-6- 



Our findings agree with a similar study conducted by Lord and Sincuk (2) with Spartan 

 apple trees and with experiments of Elfving and Forshey in New York state (1). The latter 

 workers used heading cuts of various severity on vigorous 1-year-old wood of a non-spur 

 Delicious. Increased severity (removal of a greater fraction of 1-year-old wood) produced 

 increased shoot growth from 1 and 2-year old wood. Fruitfulness decreased as severity increased. 



It is of interest to note in Table 1 that yields on the Conventional and Slender Spindle 

 trees were comparable. However, the annual practice of removing the strong extension 

 shoots of the central leader and using a weaker upright growing competitor as the new 

 extension shoot on Slender Spinle trees to produce a zig-zag growth pattern was discontinued 

 after the 1979 dormant pruning season due to difficulty in maintaining leader dominance. 

 Trees on M26 seem to react more to unfavorable growing conditions tha those on more vigorous- 

 size controlling rootstocks and the central leaders often require support but we also encounter- 

 ed problems with apical dominance with Spartan trees on IV17a rootstock trained as Slender 

 Spindles (2). These results and observations in a trial with Gardiner Delicious on MM106, 

 IVIYa and M26 suggest that pruning the leaders to develop a zig-zag growth pattern and to 

 reduce growth should be delayed on free standing trees until the leader nearly attains 

 the height desired for the tree. 



Summary 



In todays economic climate of high interest rates growers must obtain a return on 

 capital investment as soon as possible. The key to early fruiting is the planting of a well- 

 feathered (branched) tree and the rapid development of a productive bearing surface. 

 The grower has little control over the quality of the nursery stock, except to reject inferior 

 trees; but has no one to blame but him/herself if early yields are reduced by improper 

 pruning, especially an excessive number of heading cuts. Emphasis should be on training 

 rather than pruning young trees since fruiting is the key to control of vegetative growth. 



Certainly, some pruning is necessary but the majority of cuts should be thinning rather 

 than heading cuts on trees of all ages. Thinning cuts usually improve light penetration 

 into the tree, thus increasing carbohydrates that encourage flower bud initiation. Heading 

 cuts encourage vegetative growth which may increase shading in the interior of the tree and 

 reduces fruitfulness. 



Fruiting decreases from the exterior to the interior of the tree and much of the wood 

 4 years or older may have few, if any, flowering spurs. Thus, the 2- and 3-year-old wood 

 is of great importance to the fruitfulness of apple trees and should be subjected to only 

 modest pruning using thinning rather than heading cuts. 



Literature cited 



1. Elfving, D.C. and C.G. Forshey. 1972. Growth and fruiting responses of vigorous 



apple branches to pruning and branch orientation treatments. J. Amer. Soc. 

 Hort. Sci. 101:290-293. 



2. Lord, W.J. and J. Sincuk. 1980. Progress report: Pruning effects on growth and 



fruiting of Spartan apple trees. Massachusetts Agr. Ext. Serv. Fruit Notes 

 45(5):l-8. 



