For over 25 years, rootstocks for sweet cherries are evaluated in different locations in the german federal state of Rhenania Palatinate. They are situated in a vine growing climate and have medium-heavy soils. Replant disease of stone fruit plays a significant role in most orchards. In general, all trees in the rootstock trials are trained as central leader and planted 4.0 to 4.5 m by 2.0 to 3.0 m depending on the expected vigour. In addition to the common performance parameters, tree health, anchorage and tendency for root suckers are observed. In 2013 a new rootstock trial has been established including, inter alia, the new Weigi series and some recent Gisela numbers. In the experimental orchard of Oppenheim, replanted soil can be compared to new land. Up to now, Weigi 2 is slightly more dwarfing but also less productive in this trial what is no disadvantage regarding the fruit size. In the group of semi-dwarfing rootstocks Weigi 1,
Weigi 3, Gisela 13 and Gisela 17 seem to be similar both in vigour and yield efficiency. In this group there is an interest to replace PiKu 1 which turned out to be not winter hardy enough and susceptible to heavy soils and bark beetles under German conditions. Training trials revealed that also with low tree forms, yields and qualities comparable to the spindle can be obtained. The picking performance can be improved in many cases. Mechanical pruning only makes sense if it is combined with manual correction pruning. An exclusive mechanical pruning reduces the fruit size and can also reduce the picking performance.
Keywords: sweet cherry, vigour, yield efficiency, tree training