Columnar Peach Trees Grown using High Density ... - Plant Agriculture

Columnar Peach Trees Grown using High Density Orchard Systems
April, 2003
Dr. John A. Cline and Debbie Norton, Dept. of Plant Agriculture, University of Guelph
Dr. Scorza and co-workers of the United States Department of Agriculture,
Kearneysville, West Virginia, have developed peach trees with more upright growth
habits - referred to as ‘columnar’ trees. The purpose of this research is to provide trees
that have characteristics more favourable for higher densities orchard systems.
In Ontario, peach trees are commonly planted at approximately 150-200 trees per acre
using a free-standing open canopy/vase system. For the development of high density
peach production systems using traditional cultivars, severe pruning is necessary.
However, pruning invigorates trees and leads to excessive vegetative growth which can
adversely affect fruit quality and flower bud formation because of shading.
A more upright tree form should reduce the need for extensive pruning when planted at
closer spacings. The columnar form is a cylindrical-shaped tree which produces many
side branches with an upright, apically dominant growth tendency. The appearance of
the columnar trees resembles a fusetto/spindle trained tree.
The upright form was derived by crossing columnar with standard trees. Since tree habit
is determined by the cultivar rather than rootstock, breeders have been challenged with
trying to modify habit without sacrificing fruit quality. Improvements in fruit quality and
horticultural characteristics, that now nearly emulate commercial cultivars, have resulted
in the release of KV930455 (columnar form) (Figure 2) and KV930278 (upright form).
‘Sweet-N-UP’ is the first upright peach tree named by the USDA. It produces fruit of
excellent quality. Fruit are sweet and flavourful, have bright red blush covering 80% of
the fruit surface over a bright yellow background. Fruit size averages 2.75 to 3.0 inches
in diameter . Fruit ripen in mid August (‘Loring’ season) and the flesh is yellow
freestone and firm, smooth and melting.

Figure 11. Schematic showing different peach tree forms. ST = Standard; UP = upright
form (ie, KV930278 named ‘Sweet-N-Up’), PI= Pillar/Columnar Form (KV 870455)
Figure 2. Two-year-old columnar peach
‘KV930455' on ‘Bailey rootstock’ growing at the
University of Guelph, Vineland Campus
Current Research in Vineland
In order to examine the feasability of growing upright peach forms commercially in
Ontario, Drs. Neil Miles and John Cline initiated an experiment in 2001 at the University
of Guelph, Vineland Campus. The purpose of this project is to compare peach trees
with standard (HW261), intermediate (Babygold 5), upright (‘KV930278' - recently
named ‘Sweet-N-Up’) and columnar growth forms (‘KV930455'). All trees are planted
on Bailey rootstock. Each cultivar is trained to either a ‘Fusetto’ (spindle) system
(planted 1.2 m within x 4.5 m between rows; 1851 trees/ha or 750 trees/acre) or central
leader system (planted at 2.0 m within x 4.5 m between rows; 1111 trees/ha or 462

trees/acre). Standard cultural practices for the Niagara Region, including mineral
nutrition, IPM, fruit thinning etc. are being used. Permanent sod is established between
rows and woodchip mulch is used within the drip-line for weed control and to enhance
soil moisture levels.
Preliminary Results (Table 1)
The first year of fruiting was 2002. A number of parameters were measured included:
tree trunk cross sectional area, tree height, number of pruning cuts, and fruit set, total
yield, total number of fruit and mean fruit weight. This is a long term study focussing on
differences in yield, fruit size, fruit quality and labour requirements between the four tree
forms.
In 2002, the second year of the trial, trees of both the upright (Sweet-N-Up) and
columnar (KV930455) form were already exhibiting their natural shape and were the
tallest and narrowest, followed closely by the intermediate form (Babygold 5). The
standard form (HW261) was shorter than the other three cultivars. Trunk cross
sectional area (TCA) was similar for columnar, upright and intermediate forms but the
TCA for the standard form was about 30 % smaller than the others. The results were

similar for both training systems (Fusetto vs Central Leader).
The amount of pruning required was impacted by both tree form and training system.
Under the central leader system, the intermediate form required the most pruning, while
the standard required the least. It is anticipated that as the trees mature the standard
form will require more ‘containment’ pruning to keep it confined to its allotted spacing.
Under the Fusetto training system, the standard form required the most pruning
followed by the intermediate form. The columnar and upright forms required the least
amount of pruning. Fruit yield was light in 2002, the first year of production. It is too
early in the project to draw conclusions about yield, but the upright form (Sweet-N-Up)
produced the highest yield in both training systems and had an average fruit weight of
about 175 grams. Fruit quality was quite acceptable.
As this study continues, it will provide insightful information on the practical benefits of
high-density columnar and upright trees for commercial peach growers.
We gratefully acknowledge the financial support of the Niagara Peninsula Fruit and
Vegetable Growers Association and the Ontario Ministry of Agriculture, and for the
assistance of Rocco Guarnaccia and Darcia Fraser.