Submitted to: United States-Israel Binational Agricultural Research and Development Fund Workshop for Promoting Regional Cooperative Agricultural R&D in the Middle East
Publication Type: Abstract only
Publication Acceptance Date: 6/18/2004
Publication Date: 7/20/2004
Citation: Levi, A. 2004. Collaborative research in enhancing watermelon germplasm for disease and pest resistance and for horticultural qualities. United States-Israel Binational Agricultural Research and Development Fund Workshop for Promoting Regional Cooperative Agricultural R&D in the Middle East. Kuc University, Istanbul Turkey. p.16. Interpretive Summary:
Technical Abstract: Watermelon is an important vegetable, accounts for 2% of the world area devoted to vegetable crops. Watermelon production in the United States has increased from 1.2 million tons in 1980 to 4.2 million tons in 2003 with a farm value of $310 million. There is great demand for seedless watermelon and production of this watermelon type has significantly increased in recent years. Over 80% of watermelons produced in California were seedless, while over 54% of watermelons in the South Eastern states of the U.S. were seedless during 2003. Watermelon contains high levels of carotenoids known to reduce the risk of some forms of cancer, heart disease and eye degeneration. Although the wide phenotypic diversity, low genetic diversity exists among many of the watermelon cultivars developed in North America during the last two centuries. The low genetic diversity is mainly due to continuous selection for watermelon with desired horticultural traits. As a result, cultivated watermelon is susceptible to a large number of diseases and pests. There is vital need to 1) enhance watermelon germplasm for disease and pest resistances using Citrullus germplasm collected throughout the world, 2) enhance female flower production and develop male sterile lines useful in production of triploid seedless hybrid lines, 3) enhance carotenoid biosynthesis and content in watermelon. There are collaborative efforts between Israeli and U.S. scientists with respect to these research subjects. U.S. plant introductions (PIs) of Citrullus lanatus var. lanatus, C. lanatus var. citroides, and C. colocynthis are being screened for resistance to major watermelon diseases including fruit blotch, gummy stem blight, Fusarium wilt, powdery mildew, papaya ring spot virus, and watermelon virus. In addition, Citrullus PIs are being screened for nematode, whitefly and spider mite resistances. A few C. lanatus var. citroides and C. colocynthis PIs found to be resistant to these diseases and pests. There are collaborative efforts to introduce these resistances to cultivated watermelon. Also, there is collaboration in constructing a genetic linkage map for watermelon, in isolating the genes controlling disease and pest resistances, and in isolating genes affecting female flower production and fruit quality. It has been demonstrated that gene order and content are conserved within the same family and even between members of different families. Our long term goal is to take advantage of this synteny to facilitate gene discovery in watermelon and in other important crops of the economically important family Cucurbitaceae.