In order to achieve this result, you should edit the template of the GridViewRow and change the brushes respectively named ItemBackground_Over and ItemBackground_Selected that are used to paint GridViewRow's background in these states. Also I have prepared an example for you that demonstrates this approach.
Please check the attached project and let me know if you need any additional information.
the Telerik team
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Public Issue Tracking
system and vote to affect the priority of the items