Rootstock Cultivars
Selection of rootstock cultivars can be difficult: vigorous roots tend to give trees that are healthy but grow too tall to be harvested easily without careful pruning, while dwarfing rootstocks result in small trees that are easy to harvest from, but are often shorter-lived and sometimes less healthy. Most modern commercial orchards use one of the "Malling series" (aka 'M' series), introduced or developed by the East Malling Research Station from the early 20th century onward. However, a great deal of work has been done recently introducing new rootstocks in Poland, the U.S. (Geneva), and other nations. The Polish rootstocks are often used where cold hardiness in needed. The Geneva series of rootstocks has been developed to resist important diseases such as fireblight and collar rot, as well as for high fruit productivity.
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