Mexico is home to thousands of maize varieties

Flickr/CIMMYT

[MEXICO CITY] Mexico has authorised a field trial of genetically modified (GM) maize that could lead to commercialisation of the crop, sparking debate about the effects on the country's unique maize biodiversity.

Although Mexico already commercially grows some GM crops, such as cotton, GM maize is controversial because the country is home to thousands of the world's maize varieties that originated there.

The multinational corporation Monsanto will test a variety of maize resistant to the herbicide glyphosate on less than a hectare of land in north Mexico before it can commercialise the GM crop. Unlike experimental trials, such pilot projects do not require containment measures to prevent the spread of the GM crop.

Mexico's agriculture ministry said the project, approved last month (8 March), will occur "under the strictest biosecurity measures to guarantee the prevention of involuntary dispersion of the GM maize's pollen".

But Elena Álvarez-Buylla, head of the Union of Scientists Committed to Society (UCCS), said: "This opens up the door to contamination of native species in the most important centre of origin [of maize] in the entire world."

The UCCS stated last month (25 March) that the coexistence of GM and non-GM varieties in fields — which may happen if commercial approval is given — could contaminate the unique non-GM varieties.

"There are alternative technologies to address the non-GM maize shortage and loss of crops due to climate events. GM [crops] are not more resistant to droughts and plagues, and they threaten our food sovereignty," its statement says, referring to multinational companies owning GM technologies.

Transgenic crops were banned in Mexico until 2005, but the government has since granted 67 permits for GM maize to be grown experimentally on over 70 hectares. This would be the first trial that could lead to commercialisation if it is successful.

At the third Mexican Congress of Ecology this month (3–7 April) in Veracruz, scientists were cautious about growing GM maize.

Andrew Stephenson, an ecology professor at Pennsylvania University, United States, said the indirect effects of mixing GM and non-GM varieties are largely unknown, especially under Mexico's complex environmental conditions.

And Mauricio Quesada of the National Autonomous University's Centre for Ecosystems Research said Mexico should prioritise research on the natural diversity of local crops instead of "jumping" into GM.

But Luis Herrera-Estrella, chief of the National Laboratory of Genomics for Biodiversity at the Research and Advanced Studies Center of the National Polytechnic Institute of Mexico, said the country's legal biosafety framework should be trusted.