A micropropagation system for 'Yamatoimo' Chinese yam (Dioscorea opposita Thunb.) was developed. Immature leaves collected from virus-free plants growing in the greenhouse were cultured on MS medium supplemented with 8.9 laM benzyladenine (BA), 3% (w/v) sucrose and 0.8% (w/v) agar. After 2-3 months, multiple buds that were clumps of green-colored bulbous structures including adventitious buds and meristematic regions 2-3 mm in diameter were formed on immature leaves. Transplanting clusters of multiple buds to fresh MS medium supplemented with 0.11 laM a-naphthaleneacetic acid (NAA), 0.89 p.M BA and 6% (w/v) sucrose was effective for inducing shoot formation, leading to plantlet formation. After 6 months, a large number of microtubers, about 3-7 mm diameter, were obtained.
Summary
Micropropagatedclonal plants were derived through somatic embryogenesis (from young spears in adult plants or nodal segments of seedlings) of asparagus (Asparagus officinalis L. cv 'Hiroshima Green' (2n = 30), 'Mary Washington 500W'). They were cultivated by "mother stalk method" in the field of HPARC for 4 years (1990)(1991)(1992)(1993)(1994) and their growth characteristics and yields were compared with those of 4 cultivars propagated by seeds or crown division. In micropropagated plants, the flower types were identical with the parent and flowering occurred simultaneously. The quality of young spears, such as head shape and colors resembled the parent. Spear size and shoot diameter of mother stalks, yield and other growth characteristics of them were more uniform than those of seed propagated cultivars. In the triploid clone of 'Hiroshima Green', the high brix content of spears and resistance to disease were maintained through propagation by somatic embryogenesis. Thus, micropropagation of superior asparagus clones through somatic embryogenesis is an economical means of producing uniform spears of high quality and yield.
IntroductionIn asparagus (Asparagus officinalis L.), characteristics of spears such as head shape and color are very important for the strict Japanese agricultural market. Farmers wish to cultivate a superior, male cultivars with high yield and high profitability.Therefore, clonal propagation by lateral bud culture of superior male plants, has been conducted (Yang et al., 1973) ; but, this technique could not be put into practice at low cost because of poor rooting in vitro.For these reasons, the micropropagation of superior male plants of asparagus through somatic embryogenesis has been researched (Harada, 1977 ; Kohmura and Imoto, 1994 ; Kohmura et al., 1990a Kohmura et al., , b, 1991 Kohmura et al., , 1994 Saito et al., 1991 Center (HPARC), were the source of young spears.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.