Plastochron estimate in grapevine 'Marselan' and 'Tannat' cultivars
Plastochron safe estimates contribute for modeling improvement of grapevine development and allow identifying the phenological behavior of culture, to check the adjustment, to set more appropriate management practices and to assist in agricultural zoning culture. Thus, the aim of this study was to estimate the plastochron in Marselan and Tannat grapevine cultivars in the region of the Border West of Rio Grande do Sul. The experiment was conducted in grapevine orchard with Marselan and Tannat cultivars in the municipality of Itaqui-RS in 2010, between September and December. The plastochron was estimated by the inverse of slope of the linear regression between the number of visible nodes by branches and thermal time (base temperature of 10 °C). For Marselan and Tannat grapevine cultivars can be used plastochron value of approximately 56.25 ºC day node-1.