Modelling the chronology and dynamics of the spread of Asian rice from ca. 8000 BCE to 1000 CE

This paper presents a quantitative chronology for the spread of rice, based on the global Rice Chronology Database that builds upon direct datings of archaeological rice remains. Bayesian and spatio-temporal modelling suggest eastern China (lower Yangzi, middle Yangzi, southern Huai River, and Shandong) and northeastern South Asia as two key origins of rice cultivation, dating to ca. 7430 and 6460 BCE, respectively. At least two episodes of spread of rice are identified. The first, dating to the 4th and 3rd millennia BCE, accounts for the appearance of rice in the middle Yellow River and Wei River regions, southeastern China, southwestern China, and Southeast Asia. An examination of population dynamics in China shows that this episode of spread might be associated with farmers whose subsistence was based largely on millets. During a second episode of spread, dating between the 1st millennium BCE and 1st millennium CE, rice spread to the Liao River region, Central Asia, and Africa.