Sustainable alternatives for ethefon and ethrel 28 April 2018
As the days shorten in the autumn, the ripening of the last tomatoes is becoming increasingly difficult. To keep the production speed up to standard, ethefon is used. Ethefon is absorbed by the plant and gradually converted to ethylene, a natural plant hormone that stimulates the ripening of tomatoes. However, the use of ethephon is increasingly being questioned because of its potential toxicity. Under pressure from green NGOs, there is more and more demand for ethefon-free products from the vegetable trade. It is to be expected that this pressure of trade will only increase. In order to remain competitive, the sector is therefore obliged to look for alternatives to ethefon. The use of ethylene as gas in the greenhouse or the in vivo generation of the plant's own ethylene production are possible residue-free alternatives for ethephon use.
The main objective of this project is therefore to investigate the in situ and in vivo application of ethylene in the greenhouse on the ripening and the quality of tomatoes at the end of the year round crop. Within this IWT project will be deployed on different alternative slopes for the ripening of tomatoes. Ethylene gas can be introduced directly into the greenhouse using gas cylinders to stimulate the autocatalytic production of ethylene. In this technique, the effect of various factors such as ethylene concentration, duration of treatment, climate conditions will be mapped. The fruit quality is the most important parameter to arrive at an optimal protocol for the application of ethylene.
For a homogeneous and qualitative result, uniform treatment conditions must be realized in the greenhouse. For example, the distribution of ethylene in a number of greenhouses will be studied and optimized on the basis of computer simulations. Attention will also be paid to other aspects such as the removal of ethylene from the greenhouse in order to avoid adverse effects for the next crop.
Because there is no legal framework for the use of ethylene gas in a greenhouse to promote the ripening of tomatoes, an attempt will be made to support an approval procedure for ethylene gas from this project.
In addition to the use of ethylene gas, the production of endogenous ethylene can also be stimulated. This endogenous ethylene, produced by the plants themselves, can be generated by the application of stress conditions. For example, a plant will produce precursors for oxygen or salt stress that activate the production of endogenous ethylene. Research will have to show whether this stress can produce a sufficiently large effect to activate endogenous ethylene production.
The results were obtained from the VLAIO LA route "Sustainable alternatives to ethephon in tomato cultivation" (IWT 135073) carried out by KU Leuven, the Proefstation voor de Groenteteelt, Proefcentrum Hoogstraten and Vlaams Centrum voor Bewaring van Tuinbouwproducten. The project was financially supported by EMS, the LAVA auctions, Boerenbond and suppliers of ethylene gas.