If I remember it right, the Bradford Pear Tree was "invented" by the U.S. Department of Agriculture:
- It was a hybrid, bred to be the perfect urban tree
For my two bits, it seems like they claimed success with their Beta version, and quit their research too early in the game.
They should have gone to maybe Bradford 3.0, or 4.0
The things tend toward multiple trunks, and they are a disaaster-waiting-to happen when those trucks inevitably split.