Sweet cherry (Prunus avium) growth is mostly affected by rootstock and much less by budding height

The effects of several rootstocks and budding heights upon the growth of three cherry (Prunus avium) cultivars were investigated during the first 4 years of growth. The trial was established in 1998 in north-east Portugal using 'Burlat', 'Summit', and 'Van' cultivars grafted onto Edabriz, Gisela 5, and Maxma 14 at 10, 20, and 30 cm above soil level, and onto Cab and Prunus avium (Mazzard) at 10, 30, and 60 cm above soil level. Total shoot length and trunk diameter were recorded at transplantation from the nursery and at the end of the 3rd leaf stage in the orchard. As early as at transplantation, the effects of budding height, rootstock, rootstock x budding height interaction, and cultivar were significant in the trunk cross-sectional area (TCSA), being responsible for 11.6%, 9.6%, 9.3%, and 7.8% of the total variance, respectively. At the 3rd leaf stage, 79.2% of the expected variance was attributable to rootstock, and 4.1% to budding height. TCSAs of the trees on Edabriz, Gisela 5, Cab 11E, and Maxma 14 were, respectively, 30%, 32%, 62%, and 74% of those on Mazzard. Increasing budding height decreased tree vigour for all the rootstocks. In the nursery, it was already noticeable that vigour reductions between extreme budding levels were evident, first on the rootstock Cab 11E (44%) and then in Gisela 5 (35%), Edabriz (22%), and P. avium (20%). In the 3rd year in the orchard, tree TCSA reduction on Edabriz and Gisela 5 was 30% and on Maxma 14 it was 15%, when comparing buddings made at 10 and 30 cm. The reduction for the trees on Cab 11E and P. avium was 24%, when comparing buddings made at 10 and 60 cm. In our trial conditions the rootstock was the main influencing factor on plant growth and budding height was revealed to be the second most determinant factor on tree growth, irrespective of rootstock vigour. Consequently, budding height, although not so decisive in dwarfing as with apple and pear trees, can contribute to cherry tree growth and can also control and help to manage canopy size and crop rentability.