Abstract:
The purpose of this research was to assess the influence of several orchard systems
involving trees trained to different leader numbers on growth, cropping, and fruit quality
of two apple cultivars. The study was conducted during 1994-2007 at the Fruit
Experimental Station in Samotwór, next to Wrocław (south-western Poland). One-yearold
trees of ‘Elstar’ and ‘Jonagold’ cultivars on the M.9 rootstock were planted in the
spring 1994 using 3.5 m spacing between rows and a variable in-row spacing: 2.4 m
(Mikado-four leaders), 1.8 m (Drilling-three leaders), 1.2 m (Tatura-two leaders), and 0.6
m (Güttingen-V-one leader). In this way, the number of leaders per hectare was almost
the same, regardless of the system. The most vigorous growth occurred on the most
sparsely planted trees under the Mikado system, whereas the Güttingen-V apple trees
developed thinnest shoot systems. The bloom abundance registered in the 2004-2007
periods was more related to the year, rather than to the planting system. The 1995-2007
total per-tree yield was decreasing as the planting density increased. When yield per
hectare was considered instead, the Güttingen-V system still produced the lowest. As the
trees aged, the quality of apples diminished-possibly as a result of increasing tendency
toward biennial bearing. In the last years of the study (2003-2007), the trees with the
largest numbers of leaders, i.e. Mikado and Drilling, showed the most irregular yielding
patterns. The orchard planting system had no significant influence on the fruit mean
weight.
Keywords: Biennial bearing, Fruit quality, Training system.
