Apple breeding for tree architecture in Bulgaria: spindle and Solaxe trees

Apple breeding for resistance to major diseases and for spindle and Solaxe tree architecture aims to significantly lower the total cost of fruit production. During the second stage of our breeding program for resistance to scab, mildew and the aphids Dysaphis plantaginea Pass. and Aphis pomi De Geer, we selected hybrids with naturally attained spindle and Solaxe trees. In the progenies of 'Enterprise', 'Freedom', 'Avrora', 'Generos', 'Paulared', 'Prima', 'Tavria', 'Pionier' o.p. and 'Akane' ('Primrouge') × 'Krimskoe', 'Akane' × 'Florina', and 'MacIntosh Wijcik' × 'Paradox', we found trees with a habit resembling the characteristics of the spindle training system. Plants with a weeping habit were selected from crosses of 'Paradox' × 'Prima' and 'Elize Rathke' × 'Florina', and between those hybrids a further set was selected which exhibited a natural Solaxe, the modern system for training and pruning in apple orchards. Selected hybrids with the Solaxe growth habit will be crossed to improve fruit quality and to study the mode of inheritance of the Solaxe growth habit.