Effects of GA on ACC contents in cluster rachis,cellulase activity in berry skin tissues and berry splitting were investigated in 'Delaware' grapes GA was applied at 1OO ppm, 10 days before harvest and removed the plastic film covering the roof on the next day. The precipitation was about 135mm in 8 days after the removal of plastic cover.
Berry splitting was significantly decreased by GA applicatlon without effect on berry enlargement and soluble solids contents in juice. Cellulase activity in berry skin decreased just after GA application,however ACC contents in cluster rachis did not differ between both treatments.