山药（Ｄｉｏｓｃｏｒｅａｏｐｐｏｓｉｔａ）又名薯蓣,为薯蓣科植物。我国山药资源丰富,主产河南,在黄河以南各省区均有分布。山药的块根和珠芽（中药称零余子,俗称山药蛋）均可药用,具有健脾、固精、补肺、益肾等功效。但由于山药长期进行营养繁殖,导致其品质退化,产量?.. Yam (Dioscoreaopposita), also known as Dioscorea, Dioscoreaceae. Our country yam is rich in resources, the main producing Henan, south of the Yellow River provinces and regions are distributed. Yam tubers and pearl buds (Chinese medicine more than a child, commonly known as yam eggs) can be medicinal, with spleen, solid essence, lungs, kidney and other effects. However, due to long-term vegetative propagation of yam, the quality of the yam is degraded and the yield is too high.