|Authors: ||A. Mika, E. Piskor|
|Keywords: ||Malus domestica, planting systems and density, tree training|
Feathered 'Jonagold' cv. ('Jonica' clone) apple trees on M.9 were planted in spring 1991 on light sandy soil in single row system: 3.5 × 1.43; 3.0 × 1.11; 2.75 × 0.91 m (2000, 3000 and 4000 trees per ha), and in multiple row system (4 row-beds): 3+3 × 1.5 × 1.85 and 2.75+3 × 1.25 × 1.60 m (3000 and 4000 trees per ha). All these trees were trained as slender spindle.
For super spindle system trees were planted in single rows: 2.5 × 1.0; 2.5 × 0.5 and 2.5 × 0.4 m (4000, 8000 and 10,000 trees per ha), and for V system at the distance 2.5 × 0.4 m (10,000 trees per ha). Irrigation was not available and in the dry climate of central Poland, where apple trees grafted on seedlings grow reasonably well at lower densities than studied here, trees on M.9 rootstocks suffered from drought.
Summer shoot growth was poor (30–40 cm), leaves and fruit small.
Trees started to yield in the second year, but the crop per tree was low (from 1.5 to 6.5 kg annually). Very dense planting suppressed growth of shoots, trunk increment and yield per tree, which varied from 5 to 6.5 kg annually at the lowest densities and 1.8 to 3.3 kg at the highest densities.
On the contrary, yield per ha has been increased from about 12 t (lowest densities) to 25 t (highest densities) annually.
Multiple row system yielded lower than single row system.
The V system was not better than super spindle.
Fruit size and color deteriorated with increasing planting density.
Fruit quality was very poor in multiple row system and in the super spindle at the density of 8,000 and 10,000 trees per ha.
Planting over 3000 dwarf trees per hectare was uneconomical.
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