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ARS Home » Southeast Area » Charleston, South Carolina » Vegetable Research » Research » Publications at this Location » Publication #419895
Research Project: Basic and Applied Approaches for Pest Management in Vegetable Crops

Location: Vegetable Research

Title: Watermelon germplasm with resistance to whitefly-transmitted viruses

Author
item LUCKEW, ALEX - University Of Georgia
item SARI, NEBAHAT - University Of Georgia
item PANDEY, SWIKRITI - University Of Georgia
item MCAVOY, TED - University Of Georgia
item SIMMONS, ALVIN
item MERU, GEOFFREY - University Of Georgia
item MCGREGOR, CECILIA - University Of Georgia

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/8/2024
Publication Date: 2/1/2025
Citation: Luckew, A., Sari, N., Pandey, S., Mcavoy, T., Simmons, A.M., Meru, G., Mcgregor, C. 2025. Watermelon germplasm with resistance to whitefly-transmitted viruses. HortScience. https://doi.org/10.21273/HORTSCI18262-24.
DOI: https://doi.org/10.21273/HORTSCI18262-24

Interpretive Summary: Whiteflies are mostly controlled with insecticides. However, other strategies are needed because pesticides are costly, the pests become resistant to the chemicals, and the insecticides do not provide effective control of whitefly-transmitted viruses. A study was conducted to evaluated 21 commercial cultivars and wide types of watermelons for their resistance against some whitefly-transmitted plant viruses. Measuring the level of viruses in the plants was more reliable than determining infection based on visual observations. The performance of two wild types (PI 494528 and PI 595203) were found to be of particular potential for use as sources for breeders to develop Cucurbit leaf crumple virus resistance in watermelon. The findings of this study will be of use to scientists and the seed industry in developing watermelon with resistance to whitefly-transmitted viruses.

Technical Abstract: The current management of whiteflies is largely dependent on insecticides. However, pesticides are costly and do not provide effective control of whitefly-transmitted viruses (WTVs). On the other hand, breeding for resistant cultivars can provide a more effective and sustainable solution. Twenty-one Citrullus genotypes, including 10 Citrullus lanatus, four C. mucosospermus, six C. amarus, and one C. ecirrhosus were evaluated for resistance to three WTVs common in Georgia, USA, in the field for two years. Phenotypic data were collected weekly for viral disease severity (AUDPC). Leaf samples were collected five weeks after transplanting (WAT) in 2022 and seven WAT in 2023 to determine the viral loads of Cucurbit leaf crumple virus (CuLCrV), Cucurbit yellow stunting disorder virus (CYSDV), and Cucurbit chlorotic yellows virus (CCYV) via qPCR. CuLCrV and CYSDV viral loads were higher in 2022 than 2023, while CCYV load was higher in 2023. Three accessions (PI 494528, PI 595203, and Grif 16444) outperformed the cultivars for viral disease severity and CuLCrV load (2022). In 2022, there was a significant difference among cultivars for CYSDV load, with ‘AU-Producer’, ‘Crimson Sweet’ and ‘Estrella’, having lower loads than ‘Charleston Gray’ and ‘Sugar Baby’. There were no statistical differences in CCYV loads between the best performing accessions and ‘Charleston Gray’ in either year. Grif 16444 is a C. ecirrhosus accession, and this species has previously been reported to have resistance to whiteflies. The two accessions PI 494528 and PI 595203 (C. mucosospermus) provide a valuable resource for breeders to develop CuLCrV resistance in watermelon. This species is closely related to cultivated watermelon and resistance introgression could be relatively easy because there is no reproductive barrier between the two species.