PT  - JOURNAL ARTICLE
AU  - Mark Steele
AU  - Anatoly A. Gitelson
AU  - Donald Rundquist
TI  - Nondestructive Estimation of Leaf Chlorophyll Content in Grapes
AID  - 10.5344/ajev.2008.59.3.299
DP  - 2008 Sep 01
TA  - American Journal of Enology and Viticulture
PG  - 299--305
VI  - 59
IP  - 3
4099  - http://www.ajevonline.org/content/59/3/299.short
4100  - http://www.ajevonline.org/content/59/3/299.full
SO  - Am J Enol Vitic.2008 Sep 01; 59
AB  - Leaf chlorophyll content provides valuable information about the physiological status of plants, and there is a need for accurate, efficient, practical methodologies to estimate this biophysical parameter. Reflectance measurement is a means of quickly and nondestructively assessing, in situ, the chlorophyll content in leaves. The objective of this study was to develop a precise, efficient, nondestructive technique to estimate leaf total chlorophyll (Chl) content in grapes. A relationship was established between Chl content and the red-edge chlorophyll index, based on reflectances in the red-edge (710–720 nm) and near-infrared (755–765 nm) spectral ranges, and the algorithm for Chl retrieval was calibrated. The accuracy of Chl prediction using an independent data set, containing sampled leaves from three field-grown grape cultivars (Edelweiss, Saint Croix, and DeChaunac), was evaluated with no re-parameterization (adjustment of the coefficients) after initial calibration. Although Chl in the validation data set was widely variable, from 3 to 506 mg m−2, the calibrated algorithm was capable of accurately predicting grape leaf Chl with RMSE <30 mg m−2. Such an approach has potential for developing simple hand-held field instrumentation for accurate nondestructive Chl estimation and in analyzing digital airborne or satellite imagery to assist in vineyard management decision making.