Effects of Cane Density on Plant Growth and Fruit Production in Floricane Raspberry in the Upper Northern Climate

Raspberry pruning is a major operation that helps optimize fruit loading, disease management, and development of fruit quality, including fruit size and Brix. This study investigated the effect of cane density on cane growth, fruit quality, and yield of two floricane raspberry cultivars, Prelude and Killarney, in Fargo, ND, USA during 2019 and 2020. Floricanes were thinned in April to 5, 10, or 20 canes per planting hill. The fruit size, juice Brix, and yield were recorded. Before pruning, overwintering canes were counted and had their height measured in early April. Results showed that cane density had no significant effect on fruit size or Brix for both cultivars. However, the effect of cane density on yield differed by cultivar. In ‘Prelude’, the five canes/hill treatment led to significantly lower yields relative to the 10 and 20 canes/hill treatments. In ‘Killarney’, cane density did not impact yield. Among the three cane density treatments, there were no significant differences in cane height and number. This study indicates that the effect of cane density on raspberry production is different among cultivars. Thus, winter pruning should be optimized for each of individual cultivars.