Bonarda was the most broadly planted grape in Argentina.  That is, until Malbec took its place.  Used to make bulk table wines, Bonarda produces a lighter bodied wine, fruity with full flavors of cherry and plum. Originally from Italy in the Piedmont region that is also known as Bonarda, Piemontese.  There is a debate on if the Bonadra Piemontese is related to Argentine Bonarda; it is hard to tell since there are many different varietals called Bonarda. 
When older vines are oak aged, it brings out the concentrated fruit, and the wines are dense and tannic.  Bonarda can be the same grape as Charbono found in California. There are also wines labeled Bonarda found in the North Central region of Italy, but they are actually made from the Croatina grape.