| Rootstock |
G.30 |
Resulted from a cross between M.9 and Robusta 5 and introduced by the New York State Agricultural Experiment Station, Geneva, NY. G.30 produces a fairly vigorous dwarf tree, similar in size to M.26. Precocity and productivity are also similar to M.26. G.30 is highly resistant to fireblight and quite resistant to crown and root rots, but susceptible to woolly apple aphid. G.30 was tested at 20 locations in the NC-140 1994 semi-dwarf rootstock trial with ‘Gala’ as the scion cultivar. Compared to M.26 EMLA, the trees were similar in size and in yield efficiency, but produced more rootsuckers. Some of the trees on G.30 broke at the graft union during wind storms. Further testing at Geneva indicated that G.30 has brittle wood and when brittle scions are budded or grafted onto it, trees may break at the union. Therefore, trees on G.30 should be supported better than for most other rootstocks: tying branches to two or more wires has helped prevent tree breakage.
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