strain. Gardiner trees were tallest on MM. Ill, followed by 

 those on M.7A. The two interstem combinations were 

 similar in size, and trees on M.26 were the shortest. 

 Siarkrimson trees were tallest on MM. Ill and M.7A, and 

 the M.26, M.9/MM.111, and M.9/MM.106 trees were of 

 similar height. Tree spread was greatest for trees on 

 MM.lll and M.7A. 



As expected, the size of the spur trees allowed for 

 significantly more trees per acre than for the standard 

 strain (Table 1). For both strains the M.26 and M.9/ 

 MM.lll rootstocks resulted in the smallest trees and most 

 trees per acre. The M.7A, M.9/MM.106, and MM.lll 

 trees were of similar tree spread which resulted in similar 

 values for trees per acre. Differences in precocity may 

 cause inaccuracies in determining theoretical densities 

 using these young trees. For instance, the trees on M.9/ 

 MM. 106 had the highest yields for 1984 and 1985, and as a 

 result their growth rate may have been slower than trees on 

 M.7A. When a similar formula is used to calculate ultimate 

 spread for trees on M.7A and M.9/MM.106, it would be 

 expected that either the density for M.9/MM.106 would be 

 underestimated or that for M.7A would be overestimated. 

 In this case it appears that the theoretical density for trees 

 on M.9/MM.106 maybe lower than the ideal density. The 

 situation may be the reverse for trees on MM.lll, where 

 the theoretical density was substantially higher than com- 

 monly recommended. 



Flowering and Fruit Set 



Table 2 shows the flowering and fruit set data for 1983 

 and 1984. No significant differences existed between 

 Gardiner and Starkrimson as to the quantity of bloom in 

 1983, but in 1984 Gardiner had significantly more bloom 

 than Starkrimson. These trees were in their fourth leaf in 

 1984 and the greater bloom on Gardiner, the standard 

 strain, may have been due simply to variation in these trees 

 which were just coming into production. In general the 

 interstem trees and trees on M.26 had more blossom 

 clusters than did trees on M.7A or MM.lll. 



Fruit set in 1984 (Table 2) was similar for the 2 strains, 

 but trees on M.9/MM.106 had the highest set and those on 

 MM.lll and M.9/MM.111 had the lowest. 



Yield 



Yield per tree and theoretical yield per acre are 

 presented in Table 3. On a per-tree basis the cumulative 

 yield for 1984 and 1985 was significantly higher for the 

 Starkrimson than the Gardiner trees. Some studies have 

 shown a similar relationship, with the spur strain yielding 

 more than the standard strain; however, most studies have 

 shown the reverse. Cases such as this one, where the spur 

 yielded more than the standard strain, may reflect precoc- 

 ity rather than ultimate yield potential. As the standard 



trees become Wger it would be expected that they would 

 yield more than the spur trees. 



Theoretical production per acre was significantly 

 higher for Starkrimson. Since the spur strain was smaller 

 and more productive it had a much higher theoretical yield 

 per acre. 



Yields per tree for the various rootstocks showed that 

 trees on M.9/MM.106 produced the most fruit, whereas 

 those on MM.lll produced the fewest. The MM.lll root, 

 with or without an M.9 interstock, appeared to confer a low 

 yield potential to the tree, or at least resulted in less 

 precocity. There also was a lower fruit set for trees with 

 these roots. It is particularly interesting to note the 

 difference between the two interstem trees. Trees on M.9/ 

 MM. 106 had the highest theoretical yield per acre, fol- 

 lowed by those on M.26, M.9/MM.111, M.7A, and 

 MM.lll. These data suggest that the interstem trees and 

 those on M.26 can result in the highest productivity. 



Anchorage 



Information already presented suggests that MM.lll 

 is a poor rootstock for Delicious, because first of all, it 

 produces the largest tree, and secondly, it has the lowest 

 yield per tree and theoretical yield per acre. However, it is 

 commonly thought to be well anchored. We were able to 

 measure anchorage easily in 1985 because of the effects of 

 Hurricane Gloria. Trees were subjected to winds in excess 

 of 65 miles per hour, and substantial tree movement 

 resulted. After the hurricane, several trees were leaning, 

 and the angle from vertical was measured (Table 4). The 

 poorest anchorage was seen with trees on M.7A roots, 

 where the average angle oflean was 43°. Treeson MM.lll 



