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 on Monday that an analysis of well-preserved ancient peach pits traces the cultivation of this sweet fruit back at least 7,500 years to the lower Yangtze River valley near Shanghai.
Peaches were among the first tree fruits to be cultivated as early human societies embraced horticulture, the study indicates.
"There is a long history of peach cultivation in China," said one of the researchers, Zheng Yunfei of the Zhejiang Provincial Institute of Relics and Archaeology in Hangzhou, adding 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 about 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 cultivating this fruit.
It took perhaps 3,000 years before the peaches came to look like those 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 are many reasons why the peach tree is a good candidate for cultivation.
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 is apparently 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 has been that the peach originated somewhere else in China.
A capable Chinese culture called the Kuahuqiao seems to have begun cultivating the peach. Rice cultivation was already under way.
"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 to manage 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.