Peaches and nectarines grafted onto seven rootstocks were evaluated during the 2008-2009 growing season with the objective of discerning possible effects on fruit quality and postharvest performance. The scion cultivars used in this trial were 'Rich Lady' and 'Ryan Sun' peaches, and 'Venus' and 'Ruby Diamond' nectarines. The rootstocks included 'Cadaman-Avimag', 'Viking', 'Atlas', 'GxN-15', 'GF-667', 'MRS 2/5' and 'Nemaguard' (as a control). The trial was done using 8-year-old trees from the Univiveros orchard, in Paine (Metropolitan Region, Chile). Fruit quality parameters including flesh firmness and soluble solids content were measured at harvest. Flesh firmness, soluble solids, mealiness and internal browning were measured after 15 and 30 days of cold storage at 0 degrees C, plus 4 days at room temperature (20 degrees C). For fruit quality at harvest, using data averaged from the four scion cultivars, 'Viking' rootstock resulted in the highest accumulation of soluble solids (11%) with respect to the fruit of the control rootstock, while 'GxN 15' had the lowest (9.8%). The 'GF 677' rootstock produced the firmest fruit and 'MRS 2/5' the softest. After 15 days of cold storage, 'GxN 15' had the firmest fruit, and 'MRS 2/5' had the softest, with both trends continuing after 30 days of storage. 'Viking' and 'MRS 2/5' resulted in the highest incidence of mealiness at both 15 and 30 days postharvest and 'Atlas' had the lowest incidence. With regard to internal browning, no significant differences were observed due to rootstock.
