Which fruit has varieties called Cavendish and plantain?

The banana - and the Cavendish is not merely a variety but a clone. Every Cavendish banana in every shop in the world is genetically the same plant, propagated from cuttings, because the cultivated banana is a sterile triploid with no viable seeds.

That monoculture has already collapsed once. The Gros Michel, the variety exported until the 1950s, was destroyed commercially by a soil fungus called Panama disease, and the industry survived by switching wholesale to the Cavendish because it resisted that strain. A new strain, Tropical Race 4, attacks the Cavendish, has spread through Asia, Africa and the Middle East and reached Latin America in 2019, and there is no resistant replacement ready.

The plantain is the same species treated differently - starchier, cooked rather than eaten raw, and a staple food rather than a dessert for hundreds of millions of people. The line between banana and plantain is culinary rather than botanical and does not exist in most languages. And the persistent story that artificial banana flavouring tastes wrong because it was formulated for the Gros Michel is, unusually for that kind of claim, broadly supported.