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Title: Watermelon resistance to powdery mildew race 1 and race 2

Author
item Davis, Angela
item Levi, Amnon
item TETTEH, ANTONIA - NCSU, RALEIGH, NC
item WEHNER, TODD - NCSU, RALEIGH, NC
item PITRAT, MICHEL - INRA, MONTFAVET, FR

Submitted to: Cucurbitaceae Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 8/1/2006
Publication Date: 9/15/2006
Citation: Davis, A.R., Levi, A., Tetteh, A., Wehner, T., Pitrat, M. 2006. Watermelon resistance to powdery mildew race 1 and race 2. In: Cucurbitaceae 2006, September 17-21, 2006, Asheville, North Carolina. p. 412-420.

Interpretive Summary: Powdery mildew is an emerging disease of watermelon in the United States. To date, race 1 and race 2 of this fungus have been detected on watermelon. In this study watermelon lines from the U.S. Plant Introduction collection was evaluated for resistance to race 1 and race 2 of this disease. Six randomized greenhouse studies of one plant per watermelon line were performed. Eight lines were resistant to race 1 and five lines were resistant to race 2. The majority of the resistant lines for race 1 came from plants collected from Zimbabwe, while resistant lines for race 2 came from Iran, Egypt and Zambia (along with one unknown). Replicated evaluations are under way to confirm disease reactions using the most resistant and most susceptible accessions.

Technical Abstract: Powdery mildew is an emerging disease of watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) in the United States. To date, race 1 and race 2 of Podosphaera xanthii have been detected on watermelon. In this study the available U.S. Plant Introduction collection for watermelon was evaluated for resistance to P. xanthii race 1 and race 2. Six randomized greenhouse studies of one plant per accession were performed. Eight accessions were resistant to race 1 and five accessions were resistant to race 2. The majority of the resistant lines for race 1 came from plants collected from Zimbabwe, while resistant lines for race 2 came from Iran, Egypt and Zambia (along with one unknown). Replicated evaluations are under way to confirm disease reactions using the most resistant and most susceptible accessions.