Inheritance of fire blight resistance in Asian &amp;lt;i&amp;gt;Pyrus&amp;lt;/i&amp;gt; species

Kamila L Bokszczanin,Malgorzata Schollenberger,Wieslaw Madry,Dariusz Gozdowski,Andrzej A Przybyla,Slawomir Odziemkowski

doi:10.4236/ojgen.2012.22016

Abstract

Since several Asian pear species are considered to be potential source of fire blight resistance, we crossed “Doyenne du Comice”, the susceptible European cultivar, with four Asian pear species. The aim of the study was to establish the level of resistance of each genotype and the mode of transmission of fire blight resistance to each F1 full-sib progeny. The best sources of resistance were P. ussuriensis 18 and P. ussuriensis var. ovoidea 8 ranked to resistant and highly resistant, respectively. Although pear resistance to fire blight is suggested to be polygenic, distribution of phenotypes in “Doyenne du Comice” × P. ussuriensis var. ovoidea 8 hybrid family suggests the possibility of monogenic inheritance with the dominance of resistance derived from P. ussuriensis var. ovoidea 8. Polygenic inheritance of pear resistance to fire blight was identified in cross combinations of “Doyenne du Comice” with P. pyrifolia 6, and contributed by the major gene, with P. ussuriensis 18 and P. calleryana 12. Transgressive segregation was observed within the progenies of susceptible, moderately susceptible and resistant parents.

Highlights

Fire blight is the most devastating disease of pears and apples caused by the bacterium Erwinia amylovora (Burrill) Winslow et al Symptoms of the disease were noticed as early as 1780 in New York [1]
Pear resistance to fire blight is suggested to be polygenic, distribution of phenotypes in ‘Doyenné du Comice’ × P. ussuriensis var. ovoidea 8 hybrid family suggests the possibility of monogenic inheritance with the dominance of resistance derived from P. ussuriensis var. ovoidea 8
Polygenic inheritance of pear resistance to fire blight was identified in cross combinations of ‘Doyenné du Comice’ with P. pyrifolia 6, and contributed by the major gene, with P. ussuriensis 18 and P. calleryana 12

Summary

Introduction

Fire blight is the most devastating disease of pears and apples caused by the bacterium Erwinia amylovora (Burrill) Winslow et al Symptoms of the disease were noticed as early as 1780 in New York [1]. The bacterial etiology of the disease was recognized in the early 80’s of the 19th century by the pioneer of plant pathology Thomas J. In 1871 he reported the results connected with peach and pear diseases near Cobden, Illinois, where he found first symptoms of fire blight [2]. In 1885 Arthur [3] published his classic paper on the completion of Koch’s postulates with the bacterium, proving beyond doubt that fire blight was caused by this organism. Erwinia amylovora is considered to be the first proven bacterial plant pathogen [4,5]

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