Calibration and validation of a biological model to simulate the development and production of tomatoes in Mediterranean greenhouses during winter period

The aim of this work is to calibrate and validate the adaptation of TOMGRO (TOMato GRowth), a crop growth simulation model for tomato, to the short-term cropping technique and to conditions in Greece. Current practice in plastic greenhouses in Mediterranean regions is to stop the indeterminate development of the plant after a limited number of trusses by removing the terminal bud of the plant (i.e. topping). Experiments were carried out in the farm of the University of Thessaly, Volos, Greece, during the autumn and winter periods of 2005 and 2007. Crop development, growth and greenhouse climate were measured. Results showed that dry matter partitioning in the plant was not altered by the topping of the plant but the duration of the life of the fruit, from setting to maturity, was shortened. The TOMGRO model was modified accordingly, calibrated over the winter 2005 data and then using data from winter 2007. Good agreement was observed between the measured and simulated plant development indicators, biomass and fruit production. Satisfactory agreement was obtained for the plant leaf area (LA), usually one of the weak points of TOMGRO. Based on these results, we conclude that this adaptation of TOMGRO accurately simulates the development of short-term tomato crops grown in greenhouses and can therefore be used for decision support to help growers optimise the operation of the greenhouse.