Influence of retained cane number and pruning time on grapevine yield components, fruit composition and vine phenology of Sauvignon Blanc vines

Background and Aims: Traditionally, the start of cane pruning is delayed until after leaf fall, when carbohydrate accumulation and cane maturity are complete. However, by starting immediately after harvest, the period for pruning may be increased by at least 4 weeks, reducing peak labour demands. Trials were conducted to investigate the consequences of various pruning times on vine phenology and yield. Methods and Results: Vines were pruned using 2- or 4-canes at one of four times during the winter from shortly after harvest to just before bud break in the spring. Pruning shortly after harvest caused no significant adverse effects on vine phenology or productivity. Pruning just before bud break delayed vine development. Stored total carbohydrate concentrations in the trunk were unaffected by pruning time or cane number retained after pruning. Conclusions: Carbohydrates accumulated in the trunks of grapevines to adequate levels by harvest and any post-harvest photosynthesis and/or cane maturation that may be occurring at this time had little effect on subsequent vine growth and development. Pruning shortly before bud break delayed bud break and may be an advantage where vines are at risk to spring frosts. Significance of Study: In cool climates where leaves senesce shortly after harvest, pruning immediately after harvest will have no adverse effects on subsequent vine phenology or yield, but will extend the period available to prune the vines, reducing the peak labour demand in the vineyard. Pruning late, slightly delays bud break potentially providing greater tolerance to late spring frosts.