Corn's roots dig deeper into South America

Corn has long been known as the primary food crop in prehistoric North and Central America. Now it appears it may have been an important part of the South American diet for much longer than previously thought, according to new research by University of Calgary archaeologists who are cobbling together the ancient history of plant domestication in the New World.

In a paper published in the March 24 advanced online edition of the Proceedings of the National Academy of Sciences, U of C PhD student Sonia Zarrillo and archaeology professor Dr. Scott Raymond report that a new technique for examining ancient cooking pots has produced the earliest directly dated examples of domesticated corn (maize) being consumed on the South American continent.

Their discovery shows the spread of maize out of Mexico more than 9,000 years ago occurred much faster than previously believed and provides evidence that corn was likely a vital food crop for villages in tropical Ecuador at least 5,000 years ago.

“The domestication and dispersal of maize has been a hot topic in archaeology for decades and these are the earliest indisputable dates for its presence in South America,” Raymond said. “It has long been thought that maize may have been used south of Panama at this time for ritual purposes but this shows it was also being consumed as food.”

Raymond led the excavation of tropical village sites in western Ecuador in the early 1980s, which are the oldest known villages in the Americas. Using pottery fragments recovered from the sites, Zarrillo obtained the charred remnants of prehistoric meals and found they contained starch granules from domesticated corn.

“Plant material typically does not preserve very well in tropical sites but it turns out that microscopic starch grains do survive very well over the years and can be used to identify exact species of plants,” Zarrillo said. “Analyzing starch from charred food residues is a new technique in archaeology and it is exciting because it will stimulate research around the world when people realize they can recover starch from cooking pots and use it to date and identify what people were using as food.”

Starch analysis was also used by Zarrillo and Raymond for a study published in Science last year that traced the domestication and spread of chili peppers throughout South America, Central America and the Caribbean more than 6,000 years ago.

Source: University of Calgary

Related stories:

Scientists Finds Earliest Evidence of Maize Farming in Mexico
A Florida State University anthropologist has new evidence that ancient farmers in Mexico were cultivating an early form of maize, the forerunner of modern corn, about 7,300 years ago - 1,200 years earlier than scholars previously thought.
Practice of farming reaches back farther than thought
Ancient people living in Panama were processing and eating domesticated species of plants like maize, manioc, and arrowroot at least as far back as 7,800 years ago – much earlier than previously thought – according to new research by a University of Calgary archaeologist.
South Korea begins imports of biotech corn
(AP) -- Major South Korean corn processors have begun importing genetically modified varieties of the crop because of shortages of conventional corn on the world market since China began limiting its exports, officials said Friday.
Arctic seed vault opens doors for 100 million seeds
The Svalbard Global Seed Vault opened today on a remote island in the Arctic Circle, receiving inaugural shipments of 100 million seeds that originated in over 100 countries. With the deposits ranging from unique varieties of major African and Asian food staples such as maize, rice, wheat, cowpea, and sorghum to European and South American varieties of eggplant, lettuce, barley, and potato, the first deposits into the seed vault represent the most comprehensive and diverse collection of food crop seeds being held anywhere in the world.
Impoverished areas of Africa and Asia face severe crop losses from climate change in 20 years
Many of the world’s poorest regions could face severe crop losses in the next two decades because of climate change, according to a new study by researchers at Stanford University’s Program on Food Security and the Environment (FSE). Their findings will be published in the Feb. 1 issue of the journal Science.
Scientists call for urgent research into 'real' impacts of invasive species
Invasive alien species are those that occur outside their natural range and threaten the existence of native plants and animals. They can be plants, animals or microorganisms that are introduced intentionally for economic or agricultural purposes, or accidentally, through tourism, travel or trade, or when domestic animals become feral.
First all-African GM crop is resistant to maize streak virus
The first all-African genetically modified crop plant with resistance to the severe maize streak virus (MSV), which seriously reduces the continent’s maize yield, has been developed by scientists from the University of Cape Town and PANNAR PTY Ltd, a South African seed company.
First all-African produced genetically engineered maize is resistant to maize streak virus
Maize streak viruses (MSV), geminiviruses that can destroy most of a maize crop, are endemic to sub-Saharan Africa and adjacent Indian Ocean islands where they are transmitted by leafhoppers in the genus Cicadulina. Maize can supply 50% of the caloric intake in sub-Saharan Africa but, in certain years, a farmer’s entire crop can be wiped out. Now, scientists at the University of Cape Town, South Africa, along with colleagues at the South African seed company, PANNAR Pty Ltd, have developed a resistant variety of maize that they hope will help alleviate food shortages as well as promote the reputation of genetically engineered (GE) foods in Africa.

News discussion:

General Science news