Variability of fruit quality parameters based on the position within apple tree canopy

Abstract

Investigations were carried out in 2016-2018 with apple-tree cultivar "Ligol" on rootstock P 60 planted at the distance 4X1.25 m in 2002. Orchard row direction was South-North. The aim of the experiment was to test fruit quality variability within tree canopy. Apples from following growing positions were tested: 1) top of the apple-tree (above 2.3 m), 2) lower inside part of the canopy (bottom) and 3-4) east and west sides of apple-trees. Fruit growth position in apple-tree canopy had a significant effect on fruit color, firmness and average fruit weight, chemical composition of the fruits. Fruits grown at the top of the tree had harder skin, up to 35% higher weight and better coloration than fruits which were grown at the lower inside part of the canopy. Latter fruits accumulated less total sugars but more acids. The amount of sorbitol was up to one third lower than in fruits from other parts of the canopy. Accumulation of glucose had the opposite trend: apples from the lower inside part of the canopy had up to 23% more glucose. Fruits from the top accumulated significantly higher amount of total phenols while fruits from the lower inside part of the canopy distinguished by higher amount of triterpenic compounds. Quality of fruits that grew on the east and west side of canopy were closer to fruits that grew on the top of canopy.