New evidence for the exploitation of the Triticeae tribe at approximately 4,000 cal. BP in the Gansu-Qinghai area of Northwest China

The Triticeae tribe, especially wheat (Triticum aestivum) and barley (Hordeum vulgare), has played an important role in human civilization and the development of agriculture in Eurasia. However, their dispersal route in China has been disputed due to a lack of sufficient evidence for the exploitation of wheat and barley. In this study, starch grains were retrieved from artifacts, ash pits, ancient house-floor sediment, and ancient human dental calculus from five sites dated to approximately 5000-4000 years before present (cal. BP) in the Gansu-Qinghai area of Northwest China. Using modern starch grain references, nine major types of starch grains were identified. The proportions of Triticeae tribe ranged from 14.7% to 60.6% of the total, indicating that this tribe was a component of the diet. In conjunction with existing archaeological evidence from previous studies, it is proposed that wheat and barley were likely used by ancient humans (approximately 4000 cal. BP) in a large area in Gansu and eastern Qinghai in Northwest China. The results provide new evidence for the exploitation of the Triticeae tribe at this time in this region of China and a valuable dataset for discussing the dispersal of wheat and barley in China during the late prehistoric period.