Dioscorea opposita, as a Chinese herbal medicine for both 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 Wuzhi and wen county, Henan Province, and also cultivated in Shanxi, Shaanxi, Shandong, Hebei, Zhejiang, Hunan, Sichuan, Yunnan, Guizhou and Guangxi. At present, Guangxi, Hebei, Henan and other major producing areas constitute the main Chinese yam cultivation areas.

Guangxi producing areas: mainly produced in Guiping City and Nanning City in southeast Guangxi. In recent years, the total annual output is above 1 10,000 tons. The products are mainly sold to provinces and cities in South China, East China and Southwest China. The main digestive channels are medicine, vegetable sales and export.

Hebei producing areas: Lixian, Rongcheng and Anping. The main cultivated varieties are Fengshan medicine (flower seed yam and water yam). The main purpose is to eat.

Henan producing area: mainly produced in Jiaozuo, Henan and other places. Huai yam, also known as white yam and Huai Shen, is the highest in China. Many large medicinal materials markets and pharmaceutical manufacturers in China have purchased or established designated planting bases in Jiaodian.

It is found in the investigation that Huai Yam is the most famous yam with a long history, which is well-known at home and abroad and has the reputation of "Chinese medicine". Ancient and modern medical scientists called it top grade, feudal dynasties collected it as a tribute, and foreign medical circles called it "Chinese medicine" Domestic experts have proved that the content of total amino acids, the content of essential amino acids and the content of soluble total sugar in Dioscorea opposita, especially in wen county, are higher than those in other regions. Further confirm that high quality of Dioscorea opposita.