Modern requirements for new apple varieties include not only high yield and improved fruit quality, but also resistance to the most dangerous diseases, including bacterial canker caused byErwinia amylovora. The aim of this study was to evaluate the resistance of modern apple varieties common in Kyrgyzstan to the causative agent of fire blight under artificial infection conditions. For the experiment, a pure culture of the phytopathogenic bacteriumE. amylovora(strain ZH-2) isolated from infected branches of the ‘Talgarka’ pear variety was used. Infection was carried outin vitroby applying a bacterial suspension with a concentration of 109CFU/ml to the wound surfaces of shoots and leaves of two-year-old seedlings. The degree of damage was assessed visually 1, 6, 12 and 30 days after inoculation on a five-point scale, taking into account the percentage of damaged tissue. The results of the study showed significant differences in resistance between the eleven apple varieties studied. The most resistant varieties were ‘Red Chief’, ‘Bishkek’, and ‘Golden’, with damage levels ranging from 6.3 to 9.5%, indicating strong defensive responses and low levels of necrosis symptoms. The ‘Fuji’ variety showed an average level of susceptibility (about 16-18%), characterised by moderate damage to shoot tissues. The most susceptible to infection were the varieties ‘Idared’ (48%), ‘Gala’ (43%) and ‘Ligolina’ (37%), which showed rapid development of necrotic spots and wilting of shoots. The results obtained allow for identifying varieties that are promising for further propagation and breeding work, resistant to bacterial burn, and also give an idea of the range of susceptibility of modern apple varieties in the conditions of Kyrgyzstan
Konurbaeva et al. (Tue,) studied this question.