As a Chinese herbal medicine with the same origin of medicine and food, Dioscorea opposita 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 planting areas of yam.

Guangxi producing area: mainly produced in Guiping City and Nanning City in the southeast of Guangxi. The total output in recent years is above 654.38+10,000 tons. Products are mainly sold to South China, East China, Southwest China and other provinces and cities. The main digestion 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. Dioscorea opposita, also known as sweet potato and ginseng, is the highest in China. Many large domestic medicinal materials markets and pharmaceutical manufacturers have purchased or established designated planting bases in Jiaodian.

In the investigation, it is found that Dioscorea opposita 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 call it the top grade, and feudal dynasties collect it as a tribute. Foreign medical circles call it "Chinese medicine". Domestic experts have proved that the content of total amino acids, essential amino acids and soluble total sugar in Dioscorea opposita, especially in wen county, is higher than that in other regions. The high quality of yam was further confirmed.