3. Treatment Methods for chemical Mutation A. Soaking g B. Injection C. Daubing or Dropping D. Suffocation熏蒸 E. Application to Culture media 4. Combination of Physical and chemical Mutation Higher mutant rates; combined advantages of both methods3. Treatment Methods for Chemical Mutation A. Soaking B. Injection C. Daubing or Dropping D. Suffocation 熏蒸 E. Application to Culture Media 4. Combination of Physical and Chemical Mutation Higher mutant rates; Combined advantages of both methods