Early evidence of naked barley in western Tibet: cereal cultivation at extreme altitude along the upper Sutlej River, c. 3500 BP

Despite being almost 4000m above sea level, cereal crops have been grown in the Ngari Prefecture on the Tibetan Plateau for thousands of years. Where and when domestic crop species adapted to high-altitude growing conditions is a matter of ongoing debate. Here, the authors present a new radiocarbon date from the Gepa serul cemetery, providing the earliest evidence of naked six-rowed barley in Tibet (c. 3500 BP). Evaluating the available evidence for barley cultivation and interregional connections in central Asia at this time, two hypotheses are considered—a generational advance with farmers migrating up river valleys or rapid, long-distance trade through mountain corridors.