• Research in Plant Disease
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• v.10 no.2
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• pp.105-111
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• 2004

Mycelial growth and days required for sclerotial formation(DRSF) in vitro, and disease incidence of infected plants in the field were investigated to evaluate disease resistance of nine garlic cultivars against two species of Sclerotium causing garlic white rot. There were differences among mycelial growth and sclerotial formation of two white rot pathogens on different garlic cultivars in vitro. Mycelial growth showed the highest level on the clove of 'Daeseo'. Sclerotia of two white rot pathogen were formed the earliest on the clove of 'Kodang' and the latest on the clove of 'Namdo'. In field trial all of nine garlic cultivars were highly susceptible to Sclerotium cepivorum and cold-type garlics were less susceptible than warm-type garlics. Meanwhile garlic cultivars used showed differences among resistant responses to Sclerotium sp., forming large sclerotia. All of warm-type garlics showed highly susceptible response, but three cold-type garlics, 'Seosan', 'Danyang' and 'Yechon' showed moderate resistant response and 'Euisung' showed resistant response. To evaluate cultivar resistance of garlics quantitatively disease progress curve was transformed as linear regression equation. Among the intercept (early disease incidence) and the slope (disease infection rate) obtained from the transformed equation, final disease incidence, and area under disease progress curve(AUDPC), AUDPC was the most effective to evaluate disease resistance of garlics to both of white rot pathogens. There was little correlation between mycelial growth and sclerotial formation on garlic cloves in vitro, and epidemiological parameters (early disease incidence, final disease incidence, disease infection rate, AUDPC) obtained from the field trial. Mycelial growth of S. cepivorum was positively correlated with final disease incidence and disease infection rate obtained from the field trial, meanwhile DRSF was negatively correlated with the epidemiological parameters.