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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Soil Management and Sugarbeet Research » Research » Publications at this Location » Publication #404831

Research Project: Development of Sugar Beet Germplasm Enhanced for Resistance to Important and Emerging Plant Pathogens

Location: Soil Management and Sugarbeet Research

Title: USDA-ARS Plant Introduction lines evaluated for rhizomania and storage rot resistance in Idaho, 2022

item Dorn, Kevin
item Strausbaugh, Carl
item Majumdar, Raj

Submitted to: Plant Disease Management Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/11/2023
Publication Date: 8/30/2023
Citation: Dorn, K.M., Strausbaugh, C.A., Majumdar, R. 2023. USDA-ARS Plant Introduction lines evaluated for rhizomania and storage rot resistance in Idaho, 2022. Plant Disease Management Reports. 17. eArticle V114.

Interpretive Summary: Fungal, viral, and bacterial pathogens can cause substantial yield loss in sugar beet production. These include the viral pathogen that causes rhizomania, as well as bacterial and fungal pathogens that cause post-harvest storage rot. Plant breeders aiming to improve resistance to these diseases rely on plant genebanks, like the USDA-ARS National Plant Germplasm System, to discover new sources of resistance. USDA-ARS scientists in Fort Collins, CO and Kimberly, ID screened 30 lines from the beet genebank for resistance to rhizomania and storage rot. The team discovered one recently collected 'sea beet' line with excellent resistance to both rhizomania and storage rot. Multiple other lines had different combinations of resistance to rhizomania and storage rot. Screening wild beet lines for resistance to critical diseases is one of the ways that USDA-ARS researchers support breeding efforts to develop improved varieties. These results will be useful to sugar beet breeders to identify new genetic sources of disease resistance to improve the resiliency of American beet sugar production.

Technical Abstract: Thirty sugar beet (Beta vulgaris L.) USDA-ARS Plant Introduction (PI) lines and five check cultivars were screened for resistance to Beet necrotic yellow vein virus (BNYVV), the causal agent of rhizomania, and to storage rot. The rhizomania evaluation was conducted at the USDA-ARS North Farm in Kimberly, ID. The germplasm was planted on 3 May. The plots were one row 10-ft long with 22-in. between-row spacing and arranged in a randomized complete block design with 6 replicates. The trial relied on endemic field inoculum for rhizomania and storage rot development. The plots were rated for rhizomania foliar symptom (percentage of plants with yellow, stunted, upright leaves) development on 15 Aug. The plants were mechanically topped and hand harvested on 11-12 Oct. At harvest, ten roots per plot were rated for rhizomania symptom development using a scale of 0 to 9 (0 = healthy and 9 = dead). At harvest, eight roots per plot were also placed in a mesh-onion bag and kept in an indoor commercial storage facility (temperature set point 34°F) in Paul, ID on 13 Oct. On 14 Mar 23, after 152 days in storage, the roots were evaluated for the percentage of root surface area covered by fungal growth or rot. Except for root ratings, data were analyzed in SAS using the general linear model (Proc GLM) procedure, and Fisher’s protected least significant difference (a = 0.05) was used for mean comparisons. The root ratings were analyzed in a nonparametric analysis. Rhizomania symptom development was uniform and other disease problems were not evident in the plot area. The BNYVV susceptible check plots (Check 1 and Red beet) had 95 to 100% foliar symptoms and high root disease ratings. Resistant checks 3 and 4 had 0% foliar symptoms and a low root rating which indicates that resistance based on these genes is holding up. Single gene resistance in Check 2 had 8% foliar ratings indicating Rz2 resistance is not completely effective, but the root ratings were still good. Entries 28 and 29 had a level of BNYVV resistance similar to the resistant checks based on both foliar and root ratings. Entry 24 also had root ratings similar to the resistant checks but had higher foliar ratings. Entries 23 and 27 had very good foliar ratings, but the root ratings were subpar. Entries 23, 24, and 27 should be evaluated again to be sure these evaluations can be repeated. A number of the entries had resistance to fungal rots in storage, but only entry 29 performed well for all three variables. Some entries may serve as a starting point for identifying additional sources of resistance to BNYVV and storage rots.