A measure of leaf quality in burley (Type 31) tobacco Nicotiana tabacum L.), which is independent of average market price, was created by means of a grade index similar to what has been devised for flue-cured and Maryland tobacco. The formula for calculating the numerical value for the grade index is (Leaf Group X Color) + Quality. Numbers were assigned to leaf groups, colors, and quality groups and these were used to calculate indices. The nondescript grades were arbitrarily assigned grade indices.

(Full article published with kind permission from "Tobacco International")