Yield and quality of primocane-fruiting raspberry grown under plastic cover in southern Brazil

Raspberry (Rubus idaeus L.) is an economically important crop and its cultivation has been expanded across temperate and subtropical regions of Brazil. Growing raspberries under plastic cover has becoming more common worldwide. This study investigated the effect of plastic cover on productive and morphological performance of primocane-fruiting raspberry cultivars, in southern Brazil. The experiment was arranged in a 3 x 2 x 2 factorial design, with three raspberry cultivars, 'Heritage': 'Fallgold' and Alernazinha'; two cultivation systems, presence and absence of plastic cover; and two production cycles, fall and spring. We measured days from transplanting to flowering and harvesting. Plants were evaluated for dry mass of pruning, plant height, stem diameter, plant leaf area, fruit production, number of fruits, fruit weight, fruit longitudinal and transversal diameter, and harvesting period. Plastic cover reduced incident radiation on the canopy by 17 %. Cultivar 'Heritage' is early ripening in the fall cycle. The management under plastic cover prolonged the harvesting period of raspberries in the fall productive cycle for the cultivar 'Heritage' and, in spring, for cultivars 'Alemazinha' and 'Fallgold'. In the spring cycle, plants increased their leaf area, fruit production and number of fruits. The cultivar 'Alemazinha' performed better in the spring cycle when managed under plastic cover and was more productive, with a longer productive cycle and larger fruits.