Vegetative compatibility, biosynthesis of GA3 and virulence of Fusarium moniliforme isolates from bakanae disease of rice

Twenty-eight isolates of Fusarium moniliforme were established from bakanae-infected rice plants of a range of cultivars collected from various localities in Haryana, India. They were characterized by vegetative compatibility, virulence pattern on five paddy cultivars, and biosynthesis of gibberellins and were assigned to 10 vegetative compatibility groups (VCGs). Isolates from different VCGs and also within the same VCG varied considerably in virulence and GA₃ production. The 28 isolates were categorized into five gibberellic acid production groups (GPG-I–GPG-V) and five virulence groups (VG-I–VG-V). Vegetative compatibility was independent of pathogenicity and of ability to produce GA₃. However, GA₃ production was positively correlated ( r  = 0.731) with pathogenic behaviour.