The aim of this study was to determine the duration of the production cycle and the thermal requirement of six clones of the 'Concord' grapevine, on three rootstocks, in the North of Paraná. The 'Concord' clones '22', '28', '49', '202', '211' and '225', obtained by Embrapa Grape and Wine, were evaluated grafted on '420-A', 'IAC 766' and 'IAC 572' rootstocks. The trial was carried out in an experimental vineyard located at the Technology Center of COROL Cooperative, in Rolândia, PR. A completely randomized design was used as statistical model, arranged in a factorial system (six clones x three rootstocks) with five replications. The grapevines were trained in a overhead trellis system, spaced at 4.0 x 2.0 m. The evaluations were performed during the harvest of 2009/2010 and 2010/2011. It was verified that '202' is the earliest 'Concord' clone, by showing the lowest cycle duration from pruning to harvest. Among the rootstocks, the '420-A' induces the highest daily rate accumulation of solid soluble, reducing the total cycle and the thermal demand, while the 'IAC 572' induces the lowest rate, increasing the cycle and the thermal demand of the clones.
SS accumulation; degree-days; Vitis labrusca; rootstocks
