IDENTIFICATION OF HOST RESISTANCE TO BACTERIAL CANKER DISEASE ON APRICOT, PLUM AND PEACH GROWN IN PUNJAB AND KPK, PAKISTAN

Abstract

Bacterial canker disease caused by Pseudomonas syringae pv. syringae (Pss) has expanded rapidly in Pakistan, notably on stone fruits. The present research aimed to determine peach, plum and apricot cultivars' resistance to Pss bacterial canker. During the 2014–2015 growing season, diseased samples exhibiting symptoms of bacterial canker were collected from peach, plum, and apricot trees in Punjab and KPK provinces, and 48 P. syringae isolates were recovered. In a pathogenicity test, three Pss isolates (PS3, PS9, and PS17) were found to be highly virulent on peach, plum, and apricot, and their resistance to Pss was evaluated. Leaves and shoots of five peach varieties; Early grand, Florida king, 4 ½, 5 ½, 6 ½, four plum varieties; Red beauty, Fazal-e-man ani, Stanley, Producer, and two apricot varieties; Chinese apricot and golden amber, were foliar sprayed with a mixed culture of Pss at a concentration of 10-8 cfu ml-1. Sprayed cultivars were covered with plastic bags for three days to retain moisture and kept in a glass house, where they were closely monitored for the appearance of symptoms. 5 ½ peach, Fazal-e-Manani plum, and Chinese apricot were found resistant to Pss, 6 ½ peach, Stanley plum were susceptible while Golden amber apricot was found moderately susceptible to Pss. This is the first report of apricot, peach, and plum host resistance to Pss in Pakistan.