What grape varieties make up the hybrid Vidal?

Vidal is indeed a hybrid grape variety that is a cross between Ugni Blanc and Seibel 4986. This hybrid was specifically developed to create a grape that could thrive in cooler climates, making it particularly popular in regions known for their cold winters and shorter growing seasons, such as parts of Canada.

Ugni Blanc, also known as Trebbiano, is a versatile white grape that is well-suited for producing wines that are fresh and fruity. Seibel 4986, while less common, was developed to have resilience against cold temperatures and diseases. When these two varieties are combined, they produce Vidal, which is known for its ability to retain acidity while also achieving high levels of sugar, making it ideal for ice wine production, especially in Canada.

The other choices listed do not correctly describe the varietal makeup of Vidal. For instance, Riesling x Chardonnay suggests a different style of wine focused on aromatic and crisp profiles rather than the unique characteristics of Vidal. Similarly, Cabernet Sauvignon x Merlot represents a classic blend often associated with red wines, and Pinot Noir x Gamay refers to a different pairing generally associated with specific red wine profiles, all of which do not pertain to Vidal's parentage.