Full screen gradient background (optimized for mobile)

I’d like to have a full screen radial gradient background in my game in such a way that will affect performance minimally.

Initially, I had one huge 2048x1536 for the iPad 4, but that ate too much memory. I then split it into half and mirrored. While this was better, it’s still pretty big. Now, before I go split this into quarters, is there a better way to do a full screen gradient background that will be more optimized than a big image? Is there a way to do this cheaply with a shader? What about if I wrote code to draw this on run-time?

Thanks in advance.

One approach could be to generate a circular mesh and set the center point of mesh to one color and the rest to the other, and position that mesh accordingly. This eliminates the need for a texture.