The effect of strobilurin on ethylene production in flowers, yield and quality parameters of processing tomato grown under a moderate water stress condition in Mediterranean area

This research was conducted in Southern Italy over two growing seasons to evaluate the effect of strobilurin application on the ethylene production of flowers (EF) and on the yield and quality parameters of processing tomato grown under moderate water deficit conditions. The following two irrigation regimes were applied: IR100, full irrigation that restores 100% of the maximum crop evapotranspiration (ETc) and IR75, which is 75% of the amount of water of IR100. Furthermore, from the beginning of flowering two fungicide treatments were applied three times: fungicide treatment without strobilurin (ST0) and strobilurin fungicide with an azoxystrobin based product (STaz). At full flowering, ethylene production in the flowers (EF) was determined. At harvest, the main yield and qualitative parameters were evaluated. The strobilurin treatment caused a significant decrease of EF, which was less evident in the first warmer year than in the second. This result was presumably because of the interference of high temperatures on the inhibition of ethylene synthesis described for the strobilurin. In contrast, the decrease of EF due to strobilurin treatment was more evident under IR75 than under IR100. Finally, the decrease in the number of marketable fruits with respect to the EF increase was lower under strobilurin treatment presumably because of the protective effect of this molecule on the flower drop. Further studies are needed to investigate this hypothesis in greater detail.