Chlorophyll role in berry sunburn symptoms studied in different grape (Vitis vinifera L.) cultivars

In grape berries, extreme oxidative stress results in skin tissue bleaching and brownish areas appearance. Thus,these damages could negatively affectthe fruit quality and the commercial value. The paper focuses on the chlorophyll roles in sunburn symptoms appearance in white skinned grape berries. In the present work, 20 cultivars were studied in three phenological stages. Berries were kept under temperature and light controlled conditions. Chlorophyll content and symptom appearance were quantified by reflectance spectroscopy indexes. The central role of radiation (and,thus, photo-oxidative damages)in berry sunburn injuries was underlined. Cultivars were classified, based on their susceptible or tolerant responses to radiation excess.