The rootstock effects on vigor, production and fruit quality in sweet cherry ( Prunus avium L.)

BACKGROUND: New sweet cherries rootstocks and cultivars can be valorized on the market if they express improved plant yield efficiency and fruit quality, and also including highest content of antioxidant compounds (mainly anthocyanins but also significant amounts of phenolic acids and flavonols). OBJECTIVE: The goal of this study was to compare the effect of 10 new rootstock genotypes, now available for cherry, on plant growth and fruit quality of the cultivar “Sweetheart”, a very late auto-fertile sweet cherry cultivar. METHODS: Plants vegetative and productive parameters, as well as fruit sensorial quality, were measured during a 5-year cycle (2011–2015), while fruit nutritional quality was investigated for the last 3 years (2013–2015). RESULTS: For the agronomical traits, the vigorous rootstock Adara/Major and intermediate Gisela 6 stands out for the plant yield. From the qualitative point of view, the intermediate MaxMa 14 and Gisela 6, and the dwarf Gisela 5, differed for reduced fruit size but with optimal sugar/acid ratio. The higher fruit nutritional value were detected for “Sweetheart” trees grafted on Adara/Major (vigorous), the best MaxMa 14 (weaker) and Gisela 5 (dwarfing) rootstocks. CONCLUSIONS: There is not a univocal combination between the scion and rootstock equally valid for all the considered parameters. The rootstock capable of ensuring good yields, sensorial and nutritional quality is Adara/Major. From the productive and qualitative point of view, Gisela 6 is well adapted to these conditions, while MaxMa 14 rootstock stands out for nutritional quality, although induces a high reduction of vigor, poor vegetative renewal and low average fruit weight.