Articles
ENVIRONMENTAL-FRIENDLY THINNING IN APPLE BY USE OF THE ‘BAUM’ DEVICE, ALONE OR COMBINED WITH BENZYLADENINE AT REDUCED RATE
Article number
998_4
Pages
43 – 50
Language
English
Abstract
Experiments on mechanical thinning using the BAUM device, designed at the Univerity of Bonn, were initiated in 2008 on 12-year-old apple trees orchards of cvs. ampion, Jonagored and Pinova, on M.9 rootstocks, growing in neighboring rows under similar conditions.
All three cultivars were thinned mechanically on the same day, irrespective of flowering stage.
Ten treatments were tested on each cultivar.
In four years, the effect of thinning as related to two vehicle speeds (5 or 7.5 km/h) versus two rotor speed (360-380 and 420-460 rpm) was evaluated.
At the time of mechanical thinning, the flowering of ampion was the most advanced (2-3 flowers open/cluster), while Pinova and Jonagored fllowers were mostly at the balloon stage, with the king flower frequently open.
Mechanical thinning was performed with a vehicle speed of 5 km/hour and 360 rpm rotor speed and also combined with BA 50 mg/L (Paturyl 47 ml/100 L) at the 10-12 mm fruitlet diameter or by hand thinning after June drop.
Apple trees thinned with BA or by hand only were used for comparison.
The use of the BAUM machine caused a reduction of fruit set, depending on the cultivar and on the combination of tractor speed and rotors speed.
Chemical thinning performed with BA reduced fruit set more efficiently than mechanical thinning alone.
Combined application of BA at low dose and mechanical thinning caused the strongest reduction of fruit set and the largest increase in mean fruit weight and the yield of marketable fruits while slightly diminished the red colouration of the skin of the cultivars ampion and Jonagored. Hand thinning after June drop increased the effects of mechanical thinning, too, but was less effective than use of BA. No major damage of leaves and fruits were noticed as well as effects on return bloom as related to the thinning methods tested.
All three cultivars were thinned mechanically on the same day, irrespective of flowering stage.
Ten treatments were tested on each cultivar.
In four years, the effect of thinning as related to two vehicle speeds (5 or 7.5 km/h) versus two rotor speed (360-380 and 420-460 rpm) was evaluated.
At the time of mechanical thinning, the flowering of ampion was the most advanced (2-3 flowers open/cluster), while Pinova and Jonagored fllowers were mostly at the balloon stage, with the king flower frequently open.
Mechanical thinning was performed with a vehicle speed of 5 km/hour and 360 rpm rotor speed and also combined with BA 50 mg/L (Paturyl 47 ml/100 L) at the 10-12 mm fruitlet diameter or by hand thinning after June drop.
Apple trees thinned with BA or by hand only were used for comparison.
The use of the BAUM machine caused a reduction of fruit set, depending on the cultivar and on the combination of tractor speed and rotors speed.
Chemical thinning performed with BA reduced fruit set more efficiently than mechanical thinning alone.
Combined application of BA at low dose and mechanical thinning caused the strongest reduction of fruit set and the largest increase in mean fruit weight and the yield of marketable fruits while slightly diminished the red colouration of the skin of the cultivars ampion and Jonagored. Hand thinning after June drop increased the effects of mechanical thinning, too, but was less effective than use of BA. No major damage of leaves and fruits were noticed as well as effects on return bloom as related to the thinning methods tested.
Publication
Authors
A. Basak, I. Juraś, P. Wawrzyńczak, M.M. Blanke
Keywords
Malus domestica Borkh., fruit set, fruit quality, alternative bearing, sustainable horticulture
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