PRODUCTIVITY AND FRUIT QUALITY OF AROMA APPLES AS AFFECTED BY TREE DENSITY IN SINGLE ROW, DOUBLE ROW AND TRIPLE ROW PLANTING SYSTEMS IN A NORTHERN CLIMATE

摘要

In five experiments, the productivity and fruit quality of 'Aroma' apples as affected by tree density in single row, double row and triple row systems were studied over 11 years (1982-92). Tree vigour was more strongly affected by rootstocks (MM106 > M26 > M9) than by tree density within the range tested. In the single row system,'Aroma' on M26 at density 1270 trees per ha outyielded trees on MM106 (800 trees per ha) by 41%. By density 2660 trees per ha in the single and double row system of 'Aroma' on M9, an additional 31% yield increase was obtained. At this density, yield per tree was reduced significantly. Fruit quality components like fruit size, soluble solids content, ground colour, red surface colour and flavour were not affected by planting system or tree density. 'Aroma'' on M26 in the triple row system with 50% more trees per ha outyielded trees of the single row system with similar within-row spacing by 55%. Apples obtained acceptable fruit quality in the triple row system.