Harvest date and fruit size affect postharvest softening of apple fruit

The influence of harvest date and fruit size on the three phases of softening for Royal Gala and Cox's Orange Pippin apple cultivars is currently not known. During storage at 0.5 or 3degreesC, late-harvested fruit had a shorter initial slow softening phase and required less time before the internal ethylene concentration exceeded 1.5 mul(-1) than fruit harvested earlier. Rate of rapid phase softening was similar for fruit from each harvest date. Unlike harvest date, fruit size did not consistently affect the harvest indices of fruit from either cultivar. Once in storage at 0.5 or 3degreesC the softening profiles of different sized fruit from early harvests were similar. However, small fruit softened more slowly than medium and large fruit when harvested at a late stage of maturity. Results in this study indicate that softening of these apple cultivars is not linear in storage, and that both harvest date, and to a lesser extent fruit size, influenced the degree of non-linearity by influencing the duration of the initial slow softening phase. It is also suggested that the initial slow softening phase may be a continuation of the slow softening that occurs in fruit while still attached to the tree.