Performance of ‘Subirana’ flat peach cultivar budded on different Prunus rootstocks in a warm production area in North Africa

The agronomic performance and fruit quality traits were evaluated for ten Prunus rootstocks: Garnem, PADAC 150, PADAC 04-03, PADAC 04-01, Rootpac® 70, PM 105 AD, AGAF 0301-04, Krymsk® 1, Krymsk® 86 and PAC 847. These rootstocks were budded with ‘Subirana’ flat peach cultivar in September 2007 and planted in two adjacent plots in northern Tunisia (36°41′N, 10°15′E) on a heavy and calcareous soil typical of the Mediterranean area. Tree mortality, vegetative growth, rate of bud failure and fruit quality were assessed. Significant differences were found among rootstocks for the agronomic and fruit quality traits. Growing conditions generated varying levels of tree mortality, the highest with Krymsk® 1 rootstock. In contrast, all trees on PADAC 04-03 and PADAC 04-01 survived well. The lowest vigor was induced by Krymsk® 1 with a reduction of 90% in trunk cross-sectional area (TCSA) and canopy volume as compared to Garnem. PADAC 150 also expressed a low vigor. The highest canopy volume was found on Rootpac® 70 as similarly for Garnem. The remaining rootstocks induced a medium vigor level. Trees on vigorous rootstocks as Rootpac® 70 showed the lowest rate of bud failure, while dwarfing rootstocks induced the highest buds abscission. Yield was higher for AGAF 0301-04 in 2011 and 2012 as compared to the rest of rootstocks. The highest yield efficiency was recorded on PM 105 AD and AGAF 0301-04 rootstocks. Rootpac® 70 presented the highest fruit weight and fruit diameter. The highest level of soluble solids content (SSC) was recorded on Krymsk® 1, and the lowest on Garnem, although differences were not significant when compared to the other rootstocks. The less vigorous rootstocks seem to induce a better fruit quality of peach based on fruit sugar content. This study provides information that new Prunus rootstocks for peach can lead to a better agronomic performance than Garnem, mainly in vigor and in productive parameters. The peach-plum hybrid PADAC 04-03 induced good yield