GUELATAO, Mexico — Yank the husks off ears of
corn grown in the mountains of southern Mexico, and you may find kernels
that are red, yellow, white, blue, black or even variegated.
It's only one measure of the diversity of the 60
or so native varieties of corn in Mexico. Another is the unusual
adaptation of some varieties to drought, high heat, altitude or strong
Plant specialists describe the native varieties of corn in
Mexico as a genetic trove that might prove valuable should extreme
weather associated with global warming get out of hand. Corn, one of the
most widely grown grains in the world, is a key component of the global
But experts say Mexico's native varieties are themselves under
peril — from economics and genetic contamination — potentially depriving
humans of a crucial resource.
Farmers are punished at the
marketplace for selling native corn, and some types are dwindling from
use. Perhaps more significantly, genetically modified corn is drifting
southward and mingling with native varieties, potentially bringing
unexpected aberrations and even possible extinction.
At stake may
be more than just curious and exotic types of corn, grown in small
fields alongside beans and then ground into tortillas after harvest.
climate change," said Aldo Gonzalez, an indigenous Zapotec engineer
with long, flowing black hair who's at the forefront of protecting
native varieties, "new diseases could occur, and the only place in the
world where we can look for existing varieties that might be resistant
is in Mexico.
"These varieties of corn might at some point save humanity."
is not only a crucial crop in Mexico but also a symbol in a nation
that's the birthplace of the grain. Maize likely originated from a
grass-like, tasseled plant, teosinte, in southern Mexico. Scientists say
humans domesticated corn 7,000 to 10,000 years ago.
In the Popol
Vuh, the sacred book of the ancient Mayans, gods create humans out of
cornmeal, allowing the "people of corn" to flourish.
centuries, varieties of corn adapted to different soils, altitudes,
temperature conditions and water availability, and Gonzalez said the
seed stock handed down in his village in this corner of the Sierra
Juarez range in central Oaxaca state probably wouldn't grow well just a
few miles distant.
"In the sierra here, there are varieties of
corn that grow as high as 3,000 meters," Gonzalez said, or nearly 10,000
feet. "There are varieties that can be planted in swampy land or that
you can plant in semidesert areas. They may not be very productive but
they have allowed people to survive."
Native varieties of corn have fed humans for millennia in Mesoamerica.
elders understand the importance of various types of corn because they
had their fields in different places under different conditions," said
Lilia Perez Santiago, an agricultural engineer who works for a state
Perez was among the activists behind a petition
in 2000 to the Montreal-based Commission for Environmental Cooperation, a
panel created under the North American Free Trade Agreement. The
petition claimed that genetically modified corn, altered to be pest
resistant or herbicide tolerant, had drifted to southern Mexico and
begun contaminating native varieties.
Four years later, the panel
recommended to Mexico that it suspend modified corn imports and adopt
strict labeling rules to allow the public to identify food products that
contained such corn. Mexico ignored the recommendations, arguing that
the ruling came into conflict with its obligations to open markets under
In late 2009, the government permitted a subsidiary
of a U.S. conglomerate, Monsanto, to test genetically modified corn on
isolated plots of about 240 acres in Sinaloa and Tamaulipas states in
The head of Monsanto Mexico, Jose Manuel Madero, said
at a news conference two weeks ago that the federal government demands
further tests before allowing commercial farming of the genetically
Madero said modified corn was in use in 20 countries
around the world and would help Mexico raise agricultural productivity,
cut its reliance on food imports and slash the use of herbicides,
thereby protecting the environment.
Several scientists have joined
a Mexican grass-roots campaign, known as Sin Maiz No Hay Pais, or There
Is No Country Without Corn, to oppose the import or harvest of
genetically changed corn.
"We have a nationwide survey that shows
genetic contamination in Guanajuato, Yucatan, Veracruz and Oaxaca
(states). We also know of some large-scale plantings in Chihuahua," said
Elena Alvarez-Buylla Roces, a molecular geneticist at the National
Autonomous University of Mexico.
She said lab analysis showed that some native varieties already carried altered genes.
is no possibility of coexistence without contamination," Alvarez-Buylla
said. "One gene can make a large difference. Do we want to run the
Black-market brokers already sell genetically modified seed
corn to farmers in the north of Mexico, opponents say, and bags of
unmarked genetically altered corn have been found in the far south.
bags of corn are not secure. During transport, some bags break open and
fall out. So there are many possible ways of contamination," Perez
The vast majority of farmers of native varieties select
seeds each year to save for the next harvest, thus making what
Alvarez-Buylla described as "active, dynamic genetic elements" prone to
aberrations from genetic drift of altered corn.
Scientists don't know which varieties could prove useful for climate change.
don't really know if there is a variety with the most promise. Promise
for what?" Alvarez-Buylla said, adding that future climate conditions
While the government maintains seed banks for
native corn, Alvarez-Buylla said, "This is not a diversity that can be
preserved in a laboratory."
Some farmers already are abandoning certain native varieties, unable to make a living harvesting their small plots.
get a price penalty for not growing uniform, large volumes of corn that
the tortilla manufacturers want," said Timothy A. Wise, a rural policy
expert at the Global Development and Environment Institute at Tufts
University in Massachusetts.
Economic realities that make it
increasingly unviable for farmers to grow native varieties may be as big
a peril as genetic contamination, Wise said.
"If that traditional
knowledge isn't passed from generation to generation and those farmers
stop farming, then that seed variety is lost for economic reasons," he
In Mexico's cities, consumers have little taste for the
native varieties of corn in their own country, offering no price
advantage for the small farmers who are nurturing the nation's corn
"In urban areas," Gonzalez said, "they don't know about
the varieties. All they know is that the dining room table must have
tortillas on it."