|Authors: ||E. Duchêne, G. Butterlin, P. Claudel, V. Dumas, N. Jaegli, P. Hugueney, G. Arnold, D. Merdinoglu|
|Keywords: ||geraniol, linalool, genetics, DXS|
Linalool and geraniol are, under their free form, odoriferous molecules of the terpenol family that are found in grapes and wines.
Their concentrations, for both bound and free forms, were determined over two seasons in 120 genotypes, progeny from a 'Riesling' × 'Gewurztraminer' cross, grown in the vineyard in Alsace, France.
Berries samples were picked 230 degree.days (base 10) after veraison in order to compare the genotypes at the same developmental stage.
Aroma profiles were obtained by gas chromatography analysis after a solid phase extraction.
A genetic map based on microsatellite markers and including the genetic position of a 1-deoxy-D-xylulose-5-phosphate synthase gene (DXS1) was available for the progeny.
The DXS participates in the first steps of the terpenol synthesis.
Genotypic data were analysed together with terpenol concentrations.
We confirmed that a specific form of DXS1, on chromosome 5, provided by the 'Gewurztraminer' parent, was necessary for terpenol synthesis at a high level.
Moreover, when considering only the genotypes bearing the favourable DXS1 allele, we observed that linalool concentrations depended on allelic combinations at the VrZAG64 microsatellite locus (chromosome 10). The 'Riesling' parent provided the favourable allele.
Our results show that breeding can create new aroma profiles by combining alleles from different loci.
It is thus possible to imagine new genotypes with a 'Muscat'-like profile, with high linalool content but with other characteristics from the parent such as high acidity ('Riesling') or coloured berries ('Gewurztraminer').
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