Preliminary results of a national German sweet cherry rootstock trial

The goal of this national trial is to identify rootstocks suitable for dwarf sweet cherry tree cultivation. New rootstock selections were grafted with 'Hedelfinger' and 'Regina' sweet cherry and planted at at 9 locations across Germany (Bavendorf, Dresden, Muncheberg, Oppenheim, Veitshochheim, Witzenhausen, and partly at Weinsberg, Jork, and Randwijk/NL). The trial began in 1996 and the probable end will be 2004. The treatments were divided in 2 groups: rootstocks with and without supplemental irrigation. Through 2001, only 2 of the 6 locations examined had no tree mortality, which was influenced by location, cultivar and rootstock. Rootstocks with high mortality rates included Colt, GiSelA (R) 4 Damil Weiroot 154 and Gi 497/8. Less than 10% mortality occurred with Tabel (R) Edabriz, Piku (R) 1 and 3, Gi 318/17, and GiSelA (R) 5. The highest productivity was achieved with Tabel (R) Edabriz, GiSelA (R) 5 and Gi 195/20. Low productivity was found with Piku (R) 3, Damil (R) and Weiroot 158. Except for GiSelA (R) 4, Weiroot 158 and Damil, the vegetative performance of the rootstocks looks more consistent than the reproductive. Piku (R) 3 had the highest vegetative vigor and Tabel (R) Edabriz the lowest. Most of the rootstocks were positioned at a medium vigor level around that of GiSelA (R) 5.