Abstract

During 2009 and 2010, calibration of the Portable Chlorophyll Meter (Model CCM-200, Opti Sciences, USA) was carried out using Vitis vinifera L. cvs. Red Globe and Thompson Seedless. Aditionally, on cv. Flame Seedless, the Chlorophyll Meter was compared with the SPAD 502 meter (Konica Minolta, Osaka, Japan). The results of the portable meter CCM-200 were compared, using regression analysis, with chlorophyll extraction and subsequent spectrophotometric reading. Regression analysis for Thompson Seedless showed a high coefficient of determination (r2 = 0.99) and data adjusted to a second order linear equation; while for Red Globe there was a high coefficient of determination (r2 = 0.93), with data adjusted to a second order polynomial. The comparison between the two portable meters (Flame Seedless) showed a coefficient of determination r2 = 0.95 adjusted to a second order polynomial. Also, to 2010 seasons, the chlorophyll content evolution of ‘Flame Seedless’ and ‘Thompson Seedless’ was measured using the CCM-200 instrument. For both cvs. the highest chlorophyll content was observed close to veraison, however the optimum time to estimate chlorophyll content would be at the beginning of bloom. Variability of measurements at different times of the day and on different positions in the shoot (basal, middle, apical) was evaluated in ‘Thompson Seedless’ cv, being significant only the leaf shoot position. Results suggest that, previous calibration according to cultivar and location, portable chlorophyll meters are a suitable alternative to monitor chlorophyll content.