ISHS Acta Horticulturae 394: Plant Bioregulators in Horticulture
EFFECT OF GIBBERELLIC ACID (GA3) ON SEEDSTALK DEVELOPMENT AND FLOWERING IN CARROT (DAUCUS CAROTA L. VAR. SATIVA DC) |
| Authors: | P.M.S. Bandara, K.K. Tanino |
| Keywords: | Carrot flowering, Stem elongation, GA3, Photoperiod |
| Abstract:
Carrot is a biennial which flowers naturally following root vernalization. Many plant species are induced to flower under non-inductive conditions by gibberellin (GA) applications. Nantes type 'Coreless' carrots were grown in a greenhouse from 12-week-old roots under natural light conditions in winter. Uniform roots were selected, cleaned and planted. Plants were foliar sprayed with 0 (water), 50, 100 and 200 mg/L GA3, three weeks after replanting. On average, 84% of carrots were induced to flower. Half of the plants were treated again after one week. The second GA3 treatment advanced flowering by at least 2 weeks but only increased flowering to 88%. Initial root weights and leaf numbers were not related to dates of first flower bud emergence. In a second study, carrot plants were grown from 8-week-old roots. Following GA3 foliar treatments at 100 or 200 mg/L, over 70% of carrots growing under 16h days flowered. No flowering was observed on plants under 8h days or in controls. These results suggest a relationship between the ability of GA3 to induce flowering in physiological immature carrots, and daylength. | |
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