OPTIMIZATION OF PRIMOCANE-FRUITING RED RASPBERRY PRODUCTION GROWN UNDER HIGH TUNNELS

An experiment was conducted in 2009 and 2010 on Ile d’Orléans, Quebec, Canada to determine the effect of 2 training systems (hedgerow and V-trellis), apex pinching at a height of 1.5 m, and reflective groundcover (Extenday^TM) on yield and yield components of ‘Autumn Britten’ primocane-fruiting red raspberry (Rubus idaeus L.) grown under high tunnels. Our results demonstrate a significant increase in raspberry yield (25%) with the use of the reflective groundcover. The increase in yield is consistent with a 450% increase in reflected light reaching the lower plant canopy at 0.5 m and 1 m above the ground. In contrast, the trellising systems did not exert any substantial effect on raspberry yield. When primocanes were pinched, no significant differences in total yield were observed, in spite of the one-week delay in the onset of fruiting. The present work demonstrates that it is possible to enhance raspberry yield by using reflective groundcover. Furthermore, our results indicate that pinching could improve harvest efficiency by maintaining fruiting zone to a manageable height without any significant reduction in yield.