Several archaeologists, once split over when human beings turned from nut collectors into rice farmers, seem to have solved their differences after collaborating on a project using methodologies agreed upon by both parties.
Dorian Fuller from the Institute of Archaeology, University College London, joined by Zheng Yunfei from Zhejiang Provincial Institute of Antiquity and Archaeology and a few other Chinese archaeologists, investigated rice remains at the Neolithic excavation site of Tianluoshan, part of the local Hemudu Neolithic Culture that goes back 7,000 years in Zhejing province.
In domesticated rice grains, the spikelet remains attached to the panicle, until it is threshed.
Their research reported in the most recent issue of Science magazine concludes that rice cultivation was slowly domesticated over the course of two or three millennia in the Lower Yangtze region of Zhejiang, China between 6,900 and 6,600 years ago.
"The Hemudu people may not have been the first to initiate rice cultivation, but they certainly did cultivate rice and eventually domesticate it," Zheng tells China Daily.
As one of the oldest rice cultivation bases in the world, Hemudu has attracted much research interest. But not everyone was convinced with the results.
Chinese archaeologists, believe that by the early Holocene (the period starting about 10,000 years ago), Neolithic people in both north and south China may have been harvesting wild rice and initiating rice cultivation that eventually led to domestication, according to Zheng.
Hence, when huge layers of rice remains were discovered in the Hemudu sites in the 1970s, Hemudu was immediately regarded as China's, and probably the world's, cradle of rice cultivation, says Zheng.
Fuller doubted the conclusion as it was based on "presumed domestication", with the long process of domestication "taken for granted, unproven and unquestioned".
Instead, Fuller argued in the study of agricultural origins, it is "prudent to presume plants are wild until evidence can be found to indicate domestication."
Zheng and many other Chinese archaeologists disagreed, saying their research had uncovered traces of the domestication process in many Hemudu sites. They said they had been able to tell the wild grains from domesticated ones, from their sizes.
But professor Qin Ling from Peking University, who is a member of the research team, says: "Grain size is a very indicator as different varieties might have varied sizes in different climate and environment even over the same period of time. But Fuller wanted hard evidence."
Hence, the team turned to another important trait for rice domestication — loss of seed shattering.
Wild rice shatters automatically, while domesticated rice will not, even when it reaches maturity. It needs to be threshed, explains Qin.
As they dug at the Hemudu site, Qin explains, they observed that the percentage of rice remains among all plant remains went up from eight to 24 percent.
This pointed to the increasing dietary importance of rice over time at the site.
The researchers also separated the rice remains into three categories (wild, domestic, and immature) based on their shattering signs, and determined that as time progressed, the domestic type of rice had increased in occurrence from about 27 to 39 percent over the course of 300 years.
"It is on the basis of this indicator that we have come to our conclusion, convincing not only us but also others," says Qin.