Project Number: 6659-22000-020-00
Project Type: Appropriated

Start Date: Jul 10, 2007
End Date: Jul 09, 2012

Objective:
Diseases and nematodes are major limitations in vegetable crop production in the U.S. There are many tools available to manage plant diseases. However, host-plant resistance is probably the easiest, most economical and environmentally friendly method for managing plant diseases and is readily acceptable to growers. Identification of host plant resistance to existing, new, and emerging pathogens in vegetable crops is critical for the development of efficient and effective disease management strategies that will reduce crop loss and pesticide use. Therefore, research under this project will identify new sources of resistance, determine inheritance of previously identified resistance, and develop molecular markers for important resistance genes that will facilitate their rapid incorporation into commercial cultivars. An understanding of variability in pathogen populations also is necessary to develop new vegetable cultivars with durable resistance. Thus, the proposed research will be accomplished through the following objectives: 1) Develop improved resistance to root-knot nematodes in pepper and watermelon, and 2) Identify and develop improved resistance to diseases in cucurbits and elucidate genetic variability in the cucurbit downy mildew pathogen. Successful attainment of these objectives will result in basic knowledge that facilitates development of new resistant germplasm, identification of molecular markers that will aid selection for resistance genes in breeding programs, and development of knowledge of pathogen variability.

Approach:
Develop root-knot nematode-resistant sweet banana, sweet cherry, pimiento, and Cubanelle type peppers using backcross breeding procedures. Determine inheritance of resistance to root-knot nematodes (Meloidogyne incognita) in watermelon and identify molecular markers for root-knot nematode resistance genes in watermelon. Identify and develop improved resistance to Phytophthora capsici in watermelon and melon. Identify sources of resistance in watermelon plant introductions and develop management strategies for mature watermelon vine decline. Elucidate genetic variability in the downy mildew pathogen (Pseudoperenospora cubensis) isolated from watermelon and cucumber using conventional and molecular approaches.