Table 1. Tree size after 10 growing seasons and projected tree densities of Rogers Red 

 Mcintosh and Macspur Mcintosh on different rootstocks. 



Distance between trees within rows was projected to be 10% less than the natural tree 



spread, allowing for overlap of trees. The distance between rows was the distance 



between trees plus seven feet, with the exception of the trelhs, which was assumed to be 



spaced 13 feet between rows. 



For the three characteristics in this table, the relative differences between rootstock 



treatments were statistically similar for each strain. The letter presented between the 



Rogers and Macspur columns represents the differences among rootstock treatments only. 



For a particular characteristic, if not represented by the same letter, rootstock treatments 



are significantly different at odds of 19:1. 



Rogers and Macspur averages are different at odds of 999:1. 



were added to the distance between trees in a 

 row to determine between-row spacing, with the 

 exception of the trellis. Because of the shape of 

 the trelUs, it was assixmed that all trellis combi- 

 nations could be maintained at 13 feet. (This 

 assumption is conservative, and it depends on 

 the final width of the trellis rows.) Potential tree 

 density ranged from over 360 trees per acre of 

 Macspur/M.9 to 145 trees per acre for Rogers/ 

 M.7A, Because of the difference in spread, 

 Macspur could be planted at approximately a 20 

 percent higher density than Rogers, assuming 

 no reversion. 



Figures 1 and 2 show the cumulative 

 yield per tree for the rootstock treatments and 



the Mcintosh strains, respectively. (jeneraUy, 

 larger trees )delded more per tree than smaller 

 trees, that is, trees on M.7A yielded more than 

 those on M.26, which yielded more than those on 

 M.9. The exception is M.9/MM. 111. Trees on 

 M.9/MM.111 yielded significantly less than the 

 trees on M.26, which were of similar size. Trees 

 on M.9 trained to a treUis yielded more than 

 those trained to a post. This result may have 

 occurred because the trellis maintains wood at 

 a more desirable angle for continued Smiting 

 and allows for upper branches to fill a larger 

 portion of the canopy than when no additional 

 support is provided. Additionally, the larger 

 Rogers trees yielded more than the Macspur 



8 



Fruit Notes, Winter, 1993 



