APPLE ROOTSTOCK EVALUATION IN MASSACHUSETTS: 1986 



Wesley R. Autio 



Department of Plant and Soil Sciences 



University of Massachusetts 



With the increasing costs of land, labor, and all inputs of orchard 

 production, there is a need to intensify management. The use of dwarfing 

 rootstocks is one way to accomplish this while reducing some costs and 

 increasing returns. However, rootstocks must be evaluated thoroughly prior to 

 wide scale planting. In this paper 1 would like to present the results of two 

 rootstock plantings at the Horticulture Research Center in Belchertown, 

 Massachusetts. 



The University of Massachusetts has been involved with the NC-140 

 Regional Research Committee for a number of years, and in 1980 and 1984 

 plantings were established at about 30 locations across the country and Canada. 

 The 1980 planting consists of Starkspur Supreme Delicious on Ottawa 3, M.7 

 (EMLA), M.9A (EMLA), M.26 (EMLA), M.27 (EMLA), M.9, MAC 9 (Mark), MAC 

 24, and OAR 1. The EMLA designation means that the source of the rootstock 

 was a clone which has had the viruses removed. A similar planting of these 

 rootstocks with Summerland Red Mcintosh as the scion cultivar was established 

 in 1985. 



The 1984 planting includes Starkspur Supreme Delicious on Bud. 491, Bud. 9, 

 MAC 1, MAC 39, P.l, P. 22, seedling, CG 10, CG 24, M.4, M.7 (EMLA), M.26 

 (EMLA), Bud.490, P. 2, P. 16, P. 18, CG, and Ant. 313. Descriptions of the origins 

 of the rootstocks in both the 1980 and 1984 plantings can be found in Fruit 

 Notes 51(4):22-24. 



1980 Planting 



Tables 1, 2, and 3 show the sizes, yields, and amounts of suckering of the 

 trees in the 1980 planting after seven growing seasons. Based on trunk 

 diameter and height (Table 1), the largest trees were on MAC 24 roots, and 

 they were significantly larger than those on M.7 (EMLA). Trees on MAC 9 

 were similar in size to those on M.26 (EMLA). Trees on M.27 (EMLA) and M.9 

 were the smallest. Interestingly, those on M.9A (EMLA) were significantly 

 larger than those on M.9. 



The hypothetical number of trees per acre (Table 1) was calculated from 

 tree spread. It was assumed that spacing between trees should be 40% greater 

 than the present spread, and the distance between rows should be approximately 

 8 feet larger than the spacing between trees. These data suggest that the 

 optimal density of MAC 9 is similar to that of M.26 (EMLA). MAC 24 requires 

 a very wide spacing, approximately 20 x 28 feet. 



Yield for these trees is reported in Table 2 as yield per tree and per acre 

 (calculated from hypothetical tree density) for 1986 and on a cumulative basis. 

 Generally, the largest trees were the most productive per tree, but the 



