The maize found even in remote areas of Mexico today is not the same as the maize found in the same location hundreds of years ago. Maize is an open-pollinating species that readily exchanges genes with other maize plants growing nearby. Farmers long ago recognized this as a way to adapt varieties to their own needs. Mexican farmers say that their maize "gets tired." When this happens, they seek other varieties to mix with it. (Source: International Development Research Centre)