Not long ago I was sitting in a combine tractor on a 24,000-acre farm in Dazey, N.D. The expanse of the landscape — endless rows of corn and soybeans as precise as a Soviet military parade — was difficult to ignore. So were the skyscraper-tall storage silos and the phalanx of 18-wheeled trucks ready to transport the grain. And yet what held my attention were the couple of dozen seeds in my palm — the same seeds cultivated all around me.

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More than 90 percent of the 178 million acres of corn and soybeans planted last year in the United States were sown with genetically engineered seeds. It’s a vision as dispiriting as it is unappetizing.

Vegetables have been spared some of this genetic tinkering but are increasingly victim to the same aggressive corporate seed environment. Last year the pharmaceutical company Bayer acquired the world’s largest vegetable seed company, Monsanto.

For these megacompanies, capturing a large share of the vegetable seed market means capturing patentable genetics. Since 2001, the scope of utility patents has expanded to include novel plant traits. (Before this, you could own a variety, but not its traits, in the same way that you can own a beachfront property but not the particles of sand.)