Wanted to point out this information was released by the USDA back in 2004. After reading the pdf attached and this link Pyrus bretschneideri an interspecific hybrid of Pyrus pyrifolia x Pyrus ussuriensis - fireblight resistant It will become very transparent what im doing and why i do it.
“Fire blight. Resistance in P. communis is relatively rare, with only 5-
10% being rated as at least moderately resistant (Oitto et al., 1970; van der Zwet
and Oitto, 1972; Thibault et al., 1987; van der Zwet and Bell, 1990). Old dessert
cultivars most consistently rated as resistant are ‘Alexander Lucas’, ‘Tyson’, ‘Seckel’,
and ‘Maxine’; resistant cultivars developed by recent breeding are ‘Harrow Delight’,
‘Harrow Sweet’, ‘AC Harrow Crisp’, ‘AC Harrow Gold’, ‘Moonglow’,
‘Honeysweet’, ‘Magness’, ‘Potomac’, ‘Blake’s Pride’, and ‘Shenandoah’.
Therefore, sources of moderate to high resistance, although not immunity, do exist
in European pears. With the exception of ‘Seckel’, and to a lesser extent
‘Magness’, these cultivars have not, to our knowledge, been extensively planted or
evaluated in commercial size trials. There is a small amount of commercial
production of ‘Magness’, primarily in the eastern and southeastern US. The newer
cultivars have not yet been widely planted or evaluated, and thus, it is not certain
whether they can be considered to be suitable replacements for susceptible
cultivars. Additional resistance is available for use by the breeding program within
introduced P. ussuriensis and P. x bretschneideri germplasm and hybrid selections
from breeding programs.”
PyrusCGCReport2004.pdf (171.5 KB)