The various historical documents dealing with Ribolla allow us to deduce that there are two bio-types of this grape variety. The most important, certainly, considering its superior aromas and flavors, is the Ribolla Gialla, characterized by less abundant yelds and the higher quality of the wins, produced from smaller and less compact bunches compared to the second type, the Ribolla Verde which, by now, has almost completely disappeared inasmuch it is far more productive and susceptible to mould created by the excessive vigor and compactness of the bunches. From an amphelographic point of view, Ribolla Gialla is of medium-high vigor in the vineyard, a resonable resistance to both downy and powdery mildew, whereas in rainy vintages and on excesisvely fertile soils it is subject to attacks of mould and rot. Its productivity when the vines are still young is notable, with phenomenon of oversized bunches. In its early years, therefore, it needs careful pruning and proper training systems which limit the number of buds with vineyard practices aimed at reducing vigor. As it ages and matures, the vines tend naturally to limit their production and grow with a balanced vegetation. The buds of Ribolla Gialla are a wellowish green with both brown striation and a glabrous, golden tip. The leaves are of medium size, irregular, either whole or three-lobed, with slightly curled edges and a minute indentation of little depth. The upper side is a light green, while the lower one is darker but decidedly glabrous. The bunches vary form medium to large in size and are either cylindrical or cylindrical-conical, often asymmetric. The compacteness is rather variable: ding arrives during the third week of April, flowering during the first ten days of June, the color change in early August, and the ripening, rather late, beetwen late September and early October. The quality of Ribolla Gialla is strongly condition by the climate where it is cultivated.