Abstract: 【Objective】Effects of growth age on flower bud differentiation and quality of cut Chrysanthemum cv. ‘Jinba’ (Dendranthema×grandiflorum Ramat.) were studied.【Method】In order to study the effects of growth age on flower bud differentiation and quality, plants of different growth ages were obtained by the way of cutting and planting at different time, and all plants started short-day treatment at the same time to induce flower bud differentiation.【Result】The results showed that, growth age had great effects on flower bud initiation of cut Chrysanthemum, the younger growth age was, the later the flower bud initiation. For growth age of 0 day treatment, 18 days was essential from flower bud induction to bud initiation, which distinctly longer than 4 days which was the shortest response time to induction. Growth age had effects on time required of ‘Jinba’ from flower bud induction to bud initiation (32-38 days). The younger growth age of the ‘Jinba’ was, the longer time required from flower bud initiation to finished differentiation, and the later of bloom time. Growth age also had great effects on quality of cut chrysanthemum, the younger growth age was, the poorer quality of flower.【Conclusion】The younger growth age of ‘Jinba’ was, the longer time required from induction to flower bud initiation, the longer time required from flower bud initiation to finish differentiation, and the later of bloom time. 4 days was the shortest time of responding to induction, and 21 days was the growth age of arriving mature floral competence state of ‘Jinba’. To obtain good quality cutting flower according to the standard for export, growth age must arrive 28 days when begin flower bud induction.

Key words: Chrysanthemum, Grow age, Flower bud differentiation, quality of cut flower