Trees of ‘Gala’ apple (Malus domestica Borkh.) growing on 18 dwarf rootstocks were planted at 26 sites in North America.
Trees were planted in 1994 and evaluated for five years.
Dwarfing rootstocks included six selections of M.9 (EMLA, Flueren 56, NAKB T337, RN.29, Pajam 1, Pajam 2), three from the Budagovski (B) series (B.9, B.469, B.491), three from the Polish (P) series (P.2, P.16, P.22) and two from the Vineland (V) series (V.1, V.3). In addition, trees were included on Mark, M.26 EMLA, M.27 EMLA and O.3. M.27 EMLA, B.491, P.16 and P.22 produced the smallest trees whereas V.1, M.26 EMLA, M.9 RN29 and M.9 Pajam 2 produced the largest trees.
Among the most dwarfing rootstocks, P.16 had the highest yield efficiency while O.3, MARK and M.9 NAKBT337 were the most efficient of the intermediate sized trees.
In a separate planting, ‘Gala’ trees on 4 semi-dwarfing rootstocks were also evaluated at 24 of the same sites during the same period.
The rootstocks were P.1, V.2 G.30 and M.26 EMLA. P.1 produced the largest trees and G.30 the smallest.
Conversely, yield efficiency tended to be highest for G.30 and lowest on P.1. Tree losses were higher on G.30 and M.26 EMLA than on the other rootstocks.