It's not a genre, it's a what I call a group of African stringed instruments that are responsible for the creation of the Banjo. Not sure if you'll like them but here's another list.I will admit to a deep core love of jazz, but I don't even know what African strings is, lol. These guys are about the closest I come to any sort of tribal.
Ngoni
Akonting
Karindula
Molo
Kibangala (has different names in different countries, and is very similar to a lute. Some people think it might have been the earliest version of the lute)
Ramkie (basically a hand made guitar with an oil can body)