What two vegetables form the deliberate cross resulting in Broccolini?

Standard broccoli and Chinese broccoli (Gai Lan)

Broccolini is a product of intentional plant breeding, specifically engineered by crossing two distinct vegetables from the Brassica family. The genetic combination involves standard broccoli and Chinese broccoli, which is also known by its alternative name, Gai Lan. This hybridization was achieved through efforts in Japan during the late 1990s. The resulting vegetable aims to synthesize desirable traits from both parents, resulting in a product with longer, more slender stalks than traditional broccoli, smaller florets, and a taste profile that leans toward milder and sweeter than the more pungent Gai Lan.