Location: Soil Management and Sugarbeet ResearchTitle: Beet curly top resistance in USDA-ARS NPGS Plant Introduction lines, 2021
Submitted to: Plant Disease Management Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2022
Publication Date: 8/9/2022
Citation: Dorn, K.M., Strausbaugh, C.A., Galewski, P.J. 2022. Beet curly top resistance in USDA-ARS NPGS Plant Introduction lines, 2021. Plant Disease Management Reports. 16. Article eV166.
Interpretive Summary: Managing beet curly top resistance represents one of the ongoing challenges facing the beet sugar production, particularly in the western United States. Drawing upon crop germplasm from USDA’s National Plant Germplasm System, Agricultural Research Service scientists in Fort Collins, CO screened stored germplasm and commercial sugar beet lines to find new sources of resistance to the Beet Curly Top Virus. The researchers identified several promising germplasm lines that could be used to improve resistance to beet curly top virus in commercial sugar beet varieties.
Technical Abstract: Fifty sugar beet (Beta vulgaris L.) or wild beet (Beta vulgaris spp. maritima) USDA-ARS Plant Introduction (PI) lines and three commercial check cultivars were screened for resistance to Beet curly top virus (BCTV). The curly top evaluation was conducted at the USDA-ARS North Farm in Kimberly, ID during the 2021 field season. The field was plowed, fertilized and roller harrowed on 26 Mar. The germplasm was planted on 17 May. The plots were two rows 10-ft long with 22-in. row spacing and treatments were arranged in a randomized complete block design with six replications. The field was sprinkler irrigated, cultivated, and hand weeded as necessary. Plants were inoculated at the four- to six-leaf growth stage on 22 Jun with approximately six viruliferous (containing the following BCTV strains: California/Logan and Severe) beet leafhoppers (Circulifer tenellus Baker) per plant. The beet leafhoppers were redistributed two times a day during the first seven days by dragging a tarp through the field. The plants were sprayed with Lorsban 4E on 6 Jul to kill the beet leafhoppers. Plots were rated for foliar symptom development on 12 Jul using a scale of 0 to 9 (0 = healthy and 9 = dead), with the scale treated as a continuous variable. Data were rank transformed prior to analysis in SAS with mixed linear models using the Proc MIXED procedure. Mean separation was based on a PDIFF comparison with a probability cutoff of 0.05. Curly top symptom development was uniform and no other disease problems were evident in the plot area. The resistant and susceptible checks performed as expected for the visual ratings. Statistically, 37 of the entries contain at least some minor resistance since their visual ratings were significantly lower than those for both susceptible checks. However, only 17 entries were not significantly different from the resistant check. These 17 entries along with entries with similar levels of resistance will be retested and, if resistance is confirmed, these lines will be considered for incorporation into the USDA-ARS germplasm improvement program as a source of resistance to BCTV.