Mexico is the birthplace of modern corn, domesticated about 8,000 years ago and today the planet's most-produced grain.

If new President Donald Trump upends the North American Free Trade Agreement as he has threatened and U.S. supplies are not longer available, Tamayo said Mexico might have to look to other major corn producers, like Argentina and Brazil.

Prominent Mexican politicians, including former President Felipe Calderon, say the nation should consider ending purchases from U.S. corn producers in favor of Brazil and Argentina if Trump applies new taxes on Mexican exports to its northern neighbor.

"But there's no magic wand to do that," she said. It would be "disastrous" in the short term to source from new South American suppliers since that would mean higher transport and other costs, she added.

To boost both yellow and white corn output in the near term, Tamayo said Monsanto was about a year and half away from introducing what it dubs "nano corn," a conventional hybrid variety that she says is about 20 percent more productive.

The smaller, shorter plant with less foliage aims to divert more growth into the actual fruit, said Tamayo, who previously worked for Coca-Cola Co. and commodities trader Cargill.