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Bull. Spec. CORESTA Congress, Guangzhou 1988, p. 67, APTS-6.

Relation between visual merit-classes of flue-cured tobacco and chromaticity parameters : application of an electronic screening process

CAROTENUTO R.; TRONCONE R.; MARTINIELLO P.
Istituto Sperimentale per il Tabacco, Scafati, Italy
In tobacco cultivars color development in leaf depends on field growth conditions and post-harvest processing. The quality of tobacco can be determined by the color of the flue-cured leaves. Their merit-classes are generally based on the evaluation of the chromaticity differences. However, the most common chromatic parameters are not well defined so they represent a weakness when applied to an automatic screening process. The success of the electronic screening process in flue-cured tobacco requires an accurate definition of chromaticity parametres. The a*, b* and L* coordinate chromaticity parameters are mathematically related to the values adopted by the International Commission on Illumination. The data presented will be used to assess : a) the genetic differences in chromaticity parameters in ten commonly cultivated cultivars; b) the relation between visual merit classes (A, B and C) and chromaticity parameters; c) the variation of these parameters (in each meri t class) on different regions of the leaf (apex, median and basal) and on leaf from harvests; d) the range values of each chromaticity parameter to utilize the electronic screening process. The results high light differences in chromaticity parameters among cultivars and leaves. The range in values of chromaticity parameters (L* a* and b*) obtained from cluster analysis resulted in correlations with the merit classes visually selected.