Evaluation of Sugar Beet Breeding Lines for Resistance to Rhizoctonia Root and Crown Rot in Northwest Minnesota, 2025

Seedling damping-off and root and crown rot, caused by the soilborne fungus Rhizoctonia solani AG 2-2, are the most common root diseases of sugar beet in Minnesota, North Dakota, and Michigan. Early season infection leads to poor stands, while mid-to-late season infection of plants results in root rot with dark brown to black lesions on the surface leading to chlorotic and wilting foliage, and plant death under severe infection. In this study, fifteen sugar beet (Beta vulgaris ssp. vulgaris) breeding lines were screened for resistance to Rhizoctonia root and crown rot (RRCR). The non-irrigated trial was conducted at the University of Minnesota, Northwest Research and Outreach Center in Crookston, MN. Results from this trial will aid in breeding efforts to improve resistance to Rhizoctonia diseases in sugar beet.