Variability of properties of promising apple selections of the ‘Jonathan’ group

Apple (Malus × domestica Borkh.) is economically the most important species of genus Malus Miller. Developing new apple genotypes is carried out on a large scale in many scientific institutes throughout the world. ‘Jonathan’ is one of four cultivars which have been used as the most frequent progenitors in apple breeding programmes worldwide. The paper presents six promising apple selections bred at Fruit Research Institute, and ‘Jonathan’ as the parental cultivar. The assessed selections derived from the crosses ‘Jonathan’ × ‘Idared’ (J/3/60 and J/2/53), [‘Jonathan’ × J/54/53/59] × J/27/127/62 (J/4/106) and ‘Jonathan’ × J/54/53/59 (J/1/55, J/1/71 and J/1/15). Major phenological properties (flowering phenophase and harvest time), cropping and pomological properties (morphometrical and chemical characteristics of fruits) were assessed. The highest fruit weight (J/2/53; 188.4 g) and yield per unit area (J/3/60; 34 t ha-1) were reported in selections derived from the cross ‘Jonathan’ × ‘Idared’. Selections raised from a cross between ‘Jonathan’ and J/54/53/59 have high quality fruits. The highest soluble solids content was found in J/1/55 (15.3%), while the highest total sugars and acids content was evidenced in J/1/71 (9.61%; 1.46%, respectively).