Use of gibberellins on ‘Patterson’ apricot (Prunus armeniaca) to reduce hand thinning and improve fruit size and firmness: Effects over three seasons

Abstract

Summary‘Patterson’ apricot (Prunus armeniaca) trees were sprayed with an air blast sprayer over three seasons (1992, 1993, and 1994) in three application timings prior to and after harvest, with single sprays of 50, 75, and 100 mg l−1 gibberellic acid (predominantly gibberellin A3 (GA3); Release LC, Abbott Laboratories, North Chicago, IL). A single pre-harvest timing (first week of June) and two concentrations (50 and 100 mg l−1) were consistent across all three years and the effects of these treatments on flowering and fruit development were compared. In all years following treatment with 100 mg l−1 GA, flower numbers per cm of limb length and circumference were significantly reduced. Fruit set was not affected by GA sprays. June 1993 GA sprays of 50 and 100 mg T1 resulted in total yields per tree in 1994 that were equivalent to hand-thinned control trees with 36% and 46% reduction in hand thinning, respectively. Individual fruit weights of fruits treated with 100 mg l−1 GA sprays were equal to those of ...