برخی ویژگی های بیولوژیکی و بیماریزایی Pseudomonas syringae pv. lapsa عامل سوختگی برگ و پوسیدگی پوشینه گندم و جو

Studies conducted from 2020 to 2023 aimed to determine the frequency of pathogenic bacteria associated with leaf blight and black chaff in wheat and barley in Chaharmahal va Bakhtiary province. The results showed that strains of Pseudomonas syringae pv. lapsa (Psl) were more abundant. This research investigated some pathogenic and biological characteristics of this bacterium. In field conditions, a test was conducted to evaluate the resistance of six wheat cultivars (Pishgam, Heydari, Sadra, Mihan, Sardari, and Omid) and four barley cultivars (Bahman, Jolgeh, Mahtab, and Azaran) to Psl. All wheat and barley cultivars showed a sensitive reaction, resulting in a significant difference in grain yield and yield components compared to control plots (without bacterial treatment). The pathogen had the most significant impact on reducing seed yield, 1000 seed weight, and seed vigor. The survival and viability of the bacteria in wheat seeds under laboratory conditions ranged from 18 to 24 months inside the cover and up to 18 months in barley, indicating that Psl is a seed-borne pathogen. Testing the effect of temperature and humidity on the bacterial population revealed that a temperature of 10 degrees Celsius and saturated relative humidity are optimal conditions for bacterial blight of wheat leaves by Psl. Based on this research, it can be concluded that Psl is the dominant pathogen causing symptoms of bacterial leaf blight and black chaff in wheat and barley in rain-irrigated fields in the cold areas of Chaharmahal va Bakhtiary province. Since this bacterium is seed-borne, it is essential to use certified and pathogen-free seed for disease management.