Dwarfing rootstock for pear is

Dwarfing rootstock for pear is Quince.
Dwarfing rootstocks produce the smallest trees and range from 6 feet tall to 12 to 14 feet tall.
Quince is a deciduous tree that bears hard, aromatic bright golden-yellow pome fruit, similar in appearance to a pear. The quince (Cydonia oblonga) has been used for centuries as a rootstock for pear. Such stocks produce dwarf trees that are earlier bearing (with some varieties) than standard trees. The fruit from dwarf trees may mature a bit early, but it is of good quality.