Budagovsky, Geneva, Pillnitz, and Malling Apple Rootstocks Affect 'Honeycrisp' Performance Over Eight Years in the 2010 NC-140 'Honeycrisp' Apple Rootstock Trial

In 2010, an orchard trial of apple rootstocks was established at 12 locations in the United States, Canada, and Mexico using 'Honeycrisp' as the scion cultivar. Rootstocks included two named clones from the Budagovsky series (B.9, B.10), six unreleased Budagovsky clones (B.7-3-150, B.7-20-21, B.64-194, B.67-5-32, B.70-6-8, 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 (at initiation of the trial) 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), one unreleased Pillnitz clone (Pi PiAu 51-11), and three Malling clones as controls (M.9 NA-KBT337, M.9 Pajam 2, and M.26 EMLA). For trees on G.41 and G.935, there were both stool-bed-produced (N) and tissue-culture-produced (TC) liners used for trees. All trees were trained as Tall Spindles. After 8 years, the greatest mortality was for trees on CG.3001 (31%), CG.4814 (24%), CG.5222 (17%), CG.2034 (16%), and G.935N (16%). Rootstocks were partitioned into size classes from sub-dwarf to large semi-dwarf. B.7-3-150, B.7-20-21, B.64-194, B.67-5-32, and B.70-6-8 resulted in large semi-dwarf trees with comparably low cumulative yield efficiency and projected cumulative yield per hectare. CG.4004, CG.5222, and PiAu 51-11 produced moderate semi-dwarf trees. The most yield efficient trees in this group were on CG.4004. Trees on CG.3001 and CG.4013 were in the small semi-dwarf category. Projected cumulative yields were statistically similar. The large dwarf category included G.41N, G.202, G.935N, G.935TC, CG.4214, CG,4814, CG.5087, M.9 Pajam 2, and M.26 EMLA. Trees on CG.4214, G.41N, G.935N, CG.5087, and G.935TC were the most yield efficient and had the highest projected per-hectare cumulative yield for their size category. Trees on B.10, G.11, G.41TC, Supp.3, and M.9 NAKBT337 were moderate dwarfs. Trees on G.11, G.41TC, and B.10 were the most yield efficient and had the highest potential yield per hectare in this size category. The small dwarf category included B.9, CG.2034, and CG.4003. These three rootstocks produced trees which were similarly yield efficient and had similar projected per-hectare yields. B.71-7-22 was classified as a sub-dwarf, and produced a tree which was only moderately yield efficient, with a low projected per-hectare yield.