Improving grapevine cloning material of Welshriesling by comprehensive analysis

Abstract

The important grape variety Welschriesling for Austrian and Southeast European viticulture has been selectively bred over the years for improving some quantitative traits. Collected genotypes as well as the local clones were examined from agricultural, analytical, sensory, and genetic perspectives. The yield among the clones was relatively constant, while stronger differences appeared among the genotypes. The ripeness was further advanced in the B clones than in the H clones – both in terms of sugar and acidity. Thus, genotypes with lower yield and later ripening, which would be favorable for climate change, were also found. Differences between the selections could be verified with regard to growth vigor, shoot development, grape structure (density and length), as well as Mg content. Since Welschriesling is considered inefficient in Mg uptake, the genotype with the significantly better Mg supply will receive increased attention. The sensory evaluation of the clones showed a preference for the B clones, particularly B1-16, which was rated better than all other clones, while H 6 performed worse. The selections showed sensorial that they do not produce wines that are in any way inferior to the certified clones. One genotype stood out with higher terpene levels. The better rating of B1-16 was not based on a high content of the typical varietal aromas. Differences between the clones could be found in acetate esters, aromatic esters, ethyl esters, and others. Using PCA analysis, genotypes could be defined that are similar based on the wine aromas. Despite close phenotypes and some relationship in aromatic structure individual genotypes could be detected by genotyping and sequencing. Nevertheless genetic closer are genotypes derived from same region. Agricultural data were collected during 5 years of observations. The sensory tests were carried out by a commission and anonymously wines were presented with repetitions in series consisting of 4 wines. The assessment was carried out using the unstructured scale for overall quality. The magnesium and all other minerals contents of leaves were evaluated visually and analysed by quantitative atomic absorption. The genetic analyses were carried out using 50 SSR , 10 InterSSR and 150 RAPD markers. Sequences were gained by applying NGS technology. The aroma analyses were performed by using different GC-SIM-MS methods for displaying 70 volatile substances. The data was calculated using SPSS program.