Identification of resistance to bacterial canker (Pseudomonas syringae pv. syringae) disease on apricot genotypes grown in Turkey

Bacterial canker caused by Pseudomonas syringae pv. syrinage (Pss) in apricot has widely spread in Turkey, especially in Malatya province, in recent years. The main objective of this study was to determine resistance of apricot cultivars to bacterial canker caused by Pss in apricot cultivars grown in Turkey. During the 2006-2007 growing period, bacterial isolations were taken from diseased apricot trees in Malatya and 53 Pseudomonas syringae isolates were obtained. Forty-two isolates were determined as Pseudomonas syringae pv. syringae and 11 isolates as pv. morsprunorum. In a pathogenicity test, leaves of cv. Hacihaliloğlu were used and five Pss isolates (K24, K25, K43, K47 and K51) were detected to be the most virulent and were used to test for cultivar resistance to Pss. Leaves of fifteen apricot cultivars (Alyanak, Çataloğlu, Çöloğlu, Erken Ağerik, Hacihaliloğlu, Hasanbey, İsmailağa, Kabaaşi, Karacabey, Sakit 2, Soğanci, Şam, Şekerpare, Tokaloğlu (Erzincan) and Turfanda Eski Malatya) were tested for resistance to Pss. Green shoots were spray-inoculated with a concentration of 10⁸ cfu ml⁻¹ Pss mixed culture. Sprayed shoots were covered with moist plastic bags for 3 days and maintained in the growth chamber and monitored for symptom development. Hasanbey, Çöloğlu, Soğanci and Şekerpare apricot cultivars were resistant and Şam, Tokaloğlu (Erzincan) and Erken Ağerik apricot cultivars were susceptible to Pss. This is the first report of a resistance source in apricot cultivars grown in Turkey against Pss.