Bovale is an Italian grape (or in this case, likely two Italian grapes which share a clonal relationship) from Sardinia. Bovale Grande is the larger of the two grapes and tends to have at least 2x more plantings then its lesser known cousin Bovale Sardo. These are blending grapes, even in Sardinia neither clone is made into a varietal specific wine.
There is currently some debate if the two clones are actually related in some way to the Spanish grape Bobal. As with many of the lesser known grape varietals, we may have to wait for some time to know the answer. While the American wine industry has benefitted from extensive genetic testing done by UC Davis, there to this point has not been the same level of testing done on lesser known European grapes.