Rootstock trials with 'Fuji' (T.A.C. 114) were established in 1993 at two sites in central Washington. The most dwarfing rootstocks, based on trunk cross-sectional area (STT), at each site were M.27, P.22 and P.16. Twelve M.9 clones and V.3, P.2, B.9 and 'Mark' were intermediate in tree size. The most vigorous rootstocks in the trial were M.26, MAC.39, C6 and V.1. The ranking of rootstocks for tree size was similar at the two sites (r = .82; n = 24). Cumulative fruit number per tree was generally related to tree size. The ranking of rootstocks for cumulative fruit number per tree was generally similar at the two sites (r = .74; n = 24).
Rootstock influenced the extent of south west trunk injury (sunscald) of 'Fuji' trunks and tree mortality caused by unusually cold (-22 to -25°C) midwinter temperatures. The extent of trunk injury (cm² of sunken/dead tissue on the southwest side of the trunk) was correlated with tree mortality (r = .73; n = 23). Trees on M.9 clones had the most severe injury (87 to 219 cm ² injured tissue) and tree death (33 to 68%). Rootstocks with minor or no injury (0 to 46 cm² injured tissue) and low mortality (0 to 12 %) were C6, M.27, V.1, M.26, P.22, 'Mark' and B.9.