GM maize and biodiversity

Tortilla crisis in Mexico: Could GM maize be the answer?

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In Mexico maize is becoming scarce and the price of tortillas, the staple food in Mexico, has risen dramatically. While the population is demonstrating on the streets, the national farmers’ association sees the cultivation of genetically modified maize as the ultimate solution. But GM maize has been banned in Mexico, the land of biological diversity for maize, since 1998.

Mexico is the birthplace of teosinte, the grass from which today’s maize is descended. Nowhere else in the world are there as many wild and cultivated varieties growing as there are here. Protecting such genetic diversity is one of the aims of the Biodiversity Convention that was adopted in Rio in 1992. The signatories pledge to avoid environmental impacts associated with the release of genetically modified organisms which could harm the preservation and sustainable use of biological diversity. As a result, in 1998 the Mexican government took the precaution of imposing a moratorium on the cultivation of GM maize.

Diversity of maize varieties: A maize farmer’s harvest in the highlands of central Mexico. From teosinte to hybrid maize: Mexico’s original inhabitants developed today’s maize varieties from the grass variety teosinte over millennia through crossing and selection. Wild forms of maize on a field in Michoacon, Mexico. So far there is no concrete evidence to suggest that the use of cultivated varieties could lead to wild and native varieties being forced out. Photos: Hugh Iltis, John DoeblyDoebley Lab, Department of Genetics, University of Wisconsin-Madison

The fear that GM maize could cross into wild and native Mexican varieties appeared to be confirmed in 2001. That year David Quist and Ignacio Chapela, two Californian researchers, published a short article in the scientific magazine Nature in which they reported that they had found traces of GM maize in maize varieties from a remote region. The article triggered fierce scientific and political debate, and at least two other studies produced similar results. Other scientists cast doubt on the detection methods used by Quist and Chapela. Then in August 2005 came the all-clear: comprehensive follow-up tests in the same region found no trace of GM maize. Mexico: Dependent on expensive maize imports The national farmers’ association, which represents 500 agricultural businesses, has called on President Felipe Calderon’s newly elected government to lift the moratorium on GM maize and authorise it for cultivation. What has prompted this is the current "tortilla crisis": A limited supply of maize has pushed up the price of tortillas, the staple food for rich and poor. Tortilla prices have risen by 100% since June. The main cause of the shortage is the growing demand for maize as a raw material for bioenergy in the USA, which has led to a dramatic rise in the global market price for maize. Mexico, which in 2006 produced only 22 million tonnes of the 30 million tonnes it needs, is dependent on imports. Until the North American Free Trade Agreement (NAFTA) comes into effect in 2008, maize imports have to be approved by the Mexican government. Yet maize imports are the subject of fierce criticism. The association of small farmers in particular fears competition from the US agricultural sector and is calling on the Mexican government to protect small family-run farms. Dependence on imports and high global market prices for maize mean that Mexicans are having to pay more and more for their tortillas and the cost of living is rising. Thousands of Mexicans have taken part in protest marches, calling on the government to act – and in doing so have brought the issue of GM maize cultivation back into the debate.

GM maize: Not a threat to biodiversity in Mexico?

In the opinion of the Mexican farmers’ association, the CNA, the crisis can only be solved once and for all if GM maize is authorised for cultivation. They believe that the ability to use insect-resistant Bt maize could significantly increase national maize production, reducing yield losses caused by pests and lowering insecticide costs.

For opponents of GM maize cultivation in Mexico, the price rise has done nothing to change their reservations. Small farmers and environmental groups in particular fear that GM maize pollen will cause outcrossings . They see this as a threat to species diversity and are warning of contamination of the seed banks. However, so far there is no indication that the genes inserted into GM maize could become established long-term in the regional native breeds, thereby threatening biological diversity. There are evidently effective genetic barriers between cultivated and native varieties. Neither has the introduction of maize hybrid varieties in Mexico had any lasting effects on the diversity of wild and native varieties in Mexico.

With regard to the seed banks at least, the International Maize and Wheat Improvement Center gave the all-clear as far back as the end of 2002: For years, they have accepted only tested seed containing no transgenic sequences. When propagating these seeds, crossing with unknown maize varieties in the environment is prevented in the field by time-consuming hand fertilisation, safety margins and buffer plantings.

The Mexican government has not yet decided whether to approve GM maize.

 

More from GMO Safety

• Mexico: "GM maize" disappeared – questions still remain (August 2005)
• Foreign genes in native varieties: A threat to biological diversity? (February 2003)
• NAFTA report on GM maize in Mexico: Only ground maize to be imported as a precaution (October 2004)