Enhancing watermelon with resistance against whiteflies

Authors: Simmons, Alvin; Jarret, Robert - Bob; Cantrell, Charles; Levi, Amnon

Submitted to: International Whitefly Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 7/16/2018
Publication Date: 9/15/2018
Citation: Simmons, A.M., Jarret, R.L., Cantrell, C.L., Levi, A. 2018. Enhancing watermelon with resistance against whiteflies. 3rd International Whitefly Symposium, September 16-19, 2018, Perth, Australia p.14.

Interpretive Summary:

Technical Abstract: Whiteflies are notorious pests in agricultural crops around the world. They attack crop plants in both field and protected environments such as greenhouses. It is well known that the Bemisia tabaci species complex (Hemiptera: Aleyrodidae) is highly polyphagous. However, there is a wide range in acceptance and performance of B. tabaci among host plant species. Moreover, in addition to damage by feeding, excessive damage results from the many plant viruses that they transmit. The B. tabaci complex is by far the most problematic among whiteflies affecting crops. The cultivated watermelon (Citrullus lanatus var. lanatus) is among the crops affected by whiteflies and whitefly-transmitted viruses. With a relatively short generation time and high rate of oviposition, whitefly populations can quickly build on host plants like watermelon. Commercial watermelon cultivars share a narrow genetic base and are highly susceptible to whiteflies. However, there is wide genetic diversity among the species of Citrullus. The Citrullus colocynthis and C. ecirrhosus are perennial desert watermelon species with a broad genetic base and viable sources of resistance to insect pests and diseases of watermelon. One of these two species (C. colocynthis) is indigenous to arid regions of Northern Africa, the Mediterranean, and Southwest Asia, while the other (C. ecirrhosus) is indigenous to Southern Africa. Insecticide is a common and convenient tool for managing whiteflies and other arthropod pests in watermelon. Yet, because of many negatives associated with that strategy, a sustainable approach of using host plant resistance is desirable. Watermelon host plant resistance against arthropod pests is based on a combination of plant tolerance, antibiosis and non-preference. Thus, we used multiple types of assays to assess plant resistance against whiteflies (B. tabaci; MEAM1). We collected olfactometer, and choice and no-choice performance assays in comparing whiteflies on cultivated watermelon versus genotypes of the perennial desert species. The data clearly demonstrated plant resistance against B. tabaci in the wild genotypes. Using traditional breeding procedures, we have been able to successfully cross C. colocynthis with watermelon cultivars (C. lanatus var. lanatus) and produced viable seeds. This research with genotypes of C. colocynthis and C. ecirrosus demonstrates their potential as sources of resistance against whiteflies for cultivated watermelon.