Agriculture's roots get a South Pacific twist. (New Guinea Went Bananas).

Situated in the South Pacific islands, remote New Guinea seems an unlikely place for the invention of agriculture. Yet that's precisely what happened there nearly 7,000 years ago, according to a new investigation.

Inhabitants of this tropical outpost cultivated large quantities of bananas about 3 millennia before the arrival of Southeast Asian seafarers, say archaeologist Tim P. Denham of Flinders University in Adelaide, Australia, and his colleagues. Agriculture thus arose independently in New Guinea, the scientists conclude in an upcoming Science.

Until now, convincing evidence for ancient agriculture came only from the Middle East (SN: 10/28/00, p. 280), China, the eastern United States (SN: 9/20/97, p. 180), South America, and a region encompassing parts of Mexico and Central America (SN: 5/24/97, p. 322). Reports in the 1970s that New Guinea belonged in this group were criticized for relying on patchy remains and uncertain dates from an excavation of a swampy highland site called Kuk.

"Only a few regions were geographically suited to become homelands of full agricultural systems," says archaeologist Katharina Neumann of J.W. Goethe University in Frankfurt, Germany, in a commentary accompanying the new article. "New Guinea seems to have been one of them."

This discovery challenges the traditional notion that agriculture inevitably led to the rise of large civilizations with stratified social classes, Denham and his coworkers assert. Current New Guinea societies are relatively small and grounded in egalitarian practices, much as they seem to have been before the rise of agriculture, according to the researchers.

In renewed investigations at Kuk, which included radiocarbon dating of charcoal in separate soil layers, Denham's team identified three early phases of land use. Limited planting of bananas and digging of starchy taro roots in a plot abutting a drainage ditch occurred between 10,220 and 9,910 years ago. The researchers unearthed microscopic crystals from bananas and found starch grains from taro on the edges of stone tools.

From 6,950 to 6,440 years ago, cultivation expanded, say the researchers. The region's inhabitants built large mounds of soil on which they planted bananas, including a wild species from which the world's largest group of domesticated bananas later arose. Recent genetic research suggests that bananas were initially domesticated in New Guinea and subsequently spread to Southeast Asia, the scientists note.

Crop growing on New Guinea was further refined between 4,350 and 3,980 years ago. Networks of ditches connected to major drainage channels improved banana cultivation in the waterlogged setting.

Archaeologist Matthew Spriggs of Australian National University in Canberra, a critic of previous reports of prehistoric cultivation at Kuk, recruited Denham to direct the new investigation. "Denham's finds and further analysis of [the] earlier data have convinced me that there really [was] agriculture at Kuk as early as anywhere in the world," Spriggs says.

The New Guinea practices later moved west into Southeast Asia, in Spriggs' view. From there, a hybrid agricultural system featuring both New Guinea--based root crops and Chinese-based rice spread across the Pacific as far as Hawaii, Easter Island, and New Zealand, with root crops eventually gaining favor, Spriggs contends.