Table 1 The fourteen rootstock selections used to compare canker susceptibility including 8 commercially available cultivars and six elite selections from the NIAB East Malling apple rootstock breeding program
Rootstock | Description |
|---|---|
M9 337 | Dwarfing rootstock selection from M9 virus-free certified clonal stock developed by the East Malling Research Station, Kent, England. M9 337 is very precocious, the measure of time to flowering within the life span of the tree, and is tolerant to a wide range of soil and climatic conditions. Clones of M9 are the most widely planted dwarfing apple rootstock globally (PSU 2018) |
M9 337 with GD interstock | Rootstock with characteristics as described above. Golden Delicious (GD) used in the interstock is known to have lower susceptibility and may provide additional protection from canker |
M9 EMLA | Developed by the East Malling Long Ashton breeding program to exclude virus infection through micro-propagation. M9 EMLA is free of known viruses and slightly more vigorous than the original M9 |
MM106 | Semi-vigorous, producing free-standing, early bearing trees. Susceptible to collar rot when planted in wet soils and not recommended for poorly drained sites (PSU 2018) |
M116 | Medium vigour. Described as having increased resistance to Phytophthora, powdery mildew and apple replant disease (ARD). Improved yield compared to MM106 (Alston 2008) |
M26 | A more vigorous dwarfing rootstock than M9 resulting from a cross between M9 and M16. Precocious and very productive. Susceptible to Phytophthora and fire blight. Reported to be susceptible to collar rot and fire blight and should not be planted on wet sites (PSU 2018) |
G11 | A cross between M26 and Robusta 5. Similar in size to M26. Fireblight resistant, and tolerant of Phytophthora, partial tolerance to ARD. Productivity/yield efficiency is better than M9. Low amount of suckering and burr knots. Geneva® rootstocks are reported to increase productivity and tree yield efficiency similar or higher than current commercial standards M9 and M26 (PSU 2018; Fazio et al. 2015) |
G41 | A cross between M27 and Robusta 5, similar in size to M9. Reported as highly resistant to fire blight and Phytophthora, tolerant of ARD (PSU 2018; Fazio et al. 2015) |
EMR-001 | NIAB East Malling advanced selection |
EMR-002 | NIAB East Malling advanced selection |
EMR-003 | NIAB East Malling advanced selection |
EMR-004 | NIAB East Malling advanced selection |
EMR-005 | NIAB East Malling advanced selection |
EMR-006 | NIAB East Malling advanced selection |