Response of Zante Grapevines to Cane and Harvest Pruning

Abstract

The effects of cane pruning and harvest pruning on the growth, productivity and fruit quality of Zante grapevines growing in the Australian Murray Valley were assessed over seven seasons. Spur pruned vines (56 nodes) were compared with three levels of cane pruning — four 14-node canes (56 nodes), six 14-node canes (84 nodes) and eight 14-node canes (112 nodes). The mean annual dry weight yield of the eight cane treatment was significantly greater than spur pruned vines due to a greater number of clusters per vine. The dry weight of clusters and berries and the concentration of soluble solids varied inversely with the number of nodes per vine. Growth, measured as weight of annual growth removed at pruning, was consistently lower on the six and eight cane treatments. No difference in the quality of raisins was observed between the treatments.

Harvest pruning significantly reduced the mean annual dry weight yield by about 19 percent. In all years when harvest pruned vines yielded less than cane pruned vines, the number of berries per cluster was significantly lower on harvest pruned vines. There were no consistent differences in the number of clusters per vine, berry dry weight or concentration of soluble solids. Harvest pruned vines tended to have less weight of prunings than cane pruned vines. The quality of raisins was similar from trellis-dried and rack-dried treatments.

The dry weight yield reduction due to harvest pruning was greater than that previously reported for Sultana. The greater yield reduction in this experiment is attributed to the effect of removing a greater proportion of foliage at harvest pruning and to berry drop during trellis-drying and harvesting. The number of canes retained at pruning did not influence the yield losses caused by harvest pruning.