Glera is the principal grape of Prosecco sparkling wine. Originally the grape was known as Prosecco (more precisely Prosecco Tondo). The variety has an unclear origin and an even more complicated ampelographic history due to the fact that several distinct varieties have been called “Prosecco-something” in northeast Italy since the 18th century. The grape is late-ripening and prone to both fungal diseases and water stress. It is widely planted in the province of Treviso.