Apple Rootstock Info: M.9

The pedigree is unknown and it was selected in England from a group of French genotypes known collectively as “Juane de Metz” in the late 1800s. M.9 is the most widely planted dwarf apple rootstock in the world and at least 30% of the trees in the U.S. are on M.9. M.9 EMLA is free of known viruses and is slightly more vigorous than the original M.9. Over the years European nurseries have selected clones of M.9 and now a number of clones are available and they vary in vigor: Six clones were compared in the NC-140 1994 dwarf rootstock trial with ‘Gala’; vigor from highest to lowest is M.9 Pajam 2 (also known as Cepiland) = M.9 RN29 (also known as Nic29) > M.9 Pajam 1(also known as Lancep) > M.9 EMLA > M.9 NAKBT337 > M.9 Flueren 56. In a Washington state trial, M.9 NAKBT337, M.9 Janssen 337 and M.9 Burgmer 751all produced trees of similar size. M.9 NAKBT337 is currently the most widely planted of the M.9 clones. Although M.9 performs well under many conditions and is considered the standard for dwarf rootstocks, it is not without problems. It is very precocious and has high yield efficiency, but it has poor anchorage due to brittle roots and a high fruit: wood ratio and requires full tree support. M.9 is very susceptible to fire blight and woolly apple aphid and fairly resistant to crown and root rots. It produces moderate amounts of root suckers and many burrknots.