| Characteristic | Detail | Description |
|---|---|---|
| Rootstock | MM.111 EMLA |
Introduced in 1952 from a cross of Merton 793 x ‘Northern Spy’ by the John Innes Horticultural Institute and the East Malling Research Station in England. MM.111 EMLA is one of the more vigorous semi-dwarf rootstocks, producing a tree about 85 to 100% the size of seedling. It is resistant to wooly apple aphid and is quite tolerant to fire blight and crown and root rots. It is fairly winter hardy and produces moderate |
Apple Rootstock Info: MM.106 EMLA
| Characteristic | Detail | Description |
|---|---|---|
| Rootstock | MM.106 EMLA |
Selected in 1932 from a cross of M.2 x ‘Northern Spy’ by the John Innes Horticultural Institute and the East Malling Research Station in England. MM.106 EMLA is a semi-dwarf rootstock, producing a tree about 60% the size of seedling. It is quite precocious and productive and usually does not need tree support. It is resistant to wooly apple aphid, but is highly susceptible to crown and root rots, susceptible to fire blight, and |
Apple Rootstock Info: M.27 EMLA
| Characteristic | Detail | Description |
|---|---|---|
| Rootstock | M.27 EMLA |
Selected in 1934 from a cross of M.13 x M.9 at East Malling Research station in Maidstone, Kent, England and was tested as Malling 3431. M.27 EMLA is a very dwarfing rootstock and is probably too dwarfing for most commercial situations except for vigorous cultivars on vigorous sites, but it might be considered for home gardens where a small tree is desirable.. Trees on M.27 EMLA are very precocious and productive and require permanent |
Apple Rootstock Info: M.7 EMLA
| Characteristic | Detail | Description |
|---|---|---|
| Rootstock | M.7 EMLA |
Formerly known as EM VII. Selected in 1912 from unknown parentage at the East Malling Research station in Maidstone, Kent, England. Trees on M.7 EMLA produce a semi-dwarf tree about 60 to 70% as big as seedling. Trees are moderately precocious and may lean with some cultivars and may require trunk support. Trees tend to produce many rootsuckers. M.7 EMLA has been widely planted since the 1960s with cultivars such as ‘McIntosh’, ‘Empire’, ‘Cortland’, |
Apple Rootstock Info: B.9
| Characteristic | Detail | Description |
|---|---|---|
| Rootstock | B.9 |
Resulted from a cross of M.8 x ‘Red Standard’ (Krasnij Standard) from Russia. B.9 has been tested widely and is used commercially in the U.S. In general, B.9 is slightly more dwarfing than M.9 and has slightly higher yield efficiency than M.9. B.9 was selected as a dwarfing cold hardy rootstock and initial inoculation results indicated that it was as susceptible to fire blight as M.9. However, in field trials, trees grafted onto B.9 survived |
Apple Rootstock Info: P.2
| Characteristic | Detail | Description |
|---|---|---|
| Rootstock | P.2 |
Resulted from a cross of M.9 x Common Antonovka and released by the Research Institute of Poland in Skierniewice, Poland. This is a productive, cold hardy, dwarfing rootstock slightly more dwarfing than M.9 NAKBT-337. It is susceptible to fire blight, and wooly apple aphid, but fairly resistant to crown and root rots. It produces few root suckers and burr knots similar to M.9. In NC-140 trials trees survive; depaending on location tree size was similar |
Interstem Apple Trees
Because many dwarfing rootstocks have less than the desired level of cold resistance and trees on all dwarfing rootstocks require support, dwarf rootstocks are sometimes used as interstems to combine the desirable characteristics of a vigorous understock and the dwarfing interstem.
Interstem trees consist of three parts:
- A vigorous rootstock (usually MM.111 or MM.106)
- A dwarfing (usually M.9 or M.27) interstem is grafted to the rootstock. The interstem is usually about 6” long, but additional dwarfing can be obtained by
Apple Rootstock Info: G.890
| Characteristic | Detail | Description |
|---|---|---|
| Rootstock | G.890 |
G.890 is a semidwarfing rootstock that is resistant to fire blight (Erwinia amylovora), crown rot (Phytopthora spp.) and woolly apple aphid. At this time production of root suckers and burr knots is unknown. Tree size is approximately the same as M.7 but with higher and earlier production. |
| Synonyms | Geneva 890 | |
| Origin | N/A | |
| Availability | Limited availability | |
| Tree Size | 70-75% | |
| Precocity | Intermediate | |
| Winter Hardiness | Hardy | |
| Suckering | N/A | |
| Tree Support Needed | No | |
| Where tested within NC-140 or other |
Apple Rootstock Info: G.65
| Characteristic | Detail | Description |
|---|---|---|
| Rootstock | G.65 |
G.65 was developed by Dr. Jim Cummins at Cornell University. Due to errors in tissue culture buildup of this rootstock, the U.S. distribution of this rootstock has been hindered. Tree size once thought to be about that of M.9 is now considered to be closer to M.27. The rootstock is difficult to propagate in nursery stool beds. It is susceptible to tomato ring spot virus and apple stem grooving virus. Not recommended for commercial planting. |
Apple Rootstock Info: M.4
| Characteristic | Detail | Description |
|---|---|---|
| Rootstock | M.4 |
Selected in 1912 from unknown parents at the East Malling Research Station in Maidstone, Kent, England. M.4 is slightly dwarfing and produces a tree about 75-80% standard size. It is considered fairly precocious, and trees tend to lean and may require trunk support. M.4 is resistant to collar rot. In an Indian rootstock trial trees on M.4, MM.106, and MM.111 were all about the same size. Cumulative yield was greater than trees on MM.111, similar |