The importing of foods has been going on for thousands of years, archaeologists have found. Evidence that crops were being traded as goods 4,000 years ago over distances of hundreds of miles between the Amazon basin rainforests and Andean highlands has been discovered.
     Archaeologists say that the first time it was possible to draw on a range of foods grown in different regions marked a key moment in the development of human societies, when people moved from hunter-gatherer cultures to agricultural cultures, actively developing and trading new food crops.
     Reported in the journal Nature, a team who excavated a stone house at Waynuna, north of Arequipa on the western slope of the Andes, found evidence of the ancient trade in plant remains contained in sediments and three grinding stones. Dr Linda Perry, of the Smithsonian National Museum of Natural History, and colleagues found microscopic remains of three crop plants - maize, potato and arrowroot. Arrowroot tubers do not grow in the Andean highlands and probably originated from lowland Amazon rainforest sites. Maize starch grains were the most common plant remains on the grinding stones, suggesting that maize was grown at the site.
     The Waynuna house is older than any of the other sites in Peru where maize has been found and sets back the date of maize cultivation and processing in the region by around 1,000 years. The crop, known as corn in some countries, was first used in Mexico about 10,000 years ago. Although researchers knew it had migrated down to South America, exactly when it was domesticated there was poorly understood.
     "This is the earliest use of maize in this region of the Andes," said Linda Perry of the Smithsonian National Museum of Natural History in Washington. "We have good evidence they were growing the plants on site and that they were processing it into flour. hese data confirm what many archaeologists have suspected for a long time but were not able to prove," she added in an interview. The discovery of arrowroot was also significant, she said, because it probably could not have been grown in a high altitude region like Waynuna, which suggests it was brought there from another area and may have been a bartering commodity.

Sources: Reuters (1 March 2006), News Telegraph (2 March 2006)