Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/14/2002
Publication Date: 12/15/2003
Citation: Thies, J.A., Levi, A. 2003. Resistance of watermelon (citrullus spp.) germplasm to the peanut root-knot nematode (meloidogyne arenaria race 1). Hortscience. 38:1417-1421. Interpretive Summary:
Technical Abstract: Root-knot nematodes (Meloidogyne arenaria, M. incognita, and M. javanica) are serious pests of watermelon (Citrullus lanatus) in the southern U.S. and world-wide. Currently, root-knot nematodes (RKN) are controlled in watermelon by pre-plant soil fumigation with methyl bromide or other nematicides. The proposed removal of methyl bromide from the U.S. market in 2005 has focused interest in developing alternatives for managing nematodes in vegetable crops. Resistant cultivars would provide an inexpensive, environmentally compatible alternative for managing RKN in watermelon. All accessions of C. colocynthis (21) and C. lanatus var. citroides (88), and approximately 10% of C. lanatus var. lanatus (157) accessions from the USDA Citrullus germplasm collection were evaluated for resistance to M. arenaria race 1 in greenhouse tests. The C. lanatus var. lanatus and C. colocynthis accessions were susceptible; root gall severity indices (GI) = 4.0 to 9.0 (scale = 1.0 to 9.0) and GI = 8.0 to 9.0, respectively. However, 21 of 88 C. lanatus var. citroides accessions were moderately resistant (GI = 3.0 to 4.9). Conclusions: Significant genetic variability exists within the USDA Citrullus germplasm collection for reaction to M. arenaria race 1 and the C. lanatus var. citroides accessions are potential sources of resistance to M. arenaria race 1.