayans prayed to maize gods asking for healthy crops and used corn in religious offerings.

While maize is now consumed across the globe, in Mexico to this day, small peasant farmers continue to produce around 86% of maize. As the place of origin of maize, the traditional varieties, diversity and resilience of native maize is, therefore, a source of pride for Mexican farmers and a strong aspect of national identity.

Fear of ‘contamination’ by GM crops

In 2001, the fear of contamination by GM maize came to the forefront of national debate when a study showed that transgenic DNA could be found in indigenous maize samples, supposedly free from genetic modification. The public outcry that followed highlighted the national desire to protect the native maize varieties and led to the suspension of permits for GM maize. Those who oppose GM maize fear that the spread to native varieties would endanger the diversity, history and tradition of the native crop, which is central to national identity. For these reasons many, including farmers themselves, celebrated the decision to ban GM seeds, hoping that there will be more investment and opportunities.

On the other hand, some fear the ban on GM crops will limit the competitiveness of Mexican farmers in the global market, and even warn that food prices could rise as a result. Bodies such as CANAMI, Mexico’s corn industry chamber, CNA, the farm industry council and Proccyt, representatives of the crop-protection industry, have all spoken out against the ban, warning that the limitation of importation of GM corn could severely impact the food chain. Indeed, while Mexico is predominantly self-sufficient in the production of white corn for human consumption, around a third of yellow corn for livestock is imported from the USA, of which the majority is genetically modified. Some estimate that national production would need to increase by up to 60% to account for this loss.

Furthermore, as GM maize is engineered to produce greater yields, require less water and be resistant to diseases, they warn that the transgenic crop is necessary to support the growing demand for the crop for both human and animal consumption. This is disputed by those who support the ban, arguing that the diversity and resilience of the native crops are sufficient.

It seems that the Mexican state is taking firm control of GM production in the country. While some warn of the effects on the food chain, and others celebrate the protection of native biodiversity, it is clear that the rich history and continued importance of maize in the national identity are central to the fierce debate around genetically modified maize.



Mayra Teresa Garcia Ruiz, Aaron N. Knapp & Hernan Garcia-Ruiz (2018) Profile of genetically modified plants authorized in Mexico, GM Crops & Food, 9:3, 152-168, DOI: 10.1080/21645698.2018.1507601

Vargas-Parada, L. GM maize splits Mexico. Nature 511, 16–17 (2014).

Quist, D., Chapela, I. Transgenic DNA introgressed into traditional maize landraces in Oaxaca, Mexico. Nature 414, 541–543 (2001).


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