Fenologia e acúmulo de graus-dia da videira 'Niagara Rosada' cultivada ao noroeste do estado de S？o Paulo

this work aimed to evaluate the influence of the rootstocks 'iac 766', 'iac 572', 'iac 313' and 'iac 571-6' in the duration of phenological stages and in the accumulation of degree-days for 'niagara rosada' grapevine grown in votuporanga, sp, brazil. the statistical design was completely randomized blocks with split plots and five replications, the plot represented by the rootstocks and the subplots by two production cycles. after pruning the vine, evaluations were performed for phenological stages, using the criterion of eichhon & lorenz (1984). based on the phenological stages, we calculated the duration of periods: pruning to budding, pruning to beginning of flowering, pruning to beginning of fruiting, pruning to beginning of ripening of the bunches, pruning to beginning of the harvest. according to the cycle length of the vine and the daily average temperature, the accumulation of degree-days was calculated. it was observed a longer duration of the cycle and accumulation of degree-days for niagara rosada with the rootstocks 'iac 572' and 'iac 571-6' and a lower duration, with the rootstock 'iac 766'. the influence of climate on the duration of phenological stages of grapevine was showed.