Abstract: China is the distribution center of walnuts (Juglans). The most important species of this genus native to China is Juglans regia L., the persian walnut, grown throughout 18 provinces of China. It has been suggested that cultural seedling population of Juglans regia L. may be divided into 4 geoecotypes (Xin Jiang, Northern Mountain, Qin and Ba Mountain, Xi Zang Highland) The origin, geographical distribution, ecological characters and main seedling groups of 4 types are discussed. The precocious seedling group of Xin Jiang walnut is valuable in genetic improvement of potential productivity. According to the preliminary result of progeny test, it was considered that precocity is a dominating character controlled by at least 2 genes. The Northern Mountain Walnut seems more resistive to some diseases (Xanthomonas campestris pv. juglandis,). The hybrid seedlings of J. regia L. × J. mandshurica are evaluated as walnut rootstock and rootability of cuttings collected from some seedlings incressed.