Effects of Fruit Load and Reflective Mulch on Phenolic Compounds Accumulation in Nectarine Fruit

摘要

The influence of fruit load per tree and reflective mulch on the content of phenol compounds was studied in two experiments conducted on nectarines (cultivar 'Stark Red Gold') from two orchards differing in tree density (1.660 and 830 trees ha(-1)). Low crop load significantly increased fruit size and weight in both trials. Other parameters such as soluble solids, flesh firmness, acidity and skin color were affected only in nectarines from the low density orchard. At harvest, fruits from the low density orchard were more mature on low crop load trees compared to intermediate and high crop load trees. Crop load clearly affected the concentration of phenolic compounds: low-load fruits had a higher accumulation of phenolic compounds in skin and pulp tissues. Concentrations of cinnamic acids and flavan-3-ols consistently showed an inverse relationship to crop load.Inter-row reflective mulching modified average maximum temperature and the intensity of reflected light in the canopy. The mulching also changed fruit quality at harvest by promoting the ripening and generally increasing the concentration of the main classes of phenolic compounds. Our data indicate that health promoting value of nectarine fruits can be enhanced by increasing phenolic content via crop load and reflective mulches.