Getting two harvests per season on grapevine by means of pruning management

The aim of this study was to evaluate the effects of winter and summer pruning dates on harvest
anticipating of ‘Niagara’ and ‘Rose Niagara’ (Vitis labrusca L.) grapevine cultivars, as a strategy to obtain a second harvest in the same season. This experiment was carried out at UFRGS’ Agricultural Research Station, in Eldorado do Sul, Rio Grande do Sul State, Brazil. The grapevines were conducted by cordon training. The first experiment was undertaken during the 2000/01 season and considered two dates of winter pruning and two
intensities of summer pruning for ‘Rose Niagara’, while the second experiment was undertaken during the 2003/ 04 season and involved three dates of summer pruning and two grapevine cultivars (Niagara and Rose Niagara).
The summer pruning performed at the fourth leaf situated above the last cluster provided a second harvest.
Nevertheless, the summer pruning postponed the harvest in both grapevine cultivars, but did not affect plant production. The production of ‘Niagara’ grapevine were 3,6kg/plant and the ‘Rose Niagara’ were 1,3kg/plant.