Beet curly top resistance in USDA-ARS Kimberly germplasm, 2019

Authors: Eujayl, Imad; Strausbaugh, Carl

Submitted to: Plant Disease Management Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/26/2020
Publication Date: 3/9/2020
Citation: Eujayl, I.A., Strausbaugh, C.A. 2020. Beet curly top resistance in USDA-ARS Kimberly germplasm, 2019. Plant Disease Management Reports. 14:CF042.

Interpretive Summary: Curly top in the semiarid sugar beet production areas of the United States is caused by Beet curly top virus and vectored by the beet leafhopper. Resistant sugar beet cultivars became available in the 1930s prior to which curly top combined with drought almost eliminated the sugar beet industry in the western United States. However, resistance is typically low to intermediate in commercial cultivars and has a tendency to be associated with lower yield potential. Thus, novel sources of resistance need to be identified and incorporated into commercial cultivars. Eight sugar beet lines produced by the USDA-ARS Kimberly sugar beet program were screened for resistance to curly top. Four of the lines performed very well and will be investigated further for potential release to the general public so they can be utilized to improve BCTV resistance in commercial sugar beet cultivars.

Technical Abstract: Curly top caused by Beet curly top virus (BCTV) is a widespread disease problem vectored by the beet leafhopper in semiarid sugar beet production areas. Host resistance is the primary defense against this problem, but resistance in commercial cultivars is only low to intermediate. In order to identify novel sources of curly top resistance, 8 sugar beet lines produced by the USDA-ARS Kimberly sugar beet program were screened in a disease nursery in 2019. The lines were arranged in a randomized complete block design with six replications. A curly top epiphytotic was created by releasing six viruliferous beet leafhoppers per plant at the four- to six-leaf growth stage on 3 Jul. Foliar symptoms were evaluated on 22 July using a scale of 0-9 (0 = healthy and 9 = dead) in a continuous manner. 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 checks. Based on the visual rating, four entries (segregating populations) and two genetic stock line entries were not significantly different from the resistant checks. The resistant segregating populations will be suitable for single trait selection and advancement to breeding lines to enrich the BCTV resistance gene pool in the USDA-ARS sugar beet germplasm.