Regulation of flowering in Aquilegia

Aquilegia x hybrida Sims 'Purple' and 'Dove' initiated flower buds 5 months after seeding without being exposed to low temperatures. Four experiments were conducted to test the effects of gibberellic acid (GA3), long photoperiod, long photoperiod with a high level of irradiance, and cold treatments on forcing of the two cultivars. Time from treatment to anthesis was reduced by 9 days for defoliated 'Purple' plants treated with 250 mg GA3/liter, and by 14 days for defoliated 'Dove' plants treated with 125 mg GA3/liter. Defoliated 'Purple' or 'Dove' plants treated with 18 hours of supplemental high pressure sodium (HPS) light at 250 micromole-m-1-S-2 (18 SH) reached anthesis 14 or 10 days earlier, respectively, after treatment than plants grown under natural daylight (Nat). The 18 SH treatment increased the number of flowers from eight and nine per plant on Nat plants for defoliated 'Dove' and 'Purple', respectively, to 16 flowers on 18 SH plants. Cold treatments at 4 +/- 1C did not shorten the interval between treatment and anthesis, but decreased the number of flowers per plant in both cultivars. Chemical name used: gibberellic acid (GA3)