2. Induction of polyploids (1)Physical Induction(temperature, injury, irradiation) (2) Physical Induction(秋水仙素) (3)Sexual Cross (e.g 2x x 4x= 3x) (4)Endosperm Culture (5)Clonal variation of Somatic Cells2. Induction of Polyploids (1) Physical Induction (temperature, injury, irradiation) (2) Physical Induction (秋水仙素） (3) Sexual Cross （e.g 2x x 4x = 3x) (4) Endosperm Culture (5) Clonal Variation of Somatic Cells