The effect of GA sub 3 /sub and ethephon on synchronization of coffee ( Coffea arabica L.) flowering and berry ripening.

摘要

Coffee (Coffea Arabica L.) is a short day plant that flowers irregularly in many subtropical and tropical production areas. This results in a prolonged hand harvesting period which is laborious and tiresome. Synchronising or scheduling the ripening of coffee berries can help in reducing harvesting costs through reduction of the number of cycles and trips. This study was carried out to evaluate the effect of gibberellic acid (GA₃) and ethephon on stimulation of early and uniform flowering and berry ripening. In this experiment coffee 'Catimor F6' was sprayed to run off with GA₃ and a GA₃ + ethephon combination. A single application during the end of August of GA₃ at 50, 75 or 100 ppm stimulated early cumulative percent number of flowers. The highest concentration of application had significantly the highest flowering whilst the plants sprayed with distilled water had the least flowering percentage. Pre-flowering GA₃ application advanced coffee berry ripening whereas with ethephon, a bi-weekly application at 360 and 720 ppm advanced coffee berry ripening. The interaction of GA₃ and ethephon was not significant compared with controls. GA₃ may therefore be used at 100 ppm to synchronise coffee flowering whilst ethephon at 360 ppm assists in advancing coffee berry ripening.