We investigated the applicability of Tgm9 in generating knockout mutants for functional analyses of soybean genes as follows. First, we determined if the insertion following excision of Tgm9 from the mutable w4-m allele resulted in mutation among the mutants previously identified from screening germinal revertants, generated from the T322 line [20, 23, 27–31] (Table 1). Second, we investigated 124 random germinal revertants to determine the properties of Tgm9 transposition.