Evaluation of Relative Resistance of Some Apricot Varieties to Wilsonomyces carpophilus Causing Shot Hole Disease

In this study، eleven cultivars of apricot including two early ripening (Noori pishras and pishras Tabasi) varieties، four mid ripening cultivars namely (Shahroudi، Lasjrdy، Ghazi Gahani and Bagheri) and five late ripening cultivars i. e. (Shahroudi51، Shahroudi48، Shahroudi29، Shahroudi21 and Ketabi) that had a better yield and horticultural characteristics were screened to Wilsonomyces carpophilus. All cultivars under greenhouse conditions were evaluated in a completely randomized design with eleven treatments and 5 replicates. To creation disease، pathogen was cultured on PDA medium and was inoculated on leaves with concentration conidia of 105 × per ml in distilled water. Percentage of infections and number of available spots on the leaves of cultivars were evaluation criteria. To assess cultivars response in the garden، two-year-old saplings of all varieties planted at farm of KANRRC. Inoculation and cultivars'' disease assessment procedure were done as already mentioned but at the end of the season. Data were analyzed using ANOVA. The results of the evaluation of apricot cultivars in the greenhouse showed that there were very significant differences in disease severity on leaves (P≥0. 01) and number of leaf spots (P≥0. 05). Comparing of averages measurements of disease severity on leaves indicated that there was not any significant difference among Lasjerdy، Shahroudi29، Shahroudi51، and Ghazi Gahani cultivars means these cultivars are the most resistant cultivars. Comparing the averages measurements of spots numbers on leaves indicated that Lasjerdy was the most resistant cultivar. While evaluating severity and number of spots on leaves and compared to measurements obtained from the leaves of these two traits in the garden، Analysis of variance showed that there was no significant difference among eleven varieties of apricots in the garden، and all cultivars were in one group.