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United States Department of Agriculture

Agricultural Research Service

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

Location: Vegetable Crops Research Unit

Title: Genetic analyses of anthocyanin concentrations and intensity of red bulb color among segregating haploid progenies of onion

Authors
item Duangjit, Janejira -
item Welsh, Kent -
item Wise, Mitchell
item Bohanec, Borut -
item Havey, Michael

Submitted to: Molecular Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 3, 2014
Publication Date: January 1, 2014
Repository URL: http://handle.nal.usda.gov/10113/58576
Citation: Duangjit, J., Welsh, K., Wise, M.L., Bohanec, B., Havey, M.J. 2014. Genetic analyses of anthocyanin concentrations and intensity of red bulb color among segregating haploid progenies of onion. Molecular Breeding. 34(1):75-85.

Interpretive Summary: Anthocyanins are the primary red pigment in fruits and vegetables. Higher concentrations of anthocyanins are important for attractive appearance of fruits and vegetables and may offer health benefits for consumers. The goals of this study were to identify genetic factors controlling yellow versus red colors, concentrations of anthocyanins, and soluble-solids contents in onion bulbs. Segregating haploid plants from the cross of yellow (OH1) and red (5225) inbreds were asexually propagated and grown in replicated trials across three environments. Soluble solids were measured at 30 days after harvest and quantitative analyses revealed a significant region on chromosome 5 controlling concentrations. Analyses using a binary model for red versus yellow bulbs revealed significant quantitative trait loci (QTLs) on chromosome 7 and two on chromosome 4 linked in repulsion phase, likely corresponding to the previously described R, L, and L2 loci, respectively. The intensity of red-bulb color was assessed by visual scores by a panel of evaluators and by amounts of two anthocyanins [peonidin 3-glucoside and cyanidin 3-(6”-malonoyl-laminaribioside)] as measured by high performance liquid chromatography (HPLC). Quantitative analyses using a normal model revealed significant QTLs on chromosomes 1 and 8 associated with the concentrations of peonidin 3-glucoside, and on chromosomes 1 and 4 affecting concentrations of cyanidin 3-(6”-malonoyl-laminaribioside). Significant correlations were observed between these anthocyanin concentrations and visual scores, indicating that visual selection should be effective to increase anthocyanin concentrations in onion bulbs. These results should help to develop deeper red colored onions that should be more attractive to consumers, potentially provide health benefits from increased anthocyanin consumption, and represent a source of natural colorants for the food industry.

Technical Abstract: Higher concentrations of anthocyanins in vegetables are important for attractive appearance and may offer health benefits for consumers. The red color of onion bulbs is due primarily to the accumulation of anthocyanins. The goals of this study were to identify chromosome regions that condition yellow versus red colors, concentrations of anthocyanins, and soluble-solids contents in onion bulbs. Segregating haploid plants from the cross of yellow (OH1) and red (5225) inbreds were asexually propagated and grown in replicated trials across three environments. Soluble solids were measured at 30 days after harvest and quantitative analyses revealed a significant region on chromosome 5 controlling concentrations, consistent with previous studies. Analyses using a binary model for red versus yellow bulbs revealed significant quantitative trait loci (QTLs) on chromosome 7 and two on chromosome 4 linked in repulsion phase, likely corresponding to the R, L, and L2 loci, respectively. The intensity of red-bulb color was assessed by visual scores by a panel of evaluators and by amounts of anthocyanins [peonidin 3-glucoside and cyanidin 3-(6”-malonoyl-laminaribioside)] as measured by high performance liquid chromatography (HPLC). Quantitative analyses using a normal model revealed significant QTLs on chromosomes 1 and 8 associated with the concentrations of peonidin 3-glucoside, and on chromosomes 1 and 4 affecting concentrations of cyanidin 3-(6”-malonoyl-laminaribioside). Significant correlations were observed between these anthocyanin concentrations and visual scores, indicating that visual selection should be effective to increase anthocyanin concentrations in onion bulbs. These selected populations may be more attractive to consumers, potentially provide health benefits from increased anthocyanin consumption, and be a source of natural colorants.

Last Modified: 7/24/2014
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