University of Vermont

UVM Fruit

Tree Fruit: Horticulture

Potential Apple Rootstocks for Vermont

The information presented here has been gathered from various sources, our UVM NC-140 Rootstock Evaluation plot, and grower comments -M. Elena Garcia Tree Fruit Specialist

Seedling (adapted to various soil conditions)

Strong Points:

  • Well anchored
  • Hardy
  • Tolerant to fireblight
  • Very few burrknots
  • Large, vigorous tree

Weak points:

  • Yield variable
  • Variable resistance to crown rot
  • Suckering may be a problem
MM.111 (best on well to moderate drained soils)

Strong Points:

  • 80 to 85 % of seedling size
  • More tolerant of drought than other rootstocks
  • Resistant to WAA
  • Good anchorage
  • Moderately resistant to collar rot
  • Hardy
  • Spreading and rugged root system - can tolerate wider range of soil conditions

Weak points:

  • Large trees perhaps only 10 to 15% smaller than seedling trees
  • Later fruiting than MM.106
  • Excessive burrknot development
  • Doe not tolerate wet soils
  • Tree form is more upright
MM.106  (best on well drained deep soils)

Strong Points:

  • Induces early bearing - more so than other semi dwarfing stocks.
  • Cultivars usually productive on this rootstock
  • Above average tolerance to drought and low temperatures
  • Good anchorage and favors good framework and central leader development
  • Sucker free
  • Resistant to WAA
  • Hardy very spreading - penetrating root system

Weak points:

  • Susceptible to collar rot and tomato ring spot virus
  • Sensitive to "wet foot"
  • Resumes growth in the early spring and hardens off in late fall
  • Excessive vigor particularly on standard type Delicious that do not bear early
  • Dwarfing 70  to 85% of seedling tree development - too large
M.7 (best on well to moderate deep drained soils)

Strong Points:

  • Some dwarfing - 55 to 75% of seedling tree size
  • Commercially acceptable -was considered the standard planting stock
  • Early bearing
  • Above average resistance to collar rot
  • Above average tolerance to droughty soils
  • Major tap root with several branch spreading roots
  • Hardy, but not as hardy as M.26

Weak points:

  • Severe suckering
  • Anchorage only fair - not recommended for Delicious and shallow soil plantings
  • Susceptible to WAA
G.30 (well adapted to most soils)

Strong Points:

  • 60 to 65 % of seedling size
  • Early bearing and more productive than M.7a
  • Well anchored
  • Much less prone to suckering than M.7a
  • Resistant to fireblight

Weak points:

  • More testing needed
  • May be more difficult to obtain. (Available in 1998)
  • Susceptible to common latent viruses
  • Brittle graft union with some newer cultivars
M.26 (best on well drained, loamy soils)

Strong Points:

  • 55 to 65 % of seedling tree size 
  • Easy to prune, maintain and harvest
  • Early bearing in some orchards
  • Very productive if properly spaced and trees vigorous
  • Hardiest of M or MM series rootstock
  • Little suckering
  • Spreading root system

Weak points:

  • Susceptible to fire blight, WAA, collar rot and tomato ring spot virus
  • Suckers and excessive burrknots
  • Trees require support in many orchards
  • Variability in tree vigor
  • Some cultivars and spur-types on certain soils have displayed weak growth and crop performance, i.e., Cortland, Macspur and Spur Delicious - must plant on only the best well drained soils
  • Very sensitive to "wet feet"
  • Possibility of incompatibility at graft union with some cultivars, i.e.,Macoun
  • Somewhat slow to harden-off
M.9  (best on well drained, loamy soils)

Strong Points:

  • 40 to 45 % of seedling tree size
  • Early bearing and capable of good yields
  • Resistant to collar rot
  • Valuable as interstock on interstem trees
  • Easy to prune, maintain and harvest
  • Well suited for trellising or training to a post
  • Small - confining root system

Weak points:

  • Trees need support because of brittle root system
  • Bark attractive to mice
  • Suckers
  • Susceptible to fire blight and wooly apple aphids (WAA)
Bud. 9 (does not tolerate wet soils)

Strong Points:

  • Promising new rootstock
  • 35 to 40 % size of seedling
  • Very resistant to collar rot
  • Hardier than M.9

Weak points:

  • Needs support
  • Moderately susceptible to fireblight and tomato ringspot virus
  • Drought susceptible
P.2  (best in well drained soils)

Strong Points:

  • 35 to 40 % size of seedling
  • Very early bearing
  • Resistant to crown rot
  • Very little suckering

Weak points:

  • Needs support
  • Moderately susceptible to fireblight
  • Susceptible to tomato ringspot virus
M.27 (best on well drained, loamy soils)

Strong Points:

  • 25 to 30 % of seedling size, or even smaller
  • Very dwarfing (4 to 5 feet ) and somewhat hardy
  • Very early bearing
  • Resistant to collar rot
  • Useful as interstock on interstem trees
  • Easy to prune, maintain and harvest
  • Smaller - confining root system

Weak points:

  • Poor anchorage because of brittle root system - tree needs support
  • Susceptible to fire blight
  • Only suitable for vigorous growing cultivars
  • Easy to 'runt-out'
Ottawa 3 (well drained soils)

Strong Points:

  • 50 to 55 % of seedling tree size
  • Early bearing
  • Very productive
  • As hardy as M.26
  • Resistant in most soils to crown rot
  • Very few burrknots

Weak points:

  • May need support
  • Roots poorly; may be a factor in orchard establishment
  • Moderately susceptible to tomato ringspot virus and common latent viruses
EMLA, 9, 26, 7 etc. (Virus - free)

Strong Points:

  • Cultivars on virus-free rootstock are more vigorous than those on virus-infected rootstock
  • Virus-free M.9's probably will produce larger yields than virus-infected trees
  • Yield efficiency (pounds of fruit/unit of space occupied) may be higher
  • Fruit quality may be better because they have stronger growth, may require less "tender loving care"

Interstems (Best on well drained, loamy soils)

M.27M.9/MM 106 (adapted to most soils)

Strong Points:

  • 50 to 60  seedling size
  • Early bearing
  • Productive
  • Moderate hardiness
  • Easy to prune, maintain and harvest
  • Spreading root system

Weak points:

  • More expensive than single worked tree
  • Usually only available by contracting 2 years in advance of planting
  • Lack of data on long-term performance
  • On some cultivars and spur-type, it may be difficult to develop a strong central leader
  • Suckers from rootstock and interstem piece (especially when stem piece is planted above soil line)
  • The interstem piece is generally M.9
  • Burrknots* on the M.9 stempiece are common
  • Tendency to cause inconsistent tree development and crop performance
  • Posting usually required when interstem portion planted above soil line
  • Stem piece can often become distorted in form
M.27, M.9/MM.111 (good in most soils)

Strong Points:

  • 50 to 60 % of seedling tree size
  • Early bearing
  • Very productive
  • Moderately hardiness

Weak points:

  • Similar to the previous combination

Last modified March 26 2014 11:47 AM