山药种质与道地产区的沿革与变迁

山药始载于《神农本草经》,自古以来均来源于薯蓣科植物薯蓣.唐朝以前,山药主要来源于薯蓣的野生品,宋代开始有栽培,但医家认为野生者质量优良,明清以后主要来源于栽培品.随种质的变化,山药在明清以后以河南怀庆的栽培薯蓣为道地.在河南怀庆地区,山药长期的栽培出现品种分化.历代中医药学家均认为山药应以“色白、根细、坚实”为佳.这与现今怀山药的农家栽培品种之一的铁棍山药品质相一致.因此,道地药材“怀山药”不是泛指古怀庆地区（今河南焦作市、济源市和新乡市等地）种植的所有山药农家品种.怀山药的道地药材种质应该是符合中医药学家长期认可的特定农家品种——铁棍山药.

Evolution and change of the species quality and authentic producing areas of Dioscorea opposita Thunb

Yam was first recorded in Shen nong Ben cao Jing （ Shennong＇ s Classic ofMateria Medi ca） which was basically came from Dioscorea opposita since ancient time. Before the Tang dynasty, it basically came from the wild species of Dioscorea opposita. In the Song Dynasty, D. opposita began to be cuhivated, but Chinese medical practitioners claimed that the wild species was better than the cultivated one. After the Ming and Qing Dynasties, yam was mostly from cultivated resources. As the species quality changed, the authentic producing area of Dioscorea opposite was recognized to be in Huaiqing, Henan province, since the Ming and Qing Dynasties. Through long-term cultivation, the species produced in Huaiqing began to differentiate and the Chinese medicinal experts of successive ages considered that the product quality of yam is excellent and if it revealed the features of＂white, thin, solid quality＂, that was the best, and this is consistent with the species called＂ Tiegun （iron stick）＂ Diascorea opposita cultivated by Huaiqing farmers. Hence, the title of＂ Huaiqing yam＂ is not the general title for the authentic species of yam produced in the Huaiqing region （now Jiaozuo city, Jiyuan city, and Xinxiang city of Henan Province）, but strictly refers to that species commonly and long recognized by TCM specialists as the Tiegun Dioscorea opposita.