typhlonectes:

This evolutionary experiment has been going on for thousands of years.
And the efforts of small-scale farmers, a recent study suggests,
generate the bulk of corn’s genetic diversity in North America. In the
face of more aggressive weather threats researchers say the finding
comes at a critical time. “This takes things a step further,” says
Daniel Piñero, a plant population geneticist at the National Autonomous
University of Mexico. “Family farmers are not only preserving the
[genetic] diversity of maize,” or corn, Piñero says—they are
contributing more of it. 

In the study Mauricio Bellon, a social scientist who works for Mexico’s
National Commission for the Knowledge and Use of Biodiversity, and his
colleagues used government numbers from the 2010 rainy season—the last
year a national census was done. The team narrowed in on the
municipalities with maize yields of up to three metric tons per
hectare—in other words, where people still grow their own food and
cultivate native varieties. The researchers then estimated the area
where corn hybrids are produced at a commercial scale…

Small Farmers in Mexico Keep Corn’s Genetic Diversity Alive