Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 28, 2006
Publication Date: October 1, 2006
Citation: Jackson, D.M., Bohac, J. 2006. Improved Dry-fleshed Sweetpotato Genotypes Resistant to Insect Pests. Journal of Economic Entomology 99:1877-1883. Interpretive Summary: Most commercial dry fleshed 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 nine field evaluation of advanced dry fleshed sweetpotato entries from the USDA ARS sweetpotato breeding program at the U. S. Vegetable Laboratory (USVL), Charleston, SC. Thirty-five sweetpotato clones, including insect susceptible check cultivars, were evaluated for insect resistance in replicated field trials at Charleston, SC. Several of the advanced, dry fleshed germplasm lines were more resistant to soil insect pests than were the susceptible check varieties. The most promising of these advanced clones are being developed as breeding lines or new sweetpotato varieties.
Technical Abstract: Thirty-five mostly dry fleshed sweetpotato genotypes from the USDA ARS/Clemson sweetpotato breeding program were evaluated in nine field experiments at the U. S. Vegetable Laboratory (USVL), Charleston, SC, 1998-2004. There were highly significant entry effects for percent uninjured roots, WDS index (Wireworm, Diabrotica, Systena), percent roots damaged by sweetpotato weevil (Cylas formicarius elegantulus), percent roots damaged by flea beetle (Chaetocnema confinis Crotch), and percent roots damaged by white grub larvae (Plectris aliena Chapin and/or Phyllophaga spp.). The susceptible control cultivar, SC1149-19, had a significantly lower percentage of clean roots, a significantly higher WDS rating, and higher percentage infestations of flea beetle, grubs, and sweetpotato weevils than all other sweetpotato entries in this study. Twenty seven genotypes had significantly less insect damage than Beauregard, and 11 of these genotypes were significantly cleaner than Picadito, a commercial boniato-type sweetpotato grown extensively in south Florida. Overall, none of the experimental sweetpotato genotypes were more resistant to soil insect pests than the resistant check cultivars Sumor and Regal. Many of the advanced dry-flesh sweetpotato genotypes had high levels of resistance to soil insect pests, and they represent a useful source of advanced germplasm for use in sweetpotato breeding programs.