This research evaluated the effects of auxins and gibberellin, combined and applied preharvest in the development of the orange cv. Hamlin tree fruit and natural fall percentage. The orange trees (Citrus sinensis Osbeck) cv. Hamlin were grafted in lemon 'Cravo' (Citrus limonia Osbeck). The treatments used were made in 3 applications with intervals of 45 days: GA3 + NAA at 12.5mg.L-1; GA3 + NAA at 25.0mg.L-1; GA3 + 2,4-D at 12.5mg.L-1; GA3 + 2,4-D at 25.0mg.L-1; NAA + 2,4-D at 12,5mg.L-1; NAA + 2,4-D at 25.0mg.L-1 and control (water). The parameters evaluateds were: natural fruit fall percentage, fresh fruit weight (g) and juice content (%). The results showed that the treatment with GA3 + 2,4-D 25.0mg.L-1 provided a reduction in the natural fruit fall percentage compared to the control, thus extending the harvest time. The treatments didn't increase the fruit weight and juice content.
Citrus sinensis; bioregulators; fruit drop
