GIBBERELLIC-ACID CAUSES EARLIER FLOWERING AND SYNCHRONIZES FRUIT RIPENING OF COFFEE

The effect of 100 mgl-1 gibberellic acid (GA3) on flowering and fruit ripening synchrony, fruit set, fruit fresh weight, and vegetative growth were studied for different size classes of coffee (Coffea arabica L. cv. Guatemalan) flower buds. Flower buds that were > 4 mm, but not developed to the candle stage at the time of GA3 treatment, reached anthesis 20 days earlier than the controls, and their development was independent of precipitation, unlike the controls. Fruit from buds that were treated with GA3 at the candle stage showed earlier and more synchronous ripening than the control, although no differences in flowering were found during anthesis. Buds that were smaller than 4 mm at the time of treatment did not respond to GA3 applications. Treatment with GA3 did not affect fruit set, fresh weight of fruits, or vegetative shoot growth. © 1990 Kluwer Academic Publishers.