Kimberly sugar beet germplasm evaluated for rhizomania and storage rot resistance in Idaho, 2023

Authors: Vincill, Eric; Strausbaugh, Carl; Majumdar, Raj

Submitted to: Plant Disease Management Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/24/2024
Publication Date: 8/23/2024
Citation: Vincill, E.D., Strausbaugh, C.A., Majumdar, R. 2024. Kimberly sugar beet germplasm evaluated for rhizomania and storage rot resistance in Idaho, 2023. Plant Disease Management Reports. 18:CF084.

Interpretive Summary: Rhizomania, caused by Beet necrotic yellow vein virus (BNYVV), is an important viral disease problem worldwide, leading to significant yield loss in both the field and storage. Preventing rot and sucrose losses in storage is important to the economic viability of the sugar beet industry. The primary means of controlling these problems is through host resistance. Thus, 33 Beta vulgaris germplasm lines from the USDA-ARS Kimberly sugar beet program and five check cultivars were screened to characterize them for both resistance to BNYVV and storability. 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 100% foliar symptoms and high root disease ratings. Resistant checks 2 and 3 had 3 to 8% foliar symptoms and a low root rating, which indicates that resistance based on the Rz2 gene is reasonably good. Rz1 resistance in Check 4 had a foliar rating of 48% indicating single gene resistance is rather poor, but the root ratings were still low. Entries 21, 26, 33, and 36 performed well for rot in storage along with having good rhizomania root ratings, but only entries 33 and 36 had good foliar ratings as well. Thus, some entries will serve as genetic sources for identifying additional resistance to BNYVV and storage rots, which will aid the sugar beet industry in improving sucrose yield and retention in commercial sugar beet cultivars.

Technical Abstract: 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, 33 Beta vulgaris lines and five check cultivars were screened. The lines were grown in a sugar beet field infested with BNYVV during the 2023 growing season in a randomized complete block design with 6 replications. At harvest on 16-17 October, roots were dug and evaluated for rhizomania symptoms and then placed in an indoor commercial sugar beet storage building. After 145 days in storage, samples were evaluated for the percentage of root surface area covered by fungal growth or rot. Rhizomania symptom development was uniform and other disease problems were not evident in the plot area. Lines 7, 31, and 32 failed to produce enough plants, so there is no data for them. The BNYVV susceptible check plots (Check 1 and Red beet) had 100% foliar symptoms and high root disease ratings. Resistant checks 2 and 3 had 3 to 8% foliar symptoms and a low root rating, which indicates that resistance based on the Rz2 gene is reasonably good. Check 4 had a foliar rating of 48% indicating single gene resistance based on Rz1 is rather poor, but the root ratings were still low. Entries 21, 24, 25, 29, and 33 had root ratings similar to Check 3, but foliar ratings for entries 21, 25, and 29 were poor. Entries 13, 14, 28, and 36 had root disease ratings similar to the single gene checks and good foliar ratings. Entries 21, 26, 33, and 36 performed well for rot in storage along with having good rhizomania root ratings, but only entries 33 and 36 performed well for all three variables. Thus, some entries will serve as genetic sources for identifying additional resistance to BNYVV and storage rots, which will aid the sugar beet industry in improving sucrose yield and retention in commercial sugar beet cultivars.