Climate change effects on processing tomato in southern Italy: a simulation study

In the recent decades, processing tomato (Solanum lycopersicum L.) yields have increased due to the introduction of new genotypes with improved morphological, physiological and resistance traits. However, in southern Europe, yield increment was not as high as that attributed to resistance to biotic stresses such as late blight and viruses, that represent the major threats for this fruiting vegetable crop. Such effect is likely due to climate change and future projections for the Mediterranean basin indicating an increase of warm and dry periods. Crop growth and development are very sensitive to climate change and variability. In this study, we aimed to understand the projected impact of climate change on processing tomato grown in the southern Italy. A generic tomato cultivar was calibrated and evaluated using data recorded in open field cropping 'Messapico' hybrid for two consecutive years. Plants were transplanted into twin rows (3.36 plants m-2). Drip irrigation scheduling system was based restoring 100% of Etc when 40% of total available water was depleted. Two nitrogen (N) treatments were investigated (N-150 and N-200 kg ha-1). N-150 treatment of the first trial-year, representing to the typical nitrogen supply in the investigated area, was adopted for the DSSAT v4.7 model calibration (biomass: RMSE = 1584 kg ha-1, D-index = 0.93). This N rate was evaluated on the N-200 (biomass: RMSE = 1648 kg ha-1, D-index = 0.91). Contrasting Global Climate Models were compared respect to the integrated 30-years of historical weather from NASA-AgMERRA data set. The climate change variability affected full flowering and harvest dates. Simulation of the soil water content and air temperature indicates, for some years, negative impacts on the optimal crop growth due to drought and nutrient stresses which negatively impacts on fruit yield. Hence, innovative agronomic and breeding strategies are advisable to overcome the negative effects of climate changes occurring in this production area of the processing tomato.