The most commonly-used rootstock worldwide among dwarf rootstocks is the M9 rootstock. It grows better in fertile lands. It requires support all its lifetime ever since it is planted. It starts to grow fruits in the following year of its planting and it does not grown any longer than 270 cm even under optimum circumstances. It grows as big as20-40% of its seedling. M9 is resistant to crown rot disease (Phytophytoraspp); but vulnerable to fire blight disease (erwinaamylovora) and woolly aphid (EriosomaLanigerum).
M9 rootstock can be reproduced by Stool Bed Layering or Mound Layering
Varieties grafted on M9 rootstock are shaped and pruned in accordance with Slender Spindle training system. Planting distance to be applied in gardens formed with varieties grafted on M) rootstock should be (1.5 m x 3.5 m) or (2.0 m x 3.5 m) depending on soil fertility.
Varieties that grow as semi-dwarf such as StarkrimsonDelicious or Starkspur Golden Delicious must never be grafted on M) rootstock; gardens should be formed with seedlings obtained by grafting varieties that grow strong (standard) such as Starking Delicious, Golden Delicious or Granny Smith.
Economic lifetime of varieties grafted on M9 rootstock is 15-20 years. They yield 60-70kg of fruit per tree, which means 7 tons of product per decare. Number of trees per decare should be calculated as minimum 80-100; and in fertile lands, minimum 140-150