Chinese yam belongs to Dioscorea species. The breed of our company is Bar Yam Rhizome with average length 60--80cm, diameter 4 --5 cm,individual weight 1.5-3kg, individual max weight 4kg, white skin, nutritious and good quality. Ministry of Health P.R.China also approves common Yam Rhizome as both food and medicine. It contains choline, glycoprotein, choline-chloride, polyphenol oxidase, hetero polysaccharide, amino acid, vitamin and copper, zinc, iron and so on which are necessary for human health. Yam has the functions of lowering blood pressure and resisting cancer.