Semicolon or colon?

Hi,
I cannot figure out if I should use a colon or a semicolon in the following sentence. I could separate the sentences, but then it sounds choppy to me.

His research on leadership development has greatly influenced my research interests: his work on leadership styles is the basis of this research project.

OR

His research on leadership development has greatly influenced my research interests; his work on leadership styles is the basis of this research project.

Thanks for your help!