The parent rootstock of M-9 T337 is M-9. The General Netherlands Inspection Service for Woody Nursery Stock (NAKB) is responsible for elimination of viruses from propagation material and the maintenance and multiplication of varieties. Several virus certified selections of M-9 were tested and the T337 selection proved to be the most popular with growers in Holland. M-9 T337 is now the most widely used M-9 in Europe.
Influence on Scion Habit
Trees with M-9 T337 rootstock perform very similarly to those grown on EMLA 9. M-9 T337 induces early cropping with large fruit size and has the same influence as EMLA 9 on all scions. Some reports indicate that M-9 T337 may be slightly less vigorous than EMLA 9.
M-9 T337, like EMLA 9, is resistant to collar rot (Phytophthora cactorum) but is susceptible to mildew in the nursery. A regular spray program is recommended.
In layer beds, M-9 T337 roots slightly better than EMLA 9. Under our conditions, M-9 T337 develops well-rooted, straight rootstocks.
When considering high density plantings, M-9 T337 is another virus certified selection of M-9 from which to choose.