LAUSR

Stem rot caused by Sclerotium rolfsii is a major problem in Jerusalem artichoke production. Breeding of Jerusalem artichoke for stem rot resistance is a promising method for disease control, and identification of sources of resistance is necessary to initiate Jerusalem artichoke breeding programs. The objective of this study was to characterize the diversity of Jerusalem artichoke germplasm for resistance to stem rot under field conditions. Forty Jerusalem artichoke genotypes were evaluated in a randomized complete block design with four replications in two environments that differed in soil fertility. Jerusalem artichoke plants were inoculated with S. rolfsii at 40 days after transplanting using a single colonized sorghum seed per plant as inoculum. Data were recorded for disease incidence, lesion length, days to permanent wilting, area under disease progress curve and severity index. The Jerusalem artichoke genotypes were classified into three clusters based on traits related to disease resistance. Cluster 1 had eight resistant genotypes, cluster 2 included 15 moderately resistant genotypes, and cluster 3 consisted of 17 susceptible genotypes. The field resistance of Jerusalem artichoke is important to be use as source of resistance to stem rot disease. Jerusalem artichoke genotypes HEL65, HEL246, HEL293, HEL69 and JA98 were identified as source of resistance under field conditions. These genotypes can be used as sources of stem rot resistance in Jerusalem artichoke breeding programs.