Fourteen strains of Fusarium oxysporum f.sp.cubense were induced to produce 146 nitrate-nonutilizing(nit) mutants on a chlorate-containing medium.Among them,there were 117 nit1 mutants(80.14%),17 nit3 mutants(11.64%) and 12 nitM mutants(8.22%).These strains were divided into two vegetative compatibility groups(VCGs) by the vegetative compatibility tests.Twelve strains of F.oxysporum f.sp.cubense from Musa AAA belonged to VCG1,two trains from Musa ABB belonged to VCG2.