Preharvest calcium treatment enhanced lenticels breakdown at an environmental-dependent manner

Abstract

It has been demonstrated that postharvest calcium application enhanced lenticels breakdown (LB), occurring after storage. In this study, we examined whether preharvest in-orchard calcium foliar application can also enhances lenticels breakdown. Calcium foliar application was examined on fruit harvested separately from northern and southern sides of the trees in two orchards. Four in-orchard treatments were applied: No treatment (Control), CaCl2, Ca(NO3)2 and KCl. The orchards were located in regions with different climatic conditions. LB damage was higher in the low humidity orchard in comparison to that in the higher humidity orchard. Moreover, LB was enhanced by preharvest calcium application only in apples from the northern side of the trees, located in the lower relative humidity orchard. Preharvest calcium application reduced the peel thickness of apples from both tree sides in the high relative humidity orchard, and only in the northern side of the low humidity orchard. Hence, in-orchard calcium foliar application can enhance LB only under specific field climate conditions. Reduced peel thickness by calcium in the northern side of the low relative humidity orchard, might have led to a higher post storage LB. Nevertheless, the status of open lenticels at harvest can only partially explain the postharvest LB. In addition, the force needed to puncture the peel does not explain LB results. In conclusion, this study supports the finding that calcium increases LB, but only under certain environmental conditions.