2. Chinese yam, as a kind of Chinese herbal medicine with dual functions of medicine and food, has different origin characteristics due to the influence of regional climate characteristics, geological characteristics, growth habits and other factors. Yam is mainly produced in Aibo, Wuzhi, wen county and other places in Henan, and also cultivated in Shaanxi, Shandong, Hebei, Zhejiang, Hunan, Sichuan, Yunnan, Guizhou and Guangxi. Guangxi, Hebei, Henan and other major producing areas constitute the main planting areas of yam.