Which wine region claims the lion's share of production in Marche?

The region of Marche is known for its diverse wine production, with Verdicchio dei Castelli di Jesi DOC being one of the standout appellations. This designation is specifically associated with the Verdicchio grape, which is renowned for its high-quality white wines that often feature citrus, green apple, and almond notes. The Verdicchio dei Castelli di Jesi area is responsible for a significant portion of all wine produced in Marche, making it a crucial player in the region's viticultural landscape.

In comparison, while Frascati DOC and Orvieto DOC produce white wines, they are primarily located in Lazio and Umbria, respectively, and do not contribute to the production volumes within the Marche region itself. Conero DOCG, although noteworthy, primarily focuses on red wines made from Montepulciano and Sangiovese grapes and doesn't match the overall production level of Verdicchio dei Castelli di Jesi DOC in terms of volume. Therefore, the correct answer reflects the significant contribution that Verdicchio dei Castelli di Jesi DOC makes to the wine production in Marche.