I've submitted a patch for inclusion in the next release. It enables using a custom column as the source for Genres, in addition to the default 'Tags' source. Eligible custom column types are:
- Comma separated text, like tags, shown in the tag browser
- Text, but with a fixed set of permitted values
- Text, column shown in the tag browser
I've done moderate testing with each of these custom column types.
The 'Catalog options' section of the catalog sticky
has a preview of the updated UI.