Abstract
Shoot tip culture was applied to 139 Japanese persimmon cultivars and four Diospyros species, D. japonica, D. lotus, D. oleifera and D. virginiana, and shoot growth in shoot tip culture was investigated in relation to each cultivar′s characteristics, fruit type, tree vigor and earliness of sprouting time. Shoot tips, 1mm in diameter, were excised from dormant axillary buds and cultured in Murashige and Skoog′s medium containing half-strength nitrogen plus 10-5M zeatin, 3 % sucrose and 0.7% agar. Principal component analysis was performed using four shoot growth characters (shoot length, leaf number, leaf length and callus diameter) after six-week culture. The first principal component scores indicated a size factor, because the shoot, leaf and callus grew better with increases in the score. Eighty-two cultivars and three species, D. lotus, D. japonica and D. virginiana (female plant), had -1.0 or more of the first principal component scores and maintained good shoot growth through three subcultures. Ten cultivars and D. oleifera had -1.0 or more of the score; however, these were not established because of an inadequency of subculture medium. Established explants were obtained from 102 cultivars and three species. The cultivars of three fruit types, pollination constant and non-astringent (PCNA), pollination variant and non-astringent (PVNA) and pollination variant and astringent (PVA), had less shoot elongation. Shoot growth in shoot tip culture had no relation to tree vigor and earliness of sprouting time.
