Cultivation of Grafted Vegetables I. Current Status, Grafting Methods, and Benefits

Growing grafted vegetables was first launched in Japan and Korea in the late 1920s by grafting watermelons to gourd rootstock (Ashita, 1927; Yamakawa, 1983). After the first trial, the cultivated area of grafted vegetables, as well as the kinds of vegetables being grafted, has been consistently increased. At present, most of the watermelons [Citrullus lanatus (Thunb.) Matsum. & Nakai], Oriental melons (Cucumis melo var. makuwa Makino), greenhouse cucumbers (Cucumis sativus L.), and several solanaceous crops in Korea and Japan are grafted before being transplanted to the field or greenhouse (Ito, 1992; Kurata, 1992; Lee,. 1989; Ryu et al., 1973). The purpose of grafting also has been greatly expanded, from reducing infection by soilborne diseases caused by pathogens such as Fusarium oxysporum Schlect. (Choi et al., 1980; Hirata, 1975; Itagi, 1992; Marukawa and Takatsu, 1969; Ryu et al., 1973; Yamakawa, 1983) to increasing low-temperature (Marukawa and Takatsu, 1969; Masuda and Gomi, 1984; Masuda et al., 1981; Tachibana, 1982, 1988, 1989) and salt and wet-soil tolerance (Park, 1987), enhancing water and nutrient uptake (Gomi and Masuda, 1981; Heo, 1991; Jang et al., 1992; Kato and Lou, 1989; Kim and Lee, 1989; Marukawa and Takatsu, 1969; Masuda and Gomi, 1982), and increasing plant vigor and extending the duration of economical harvest time (Itagi, 1992; Ito, 1992; Jeong, 1986; Kim and Lee, 1989), among other purposes (Ali et al., 1991; Chailakhyan and Khrianin, 1987; Dole and Wilkins, 1991; Frankel, 1970; M1atsuzoe et al., 1991b; Mochizuchi and Yamakawa, 1979; Ohta and Chuong, 1975; Phatak and Wittwer, 1965). Growing grafted vegetables, compared to growing grafted trees, is seldom practiced in the United States or in other western countries where land use is not intensive, i.e., proper crop rotation is being practiced. However, it is highly popular in Korea, Japan, and some Asian and European countries where land use is very intensive and the farming area is small (Hartmann and Kester, 1975). The purpose of this article is to briefly describe the cultivation of grafted vegetables and to summarize relevant information on grafting and cultivating grafted seedlings.