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Economic Liberalization May Drive Down Corn’s Genetic Diversity In The Face Of A Changing Climate

Economic Liberalization May Drive Down Corn’s Genetic Diversity In The Face Of A Changing Climate

For thousands of years, maize has been cultivated by North and South American cultures, and while many of the ethnic groups that once contributed to the success of corn are now gone, the crop which sustained them is now one of the three most important agricultural products on earth.[1] (Nadal, 2000)

In 1994, Mexico entered NAFTA (The North American Free Trade Agreement) which effectively removed trade barriers between the United States, Canada, and Mexico. This meant that suddenly, a crop which was central to the Mexican labor force, GDP, and cultural heritage had to compete with heavily subsidized corn grown in North America.

Not only does Mexico’s corn industry represent 60% of all the cultivated land, but also the most significant sector of work for the population – with the sweat of 3 million farmers falling on the soil every season – totaling 40% of agricultural labor in the country.

Today, 20 years of economic liberalization and interactions with competitive foreign markets have had a tremendous impact on the lives of a large portion of Mexico’s subsistence farmers. Most of these farms are owned by a family and handed down through the generations. They cultivate corn with native seeds for immediate consumption and market-day-mongering and represent as much as 79% of all the corn producers in Mexico.

The Fort Knox of Maize

Continuing to practice a roughly 12,000 year old experiment, Mexico's campesinos – small-scale farmers, are constantly pushing evolution forward in corn by saving seeds from their last cycle and planting them during the rainy season. This has produced, according to the work of Mauricio Bellon at Mexico's National Commission for the Knowledge and Use of Biodiversity, 138 billion genetically different maize plants.

When NAFTA negotiators viewed the Mexican maize output, they found it to be inefficient when compared with American corn production. Now, many campesinos have been driven out of the market, as their small-time production could not compete with American corn which now represents a significant portion of the corn sold in Mexico. This triggered a large-scale exodus from the country to the city, as can be seen in the export of corn from the United States pre and post NAFTA, and the sharp decline in production of corn within Mexico itself.

In the years following the implementation of NAFTA in 1994, American corn flooded Mexican markets which reduced both the overall cost of corn in the country and the profits made by campesinos. Attempting to compete, lower and middle-class farmers increased their production, which in turn increased inflation and lowered the cost further.

As the desire to fight back against American imports grew, the production of Mexican maize returned to pre NAFTA levels in the following years as large-scale agribusiness amassed much of the arable land and switched to transgenic corn seeds. This added insult to injury for the small-time Mexican farmer, and as many as 800,000 campesinos from states like Oaxaca, Michoacán, Veracruz, Guanajuato and Puebla, may have immigrated to urban centers.


Campesinos are generating an evolutionary service that is essential for them, for the country and, given the global importance of maize, for the world,”

A Cultural and Genetic Legacy

Many crops available to western consumers today bear little resemblance to their genetic ancestors of millennia past. Monoculture farming allows for the feeding of a large population, but comes with a host of well-documented and significant dangers. The campesinos have been performing an international service to the maize plant, preserving its unique heritage as an incredibly diverse crop which has been cultivated for centuries to endure all manner of environmental changes.

Like so many agrarian peoples across the world, campesinos have to adapt to survive in a challenging growing environment where dust, heat, and drought can all play a part in lowering yearly average crop yields. It was these numbers which skewed the NAFTA negotiators’ views of Mexican maize production capabilities. However it’s now apparent that not only are campesinos preserving the genetic legacy of corn, they are actively contributing to it; increasing the adaptability and resilience of the maize plant with each season.

On the other hand, monocrop maize grown in America represents a far more vulnerable target, genetically speaking. Some of these species have been genetically modified to repel insect pests or certain diseases, but only through constant monitoring of the biology of potential threats can growers and scientists keep American corn safe. If a clever pest or bacteria adapts to target one of the comparatively few American corn species and neither the farmer nor the scientist notice it, thousands of tons of corn lie at risk as opposed to the maize grown on a small 1 acre family farm in Oaxaca.

Campesinos are generating an evolutionary service that is essential for them, for the country and, given the global importance of maize, for the world,” says Mauricio Bellon. 

With possible harshening weather conditions in Mexico representing a more immediate problem when compared with the harder-to-grasp reality of global climate change, Bellon’s research could come at the right time to increase public sector appreciation for what campesinos are doing.

Mauricio Bellon’s paper also includes municipality data showing that remarkably, the production of native maize species in this decade competes with the yields of large-scale mechanized maize farming proceeding elsewhere in the country, and makes up for about 25% of all maize consumed by the population.

Bellon also points out that campesino farming goes on in many municipalities where ecological conditions could prove hostile to unadapted or hybrid maize species. Since small-scale farms use native maize seeds, their operations can be conducted on a wide scale that sustains millions of families within those hostile ecologies – irrespective of adverse growing conditions like altitude, gradient, and rainfall.

PICTURED:  The Svalbard Global Seed Vault inside the Arctic Circle in Norway.

PICTURED: The Svalbard Global Seed Vault inside the Arctic Circle in Norway.

Campesinos: A Global Force For Good

Gene banks like the Svalbard Global Seed Vault, a facility in arctic Norway which houses millions of seed samples in the case of natural or man-made disasters, may help us understand what plants were like at a particular moment in time. But the properties of those frozen seeds may have no ability to cope with conditions many years from now on a post-disaster earth.

 “Mexican campesinos are generating positive externalities of national and global relevance that should be considered public goods and supported as such, particularly because there is no guarantee that they will continue to provide these goods in the future,” concludes Bellon’s paper.

If their way of life can be preserved, campesinos are helping maize adapt to changes as they come along season by season, increasing the likelihood it will continue as a reliable food source for Mexico in the face of a changing and increasingly uncertain world.

[1] The Environmental & Social Impacts of Economic Liberalization on Corn Production in Mexico. World Wildlife Fund/Oxfam, retrieved from, Nadal (2001)

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