Kieffer is a well-known American pear variety, introduced by Peter Kieffer of Philadelphia in the second half of the 10th century.
It has an unusual ancestry, being probably a seedling of a Chinese pear (Pyrus prunifolia) crossed with the widely-grown European pear (Pyrus communis) Barlett. Although in most respects it can be considered a European pear, the crisp coarse flesh hints at the Chinese ancestry.
Kieffer inherits the heavy-cropping nature of Bartlett, but ripens much later.
Kieffer quickly established itself as a major commercial variety in the eastern and southern states. Like Bartlett it was ideal for processing and canning. It is perhaps not as successful for eating fresh.
The oriental ancestry might also explain another of its key features - Kieffer has a legendary reputation for resistance to fireblight, a disease that arose in the eastern states in the 18th and 19th centuries and devastated pear orchards.
Kieffer has a very wide climate range and is equally at home in the northern or southern states.