Highland barley, English name, is a cereal crop of Gramineae barley. Because the inner and outer glumes are separated and the seeds are bare, it is also called naked barley, yuan wheat and rice wheat. Highland barley has a long history of cultivation in Qinghai-Tibet Plateau, which has been 3500 years. Its varieties are divided into white highland barley, black highland barley and dark green highland barley.

Highland barley is mainly distributed in Tibet, Qinghai, Ganzi, Aba Prefecture of Sichuan, Diqing of Yunnan, Gannan of Gansu and other places in the Qinghai-Tibet alpine region at an altitude of 4200-4500 meters.

Highland barley has been planted in Qinghai-Tibet Plateau for about 4 million years. The long planting history has cultivated highland barley to adapt to the cold natural environment. For example, the root system of highland barley belongs to fibrous root system, which consists of primary roots and secondary roots. Primary roots grow from the embryo of seeds, usually with 5-6 primary roots, and most of them have 7-8. Primary roots play an important role in absorbing and supplying nutrients to seedlings from seed germination to root group formation at seedling stage. The number of primary roots is closely related to seed size and seed vigor. The seeds are big and full, with strong vitality and many primary roots, Miao Zhuang. On the contrary, seeds with thin seeds and small 1000-grain weight are not full, with few primary roots and weak seedlings. Under good soil conditions, the depth of primary roots of autumn-sown highland barley can reach 60 ~ 70 cm during overwintering, and some varieties can reach about 200cm in the later growth stage.