How to display only parent terms of hierarchical terms  in Views field
I think my answer to a similar question would be useful:

I believe that your problem would be solved by adding a relationship to your view. Here are the steps:

Add Relationship: taxonomy terms on node
Select the vocabulary you want to use.
Add Relationship: parent term

Now you should be able to add fields from any of the terms or their parents, and to use them as contextual filters as well.

Note that this is for Drupal 7