This research aims at studying the relationships between tree crop load and fruit quality (fruit size, chemical, and nutraceutical composition) of flat peaches at harvest. The experiment was carried out in 2013 and 2014 on mature trees of the flat peach cultivar ‘UFO 4’. Five levels of fruit thinning intensity were compared, corresponding to crop loads of 327, 258, 229, 187, and 149 fruits/tree, respectively. Most of the measured fruit quality features (fruit fresh weight, soluble solid content, titratable acidity, concentration of malic, tartaric, chlorogenic, and neochlorogenic acids, flavonoids, total phenolics, and antioxidant activity of flesh juice) progressively increased with decreasing fruit load, whereas fruit yield and the percentage of cull fruits (because of split pit) progressively increased with decreasing fruit load. The results of this study demonstrate that fruit thinning is an effective management practice to improve fruit size and the nutraceutical composition of flat peaches at harvest.
Keywords: organic acids, phenolic acids, flavonoids, chlorogenic acid, neochlorogenic acid, antioxidant activity.