Ethylene + GA₃ sprays for delaying flower bud initiation in chrysanthemum (Dendranthema grandiflora Tzvelv.) stock plants

Our objective was to determine whether repeated applications of 2- chloroethylphosponic acid (ethephon) + gibberellic acid (GA₃) to stock chrysanthemum plants that are day-neutral for flower bud initiation would increase the number of quality cuttings. Across five cultivars, there were no significant differences between controls and plants receiving 250 ppm ethephon in the total number of cuttings per plant. The percentage of cuttings with crown buds was greater for cuttings from controls than for ethephon-treated plants. Applying 500 ppm ethephon significantly reduced the number of cuttings. We conclude that chrysanthemum clones day-neutral for flower bud initiation and development with low long-day leaf number could be selected to form a 4 to 5 week production group.