Differential responses of pear cultivars to Erwinia amylovora infection; evidences of involvement the hypersensitivity response in pear resistance to fire blight

Comparison of the shoot and blossom susceptibility of European and Asian pear cultivars to fire blight across different conditions

“…Inoculating EA at a natural pathogen concentration of 10 5 CFU/mL and incubating without the use of plastic bags to increase the humidity delayed the development of the first fire blight symptoms in the net house by several days compared to the nearly 100% humidity in greenhouse studies (Ruz et al 2008;Erfani-Moghadam & Zarei 2022), but approximated the conditions as close as possible to the conditions in orchards during the spring. In general, the permanently higher humidity in the net house compared to the field was of high importance for the development of the disease symptoms (Shwartz et al 2003).…”

“…The biggest differences in the TS and BS pear cultivar ratings were found in the middle of the susceptibility scale. TS to EA is not necessarily correlated with BS even under greenhouse conditions, therefore, cultivar characterisations should be determined by their susceptibility in both the blossoms and shoots (Shwartz et al 2003;Peil et al 2009;Erfani-Moghadam & Zarei 2022). The environmental conditions, predominantly the diurnally fluctuating interacting effects of the temperature and wetness duration after the artificial inoculation of the terminal shoots and blossoms were crucial for the development of fire blight symptoms and decided whether the pear cultivar would be assigned as more or less susceptible to Ea in the annual classification.…”