Classification of Fusarium oxysporum strains associated with reddish brown rot of asparagus on the basis of vegetative compatibility

Abstract

Nitrate reduction mutants (nit- mutants) were selected from 33 isolates of Fusarium oxysporum isolated from asparagus plantings showing reddish brown rot symptoms in Malaysia. These nitrate reduction mutants were used in complementation tests for vegetative compatibility. Nine vegetative compatibility groups (VCGS) were identified, but most (19) isolates fell into 4 VCGs that were found at more than one location. There was no strong interrelationship between VCG and location. However, seven isolates were identified as vegetatively self- incompatible based on their inability to form heterokaryons between complementary nit- mutants.