Horticultural factors regulating effectiveness of GA3 inhibiting flowering in peaches and nectarines (Prunus persica L. Batsch)

The application of gibberellic acid during the flower bud induction period significantly reduced flowering in peaches and nectarines. The magnitude of the response significantly depended on the total amount of active material applied per tree. Results show, for cultivars tested, a higher sensitivity of peach to GA3 in comparison with nectarine. Concentrations of 0.5 or 1.0 g tree−1 of gibberellic acid reduce flowering by about 50% in both, peaches and nectarines, respectively, and it gives rise to a reduction of costs of hand thinning by 50%, approximately, without affecting the yield. Fruit colour advanced, total soluble solids concentration increased and fruit firmness increased as a consequence of treatments. The effect was higher in the basal part of the shoots and reduced from the base to the apical part.