Mike Listman revives the discussion on Pawnee corn:
A colleague at CIMMYT has suggested a possible linkage with Mexican native maize varieties, more of the tropical rather than temperate corn belt type (possibly why the Pawnee materials might not have prospered at Oklahoma day-lengths…) You could possibly confirm the Aztec-Pawnee linkage through a quick comparative assay of the Pawnee language and Nahuatl, focusing on vocabulary for everyday objects and activities (obviously, those that would have existed in pre-Colombian times).