Rate and time of GA4/7 treatment affect vegetative growth and flowering in a genetic line of Aquilegia x hybrida Sims

Aquilegia 'Rose-White' flowered from seed in about five months without vernalization. GA(4/7) treatment increased stem height, induced earlier flowering, and increased the number of flowers/ plant. Each of these responses, however, was dependent upon both rate (10, 25, or 50 ppm) and timing of application (4-, 8-, or 12-leaf stage). Treatment at the 4-leaf stage resulted in earlier flowering at all rates, had no effect on stem height, but reduced the number of flowers/plant and total leaf area. Treatment at the 8-leaf stage induced earlier flowering at all rates, and increased both the number of flowers/plant and plant height (50 ppm), but had no effect on total leaf area. Treatment at the 12-leaf stage had no effect on time of flowering, but increased the number of flowers/plant, plant height (50 ppm) and total leaf area, at all rates. A rate of 50 ppm at the 8-leaf stage is the optimal treatment resulting in earlier flowering with increased plant height and number of flowers/plant. (C) 2000 Elsevier Science B.V. All rights reserved.