Mariano Ruiz, a deputy agriculture secretary, said in an interview that the regulatory approval process won't be finalized under the outgoing government of President Felipe Calderon, but instead will fall to his successor to see through sometime next spring.

President-elect Enrique Pena Nieto of the Institutional Revolutionary Party is set to take office on December 1.

Ruiz said he does not expect permits to be approved for four to five months but that the new government led by Pena Nieto is likeminded in its support for the introduction of large-scale GMO corn cultivation in Mexico.

"I think we are in agreement generally over the importance of having this instrument, and that farmers have the tool of genetically modified organisms," said Ruiz.

"But like they say, the devil is in the details," he added.

Scientists recognize Mexico as the birthplace of corn, and opponents of GM corn have argued that genetically modified varieties pioneered by companies like Monsanto will contaminate native strains and irrevocably harm the grain's biodiversity.

Ruiz said the government still had to designate so-called "centers of origin" where GM corn cultivation will be banned as well as set other safety regulations.

Mexico, Latin America's second-biggest economy, plants 7.2 million hectares (17.8 million acres) of corn annually to grow mostly white corn which is used for human consumption, including the country's staple tortillas.

Domestic corn production this year will total nearly 22 million tonnes, according to agriculture ministry data.

But the country relies on imports of yellow corn for animal feed, including about 9 million tonnes in 2012.

Backers of GM corn say it produces yields between 10 and 15 percent larger than conventional strains, which could boost production and curb Mexico's dependence on imports.

The delay will leave five applications for commercial-scale GM corn fields totaling about 2.5 million hectares in limbo.

Agribusiness giant Monsanto has submitted two applications, both of which seek 700,000 hectares for GM corn in Mexico's western Sinaloa state, the country's largest corn producer.

The Mexican subsidiary of Pioneer Hi-Bred International, part of DuPont, has three applications each of which would cover about 350,000 hectares in northeastern Tamaulipas state.

Meanwhile, Dow Agrosciences de Mexico, part of Dow Chemical, has one application for 40,000 hectares also in Tamaulipas state.

(Editing by Ed Davies)

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