A method for testing tuber resistance against soft rot bacterium*

Five methods of artificial inoculation of potato tubers with soft rot pathogen, Erwinia carotovora sp. carotovora were compared for their efficiency and reliability. Injection of bacterial suspension or pricking the tuber with a needle charged with bacterial cells were found to be most consistent in producing the disease. Seven potato cultivars were evaluated for tuber resistance by injection method. Based, on their reaction, the cultivars were grouped as resistant, moderately resistant, moderately susceptible, susceptible and highly susceptible.