.2 



36 



30 



24 



18 



Yield efficiency (Ibs/irT TCSA) 



f^^ 



M.9/A.2 



Ott.3 



M.7 EMLA M.26 EMLA 



M.7A 



OAR 1 



Mark 



Figure 3. Cumulative yield efficiency (1988-90) of Summerland Red Mcintosh trees on 

 various rootstocks planted in 1985. Bars with any letter in common are not significantly 

 different at odds of 19:1. 



Trees in this trial are only 6 years old, so 

 ultimate performance cannot be determined 

 yet; however, at this point trees on Ott.3 are 

 performing the best. The tree size is somewhat 

 smaller than those on M.26 EMLA, and effi- 

 ciency is twice that of M.9/Alnarp, M.7 EMLA, 

 M.26 EMLA, or M.7A Mark produced a very 

 efficient tree early in its life, but problems with 

 overproduction have weakened its potential for 

 production over the next few years. M.26 EMLA 

 did not perform any better than M.7 in this trial, 

 which is a surprising result. M.7 EMLA and 

 M.7A produced trees which were similarly effi- 

 cient but significantly different in size. 



Other trials recently planted or planned will 

 study performance of new rootstocks with culti- 

 vars of importance to the New England apple 

 industry. A trial was planted in 1990 at the 

 Horticultural Research Center which compares 



M.9 EMLA, Bud.9, and M.26 EMLA, using 

 Marshall Mcintosh as a scion. A cooperative 

 trial with James Schupp at the University of 

 Maine was established in 1991 at the Horticul- 

 tural Research Center and Highmoor Farm 

 (Monmouth, ME) which compares Marshall 

 Mcintosh, Rogers Red Mcintosh, Chic-a-dee 

 Mcintosh, and Pioneer Mac on Mark, M.27 

 EMLA, M.7 EMLA, and M.26 EMLA. Another 

 cooperative trial with James Schupp is planned 

 for 1993 that will compare P.2, P. 16, P.22, M.27 

 EMLA, M.9, Bud. 146, Bud.469, V605-1, V605- 

 3, Burgmer 984, Burgmer 756, Burgmer 751, T- 

 337, and Pajam I using Summerland Red Mcin- 

 tosh, Cortland, and Macoun as scions. Another 

 NC-140 trial is also scheduled for 1993 which 

 will include eight new rootstocks from the 

 Cornell breeding program. Liberty will be the 

 scion cultivar. 



Fruit Notes, Summer, 1991 



