Rootstock affects quality and phytochemical composition of 'Big Top' nectarine fruits grown under hot climatic conditions

This study aimed to evaluate the stability of 'Big Top' nectarine fruit quality (fruit weight, fruit mineral elements and fruit phytochemical composition such as soluble solids content, titratable acidity, individual sugars, individual organic acids, total ascorbic acid content, total phenolics content, and antioxidant capacity) when grafted on 20 Prunus rootstocks over two consecutive seasons. For most of the evaluated traits, rootstock was the main source of variability, whereas for Mg, malic and citric acids, and glucose most of the variability was observed among years. Similarly, the interaction year x rootstock was not significant for most traits (14 out of 21), hence highlighting that most rootstocks responded in a similar manner to changes in the weather conditions. Thus said, some important micro- and macro-nutrients such as Ca, Mg, Fe, Zn, together with taste- (fructose, glucose and sucrose) or health-related (antioxidant capacity) compounds showed a differential influence of the rootstock depending on the year conditions and thereby suggested that climatic conditions can be a limiting factor in the choice of rootstocks for a given nectarine cultivar. Overall, the results from this study indicated that the cherry-plum hybrid Krimsk-1 and the peach-plum hybrid PS rootstocks are the most suitable rootstocks for 'Big Top' under the conditions investigated herein. Both rootstocks induced high values on sugar profile, ascorbic acid, antioxidant activity, and TPC of 'Big Top' nectarine being relatively stable regardless of the weather conditions. Finally, the rootstocks IRTA-1 and Rootpac-20 also induced good fruit quality and phytochemical properties to 'Big Top' fruit.