DIFFICULTY TO ESTABLISH VEGETATIVE COMPATIBILITY OF JAPANESE ISOLATESOF VERTICILLIUM-DAHLIAE KLEB. USING MELANIN-SYNTHESIS DEFICIENT MUTANTS

Japanese isolates of Verticillium dahliae were formerly designated as tomato pathotype and non-tomato pathotype by pathogenicity tests. We a ttempted to classify 18 Japanese isolates based on vegetative compatib ility. Only three isolates of the tomato pathotype induced compatible alm-brm mutants. A non-secreting brm mutant was not induced from isola te of the non-tomato pathotype. Complementation was not achieved by a pair of mutants from the tomato pathotype and those from the non-tomat o pathotype. From these results, Japanese isolates of V. dahliae could not be separated into any vegetative compatibility groups using melan in synthesis-deficient mutants.