Genetic diversity in gooseberry (Ribes uva-crispa), as estimated with SSR markers

Abstract

• Two hundred forty two gooseberry accessions were analysed by 15 SSR markers enabling the identification of 153 unique genotypes. • The genetic diversity of the analysed accessions indicated a slightly negative assortative mating as expected for an outcrossing species. • Cultivars that have been wide spread in cultivation in sweden had a large number of synonymous samples. • The studied genotypes clustered into four posterior groups corresponding to the three a priori anticipated groups: old cultivars, modern cultivars, eastern cultivars, and an additional northern swedish cluster. • Pedigrees for a number of cultivars were confirmed and supported the true-to-typeness of the involved accessions. Additionally three likely parent-parent-offspring relationships were identified. European gooseberry ( Ribes uva-crispa L. ) is a popular berry crop in many European countries, including Sweden, Denmark and Ukraine. There is no active gooseberry breeding programme in either Sweden or Denmark, but a successful programme is operating in Ukraine. In Sweden and Denmark, research on gooseberries is primarily focused on collection and phenotypic evaluation of genetic resources. As part of these activities, a large number of inventory finds have been collected but have not yet been characterised morphologically or molecularly. The goal of this study was thus to characterise gooseberry germplasm with 15 simple sequence repeat (SSR) markers. From 242 accessions analysed, 153 unique genotypes were identified. Cultivars that have been in widespread cultivation in Sweden, such as the Finnish cultivars ‘Hinnonmäen Keltainen’ and ‘Hinnonmäen Punainen’, had relatively large numbers of synonymous samples. While many inventory finds were identifiable as synonyms of known cultivars, several were found to constitute unique genotypes within the germplasm studied. The studied genotypes clustered relatively well in three posterior groups, consisting of cultivars originating before and after the American gooseberry mildew ( Sphaerotheca mors-uvae ) outbreak around 1900 and cultivars originating from the territory of the former Soviet Union. A fourth genetic cluster consisting mainly of inventory finds from central and northern Sweden was also identified. In addition, it was possible to verify recorded and stipulated parentages for some of the cultivars studied and to identify three likely parent-parent-child trios. Thus, inventories of local gooseberry germplasm and a subsequent genotyping proved successful in finding unique local genotypes, with potential local adaptation. The data obtained provide a foundation for future studies of gooseberry genetic resources, while also illustrating the importance of a well-curated and phenotypically characterised set of reference cultivars for future studies.