You have to look at a lot of different sources if you're trying to piece together a large story like this. There is a story for corn that has been evolving also. It migrated around North America from it's original location in the Andes, where it was a simple grain with a few kernals. It was nurtured and just as farmers of today work to increase the output of a plant, native farmers brought it to a point where what was traded was a much improved food crop with the ear as we see it today. The biologists who have been looking into the earliest forms of corn are upset that Monsantos' varieties are going to cross-pollinate and destroy the native plants that still grow in the wild, or those that are cultivated in remote regions.

I suspect that someone looking into the ethnographic materials from as far back as they have been collected could shed light on attitudes toward some of these plants that came through in stories but weren't the primary reason for the interviews so haven't been highlighted in the literature. This has certainly been the case in my research toward cultural attitudes toward this nebulous thing we call "The Environment" among native North Americans prior to or early into the exploration and colonial periods.

Last year at this time I was writing a book chapter on sports and recreation in the Southwest. It went back far before colonization, and one way to try to interpret early activities is to look at the writings of the first Europeans to have extensive contact within cultures. Admittedly a lot of it is dismissive and biased, but you can still pick up information simply by looking at what they dismiss. I was researching the ancient ballcourts and games, and this sentence is extracted from that chapter:

The writings of Fray Diego Duran (1537-1588), a Spaniard who moved to Mexico as a child, provide valuable information about the historic sources about ball courts and games. As a Friar, Duran was a prolific chronicler of the customs and religion of the indigenous people. Book of the Gods and Rites and the Ancient Calendar was reprinted by the University of Oklahoma Press in 1977.

Who knows, maybe something about tomatoes and other foods or plants turns up in passing in a text like this.

SRS