The results of these studies suggest that rootstocks differ in the root distribution patterns
and the total root numbers, both of which influence the yield and pruning weight as well as the yield to pruning weight ratio (Morano & Kliewer 1994). Schmid et al. (2005) state that, with the cv. Pinot Noir cl. 20, the yield was higher on Kober 125AA cl. 3 Gm rootstock in 2001, whereas in 2002 and 2003 it was higher on Börner rootstock.