Do you ever heard about the term "music from the desert" or "african blues". If not i tell you that this terms refer to the Mali music. I am only discovering this type of music, so i only know few things about this country music history. All i can say is that i found three great Mali artists that i think you should listen principally if you like root blues. They are: father and son Ali Farka Touré (died last year) & Vieux Farka Touré and Tinariwen.
Ali Farka Touré (Biography)
Vieux Farka Touré (Biography)