S23 - Session O6 - Overview of sunscald on pears, a new increasing storage disorder in hot and dry environments

Authors: Carolina A. Torres *, Rene Mogollon, Jingi Yoo

Climate change and season's weather variability has brought significant challenges to fruit production and supply chain management in many different parts of the world. Sunscald on pears is a newly identified physiological disorder in this crop. During two growing seasons fruit was harvested from five different orchards and sorted according to sunburn level (no sunburn, mild, moderate and severe) prior storing them at 0-1°C/ > 80% for up to 6 months. Incidence and severity of sunscald was evaluated weekly, as well as color and Vis-NIR reflectance change on the fruit surface. Sunscald symptoms appeared only in sun injured tissue, as darkening of the skin. Incidence, severity and time of appearance was lot-dependent ranging from 2.5 to 18%. Sunscalded tissue had significantly lower L and b* values, and overall reflectance intensities at harvest, regardless of sunburn severity. Quercetin and kaempferol levels increased with sunburn severity but decreased in tissue with sunscald. Other phenylpropanoids are also differentially accumulated in both sunburn and sunscald.