INFLUENCE OF GIBBERELLIC-ACID, 2,4-DICHLOROPHENOXYACETIC ACID AND 6-BENZYLAMINOPURINE ON FRUIT-SET OF CLEMENTINE MANDARIN

A study was made of the influences of gibberellic acid (GA3), 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BA) on leafy inflorescences - and of GA3 on entire trees - on fruit-set and fruit-weight of Clementine mandarin (Citrus reticulata Blanco). Applying GA3 to inflorescences of cultivar 'Fino' (seedless Clementine) between anthesis and 14 days after anthesis increased fruit-set and weight of the fruits at harvest. No significant differences in effects were observed between the application to leaves, to flowers or to leaves and flowers simultaneously. GA3 induced the development of parthenocarpic fruits of cultivar 'Monreal' (Clementine with seeds) and a fruit-set similar to that obtained with self-pollination. Spraying GA3 (5-200 mg/l) to entire trees of cultivar 'Fino' increased the number of fruits per tree and decreased the average weight of the fruits. However, the commercial yield per tree increased with the concentration of GA3 employed. The application of 2,4-D and BA to inflorescences of cultivar 'Fino' increased fruit-setting and weight of the fruits, although not as efficiently as GA3, both the concentration and the time of application being more critical. © 1979.