Sweet cherry growth and early bearing on different rootstocks

The effects of several rootstocks on the growth of three cherry cultivars were investigated for four years, with the aim of selecting appropriate rootstocks for the local conditions. The trial was set up in 1999 at Mirandela, in north Portugal. The experimental design was a double split plot, in randomised blocks. Rootstocks were assigned to the main plots, cultivars to the sub-plots and budding heights to the subsub-plots. There are two plants per experimental unit in each replication. The plants were previously prepared in a nursery using the cultivars 'Burlat', 'Summit' and 'Van' and the rootstocks Edabriz, Gisela 5, Maxma 14, Cab 11E and P. avium. Trunk diameter and tree height were recorded annually from scion formation (plant raising) in the nursery to the end of the 3(rd) leaf in the orchard. The rootstock was the main factor influencing plant growth. Trunk cross sectional area (TCSA) at the end of the 3(rd) leaf was 25% (Gisela 5), 48% (Edabriz), 59% (Cab 11E), and 80% (Maxma 14) of of the TCSA of Mazzard. No suckering was observed on Maxma 14, and very little on Gisela 5 and Edabriz. This contrasts with an excessive number of suckers on Cab 11E. Cultivars 'Van', 'Summit' and 'Burlat' had similar trunk growth. Different rootstock/cultivar combinations resulted in a wide range of vigours: the trees of the cv. 'Summit' on P. avium roots attained the maximum TCSA (123.6 cm(2), 100%) and the cv. 'Van' on Gisela 5 resulted in the poorest growth (18.6 cm(2), 16%). As expected, 'Van' had the highest productivity on all the rootstocks, particularly on Edabriz, but fruit size was too small and unmarketable.