Promotion of Fruit Enlargement of 'Whangkeumbae' Asian Pear Fruits by Gibberellins

摘要

Fruit of 'Whangkeumbae' Asian pear (Pyrus pyrifolia Nakai) exhibited a single sigmoid growth curve by showing slow volume increase until 90 days after full bloom (DAFB), rapid increase from 90 to 120 DAFB, and then slow increase again until the harvest time. The fruits treated with gibberellic acid (GA) paste at 35 DAFB exhibited considerable increases in their volume during the whole growing period. However, the fruits treated with GA+A-benzyladenine (BA) spray failed to show such significant volumeincreases until 120 DAFB as compared to the untreated fruits. GA had little effect in fruit shape index (length/diameter ratio). During the early growing stage, 'Whangkeumbae' pear fruits showed fruit shape index higher than 1.0, but showed index of lower than 1.0 at later stages. GA pasting was highly effective for persistent fruit weight increase up to the final harvest, but GA +BA spray treatments were only partially effective, depending upon the applying times and concentrations. All the GA+BA sprays had little effect on the changes of fruit elongation and enlargement pattern during the earlier stages. Total soluble solids contents and titratable acidity in fruit juice were not significantly influenced by GA treatments. GA treatments also influenced on the fruit stalk development. While GA paste resulted in uniform swelling of fruit stalk, GA+BA spray caused uneven swelling in fruit stalk which might be associated with the inconsistent effectiveness of spray treatments.