Estimation of leaf area by means of linear regression aquation in Vitis Vinifera L.: limits and advantages

The aim of the study was to calculate regression model between leaf area and shoot length to obtain leaf area evaluation by indirect method and the factors influencing this relathionship. This research was carried out for 4 years in a vineyard located in Trapani area on three red cultivars grafted onto 1103 p, trained to simple cordon system and pruned with different methods. The vines were drip irrigated. High correlation existed between leaf area and shoot length and no influence played numerousness of samples. b1 of linear regression showed an increment of values at veraison than at berry set, because of b1 increment in lateral shoots in manual pruning and in the main lateral shoots for the other two pruning system. Difficulty was found to apply a phenological linear equation to another stage. Only manual pruning linear equation showed positive result when applied in different years. Definetly, the use of a linear equation to estimate leaf area, determined an estimation error. It is still necessary to evaluate the error range determining no influence on evaluation of plant vegetative and physiological parameters.