Dwarfing rootstocks

In both studies the apples were grown in the biodynamic orchard Boomgaard ter Linde in the south-western part of the Netherlands. We used full grown apple trees of the Dutch variety Elstar on dwarf rootstock M9,2460 trees/ha, grown on limey humus sea loam with trickle irrigation. The experiment was replicated four times. 

In many cases cultivated soils have compacted areas which can severely impair tree growth. Compaction in soil may be due to factors associated with soil formation or geology, or it may have been caused by mechanical pressure from machinery or by deposits by transport and ground-levelling vehicles. If the soil is compacted it is absolutely essential to loosen the subsoil (e.g. by trenching or deep cultivation) before a new orchard is set up. Dwarfing rootstocks for apples and pears (M9, M27, quince C), elder and small fruit trees are particularly sensitive to soil compaction. 

Orchards with more than 4000-5000 trees/ha have very high establishment costs and increase the production risk. In many cases they do not achieve economically viable yields and make it difficult to produce quality fruit. In increasing the planting density on dwarfing rootstocks, the ecological requirements should be taken into account as well as the... 

The effect of the level of the graft union on growth is undisputed. This property of dwarfing rootstocks is used to obtain bees with less shoot... 

While they generally are considered a problem, viruses can sometimes give a plant desirable properties. For example, solid-color tulips, when infected with certain viruses, become mottled with bold blotches of color (these types are sold as Rembrandt tulips). Another virus infects an apple cultivar known as Mailing 9, which is used as a rootstock to dwarf apple trees. When special propagation techniques were used to rid some Mailing 9 plants of the virus, resulting trees no longer were as dwarfed. 

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