V-shaped Canopies in an Apple Orchard from the Perspective of over a Dozen Years of Research

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-year-old 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.