Location: Soil Management and Sugarbeet ResearchTitle: Beet curly top resistance in USDA-ARS Plant Introduction lines, 2022
Submitted to: Plant Disease Management Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/17/2023
Publication Date: 3/15/2023
Citation: Dorn, K.M., Strausbaugh, C.A., Galewski, P.J. 2023. Beet curly top resistance in USDA-ARS Plant Introduction lines, 2022. Plant Disease Management Reports. 17. Article eV033.
Interpretive Summary: Beet curly top is a viral disease that can cause substantial yield losses in sugar beet production. This virus is transmitted to sugar beet plants by an insect, the beet leaf hopper. Sugar beet farmers often rely on spraying insecticides to control leaf hopper populations to reduce the transmission of the virus. Breeding for improved plant resistance to the Beet Curly Top Virus represents another important strategy for managing this disease. Scientists at the USDA-ARS in Fort Collins, CO and Kimberly, ID screened a panel of beet germplasm from the U.S. National Plant Germplasm System to identify lines with resistance to Beet Curly Top Virus. The scientists identified nine lines that were resistant to the virus that were all derived from the USDA-ARS sugar beet research program in Logan, Utah. These resistant lines represent potentially useful breeding resources for improving resistance to Beet Curly Top Virus in sugar beet.
Technical Abstract: Thirty beet (USDA-ARS Plant Introduction (PI) lines and three commercial check cultivars were screened in 2022 for resistance to Beet curly top virus (BCTV) in Kimberly, ID. This panel of germplasm represents a continuing effort to systematically screen NPGS Beta germplasm for resistance to multiple sugar beet diseases and pests to aid germplasm improvement activities. The germplasm was planted 3 May. Treatments were arranged in a randomized complete block design with six replications. Plants were inoculated at the four- to six-leaf growth stage on 15 Jun with approximately six viruliferous 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 an insecticide (Admire Pro) on 27 Jun to kill the beet leafhoppers. Plots were rated for foliar symptom development on 6 Jul using a scale of 0 to 9 (0 = healthy and 9 = dead). Data were rank transformed prior to analysis in SAS with mixed linear models. 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, 13 of the entries contain at least some minor resistance since their visual ratings were significantly lower than those for both susceptible checks. Nine entries from the USDA-ARS Utah sugar beet program that were donated to the NPGS in 1983 were not significantly different from the resistant check. All nine of these entries were statistically more resistant than both susceptible check lines. An additional two entries from the USDA-ARS Utah sugar beet program and one Beta vulgaris spp. maritima accession collected by USDA-ARS researchers in Morocco (W6 45822) were statistically more resistant than the susceptible sugar beet check, but had statistically lower curly top ratings than the resistant check. These entries along with entries with similar levels of resistance from prior years evaluations 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.