1999 NC-140 Dwarf Apple Rootstock Trial 



As part of the 1999 NC-140 Dwarf Apple 

 Rootstock Trial, a planting was established at the 

 University of Massachusetts Cold Spring Orchard 

 Research & Education Center, including Mcintosh on 

 CG.3041, CG.4013, CG.5179, CG.5202, G.16 (both 

 tissue cultured and stool bedded), M.26 EMLA, M.9 

 NAKBT337. Supporter 1. Supporter 2, and Supporter 

 3. Trees were individually staied and maintained as 

 vertical axes. Trunk cross-sectional area, root 

 suckering, yield, and fruit size were assessed annually. 



After fi\e growing seasons, trees on CG.4013 

 were the largest, followed by those on CG.5202 and 

 CG.5179 (Table 2). The rest had statistically similar 

 trunk cross-sectional areas. Cumulative yield (2001- 

 03) was greatest for trees on CG.4013. Across all 

 rootstocks, however, yield was roughly related to tree 

 size. Cumulative yield efficiency (adjusting yield for 

 tree size) was similar for all but trees on M.26 EMLA. 

 Those trees were significantly less efficient than trees 

 on CG.4013. CG.5179, or any of the Supporter 

 rootstocks. Fruit size was not dramatically affected by 

 rootstock. The only statistically significant difference 

 was that fruit from trees on M.9 NAKBT337 were 

 larger than those from trees on Supporter 2. 



1999 NC-140 Semidwarf Apple 

 Rootstock Trial 



As part of the 1999 NC-140 Semidwarf Apple 

 Rootstock Tnal, a planting was established at the 

 University of Massachusetts Cold Spring Orchard 

 Research & Education Center, including Mcintosh on 

 CG.4814, CG.7707, G.30. M.26 EMLA, M.7 EMLA, 



and Supporter 4. Trees were maintained as free- 

 standing central leaders. Trunk cross-sectional area, 

 root suckering, yield, and fruit size were assessed 

 annually. 



After five growing seasons, trees on G.30 were 

 significantly larger than all other except those on M.7 

 EMLA (Table 3). The smallest tree was on CG.4814, 

 which was obviously misplaced in the semidwarf 

 group. Its trunk cross-sectional area, yield, and yield 

 efficiency were similar to the dwarf trees in the trial 

 reported above. G.30 resulted in many fewer root 

 suckers than did M.7 EMLA, and had significantly 

 greater yield per tree (2001-03). Although the 

 difference was not statistically significant, trees on 

 G.30 were 75% more efficient than those on M.7 

 EMLA. Fruit size was apparently unaffected by 

 rootstock. 



Conclusions 



It is much too early to make conclusions based on 

 the data reported here. The variability that exists now 

 will dissipate over the next few years and expose more 

 statistically significant differences. That said, G.16 

 apjjears to be producing a tree somewhat larger than 

 does M.9 but one that is comparably yield efficient. 

 Fruit size from trees on G.16, however, bears 

 watching. Trees on G.30 have performed very well 

 for semidwarf trees, similar in size to those on M.7 

 EMLA, but without many root suckers and with 

 app>arently greater yield. The other Cornell- 

 Geneva rootstocks in these trials (CG.3041, 

 CG.4013, CG.4814, CG.5179, CG.5202, and 

 CG-7707) all appear to be performing well but vary 

 considerably in size, from full dwarf to semidwarf 



%X^ %i^ %i^ %i^ *A^ 



#T* #T* #T^ *T* #T* 



30 



Fruit Notes, Volume 68, Spring, Summer, & Fall, 2003 



