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Sweet cherry (Prunus avium L.) is an economically important and profitable stone fruit species grown in the temperate and subtropical climates, bearing fruits with unique flavour and nutritional benefits. There is also a long tradition of sweet cherry breeding in the Czech Republic. We report here the evaluation of economically important fruit and vegetative characters in 27 sweet cherry cultivars grown in the Research and Breeding Institute of Pomology (RBIP) in the genebank plantation. The cultivars were evaluated phenotypically using standard descriptors for sweet cherries. Established cultivars 'Burlat' (early ripening) and 'Kordia' (late ripening) were included in the study as commercial standards. The cultivar 'Früheste der Mark' was used as the earliest cultivar of the sweet cherry season. The results presented in this study demonstrate the high diversity of the analyzed sweet cherry germplasm. The cultivars 'Horka', 'Justyna', and 'Sandra' stood out in terms of fruit size and taste quality. The evaluated newly bred Czech sweet cherry cultivars are broadly described at the end of the presented paper. [ABSTRACT FROM AUTHOR]

In sweet cherry (Prunus avium L.), quantitative trait loci have been identified for fruit maturity, colour, firmness, and size to develop markers for marker-assisted selection. However, resolution is usually too low in those analyses to directly target candidate genes, and some associations are missed. In contrast, genome-wide association studies are performed on broad collections of accessions, and assemblies of reference sequences from Tieton and Satonishiki cultivars enable identification of single nucleotide polymorphisms after whole-genome sequencing, providing high marker density. Two hundred and thirty-five sweet cherry accessions were sequenced and phenotyped for harvest time and fruit colour, firmness, and size. Genome-wide association studies were used to identify single nucleotide polymorphisms associated with each trait, which were verified in breeding material consisting of 64 additional accessions. A total of 1 767 106 single nucleotide polymorphisms were identified. At that density, significant single nucleotide polymorphisms could be linked to co-inherited haplotype blocks (median size ~10 kb). Thus, markers were tightly associated with respective phenotypes, and individual allelic combinations of particular single nucleotide polymorphisms provided links to distinct phenotypes. In addition, yellow-fruit accessions were sequenced, and a ~ 90-kb-deletion on chromosome 3 that included five MYB10 transcription factors was associated with the phenotype. Overall, the study confirmed numerous quantitative trait loci from bi-parental populations using high-diversity accession populations, identified novel associations, and genome-wide association studies reduced the size of trait-associated loci from megabases to kilobases and to a few candidate genes per locus. Thus, a framework is provided to develop molecular markers and evaluate and characterize genes underlying important agronomic traits. [ABSTRACT FROM AUTHOR]