GIBBERELLIC ACID-INDUCED FRUIT-SET OF RABBITEYE BLUEBERRY FOLLOWING FREEZE AND PHYSICAL INJURY

In a series of experiments, gibberellic acid (GA(3)) was applied to ra bbiteye blueberries (Vaccinium ashei Reade) under field and greenhouse conditions to determine if fruit set could be improved following phys ical or freeze injury to flowers, In field experiments, physically dam aged flowers (i.e., corollas and styles removed, styles only removed, or ovaries lanced) of 'Climax' and 'Tifblue' treated with GA(3) (4% Pr oGib at 250 mg liter-l) set substantially more fruit than nontreated, damaged flowers, Under greenhouse conditions, GA(3) applied postfreeze to 'Tifblue' and 'Brightwell' resulted in increased fruit set compare d to unsprayed control plants of the same cultivars. Freeze-damaged pl ants had substantially reduced fruit set overall but to a much lesser extent for GA(3)-treated plants than for those not treated with GA(3): Individual fruit weight was reduced by GA(3) applications, as was ber ry seediness, Results from these greenhouse and field trials suggest t hat GA(3) can be used to salvage a blueberry crop following a moderate freeze during bloom.