Effects of rootstock and training system on fruit quality of new sweet cherry cultivars

The current trend towards high-density plantings in the sweet cherry industry necessarily implies the use of dwarfing or semi-dwarfing stocks. While many exert a positive effect on growth habit and cropping performance by reducing vigour and inducing early bearing, high yield and yield efficiency, these rootstocks can often have a negative impact on fruit quality, an effect that becomes evident even in initial cropping years. Yet it is also a fact that tree training and pruning practices can be used to control fruit load while adapting growth habit and cropping so as to combine high yield and high fruit quality. We thus tested the new cultivars 'Sweet Aryana' and 'Sweet Lorenz', planted in 2008, grafted to the dwarfing stock Gisela 6 and the vigorous Colt and trained to narrow hedge and multi-leader vase at planting densities of 1250 and 667 trees ha(-1) in plots at Vignola, Modena Province. The trial data, which have been recorded up to 2012, include total yearly cropping per plant and per hectare, fruit size and weight, flesh firmness, sugar and acid content, and colour. Preliminary results show that Gisela 6 has positively affected early bearing and yield levels up to year 4, whereas by year 5 yield levels with Colt and the multi-leader system have reached those of Gisela 6. Fruit quality has been high in both combinations, indicating that specifically targeted management practices can obviate the limitations of a given stock.