Effects of Gibberellin A3 on Fruit Shape and Subsequent Seed Dormancy of Apple1

Abstract

Considerable work has been done on the effects of gibberellins on parthenocarpic set and growth of apple fruits. Bukovac (1) has reviewed the literature in this field and has presented further evidence that seedless fruits induced to set by gibberellins A3 and A4 (GA3 and GA4) are distinctly more elongate than normal seeded fruits. More recently Dennis and Edgerton (2) found that GA made seeded fruits of one variety of apple more elongate than controls, although shape was not altered on several other varieties. Westwood and Blaney (6) reported several factors other than applied GA that also affected apple shape. Among these were crop density (i.e. leaf: fruit ratio), varietal strain, cluster position, and rootstock. To further study the effect of GA on fruit shape without confounding it with seedlessness, a test was set up using seeded fruits in which crop density and rootstock were held constant.

Comparative Effects of Gibberellin and Parthenocarpy on the Shape and Maturation of Peaches1

“…These results indicate that the advanced maturity and elongated shape previously noted in parthenocarpic peaches (2,3,4) should not be ascribed to the absence of developing ovules, but rather to the applied GA. The increase in length-diameter ratio of nonparthenocarpic peaches as a result of GA treatment parallels a similar response in apples (6,7).…”

“…Gibberellin sprays have been used successfully in Europe to increase fruit-set of pears when the developing ovules were killed by frosts or when pollinating conditions were unsatisfactory (6,8,9,11,12,13). Tests of gibberellin on 'Bartlett' in California indicated limited commercial benefit, coupled with severe inhibition of flowering (4).…”

Immediate and Residual Effects of Succinic Acid, 2,2-Dimethyl Hydrazide (Alar) on Young ‘Delicious’ Apple Trees1

“…Sullivan (18) found that the temperature for the first few days after the flowers opened influenced the ultimate shape of the apples. Westwood and Bjornstad (21) reported that gibberellin applications before bloom produced elongated apples. Fisher and Looney (7) found no effect on fruit shape from postbloom Alar sprays, and most reports do not mention any effects of Alar on fruit shape.…”

Identification of Key Genes of Fruit Shape Variation in Jujube with Integrating Elliptic Fourier Descriptors and Transcriptome

“…Fluctuating endogenous hormone levels in the fruit during different growth stages impact fruit shape. The role of hormones in fruit morphology varies, with gibberellins promoting cell elongation and fruit lengthening [16,18]. These phytohormones act both individually and synergistically to regulate plant fruit growth and development.…”