EVALUATION OF BLACKCURRANT CULTIVARS FOR MACHINE HARVESTING IN ESTONIA

Commercial blackcurrant producers rely on mechanical harvesting and selection of suitable cultivars is of major importance. In Estonia, the main blackcurrant cultivar used in commercial plantations is ‘Öjebyn’, although it has a moderate yield and is susceptible to the blackcurrant gall mite, Cecidophyopsis ribis. The goal of this study was to find better blackcurrant cultivars for mechanical harvesting. In 2003, we established a trial to compare 10 cultivars, including three new ones (‘Karri’, ‘Almo’ and ‘Varmas’) from our breeding program and the three best ones (‘Pamyati Vavilova’, ‘Zagadka’) from a previous trial; ‘Öjebyn’ was our standard. Four more cultivars of potential interest for commercial production (‘Titania’, ‘Intercontinental’, ‘Prikarpatskaja’ and ‘Polar’) were included. Mechanical harvesting was assessed on 20 bushes per cultivar and was compared to hand harvest on two bushes in each of four replications in 2006, 2008, and 2009. The highest yields were harvested in 2009. On average, five cultivars ‘Pamyati’, ‘Vavilova’, ‘Varmas’, ‘Almo’, ‘Prikarpatskaja’, and ‘Intercontinental’ produced a higher yield than the standard cultivar ‘Öjebyn’. ‘Varmas’ and ‘Prikarpatskaja’ were the best performing cultivars when hand picked. The losses in mechanical harvesting were least with ‘Pamyati Vavilova’, resulting in the highest mechanically harvested average yield (1.4 kg/bush). Mechanical harvesting was effective also for ‘Varmas’, ‘Titania’, ‘Zagadka’, and ‘Prikarpatskaja’.