Domestication origin and spread of cultivated tea plants

Abstract

Tea is the most popular non-alcoholic beverage in the world. The domestication origin of cultivated tea plants has always been a focus of ecological research. This article summarizes the recent research progress, discusses remaining questions and makes suggestions for future research directions. Many wild relatives of cultivated tea plants are distributed in the Yangtze River Basin and its southern reaches, particularly in Yunnan, Guizhou, and Guangxi provinces. The pronunciation of “cha” is similar in the languages of southern ethnic groups, implying a single domestication origin of cultivated tea plants, most likely from ancient Bashu or Yunnan. However, studies on genetic structure reveal that multiple centers occur in the domestication origin of cultivated tea plants. For example, cultivated Camellia sinensis (L.) O. Kuntze, including some varieties, may have multiple domestication events. According to research from historical text, the cultivation center of tea plants migrated from west to east and then to south, which is supported by changes in genetic diversity. However, the first cultivated tea plant might have arisen in the most eastern region of the Yangtze River Basin based on a recent archaeological finding. We speculate that during the spread of tea knowledge, cultivated varieties introgression occurred from wild relatives to cultivars, or new cultivated tea plants were directly domesticated from local wild tea plants, leading to the genetic complexity and the language consistency of cultivated tea plants. More evidence is needed to confirm the ancestral types, origin sites and time, and domestication processes of cultivated tea plants, and the integration anaylysis of multiple disciplines such as tea culture, population genetics, phylogeography, anthropology, climate change, and archaeology should be more encouraged.