Influence of improved seedling rootstocks on dwarfism, uniformity, and fruit set of apple cultivars in a 15-year scheme

Abstract

ABSTRACT A study was carried out to determine the influence of five pre-selected F1 half-sib seedling rootstocks, including ‘Morabbaei’ and ‘Zinati’ (the self-compatible crabs), ‘Azayesh’ (the self-incompatible crab), ‘Northern Spy’, and ‘Golden Karaj’, on commercial apple cultivars in 2017–2018. For this purpose, bloom phenology, ripening time, flowering intensity, fruit set, total fruit number and yield, tree height, and shading area were evaluated. Bloom end was postponed by the three crabs and ‘Northern Spy’ seed rootstocks. Overall, scions on ‘Zinati’ and ‘Morabbaei’ had higher inflorescence and on ‘Morabbaei’ seedlings managed to retain more fruits. In addition, the highest total fruit number and yield were achieved by ‘Morabbaei’ seed rootstocks. Through the lowest tree height and shading area, the cultivars’ highest vigour control was performed by ‘Morabbaei’ and ‘Zinati’. It was concluded that the self-compatible dwarf seedlings (‘Morabbaei’ and ‘Zinati’) elevated the trees’ uniformity and induced high yield and long blooming period.