Bananas!

Killerplants has an article on bananas...

Wild (species) bananas must be pollinated to have fruit, but the domesticated banana is a 'mule' (cannot reproduce). The plant is a triploid (having 3 sets of chromosomes) as the result of inheriting one set from the diploid, Musa acuminata (AA) and 2 sets from the tetraploid, Musa balbisiana (BB BB). The domesticated banana (ABB) has 33 chromosomes.

In most plants, if the ovules are not fertilized to form seeds, the fruit never develops. The female flowers of wild bananas develop relatively dry fruit with little or no pulp and large seeds. But the domesticated banana develops large, pulpy, nutritious fruit with no seeds. Because the chromosomes cannot divide equally, the domesticated plant cannot produce seeds. The nourishment that would normally go into the seeds goes instead to the fruit.

and did you know a banana is a berry?