WASHINGTON - Peaches fresh from the tree or in treats like pie, jam and ice cream have been enjoyed by people for a long, long time. But, until now, it was not clear just how long it has been.
Scientists said this week an analysis of well-preserved ancient peach pits traces the domestication of this sweet fruit back at least 7,500 years to China's lower Yangtze River Valley in the vicinity of Shanghai.
Indeed, peaches were among the first tree fruits to be domesticated as early human societies embraced horticulture, the study indicates.
"There is a long history of peach cultivation in China," said one of the researchers, Yunfei Zheng of the Zhejiang Provincial Institute of Relics and Archaeology in Hangzhou, China, noting that China still leads the world in peach production.
The researchers compared peach pits, also called stones, from six Chinese locations, covering a period of roughly 5,000 years. An analysis of pit size from each location showed that peaches were growing steadily larger as time passed in the Yangtze valley, illustrating that people there had been domesticating this fruit.
It took perhaps 3,000 years before the domesticated peaches came to look like peaches grown now. Peach pits, almost indistinguishable from today's, date back about 4,300 to 5,300 years, the researchers said.
Gary Crawford, a University of Toronto Mississauga anthropology professor who took part in the study published in the journal PLOS ONE, said there were many reasons why the peach tree was a good candidate for domestication.
It is relatively quick maturing - producing fruit in just two to three years - as well as being responsive to breeding for size and sweetness, among other qualities.
"It's also tasty and produces a lot of fruit. They are rich in vitamins A and C and have a lot of energy - calories - per fruit," Crawford added. "The flavor is amazing. I like eating them raw mostly, but peach pies and peach crumble are right up there."
Radiocarbon dating of the pits showed peaches split from their wild ancestors as long as 7,500 years ago. Peaches went from being small with very little flesh to a robust fruit like we see today. Crawford said the wild ancestor of the peach apparently is extinct.
"In China, the peach is a symbol of long life and has a significant role to play in Chinese culture," said Crawford, adding that conventional wisdom had been that the peach originated somewhere else in China.
It was a capable Chinese culture called the Kuahuqiao that seems to have begun peach domestication. Rice domestication was already under way in the area.
"They were settled in small towns, had a broad spectrum of foods and other resources, had dugout canoes and were burning areas of the landscape for managing the local ecosystems," Crawford said.
They also raised pigs, kept domesticated dogs, stored large amounts of acorns, used wooden tools and made high-quality wheel-turned pottery, Crawford said.