Aiming to establish a mathematical model to estimate accurately the leaf area of Niagara Rosada in the region of Cardoso Moreira-RJ, this study was held in a particular vineyard Pioneiro Ranch, installed in 2002, in trellis system. It was collected randomly in the production cycle started in 2011, 70 leaves of various sizes, and completely expanded without apparent harm to determine the relationship between the leaf area (LA) and the area of the circle (CA), considering their diameter equal to the width of the leaf. By means of regression analysis, we obtained the linear equation (LAes = 0.82 * CA + 16.12) which together with two more were used to compare the leaf area estimated by measuring the leaf area of 30 leaves from the last cycle production (March 2012). It was found that the equations presented to estimate accurately the leaf area of 'Niagara Rosada / IAC 572' conducted in trellis system, in the region of Cardoso Moreira-RJ, with only one leaf dimension: the average width of the leaf, and the regression model obtained (LAes = 0.82 * CA + 16.12) was the least underestimated leaf area compared (regression coefficient = 0.99), followed by the model indicated by Pedro Jr. et al. (1986).
Vitis labrusca; Mathematical models; Conduction system; Leaf surface
