Esigenze bio-termiche e stima del periodo di sviluppo del frutto in cultivar di pesco a differente epoca di maturazione

In this experiment carried out in Sicily (37.35N 12.58E), fruit growth was studied in relation to thermal time accumulated from bloom to fruit harvest for peach cultivars whose fruit development period ranges from 76 to 170 days. Thermal time was calculated in terms of GDH (base temperature 6.2-10 °C, optimum temperature 23.3-24.5 °C and critical temperature 33.7-39.4 °C) by the use of non-linear models. Climatic and phenological data (bloom and harvest dates) were considered for a minimum of four to a maximum of six years. Taking into account the whole FDP, the accuracy of the GDH model in predicting harvest time ranged from 0.6 day, in the early ripening peach cultivar Anita, to 6.4 days in the late ripening peach cultivar Clara. An accurate early forecast of fruit harvest time was obtained using the GDH accumulated during the first 25-35 days of fruit development period, depending on the cultivar.