Abstract
The occurrence and chemical properties of grey tobacco leaves (Type III) found in 1995 crop of flue-cured tobacco cultivated in paddy field were investigated to compare with those of normal leaves. Cured leaves of NC82 were separated by visual characters into 3 classes of slight, fair and severe symptoms of grey leaf by the percentage of grey parts to whole leaf area. Number of samples classified with discoloring portion was the order of greyish brown > reddish brown > greyish yellow, respectively. Grey leaves of this type were mostly found among the leaves harvested from upper stalk position, and it was estimated that growth rate of upper leaves also influenced on the occurrence of grey leaves. Grey leaves showed remarkably lower b* and L* values than those of normal leaves, while a* value was mostly higher in grey leaves. These tendencies in chromatic aberration showed more remarkable difference in the degree of grey symptoms. Chemical analyses of grey leaf samples indicated that they contained less total nitrogen and nicotine, and more total sugar and starch than those of normal leaves. In chemical traits, these tendencies were accordance with the degree of grey symptoms, and within the same leaf, grey parts were decreased in total nitrogen and ether extract content compared with those of normal parts, but there was no difference in nicotine and Cl contents. Key words : grey leaf tobacco (type III), grey symptom, color, chemical properties.