North American Fruit Explorers mailing list at ibiblio

[Alan Haigh <alandhaigh@gmail.com>]

Pears are quite capable of parthenocarpy under the right spring
conditions.  If days in early spring are warm and sunny, many varieties
will bear a full crop of seedless fruit.  When S. CA had a commercial
Bartlett industry some growers didn't even plant other varieties in their
orchard according to Childers in his classic "Fruit Science".

I suspect that this is the reason for confusion over what varieties are
self-fruitful- it all depends.