Procedure for Evaluating Varieties of Flue-Cured Tobacco for Performance in Soil Infested With the Black Root Rot Fungus

Abstract

Differential reaction of flue-cured tobacco varieties in soil infested with the black root rot organism Thielaviopsis basicola (Berk.) Ferr. was estimated by using data collected on the following characteristics: weight of roots, weight of aerial growth, height of growth, and rated amount of root lesions and aerial growth. The different measurements and scores produce different rankings and in order to set up a single ranking to express the relative performance of varieties, a discriminant function approach was adopted. The objective of this approach was to obtain a linear function which best discriminates among varieties. It is suggested that the discriminant function need be based on only the rated amount of aerial growth and root lesions.