Improving the Postharvest Characteristics of Table Grape by Preharvest Application of Polyamines

Although table grape is a non-climacteric fruit with low physiological activity, it is however prone to weight loss, softening and fungal infection during postharvest period. The whole vine especially fruits were sprayed with putrescine (put; 0, 1, 2 mM), spermidine (spd; 0, 1, 2 mM) at 40 and 20 days before harvest. Different fruit characteristics were analyzed after harvest and remaining fruits were stored at 1.5 +/- 1 degrees C and 90 +/- 5% RH for 25 and 55 days. Different concentrations of polyamines significantly increased firmness of grapes at harvest. Firmness was also retained and decreased weight loss of fruit during storage. Table grape storability could be extended by put and spd treatments due to their significant effect on delaying the softening, water loss, fungal infection and senescence.