Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 21, 2001
Publication Date: February 15, 2002
Citation: SIMMONS, A.M., LEVI, A. SOURCE OF WHITEFLY (HOMOPTERA: ALEYRODIDAE) RESISTANCE IN CITRULLUS FOR THE IMPROVEMENT OF CULTIVATED WATERMELON. HORTSCIENCE. 2002. v.37(3) p.581-584. Interpretive Summary: Watermelon is an important crop worldwide. In the U.S., watermelon production has increased from 1.2 M tons in 1980 to 2.1 M tons in 1998, with an at-farm value of $287 million. The watermelon crop is susceptible to pests and diseases that cause significant damage. The B-strain sweetpotato whitefly (also called silverleaf whitefly) is among the major pests of watermelon. Whiteflies harm watermelon plants by their feeding and by spreading viruses. Therefore, genes that make watermelon resistant to the whitefly pest are needed. The cultivated watermelon is related to two wild species called Citrullus lanatus and C. colocynthis which are found in Africa and in Asia. They are potential sources of genes that can give the cultivated watermelon more resistance to pests and diseases. To find a source of resistance to whiteflies, ARS scientists evaluated various accessions of these plant species that originated from different places around the world. The ARS scientists identified a group of accessions (C. colocynthis) that have resistance to whiteflies. These accessions will be used in breeding programs to introduce the resistant genes into varieties of the cultivated watermelon.
Technical Abstract: The B-biotype sweetpotato whitefly, Bemisia tabaci (Gennadius), feeds on and damages numerous vegetable crops including watermelon (Citrullus sp.). Seven watermelon cultivars, a triploid line, and 16 U.S. Plant Introduction accessions (PIs) of C. lanatus var. lanatus; 10 PIs of C. lanatus var. citroides; and 8 PIs of C. colocynthis, were evaluated for resistance to B. .tabaci. Bioassays were based on non-preference and performance of the whiteflies on the 42 Citrullus genotypes. Most of the watermelon cultivars and C. lanatus PIs tested were highly susceptible to whitefly infestation, while the C. colocynthis PIs exhibited whitefly resistance. Among the C. colocynthis accessions tested, PI 386015, 386018, and PI 386024 were most resistant to B. tabaci. This study identified useful sources of germplasm which can be used for the improvement of watermelon for resistance to whiteflies.