Yield and fruit quality of organically cultivated blackcurrant cultivars

Blackcurrants are an important berry crop in many European countries. There is increasing demand for new and economically valuable blackcurrant cultivars suitable for organic production. To meet this demand, potential candidates of blackcurrant cultivars have been studied under Estonian field conditions. Our aim was to evaluate blackcurrant cultivars with regard to their productivity, berry quality, and resistance to the blackcurrant gall mite (Cecidophyopsis ribis Westw.). Our results showed that the drop of berries was the highest in the control treatment (no fertilizers used), and the lowest in conventional treatment. Higher yields were obtained from the conventional and organic treatments. The most productive cultivar, with the biggest berries and highest ascorbic acid content irrespective of cultivation system, was the cultivar 'Pamyati Vavilova'. Organically cultivated berries had a higher content of ascorbic acid than did conventionally cultivated berries. Minor damage by mites was observed on the cultivar 'Ojebyn'. We conclude that blackcurrant is a suitable crop for organic cultivation and that the cultivars 'Pamyati Vavilova' and 'Zagadka' respond well to organic cultivation. The cultivar 'Ojebin' is not considered to be well adapted for organic growing.