Effect of eight different rootstocks on agronomic and fruit quality parameters of two sweet cherry cultivars in Mediterranean conditions

The influence of Adara, CAB 6P, Gisela 5, MaxMa 14, Saint Lucie GF 64 (SL 64), Saint Lucie GF 405 (SL 405), Tabel-Edabriz and VSL 2 rootstocks onto fruit weight, soluble solids content (SSC), pH, firmness, titratable acidity (TA) and ripening index of 'Van' and 'Stark Hardy Giant' sweet cherry cultivars was studied during three consecutive years, between the 11^th and 13^th year after budding. Trunk cross sectional area (TCSA), annual production and yield efficiency were also determined. The experiment was performed in the Ebro Valley (Zaragoza, Spain), on a heavy and calcareous soil. Significant differences for most agronomic and fruit quality parameters were observed among rootstocks. By year 13, 'Van' trees on Adara and 'SHG' on MaxMa 14 showed the highest vigour (TCSA) whereas the lowest values were shown by Gisela 5 for both cultivars. The cumulative yield was the highest on Adara rootstock for 'Van' cultivar, although no significant differences were found when compared with CAB 6P. Similarly, the cumulative yield for 'SHG' was also higher for these rootstocks and MaxMa 14. The highest yield efficiency was recorded on Gisela 5 and CAP 6P for both cultivars, although no significant differences were found between them and Adara in the case of 'Van'. Regarding fruit quality, cherries of 'SHG' trees budded on Adara and Gisela 5 showed higher firmness. Despite the higher firmness of fruits on Gisela 5 and highest yield efficiency, the smaller size of fruits resulted in a non-interesting rootstock in terms of fruit quality for the growing conditions. This study demonstrates that the scion-rootstock combination greatly influences some important sweet cherry attributes such as vigour, yield, fruit size, SSC, and firmness.