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Ethephon induction of pineapple flowering

Ethephon (2-chloroethylphosphonic acid) is an ethylene-releasing plant growth regulator used in commercial pineapple cultivation to synchronise flowering across a plantation. Pineapple is one of the few major crops that responds to exogenous ethylene by initiating reproductive growth, and ethephon application is now the standard practice for harvest synchronisation in plantation systems in Kerala, Tripura, West Bengal and the north-east.

Composition

  • Active ingredient: ethephon 39% SL (Bayer Ethrel) is the dominant Indian formulation
  • Release mechanism: at plant-tissue pH (~6-8) ethephon decomposes to release ethylene gas, phosphate and chloride
  • Regulatory class: plant growth regulator registered with CIB&RC

Mode of action

When the solution enters the leaf axil at the centre of the plant, the slightly alkaline environment of the meristem triggers slow release of ethylene. Ethylene initiates the transition from vegetative to reproductive growth, causing a synchronised inflorescence emergence across treated plants within four to six weeks.

Target use and dose

Pineapple plants are treated at the 30-40 leaf stage, approximately seven months after planting. The standard treatment is approximately 50 ml of a 25-200 ppm ethephon solution, often fortified with 2% urea and 0.04% calcium carbonate, poured into the heart (centre) of each plant in the evening. Flowering begins around 40 days after application and is essentially complete by day 70, enabling a near-uniform harvest about 5 months later.

Safety and regulatory status

Ethephon is registered for use on pineapple, mango latex flow, rubber latex stimulation and a few other crops under the Insecticides Act 1968. It is mildly irritant to skin and eyes and should be applied with gloves and eye protection; a pre-harvest interval is specified on the label. The compound corrodes mild steel, so spray equipment must be rinsed thoroughly after use.

See also: Gibberellic Acid Ga3, Mepiquat Chloride Cotton, Biostimulants Amino Acid Seaweed.

References

  1. Bayer Ethrel Ethephon 39 SL. Bayer Crop Science.
  2. Flower Induction in Pineapple. KAU Pineapple Research Station, Vazhakkulam.