Depending upon your region, you may have access to the Education Major and Education Minor in addition to the Education Mapping and Education Attribute Mapping.
Mapping a Major looks like this allows you to chose a Major from the table within Raiser’s Edge as well as typing a free text comment.

The mapping for a Minor is very similar to the mapping for a Major.

Please note that Majors and Minors share a code table with in Configuration (called Major/Minor). You will need to ensure that you have mapped to fields within that table or that you have set your Field settings to allow new code table entries.