Figure 1 Kanamycin selection strategies used in this study. Transformed somatic embryo aggregates were cultured in selection media composed of induction medium supplemented with 250 mg/L timentin and the indicated kanamycin concentrations (mg/L). The selection strategies were a standard strategy (strategy 1), where aggregates were cultured in selection medium with 50 mg/L kanamycin for 5 wk; an incremental strategy (strategy 2), with 25 mg/L kanamycin for 4 wk followed by 50 mg/L kanamycin for 1 wk; a progressively increasing kanamycin concentration strategy (strategy 3), with 6, 12, 25, 50, and 50 mg/L kanamycin for 1 wk each; and no initial selection strategy (strategy 4), with no kanamycin for 2 wk followed by 50 mg/L kanamycin for 3 wk. After 5 wk, treated somatic embryo aggregates were maintained in the presence of 50 mg/L kanamycin in all strategies.