Budagovsky, Geneva, Pillnitz, and Malling Apple Rootstocks Affect 'Fuji' Performance Over the First Five Years of the 2010 NC-140 'Fuji' Apple Rootstock Trial

In 2010, an orchard trial of apple rootstocks was established at six locations in the United States and Mexico using 'Aztec Fuji' as the scion cultivar.Rootstocks included two named clones from the Budagovsky series (B.9, B.10), seven unreleased Budagovsky clones (B.7-3-150, B.7-20-21, B.64-194, B.67-5-32, B.70-6-8, B.70-2020, and B.71-7-22), four named Cornell-Geneva clones [Geneva((R)) 11 (G.11), Geneva((R)) 41 (G.41), Geneva((R)) 202 (G.202), and Geneva((R)) 935 (G.935)], nine unreleased Cornell-Geneva clones (CG.2034, CG.3001, CG.4003, CG.4004, CG.4013, CG.4214, CG.4814, CG.5087, and CG.5222), one named clone from the Pillnitz series (Supp.3), two unreleased Pillnitz clones (PiAu 9-90 and PiAu 51-11), and three Malling clones as controls (M.9 NAKBT337, M.9 Pajam 2, and M.26 EMLA). All trees were trained a Tall Spindle. After 5 years, the greatest mortality was for trees on M.9 NAKBT337 (22%). Trees on four rootstocks (M.9 Pajam 2, Supp.3, B.71-7-22, and B.70-20-21) experienced 11-20% mortality, and all others averaged10% or less.Tree size after 5 years allowed for a preliminary partitioning of these rootstocks in to size classes from sub-dwarf to semi-standard. B.70-20-20 was a semi-standard, and PiAu 9-90 was a large semi-dwarf. B.64-194, B.67-5-32, B.70-6-8, and PiAu 51-11 were moderate semi-dwarfs. B.7-3-150, CG.3001, CG.4004, CG.5222, and M.26 EMLA were small semi-dwarfs.G.202N (N = liners from stool beds), G.935 N, G.935TC (TC = liners from tissue culture), CG.4814, and M.9 Pajam 2 were large dwarfs. B.10, G.11, G.41N, G.41TC, G.202TC, Supp.3, and M.9 NAKBT337 were moderate dwarfs. B.9, CG.2034, CG.4003, CG.4013, CG.4214, and CG.5087 were small dwarfs, and B.7-2021 and B.71-7-22 were sub-dwarfs.Trees on B.70-20-20, PiAu 9-90, PiAu 51-11, B.67-5-32, B.70-6-8, and B.64-194 were too vigorous for a high-density system, and conversely, trees on B.71-7-22 and B.7-20-21 were not vigorous enough. Among the five small semi-dwarf rootstocks, CG.4004 performed best, using cumulative (2011-14) yield efficiency as the primary determinant of performance. Among the five large dwarf rootstocks, G.935N performed best.Of the seven rootstocks characterized as moderate dwarfs, M.9 NAKBT337, G.11, and G.202TC resulted in the greatest cumulative yield efficiency. Of the six rootstocks in the small-dwarf class, CG.4003, B.9, CG.5087, and CG.2034 performed best.