This is quite odd. It is generally believed that maize was developed in Mesoamerica, and didn’t reach S. America till long afterwards.
Even when Pizarro showed up maize was mostly still a luxury food of the rich, not a staff of life for all.
FSU Anthropologist Finds Earliest Evidence Of Maize Farming In Mexico (7,300 YA)
http://www.sacredearth.com/ethnobotany/plantprofiles/corn.php
“...so far the oldest archaeological evidence for domesticated corn comes from Guilá Naquitz Cave near Mitla in the Valley of Oaxaca, Mexico, which has been dated to approximately 6250 years ago.”