Current Opinion on Agricultural Origins in the Americas

According to Dolores Piperno and Deborah Pearsall (1998), the first American agriculture began very diffusely in the lowland seasonal deciduous forests of Middle America and northern South America. They suggest that it began in a very small way, early in the Holocene by about 8000 sc, with no domestic animals, as an adjunct to a hunting and gathering economy based on a limited investment in house gardens and shifting agriculture. Piperno and Pearsall are here echoing, but modifying, earlier views on the significance of the lowland tropics by Carl Sauer (1952) and Donald Lathrap (1970).

At the same time, they are posing a scenario rather different in geographical terms from that favored by Richard MacNeish, as a result of his research in the much drier Tamaulipas and Tehuacan regions of Mexico (Byers 1967; MacNeish 1972, 1992). MacNeish, like Piperno and Pearsall, favored a gradual adoption of agriculture and settling down, but in this case in the semi-arid highland regions of Mesoamerica rather than in the wetter lowlands. Even though MacNeish maintained his views until his death in 2000 (MacNeish and Eubanks 2000), phytolith evidence now suggests that teosinte, widely considered the likely ancestor of maize, was absent in the Mesoamerican highlands until its appearance as a primitive domesticate about 6,000 years ago (Pipemo and Flannery 2001; Pohl et al. 1996; Buckler et al. 1998). This absence supports, at face value, a lowland origin for maize.

One can, however, read this absence the other way, as does Hugh Iltis when he makes the intriguing suggestion that teosinte became domesticated into maize not in its lowland biological homeland, which probably lay in or close to the Balsas basin of western Mexico, but possibly in a highland region such as Tehuacan, to which ancestral forms must have been taken by humans. To make the situation even more complex, botanist Mary Eubanks favors a derivation of maize not from annual Balsas teosinte at all, but from cross-pollination between a perennial form of teosinte and another grass species Tripsacum dactyloides, a cross that probably occurred in highland Mesoamerica (MacNeish and Eubanks

2000). Matsuoka et al. (2002) also favor a highland origin for maize domestication based on genetic analysis.

All of this is, of course, a little confusing for the non-botanist. Highland or lowland? Agricultural origins in the Americas are certainly not transparent and obvious. As Iltis (2000:37) notes, discussing the homeland of maize domestication: "Clearly, we don't know, and much more aggressive archaeology is needed in Mexico." Indeed it is.