Abstract
In addition to the well-known apple rootstocks G 11 and G 41, newer Geneva rootstocks were tested at different altitudes for their suitability for cultivation in the Trentino South Tyrol area. At Fragsburg (700 m a.s.l.), in Maso Parti (210 m a.s.l.) and in Spagolle (420 m a.s.l.) CG 3001, CG 2034, G 935 and G 969 were examined in combination with Golden Delicious, also with regard to their tolerance to replant disease. A shortlist of rootstocks was planted with Red Delicious Spur at Fragsburg, at Laimburg Research Centre (220 m a.s.l.) and in Spagolle. G 41, G 935 and G 969 showed higher yields per tree and more vigour compared to M 9 T337 and M 26, which can be interesting in replant disease conditions, at higher altitudes with growth deficits or in connection with weak growing varieties such as Red Delicious Spur. G 41 and G 969 also had a positive effect on fruit size in combination with Golden Delicious. The rootstocks CG 3001 and CG 2034 tend to be less vigorous and productive than G 935 and G 969. G 11 tended to be more vigorous and productive with Red Delicious than M 9 Pajam 2. All Geneva series rootstocks are almost free of burr knots and root suckers. Although not all questions about the new series of Geneva rootstocks have been clarified, these rootstocks could represent an alternative to M 9 for certain situations in the future