Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/31/2013
Publication Date: 1/1/2014
Citation: Kousik, C.S., Ling, K., Adkins, S.T., Webster, C.G., Turechek, W. 2014. Phytophthora fruit rot-resistant watermelon germplasm lines: USVL489-PFR, USVL782-PFR, USVL203-PFR, and USVL020-PFR. HortScience. 49:101-104.
Interpretive Summary: Watermelon is an important crop grown in 44 states in the U.S. Many different pests and diseases attack watermelon plants causing extensive damage. In recent years, an old but emerging disease called Phytophthora fruit rot has been causing serious problems in watermelon production in many states in the U.S., including FL, GA, SC, NC, DE, MI, MD, and etc. It has been particularly severe in parts of Georgia, where over 25,000 acres of watermelon are grown. ARS scientists working in South Carolina and Florida have developed four watermelon germplasm lines (USVL489-PFR, USVL782-PFR, USVL203-PFR, and USVL020-PFR) with resistance to Phytophthora fruit rot. These resistant germplasm lines can be used by private and public sector plant breeders to develop watermelon varieties and breeding lines with resistance to this dreaded disease. Development of varieties with resistance to fruit rot will help reduce pesticide use and allow watermelon growers to produce a healthy crop of fruit.
Technical Abstract: USVL489-PFR, USVL782-PFR, USVL203-PFR, and USVL020-PFR are watermelon (Citrullus lanatus var. lanatus (Thunb.) Matsum. & Nakai) germplasm lines that exhibit high levels of resistance to Phytophthora fruit rot caused by the plant pathogen Phytophthora capsici. Resistance in these germplasm lines is expressed as significantly reduced to practically no lesion development, rot or pathogen sporulation on the fruit compared to large lesions, severe rot and heavy sporulation on commercial watermelon cultivars Sugar Baby, Black Diamond Mickey Lee. These four USVL germplasm lines are each highly uniform for growth characteristics, fruit size, shape, and color. Currently, commercial cultivars with resistance to Phytophthora fruit rot of watermelon are not available. These four USVL germplasm lines may be a useful source for incorporating resistance in commercially acceptable cultivars.