• Production of seedless fruit: cucumbers and tomatoes.
• Promote fruit set.
• Prevent fruit fall, e.g. apples.
• Weed killers (herbicides) applied at high concentration promote uncoordinated growth and finally death, particularly in broad-leaved weeds.
• To promote root growth in stem cuttings synthetic auxins such as naphthalene acetic acid (NAA) and indole butyric acid (IBA)are used.
• Induction of flowering in pineapple (actually caused by the auxin-induced production of ethylene). NAA is generally employed as the auxin.

• Enhanced production of seedless grapes. Bigger, more uniform bunches with larger fruit are produced. Among other effects, the gibberellin causes lengthening of the peduncle (stalk) attaching each grape to the cluster, thus permitting larger grapes to form. Virtually all the grapes that go to market are now treated with gibberellin.
• Treatment of oranges to prevent rind senescence, to permit longer storage on the tree,thus extending the marketing period.
• Enhancement of flower bud formation and improvement of fruit quality in cherries.
• Improvement of fruit setting in apples and pears, particularly under weather conditions that are not ideal for setting fruit.
• To substitute for a chilling requirement in instances such as:
  1. flower induction for seed production (radish).
  2. increased elongation (celery, rhubarb).
  3. earlier flower production (artichokes).
• The production of hybrid cucumber seed. Most high-producing cucumbers are F1 hybrids. GA sprays induce the production of male flowers on cucumber plants that normally produce only female flowers. The seed from neighbouring all-female plants of a different strain is then exclusively hybrid.
• Increased malt production. The addition of GA to germinating barley during beer production enhances a-amylase production so that more malt is produced more quickly. As the malt is the raw material for fermentation, a greater production of beer is made possible by this technique.
• Increased sugarcane yield: GA promotes the elongation of sugarcane stalks with no change in the sugar concentration, so that the net yield of sugar is increased.

• Ethylene gas is used commercially for ripening fruit, particularly bananas. There are  also synthetic compounds, such as ethephon (chloro-ethanephosphonic acid) that can be sprayed onto plants in solution; once inside the tissues ethephon breaks down to liberate ethylene.  Ethephon is used to promote ripening on the tree, leaf abscission in ornamentals, growth control in seedlings and flowering in pineapples.
• Enhancement of uniform fruit ripening and colouration. This has been shown to be of particular value in field tomatoes picked at a single time by machine.
• Acceleration of fruit abscission for mechanical harvesting. This provides a potential area of use in a wide variety of fruits such as grapes, cherries, and citrus.
• Promotion of female flower production in cucurbits (cucumber, squash, melon) so as to increase the number of fruits produced per plant.
• Promotion of flower initiation and controlled ripening in pineapples.

• The treatment of holly for festive decorations enables its harvest many weeks prior to use.
• Post­harvest sprays or dips are now available to prolong the storage life of green vegetables such as asparagus, broccoli, and celery.
• Used to promote shoot production in tissue culture.

Abscisic Acid

• Used to increase the colour of red table grapes.