Effect of BA and GA on Fruit Drop of Citrus1

Abstract

Abstract Application of gibberellic acid (GA) and 6-benzylamino purine (BA) on whole trees of ‘Washington Navel’ orange (Citrus sinensis [L.] Osbeck) during anthesis caused flower thinning and increased leaf size of the spring growth flush. BA sprayed on whole trees at the young fruit stage induced premature initiation of the summer growth flush and resulted in serious fruit drop. Application of B A on the surface of individual young fruit of ‘Washington Navel’ orange and ‘Satsuma’ mandarin (C. reticulata Blanco) prevented postbloom drop, but not June drop. Neither GA nor BA had any influence on fruit-set of “Jeng” orange.