Mohd Norhafeez bin Jusoh, Nabihah binti Mohd Zin, and Hideyuki Nagao

pp. 615 - 621

Abstract

Five strains of Fusarium solani isolated from root rot of tobacco from Kelantan and Terengganu, Malaysia were tested
for the pathogenicity on tobacco seedlings by root dipping method. All 5 isolates showed discoloration on the roots. The
nitrate non-utilizing (nit) mutants were generated from these pathogenic strains of F. solani and a compatible nit1 and NitM
pair was obtained in each strain. Vegetative Compatible Groups (VCGs) by nit mutants were determined. All 5 strains of
F. solani were assigned to the independent VCGs. Non-pathogenic strains of F. solani previously isolated from root rot of
tobacco in Malaysia also generated nit mutants and were assigned to 10 different VCGs. However, complementation of nit
mutants between 5 pathogenic strains and 7 non-pathogenic strains of F. solani was not achieved. Both pathogenic and
nonpathogenic strains were assigned to the independent VCGs. This suggested that the isolates of F. solani pathogenic to
tobacco were derived from the progenies of crossing in the field. However, perithecium formation was not observed in their
cultures.