Ft. Collins sugar beet germplasm evaluated for rhizomania and storage rot resistance in Idaho, 2018

Rhizomania caused by Beet necrotic yellow vein virus (BNYVV) and storage losses are serious sugar beet production problems. To identify sugar beet germplasm lines with resistance to BNYVV and storage rots, 30 lines from the USDA-ARS Ft. Collins sugar beet program and four check cultivars were screened. The lines were grown in a sugar beet field infested with BNYVV during the 2018 growing season in a randomized complete block design with 6 replications. At harvest on 15 October 2018, roots were dug and evaluated for rhizomania symptoms and also placed in an indoor commercial sugar beet storage building. After 119 days in storage, samples were evaluated for the percentage of root surface area covered by fungal growth or rot. Rhizomania symptom development in the field was uniform and other disease problems were not evident in the plot area. The BNYVV susceptible check plots had 97% foliar symptoms and high root disease severity ratings. The three resistant checks had 0 to 6% foliar symptoms and low root ratings. Based on root ratings, three entries (4, 13, and 14) had resistance similar to the resistant checks. However, entry 13 (20121018HO-119) was the only entry that performed well for all variables. Entry 13 may serve as a starting point for identifying additional sources of resistance to BNYVV and storage rots