Introduced by the Agriculture Canada Research Station in Ottawa, Ontario, Canada in 1974 as a hardy dwarfing rootstock. The parents were M.9 and 'Robin' crab. Ottawa 3 roots poorly in the stoolbed and is often micropropagated. Trees are precocious and produce few rootsuckers and burrknots. It is sensitive to apple stem grooving virus. Ottawa 3 was included in the 1990 NC-140 cultivar/rootstock trial at 12 locations and the 1990 dwarf rootstock trial at 8 locations. In general tree survival was slightly lower than for trees on other dwarfing rootstocks such as M.26 EMLA, Mark, M.9 EMLA and B.9. Tree size is between M.9 EMLA and M.26 EMLA (about 45% standard size). Cumulative yield was similar to M.9 and yield efficiency was usually higher than M.26 EMLA but lower than M.9 EMLA. Fruit size was often slightly small than for trees on M.9 EMLA or M.26 EMLA.
|Origin||'Robin' crab X Malling 9|
|Tree Size||45-50% of standard|
|Tree Support Needed||Yes|
|Where tested within NC-140 or other research plantings||AR, BC, CA, CO, IA, IL, IN, MA, ME, MI, MN, NC, NJ, NY, OH, OR, PA, SC, TN, UT, VA, WA, WI, GA, IN|