ARS | Publication request: Identification of resistance to fusarium oxysporum f. sp. niveum Race 2 in citrullus lanatus var. citroides plant introductions

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 5, 2012
Publication Date: March 1, 2012
Citation: Wechter, W.P., Kousik, C.S., Mcmillan, M.L., Levi, A. 2012. Identification of resistance to fusarium oxysporum f. sp. niveum Race 2 in citrullus lanatus var. citroides plant introductions. HortScience. 47(3):334-338.

Interpretive Summary: Fusarium wilt is a major disease of watermelon in North America and around the world. Control of this disease is difficult, because the soil-borne causal agent produces resilient spores that remain infectious for many years. In this study, we used seed and seedling inoculation procedures to screen 110 United States Plant Introduction (PI) accessions of wild watermelon for resistance to the highly aggressive race 2 Fusarium wilt. Of these 110 PIs, 15 showed significantly higher resistance to race 2 Fusarium wilt than that found in the watermelon cultivars Sugar Baby or Charleston Grey, as well as in the C. lanatus var. citroides PI 296341 and PI 271769, both reported to contain resistance to Fusarium wilt. These 15 PIs may be valuable as a source for resistance to race 2 Fusarium wilt in watermelon breeding.

Technical Abstract: Fusarium wilt is a major disease of watermelon in North America and around the world. Control of this disease is difficult, because the soil-borne causal agent Fusarium oxysporum f. sp. niveum (Fon), produces resilient spores that remain infectious for many years. Although various levels of resistance to Fon races 0 and 1 exist in watermelon cultivars, no resistance for races 2 or 3 has been reported. In this study, we used seed and seedling inoculation procedures to screen 110 United States Plant Introduction (PI) accessions of wild watermelon (Citrullus lanatus var. citroides) for resistance to race 2 Fusarium wilt (FW). Of these 110 PIs, 15 showed significantly higher resistance to Fon race 2 than that found in the watermelon cultivars Sugar Baby or Charleston Grey, as well as in the C. lanatus var. citroides PI 296341 that was reported to contain resistance to FW. Another C. lanatus var. citroides PI 271769 which also was reported as containing resistance to FW is among the 15 resistant PIs described here. These 15 PIs may be valuable as a source for resistance to race 2 FW in watermelon breeding.