By 1500-1800 many types of rootstocks were in use. Not until the late 1800 that standardization was started in Europe. In 1912 R. Wellington began study of the paradise form at the Wye College Fruit Experiment Station that was later named the East Malling Research Station. By 1917 Lord Hatton had replaced Wellington at the start of WW I and had numbered 9 types of rootstock and by 1935 had increased that to 26. EM (East Malling) 1-26 this was later shortened to M1-26 of these 26 rootstocks some were already centuries old when named (M-7)and others have not been widely tested in the U.S. because they were chosen for fruiting habits and/or cold hardiness.
EMLA- (East Malling-Long Ashton) these rootstocks went through a heat process for virus removal.
Malling-Merton- MM This was a collaborative effort between Merton England and East Malling There is also just Merton rootstock such as M-793 but is not widely used in the U.S. Its offspring the MM-111 is more popular.
Budagoski – Bud is a newer rootstock out of the College of Horticulture in Michurinsk, Russia
Polish- P series is a cross between the Malling series and Antonovka.
G series- This is a joint venture between Cornell University and the USDA out of the Geneva the root stock test conducted by Dr. Jim Cummins et al. The stated objective of these rootstocks were to be as good as or better in “per acre productivity” and “tree yield efficiency” as the current commercial leaders M-26 and M-9
Most Dwarfing Tree height (TH) 6ft ( I like Michael Phillips quote concerning mini dwarfs “and though the smallest dwarfs like m-27 and p-22 are too much like raising tomato plants for my tastes”)
P-22 Is a cross between an M-9 and Antonovka. Very cold hardy and very dwarfing
EMLA-27(M-27) originally EM3431 does not have the cold hardiness of P-22, fruit size runs small
G-65 crown and root rot tolerant
Dwarfing TH 8 to 10 ft
M-9 (Yellow Metz) one of the older rootstocks however there are many strains in Europe and the U.S. The old strain has two or three latent viruses that some researchers contend make for the dwarfing characteristics. M-9 is quite resistant to collar rot but does not tolerate soil temps over 70 degrees so mulching is recommended. Good spreading of branches, somewhat brittle. Interesting side note: When this was developed the research station freely gave it away since they decided that it was for the greater good for all to have. It became the most popular rootstock in Europe.
G-11,16,41 G-11 just a touch smaller then 41 and 16
P-2 another cold hardy rootstock its size is about the same as the M-9. It is quite resistant to crown gall, various cankers and collar rot. P-2 induces early defoliation of the cultivar and late bud break in the spring.
Bud-9 is a little bigger then M-9 and is cold hardier.
Semi Dwarf TH 10-12 ft
EMLA-9 This is the same as the M-9 but with the virus removed
MARK Formally called MAC-9 Is a Michigan state patented apple clone. Not often used in this area. Starts out good but quickly loses vigor
M-26 is a cross between an M-9 and M-16 and is the workhorse of many of the nurseries in PNW due to the tree size 10 to 12 feet great for city lots. It is also a very cold hardy rootstock but it has its drawbacks. It is not very drought tolerant so you MUST have irrigation. Most nurseries suggest staking for the first three to five years but personnel experience tells me you must stake much longer. Graft incompatibility with many triploids.
G-214,935,202 G-202 is between a M-9 and M-26
Ottowa-3 As the name implies, the work on this rootstock was in Ottowa Canada. It is a cross of a Robin crab and M-9. Not really used in our Maritime climate but might be useful if you decide to plant an apple on Mt Rainier.
Semi Standard TH 12-15 ft
M-7A Very old rootstock with many names (It’s complicated) It started as a French rootstock Doucin and was collected to become part of the Malling series during WW 1. During the sixties it was cleaned up of virus and dubbed the M-7A. Shortly thereafter two research stations (EMLA and WSU) used the new improved system to clean up all of the viruses in it and renamed it EMLA-7 and IR-2.7 respectively. It is a very widely adaptable rootstock and even though the M-7A has one or two viruses in it, it is still used today
G-222,30,210,890 G-30 was one of the first to be released.
MM-106 is susceptible to collar rot and does not do well in poorly drained heavy soils. However it is well known for its early heavy cropping.
MM-111 is a cross between Northern Spy and M-793 and one of the parents of the M-793 is Northern Spy so there is a very strong Northern spy heritage. This tree is about 80% of standard and is quite resistant to drought, adapted to wide range of soils. Bud-118 Max production on a per tree basis Cherry, Plum, Apricot, Peach & Nectarine Rootstock Bailey SEMI-DWARF (6 meters / 20 feet at maturity)* Considered to be one of the best rootstocks for growing hardy peaches, Bailey can withstand severe winters. Lovell SEMI-DWARF (4.5 meters / 15 feet at maturity)* Dependable standard stone fruit rootstock, Provides good anchorage, Tolerates cold and wet soil, Hardy to zone 4. Gisela DWARF (2.5 – 3.5 meters / 8 – 12 feet at maturity)*Gisela 5,6, 12 with 12 being the largest The most productive and first true dwarfing rootstock for cherries. This rootstock makes it possible to maintain a sweet cherry tree between 2.5 – 3.5 meters (8 – 12 feet) compared to a typical sweet cherry tree which can reach up to 9 meters (30 feet). Mariana 26-24 SEMI-DWARF (4.5 – 6 meters / 15 – 20 feet at maturity)* Standard choice for apricots and plums, Mariana 26-24 has a shallow root system and has good tolerance for wet soils, Prone to Suckering. Mustang® (Prunus x ‘Jefchum’) SEMI-DWARF A very cold hardy rootstock with a fibrous root system that provides strong anchorage, Minimal suckering. Mazzard (Prunus Avium) STANDARD (4.5 – 6 meters / 15 – 20 feet at maturity)* More disease resistant than Mahaleb, Mazzard produces a very large tree that is vigorous, well anchored and hardy with very few suckers. Mazzard is most successful in sandy loam but can also tolerate heavier soils. It is the oldest rootstock and compatible with all cherry cultivars.
‘Colt’ (P. avium x P. pseudocerasus)- is a semi dwarfing rootstock however in the PNW it has been found to produce trees comparable in size to the Mazzard. Not compatible with Sam or Van cherries. Myrobalan (Prunus Cerasifera) STANDARD (5 meters / 15 feet at maturity)* A vigorous and disease resistant rootstock that adapts to a wide range of soil conditions, Myrobalan has a somewhat shallow root system but still produces well anchored trees, Prone to suckering. St. Julien A SEMI-DWARF (4.5 meters / 14 feet at maturity)* Mainly used for European plums, this rootstock is also widely used for other stone fruit such as peaches, nectarines and apricots. St. Julien produces a semi-dwarf tree that tends to bear fruit in 3-4 years that is free standing (requires no support). Krymsk Series Krymsk 1 DWARF (2.5 meters / 8 feet at maturity)* Developed in Russia, Krymsk 1 is related to a species of plum that is naturally very small. Trees start to fruit in 2-3 years (earlier than most). Krymsk 86 SEMI-DWARF (4 meters / 14 feet at maturity)* This new Russian hybrid rootstock produces mature trees faster, extends the lifespan of a tree, increases fruit size and yield, and can adapt to a broad range of soil types.
OH X F (Old Home X Farmingdale clones) Fireblight, the scourge of pear production in the eastern United States, caused Professor F. C. Reimer of Oregon State University to “search the world over” to find resistant trees. He made plant collecting expeditions to China, Korea, Manchuria, and Japan. One of the most worthwhile trips, however, was within the United States to visit Mr. Benjamin Buckman of Farmingdale, Illinois in 1915. During this trip Professor Reimer found two blight-free trees.
Good Resource http://treefruit.wsu.edu/web-article/pear-rootstocks/