Dependents (under 18) have part time income below the basic income so they are not filing tax returns. How should I enter T4 income as they don't have a T1 Net Income?

Additional Dependent Info section asks for Net Income from T1 as well as deductions ad credits from T1.  Since they aren't filing tax returns, should I enter their earning from T4 in the Net Income (T1, Line 23600) section, or leave blank?