The Influence of Fruit Position in the Crown of Trees on the Sugar Content and Morphological Traits of Apple Fruits

Abstract

Apple fruits content in sugar differ depending on many factors as environmental conditions, technology, climate, cultivars etc. The objective of this study was to determine the sugar content and morphological traits of fruit of different apples cultivars, with summer ('Mollie's Delicious', 'Jersey Mac', 'Nebuta'), autumn ('Frumos de Voinesti', 'Prima', 'Priam', 'Pionier', 'Ardelean') and winter ('Golden Delicious', 'Feleac', 'Rosu de Cluj', 'Red Delicious') ripening, under the influence of area of crown where the fruits has formed. The highest sugar content was registered in the fruits belonging to 'Red Delicious' cultivars (17.8 °Bx in the bottom of the crown) and to 'Golden Delicious'(17.2 °Bx in the top of the crown), while the lowest sugar content was registered in fruits harvested from middle position of the 'Prima' trees crown (11.3 °Bx). The genotype determines evident differences for values of sugar apples content: 'Red Delicious' and 'Golden Delicious' were registered with highest value (16.4 and 16.2 °Bx), followed by 'Nebuta' (15.3 °Bx) and 'Rosu de Cluj' (15.2 °Bx). Regardless of cultivars, the fruits position in the crown influenced significantly their sugar content. The lowest content of sugar was registered for the fruits formed in the middle third of the crown (13.9 °Bx), while the lower third of the crown determined rich sugar content in the fruits (15.0 °Bx). There were identified both phenotypic and genotypic negative correlations between the sugar content and weight of the fruits. The results help apple breeders and fruit growers to know which apples are richest in sugar content and which technology of culture, pruning etc. should be applied if they want to obtain fruits with high or low sugar content.