Effects of cultivar and rootstock on the antioxidant content and physical characters of clingstone peaches

A study was conducted to investigate the variability in the fruit antioxidant content and physical characters of six clingstone cultivars and three breeding selections of peach grafted on three rootstocks. The parameters measured were fruit weight, fruit and stone dimensions, flesh color using CIELAB color variables, total antioxidant activity using the radical DPPH, total phenolics, ascorbic acid, soluble solids and total acid content. Fruit from cultivar PI-E45 had the highest total antioxidant activity (10.7 mg g−1 DW) and total phenolic (6.9 mg g−1 DW) content, which were up to 6.3- and 5.3-fold greater, respectively, compared with the rest studied cultivars. The highest ascorbic acid content was found in Fortuna (7.3 mg 100 g−1 FW) and was up to 1.4-fold greater compared with the rest studied cultivars. A high correlation between AEAC and the phenolic content was found, but not between AEAC and the ascorbic acid content. The largest fruit was harvested in cultivar Andross followed with a descending order by PI-E45, PI-IB42, PI-A37 (seedlings of Andross), Fortuna and Loadel ≫ Everts and Catherina ≫ Romea. Changes in the fruit weight were usually according to changes in stone width. The fruit and stone shape differed among the cultivars but not among the rootstocks studied. Effects of rootstock on the fruit antioxidant contents were not pronounced. Nevertheless rootstocks altered the fruit weight since in all cultivars, apart from Romea and Catherina, when grafted on GF 677 produced the largest fruit (mean 186 g) followed by PR204 (mean 176 g) and even smaller by KID1 (mean 161 g). Results from correlation analyses showed that flesh brightness (measured in frozen fruit) may suggest for more nutritional flesh and small sized fruit may contain a redder and less bright colored flesh.