Methods for the Selection of Low-Temperature Tolerant Mutants of Chrysanthemum morifolium Ramat. by Using Irradiated Cell Suspension Cultures

In order to improve mutant selection procedures, 5000 plantlets were regenerated in three different harvests (flush A, B and C) from X-irradiated (15 and 20 Gy) and non-irradiated cell suspensions of Chrysanthemum morifolium cv. ‘Parliament’. After screening under suboptimal energy condition (12°C greenhouse temperature, winter low-light), a total of 95 early flowering plants were selected. These plants flowered at least as early as a low-temperature tolerant (LTT) mutant E₂, used as a reference. The percentage of early flowering variants was highest among plants obtained from calli, X-irradiated with 15 Gy and regenerating relatively late (flush B). It appeared that the applied selection method (e.q. harvest) had a large impact on the number of early plants obtained.