Location: Vegetable Research
Title: Native host plant resistance to whiteflies in watermelon Authors
Submitted to: Entomology International Congress Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: April 4, 2012
Publication Date: August 19, 2012
Citation: Simmons, A.M., Levi, A. 2012. Native host plant resistance to whiteflies in watermelon. International Congress of Entomology. Daegu, Korea. 19-25 August 2012. Technical Abstract: Whiteflies (Hemiptera: Aleyrodidae), notably Bemisia tabaci (Gennadius), are destructive pests on a global scale. B. tabaci is highly adaptive and polyphagous on taxonomically diverse species of plants with varying levels of infestations. It is a serious pest of watermelon [Citrullus lanatus var. lanatus (Thunbs) Matsum Nakai] because of its direct feeding and transmitting of viruses of important diseases. We have conducted several studies to enhance whitefly resistance in watermelon. We have evaluated watermelon germplasm collected throughout the world and found that the desert watermelon, Citrullus colocynthis (L.) Schrad, contains resistance to whiteflies and other pests. Bioassays for native host plant resistance to whiteflies in C. colocynthesis accessions indicate that antibiosis, antixenosis and tolerance factors exert roles in the resistance. The bioassays identified differences among accessions within and among three selected species of Citrullus. Plant phenotype and leaf chemical profiles differ between accessions of C. colocynthis and watermelon cultivars. Moreover, plants of C. colocynthis accessions were noticeably odorous, and the total flavonoid content of their leaves was elevated as compared to watermelon cultivars. Genetic similarity and relationships were examined among accessions of Citrullus spp., Cucurbita maxima Duchesne (winter squash), Cucurbita pepo L. (squash and pumpkin), Cucumis melo L. (melon), Cucumis sativus L. (cucumber), and Lagenaria siceraria (Mol.) Standl (bottle gourd) which showed that each is distinct with similar genetic distances among these species. Obtaining a good understanding of the genetics and mechanisms affecting native plant resistance of Citrullus is critical in the development of watermelon that is resistant to whiteflies.