Beet curly top resistance in USDA-ARS Plant Introduction (PI) sugar beet breeding lines, 2024

Authors: Vincill, Eric; Dorn, Kevin; Long, Evan; Majumdar, Rajtilak; STAUSBAUGH, CARL - Retired ARS Employee

Submitted to: Plant Health Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/6/2026
Publication Date: 8/3/2026
Citation: Vincill, E.D., Dorn, K.M., Long, E.M., Majumdar, R., Stausbaugh, C.A. 2026. Beet curly top resistance in USDA-ARS Plant Introduction (PI) sugar beet breeding lines, 2024. Plant Health Progress. https://doi.org/10.1094/PHP-05-26-0112-PDMR.
DOI: https://doi.org/10.1094/PHP-05-26-0112-PDMR

Interpretive Summary: Curly top disease is caused by the Beet curly top virus (BCTV) which is insect vectored by the beet leafhopper. This disease can cause considerable yield loss in the sugar beet production areas of the semiarid western United States unless crop protection measures are utilized. The primary agricultural measures to combat Curly top disease in sugar beet is through leveraging genetically resistant traits to BCTV in sugar beet, but resistance in current commercial cultivars is only low to intermediate and tends to be associated with lower yield potential. Therefore, it is important to identify and incorporate beet germplasm with new and novel genetic resistances into commercial cultivars. This field study evaluated the BCTV resistance traits from 30 beta vulgaris L. plant introduction (PI) lines from the USDA-ARS National Plant Germplasm System (NPGS). Based on the visual ratings, three of the PI lines (Ames 4376, Ames 2654, and W6_17106) showed high resistance to BCTV (as compared with commercial resistant check used in this study). Two other PI lines showed minor resistance (resistance to BCTV above the commercial susceptible check). These five PI lines will be retested and investigated as a source of new and novel BCTV resistance traits that could be utilized to improve BCTV resistance in commercial sugar beet cultivars.

Technical Abstract: Curly top disease, caused by Beet curly top virus (BCTV) and vectored by the beet leafhopper, is a widespread disease problem in semiarid sugar beet production areas. Plant host resistance in sugar beet is the primary defense against this problem, but resistance in commercial sugar beet cultivars is only low to intermediate. In order to identify new and novel sources of curly top resistance traits, 30 sugar beet lines curated by the USDA-ARS National Plant Germplasm System (NPGS), were screened in a Curly top disease nursery in Kimberly, ID, USA in 2024. The lines were arranged in a randomized complete block design with six replications. A Curly top disease epiphytotic was created by releasing six viruliferous beet leafhoppers per plant at the four- to six-leaf growth stage on 18 June. Foliar symptoms were evaluated on 8 July using a scale of 0-9 (0 = healthy and 9 = dead). Curly top symptom development was uniform and no other disease problems were evident in the plot area. The disease pressure in the test was moderately severe with good symptom development in the susceptible and moderate checks. Based on the visual ratings, three of the PI lines (Ames 4376, Ames 2654, and W6_17106) showed high resistance to BCTV (as compared to the commercial resistant check used in this study). Two other PI lines showed minor resistance (resistance to BCTV above the commercial susceptible check). These five PI lines will be retested and investigated as a source of new and novel BCTV resistance traits that could be utilized to improve BCTV resistance in commercial sugar beet cultivars.