A New Thornless Castor aralia Cultivar, “Cheongsong”

Abstract

Castor aralia (Kalopanax pictus (THUNB) Nakai.) is one of the important medicinal and edible species growing inNorth Eastern Asia - Korea, Japan, and China. The stems and roots have been used as an ingredient in folk medicines, while ter-minal buds and young leaves are in a great demand as an edible vegetable. However, because of its thorny stems and isolatedgrowth habit as an individual plant rather than as a population, they have not ben intensively cultivated. A new thornless cultivarof castor aralia was developed and selected in Cheongsong, Prov. of GyeongSangbuk-do during the period from 1994 to 1999 byKorea Forest Research Institute (KFRI). The new thornless cultivar heongsongis characterized by a thinner outer-bark and soft,wider leaves, and is particularly characterized by thornless stems (Fig. 1). The cultivar has a thinner outer-bark (8.84mm) whencompared with wild type (13.95mm). It also has a larger leaves than does thorned type. In summary, the new thornless cultivarheongsong is defined to have thinner bark and longer and wider leaves than do other thorned type trees (Table 1). It also showsexcelent survival rates when propagated by either grafting or root-cutting. Epicotyl grafting usually results in higher survival ratethan does veneer grafting. However, it is recommended that the grafting be done in late March if the highest survival rate is to beobtained (Fig. 2). Survival rate of root-cuting depends on both the type of soil and the position of scions. The artificial soil mix ofPKS2 : Perlite (1:1) in combination with the scions derived from upper part of rot results in as high as 98% survival(Table 2).However, analysis of some organic and inorganic substances shows that no significant diference exists between the new thornlesscultivar and thorned type trees (Table 3).