Location: Vegetable ResearchTitle: Insect resistance in sweetpotato plant introduction accessions Author
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/24/2012
Publication Date: 4/11/2012
Citation: Jackson, D.M., Harrison Jr, H.F., Ryan-Bohac, J. 2012. Insect resistance in sweetpotato plant introduction accessions. Journal of Economic Entomology. 105:651-658. Interpretive Summary: For any vegetable breeding program, the discovery of new genetic sources of desirable characteristics is essential for the improvement of that crop. Commercial sweetpotato cultivars have little resistance to soil insect pests, which can severely limit marketable yields. Thus, there is a need to develop new varieties that have increased levels of insect resistance. This report describes results of 17 field evaluations of sweetpotato plant introductions (PI) that were obtained from the USDA ARS sweetpotato germplasm collection in Griffin, GA. Fifty-five sweetpotato clones, including insect susceptible and insect-resistant check cultivars, were evaluated for insect damage in replicated field trials at Charleston, SC, Blackville, SC, and Homestead, FL. Several of the sweetpotato PIs were more resistant to soil insect pests than were the susceptible check varieties. The most promising of these materials are being used as parental materials in our sweetpotato breeding program and are of interest to other sweetpotato breeders in the United States focused on making this crop more resistant to insect attack.
Technical Abstract: Fifty-five sweetpotato plant introductions (PI) were evaluated in 17 field experiments at the USDA, ARS, U.S. Vegetable Laboratory, Charleston, SC (12 evaluations, 1997-2010), the Clemson University, Edisto Research and Education Center, Blackville, SC (2 evaluations, 1998-1999), and the University of Florida, Tropical Research and Education Center, Homestead, FL (3 evaluations, 2005-2007). These experiments included two insect-susceptible control entries (‘Beauregard’ and ‘SC1149-19’) and three insect-resistant control cultivars (‘Regal’, ‘Ruddy’, and ‘Sumor’). At each location, there were highly significant entry effects for percent uninjured roots, WDS (Wireworm, Diabrotica, and Systena) index, percent roots damaged by the sweetpotato weevil (Cylas formicarius [Fabricius]), percent roots damaged by the sweetpotato flea beetle (Chaetocnema confinis Crotch), and percent roots damaged by white grub larvae (including Plectris aliena Chapin and Phyllophaga spp.). ‘SC1149-19’ had a significantly lower percentage of uninjured roots, a significantly higher WDS rating, and significantly higher percentage infestations of flea beetles, grubs, and sweetpotato weevils than most other sweetpotato PIs in this study. In addition, 43 of 55 genotypes had significantly less overall insect damage than ‘Beauregard’, one of the leading commercial orange-fleshed cultivars in the United States. Ten genotypes had significantly less insect injury than ‘Picadito’, a commercial boniato-type sweetpotato grown extensively in southern Florida. Many of the sweetpotato PIs had high levels of resistance to soil insect pests, and they represent a useful source of germplasm for use in sweetpotato breeding programs.