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ARS Home » Midwest Area » Madison, Wisconsin » Vegetable Crops Research » Research » Publications at this Location » Publication #367546
Research Project: Trait Discovery, Genetics, and Enhancement of Allium, Cucumis, and Daucus Germplasm

Location: Vegetable Crops Research

Title: Amounts and types of epicuticular leaf waxes among onion accessions selected for reduced damage by onion thrips

Author
item MUNAIZ, EDUARDO - University Of Wisconsin
item GROVES, RUSSELL - University Of Wisconsin
item Havey, Michael

Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/8/2019
Publication Date: 11/14/2019
Citation: Munaiz, E.D., Groves, R.L., Havey, M.J. 2019. Amounts and types of epicuticular leaf waxes among onion accessions selected for reduced damage by onion thrips. Journal of the American Society for Horticultural Science. 145(1):30-35. https://doi.org/10.21273/JASHS04773-19.
DOI: https://doi.org/10.21273/JASHS04773-19

Interpretive Summary: Onion thrips is the main insect pest of onion and routinely causes serious yield losses. The insect also transmits Iris yellow spot virus (IYSV) for which there is no known resistance. Lower amounts of waxes on onion leaves have been associated with fewer thrips, less feeding damage, and lower incidence of IYSV. This study used gas chromatography mass spectroscopy (GCMS) to determine amounts and types of epicuticular waxes among onion selections showing reduced damage by onion thrips and IYSV in field evaluations. Hentriacontanone-16 (H16), octaconasol-1 (Oct1), and triacontanol-1 (Tri1) were the most prevalent waxes on foliage of wild-type waxy onions and H16 was significantly lower on selections visually classified as having glossy or semi-glossy foliage. Semi-glossy accessions were identified with larger amounts of total epicuticular wax than waxy phenotypes, due to lower amounts of H16 relative to the other waxes. Glossy and semi-glossy selections with varying amounts of total and specific waxes suffered significantly less damage by onion thrips in a field evaluation This research indicates that identification of unique wax profiles will be an effective approach to develop thrips-resistant onions.

Technical Abstract: Onion thrips (Thrips tabaci) is the main insect pest of onion (Allium cepa) and routinely causes serious yield losses. Lower amounts of epicuticular waxes on onion leaves have been associated with fewer thrips and less feeding damage. This study used gas chromatography mass spectroscopy (GCMS) to determine amounts and types of epicuticular waxes on the foliage of onions that had been selected in field plots for reduced damage by onion thrips. Hentriacontanone-16 (H16), octaconasol-1 (Oct), and triacontanol-1 (Tri) were the most prevalent waxes on the foliage of most selections. Amounts of H16 were significantly lower on selections visually classified as having glossy or semi-glossy foliage. Semi-glossy selections were identified with similar amounts of total epicuticular wax as waxy phenotypes, due primarily to lower amounts of H16 and higher amounts of other waxes. These semi-glossy selections suffered significantly less damage by onion thrips in a field evaluation, supporting the identification of unique wax profiles towards the development of thrips-resistant onions.