EUFRIN Apple Rootstock Trials: First Results Across Europe

In 2017, two multi-location apple rootstock trials were established at 16 sites in 12 European countries. The evaluations are performed by members of the EUFRIN (European Fruit Research Institute Network) Apple & Pear Variety & Rootstock Testing Working Group. Two separate trials were arranged, grouping rootstocks into dwarf and semi-dwarf rootstocks according to the expected vigour; 'Galaval' was used as scion cultivar. The trial of dwarf rootstocks includes 'G.11' and 'G.41' (US), 'EM_02', 'EM_03', 'EM_04', 'EM_05' and 'EM_06' (UK), '62-396-B10 (R)' (Russia), 'P 67' (Poland), 'PFR4' and 'PFR5' (New Zealand) and 'Cepiland-Pajam (R) 2' as control. The trial of semi-dwarf rootstocks includes 'G.202' and 'G.935' (US), 'PFR1' and 'PFR3' (New Zealand), 'EM_01' (UK) and 'G.11' as a control for both trials. Part of the rootstocks (from dwarf and semidwarf rootstock trials) was planted in replanting conditions to test their tolerance to apple replant disease. All test trees came from the same nursery, and a common standardised evaluation protocol was used. Based on preliminary results averaged across sites, dwarf rootstocks can be ranked in terms of vigour in the following order: 'EM_04' < 'EM_03', 'EM_05' < '62-396-B10 (R)', 'P 67', 'EM_02', 'G.11' < 'G.41', 'Cepiland-Pajam (R) 2' < 'EM_06', 'PFR4' < 'PFR5'. On average, semi-dwarf rootstocks can be ranked in terms of vigour in the following order: 'G11' < 'G.935', 'G.202' < 'PFR3', 'EM_01' < 'PFR1'. The highest cumulative yield in the young orchard was registered for trees on 'PFR5', 'PFR4', 'G.11', 'G.41', 'Cepiland-Pajam (R) 2' and 'EM_02', while the lowest production was found for trees on 'EM_04'. In the group of semi-dwarf rootstocks, the highest yield was on 'PFR3', 'G.935' and 'PFR1'. Rootstocks also had a significant effect on fruit weight and fruit quality parameters. Results from the young orchards revealed interactions between sites and rootstock, potentially leading to site-specific rootstock choice based on the combination of rootstock, soil conditions and climate.