comparative study of the mineral nutrients in grey and non-grey flue-cured tobacco

The macro- and micro-elemental composition of flue-cured tobacco (Nicotianum tabacum L. ’Delhi 76’) was compared in leaf and soil samples associated with non-grey (normal) plants and plants affected with the grey-tobacco disorder. Samples were collected from 15 different locations in Quebec. Chemical analyses (mean of 15 locations) indicated significantly less N, P, K, Ca, and B but more Fe and Al in grey tobacco leaves. Soils producing grey tobacco had significantly less N, Ca, organic matter, and cation exchange capacity but more Cl. The brown spotting and bronze cast symptoms on the leaves of Quebec grey tobacco plants seemed to resemble most closely symptoms of Fe toxicity. Principal component analyses showed that the mineral nutrient profiles of grey and non-grey tobacco leaf samples were clearly distinguishable, but corresponding profiles for soil samples were not.