Abstract
The effects of the sampling season of explants and the growth stage of mother plants on the regenerative capacity and growth characteristics of regenerants in the shoot apex culture of chrysanthemums were investigated. Shoot apices from two edible cultivars of the autumn-flowering type, 'Abokyu' and 'Enmeiraku', were cultured for three months on a modified Shizuoka Agricultural Experiment Station medium supplemented with NAA (1 mg·liter-1). Every two or three weeks from April to September 1991, shoot apices were collected from the terminal and axillary buds of non-pinching plants and cultured. The regeneration rate varied with the cultivars used and the sampling season. When the terminal buds of primary lateral shoots that developed after pinching were cultured, high percentages of regenerants were obtained from vigorously growing mother plants in both cultivars. Even in the early reproductive growth phase (involucre- formation stage), the explants maintained some regenerative capacity. The growth characteristics of regenerants differed with the cultivars used and the growth stages of the mother plants.
