Where and how was rice domesticated in China?

Rice was domesticated in the Yangtze River basin in China, about 9,000 years ago. That is the current scientific consensus, based on archaeological and linguistic evidence. It matters because rice, in its domesticated form, is the staple food of over half the world's population, particularly in Africa and Asia.

Why do many scientists think it happened once? A gene variant for non-shattering is the critical indicator of domestication in grains. That variant is identical in both major types of Asian rice, indica and japonica, so researchers in 2008 concluded there was a single domestication. A 2011 genetic study agreed: all forms of Asian rice came from one event, about 9,000 years ago in China, from a wild rice called Oryza rufipogon. Not everyone agrees: the origin of Asian rice has been much debated, and a 2012 genome study pointed to the Pearl River valley in southern China instead, in contradiction to the archaeological evidence.

There are two most likely centres, along the lower and middle Yangtze River. The second, the middle Yangtze, is believed to be the homeland of the early Hmong-Mien speakers. By the late Neolithic, around 3500 to 2500 BC, the population in these rice-growing centres had increased rapidly.

Rice did not conquer everything at once. In northern China it did not replace millet because of the different environmental conditions, though it was grown alongside it at the southern edge of the millet regions. Elsewhere it travelled with people: Austronesian settlers carried rice from Taiwan to the Philippines around 2000 to 1500 BC, and it eventually reached the Americas after 1492.