Assessment of NPGS Sugar Beet Germplasm for Resistance to Rhizoctonia Root and Crown Rot in Fort Collins, CO, 2024

Rhizoctonia root and crown rot (RRCR), caused by the soilborne fungal pathogen Rhizoctonia solani, is among the most devastating root diseases of sugar beet in the United States. Symptoms include small circular lesions on the root that advance to necrotic cavities and full necrosis of the foliage and root in severe cases. This report evaluates the resistance response of 31 beet germplasm ( Beta vulgaris and B. vulgaris ssp. maritima) from the National Plant Germplasm System (NPGS) Beta collection to R. solani. The trial was conducted in Fort Collins, CO, in the summer of 2024. Results from this trial advance the long-term effort of identifying RRCR-resistant germplasm from the Beta collection to advance resistance breeding efforts.