Over their first nine years, trees on MAC-1, 

 seedling, or Bud.490 jdelded a total of 11 to 12 

 bushels. Those on P. 18 or Ant.313 yielded 

 approximately 14 bushels. P.l, M.4, or M.7 

 EMLA produced trees in the semidwarf to 

 semistandard category. Trees on M.4 have 

 yielded the most in the trial, more than 15 

 bushels per tree ciunulatively. Trees on P.l or 

 M.7 EMLA yielded between 11 and 12 bushels 

 cumulatively. Bud.9, MAC-39, M.26 EMLA, 

 P.2, and C.6 produced trees in the dwarf cat- 

 egory. In this category, C.6 and M.26 EMLA 

 have resulted in the greatest )delds, 8.6 and 7.1 

 bushels, respectively, per tree on a cumulative 

 basis. The other dwarf roots tocks have resulted 

 in yields between 4.8 and 5.8 bushels per tree. 

 The smallest trees in the planting are on P.22 or 

 P. 16. These trees are in the very dwarf category, 

 and they have yielded only about 1.5 bushels per 

 tree cumulatively. 



To accurately assess performance of a par- 

 ticular tree, it is important to look not only at 

 size and yield but also at jdeld efficiency. Effi- 

 ciency relates yield to tree size and gives an 

 assessment of relative yield per acre. Over the 

 life of the planting, the most yield-efficient trees 

 have been on P.2, P. 16, M.7 EMLA, C.6, or 

 Bud.9. M.7 EMLA is the biggest surprise in this 

 group, because in other plantings that we have, 

 it has not been very yield-efficient. The least 

 efficient trees have been those of the standard 

 size category. 



Table 2 reports fruit characteristics from 

 this planting in 1992. For the four years that 

 fruit have been assessed, no dramatic, consis- 

 tent differences have occurred in bruit ripening, 

 but fruit fi-om trees on C.6 often have been some 

 of the largest in the planting, as they were in 

 1992. 



Overall, the most promising new rootstocks 

 in this trial are P.2, C.6, and Bud.9. All are of the 

 dwarf category. P.2 and Bud.9 produce trees 

 similar in size to those produced by M.9, and C.6 

 produces a tree very similar in size to one pro- 

 duced by M.26. They seem well adapted to our 

 conditions, they were very precocious, and they 

 have continued to be productive for their size. 

 The only concern is with the potential of trees on 

 P.2 or Bud.9 to "runt out." Trees on P.2 or Bud.9 

 were nearly spur-bound after nine seasons. 

 High productivity likely will not continue imless 

 they are pushed to produce new vegetative 

 growth. This trial, however, is with a spur-type 

 variety. Newer trials include these two 

 rootstocks with more vigorous, nonspur variet- 

 ies, and I do not expect that they will become 

 spur bovmd as readily. 



We shall continue to evaluate new 

 rootstocks in Massachusetts. We have a plant- 

 ing scheduled for the spring of 1994 which will 

 contain 19 of the newest dwarfing rootstocks, 

 including some from the "Vineland Series," the 

 newest of the "Geneva Series," and a host of M.9 

 strains from Europe. 



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Fruit Notes, Fall, 1993 



