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ARS Home » Midwest Area » Madison, Wisconsin » Vegetable Crops Research » Research » Publications at this Location » Publication #306076

Research Project: Genetic Enhancement of Allium, Cucumis, and Daucus Germplasm

Location: Vegetable Crops Research

Title: Quantitative trait loci controlling amounts and types of epicuticular waxes in onion

Author
item Damon, Steven - University Of Wisconsin
item Havey, Michael

Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/8/2014
Publication Date: 9/1/2014
Publication URL: http://handle.nal.usda.gov/10113/60055
Citation: Damon, S.J., Havey, M.J. 2014. Quantitative trait loci controlling amounts and types of epicuticular waxes in onion. Journal of the American Society for Horticultural Science. 139(5):597-602.

Interpretive Summary: Natural variation exists in onion for amounts and types of waxes on leaves. Waxy onion possesses copious amounts of these waxes, while the foliage of semi-glossy and glossy onions accumulate significantly less wax. Reduced amounts of epicuticular waxes have been associated with resistance to onion thrips, an important insect pest of onion. A segregating family from the cross of waxy and semi-glossy onions was used to map single nucleotide polymorphisms (SNPs) and identify chromosome regions affecting amounts and types of leaf waxes as measured by gas-chromatography-mass-spectrometry (GCMS). The amount of the primary wax on onion leaves, hentriacontanone-16, was controlled by one region on chromosome 5. One region on chromosome 2 affected concentrations of several primary fatty alcohols. Results indicate that the region on chromosome 2 may be associated with the acyl reduction pathway, and the region on chromosome 5 may affect the decarbonylation pathway, of leaf-wax biosynthesis. Because lower amounts of epicuticular waxes are recessively inherited, SNPs tagging regions on chromosomes 2 and 5 will be useful for marker-assisted breeding to vary amounts and types of waxes on onion foliage. These results will be of interest to onion breeders in the public and private sectors towards the development of onion-thrips resistant cultivars.

Technical Abstract: Natural variation exists in onion (Allium cepa L.) for amounts and types of epicuticular waxes on leaves. Wild-type waxy onion possesses copious amounts of these waxes, while the foliage of semi-glossy and glossy phenotypes accumulate significantly less wax. Reduced amounts of epicuticular waxes have been associated with resistance to onion thrips (Thrips tabaci Lindeman), an important insect pest of onion. A segregating family from the cross of waxy and semi-glossy onions was used to map single nucleotide polymorphisms (SNPs) and identify chromosome regions affecting amounts and types of epicuticular waxes as measured by gas-chromatography-mass-spectrometry (GCMS). The amount of the primary epicuticular wax on onion leaves, hentriacontanone-16, was controlled by one region on chromosome 5. One region on chromosome 2 affected concentrations of several primary fatty alcohols. Results indicate that the region on chromosome 2 may be associated with the acyl reduction pathway, and the region on chromosome 5 may affect the decarbonylation pathway, of epicuticular-wax biosynthesis. Because lower amounts of epicuticular waxes are recessively inherited, SNPs tagging regions on chromosomes 2 and 5 will be useful for marker-assisted breeding to vary amounts and types of epicuticular waxes on onion foliage with the goal to develop cultivars resistant to onion thrips.