Ruby on Rails

I am using a drop down box in a form, the method is GET. The data that
i am selecting in the box is not getting stored in the database. But
when i am not using the drop down box the rest of the data is getting
stored. I stored the submitted form data in an instance variable. When
i am trying to print the instance variable no output is coming…
Can anybody tell how to get the selected data in the drop down box in
the other form?