CAN M.9 ROOTSTOCKS BE USED PROFITABLY IN 

 MASSACHUSETTS APPLE ORCHARDS? 



Wesley R. Autio 



Department of Plant and Soil Sciences, University of Massachusetts 



The title of New York Agricultural 

 Experiment Station Bulletin No. 406 (1915) is 

 "Dwarf Apples Not Commercially Promising." The 

 opinions expressed in that publication certainly do 

 not reflect those held by the current researchers 

 at the New York Agricultural Experiment Station, 

 Geneva; however, there is still much resistance 

 among growers to the idea of planting fully 

 dwarfed apple trees. In this article data will be 

 presented that show that fully dwarfed trees on 

 M.9 can be substantially more profitable than the 

 much larger trees on M.7, particularly during the 

 early fruiting years. 



Figure 1 



Size of Rogers Mcintosh trees 



planted in 1979. 



Feet 



M.7 A 



M.26 M.9 Post M.9 Trellis 



M.9 was one of the earliest dwarfing 

 rootstocks available. It was selected as a chance 

 seedling in France in 1879 (2) and produces a tree 

 only 25 to 50 % of the size of a standard, 

 seedling-rooted tree. A number of dwarfing 

 rootstocks which produce a tree similar in size to 

 that produced by M.9 now are being evaluated and 

 some are available, but M.9 still is used more 



extensively worldwide than any other very 

 dwarfing rootstock (2). In the U. S. the strain 

 of M.9 which is most commonly available is M.9 

 EMLA. It was originally propagated from a 

 virus-free strain produced by the cooperation of 

 East Mailing and Long Ashton Research Stations 

 in England, hence the EMLA designation. A tree 

 on M.9 EMLA is somewhat more vigorous than 

 one on standard M.9. In this study the size, 

 productivity, and profitability of trees on M.9, 

 M.26, and M.7 were compared. 



Table 1. Trunk circumference in 1987, calculated 

 tree density, and approximate spacing of Rogers 

 Mcintosh trees planted in 1979. 



^Calculated from 1987 tree spreads (Figure 1). 

 **Means within columns are significantly 

 different if not followed by the same letter. 



In 1979 a replicated planting of Rogers 

 Mcintosh and Macspur trees on M.7A, M.26, and 

 M.9 was established by Dr. Franklin W. 

 Southwick at the Horticultural Research Center, 

 Belchertown, MA. Half of the trees on M.9 were 

 trained to individual posts and half were trained 

 to simple, 3-wire trellises. At the end of the 

 1987 growing season (ninth leaf) trees were 

 nearing their mature size. Figure 1 depicts the 

 height and spread of the Rogers Mcintosh trees, 

 and Table 1 reports trunk circumferences. As 

 would be expected, trees on M.7A were the 



