Evaluation of types and clones of the cultivar Welschriesling under agronomical and genetic aspects

Abstract The grape cultivar Welschriesling (WR), which is important for Austrian and Southeast European viticulture, has been selectively bred over the years, and the collected genotypes as well as the nationally registered clones were examined from agricultural, analytical, sensory, and genetic perspectives. The yield was relatively constant among the clones, 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. The genotypes also showed greater variation in ripeness, allowing for the identification of types with specific characteristics. Thus, genotypes with lower yield and later ripening, which would be favorable in terms of climate change, were also found. Differences between the selections were also found with regard to vigor, shoot development, grape structure (density and length), as well as Mg content. Since WR is considered Mg inefficient, the genotype with the significantly better Mg provision 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 better rating of B1-16 was not based on the typical varietal aromas. The selections showed sensorially that they do not produce wines that are in any way inferior to the z-clones. One genotype stood out with higher terpene levels. 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.