Accelerating ripening of greenhouse tomatoes in autumn at the end of harvest with ethylene application

Accelerating maturation of greenhouse tomatoes at the end of the growing season permits to save energy and to reduce the quantity of unripe tomatoes. Indeed, at the end of the cropping season, several kg m-2 of tomatoes do not reach a degree of maturity permitting them to be sold. In Switzerland, it was possible to accelerate the ripening of tomatoes by applying ethephon, a product which releases ethylene. Since August 2014, this product is no longer authorized, in Switzerland. An alternative is the application of ethylene, a naturally occurring hormone, directly in the greenhouse. In collaboration with the company Carbagas, Agroscope tested the effect of ethylene application on tomato ripening. The trials were conducted in 2012 and 2013 in two identical compartments of a Venlo greenhouse. In one compartment, ethylene was injected at a concentration of 10 ppm during nine or ten nights. The other compartment served as control. In 2012, tomatoes 'Levanzo', 'Komeett' and 'Endeavour' were planted and in 2013 'Endeavour'. In average over the two years, the application of ethylene enabled to harvest 1.5 truss m-2 or 0.75 kg m-2 (1.5% of the total yield) more compared to the control compartment. The quality of tomatoes at harvest (acidity, firmness and total soluble substances) was only slightly influenced by the addition of ethylene. Economically, such an application seems profitable. Registration for the application of ethylene in greenhouse is in progress in Switzerland.