Abstract Background The genetic diversity and population structure of breeding germplasm is central knowledge for crop improvement. To gain insight into the genetic potential of the germplasm used for potato breeding in a Nordic breeding program as well as all available accessions from the Nordic genebank (NordGen), 133 potato genotypes were genotyped using the Infinium Illumina 20 K SNP array. After SNP filtering, 11 610 polymorphic SNPs were included in the analysis. In addition, data from three important breeding traits – percent dry matter and uniformity of tuber shape and eye – were scored to measure the variation potato cultivars and breeding clones. Results The genetic diversity among the genotypes was estimated using principal coordinate analysis based on the genetic distance between individuals, as well as by using the software STRUCTURE. Both methods suggest that the collected breeding material and the germplasm from the gene-bank are closely related, with a low degree of population structure between the groups. The phenotypic distribution among the genotypes revealed significant differences, especially between farmer’s cultivars and released cultivars and breeding clones. The percent heterozygosity was similar between the groups, with a mean average of 58–60%. Overall, the breeding germplasm and the accessions from the Nordic genebank seems to be closely related with similar genetic background. Conclusion The genetic potential of available Nordic potato breeding germplasm is low, and for genetic hybridization purposes, genotypes from outside the Nordic region should be employed.

BACKGROUND: The genetic diversity and population structure of breeding germplasm is central knowledge for crop improvement. To gain insight into the genetic potential of the germplasm used for potato breeding in a Nordic breeding program as well as all available accessions from the Nordic genebank (NordGen), 133 potato genotypes were genotyped using the Infinium Illumina 20 K SNP array. After SNP filtering, 11 610 polymorphic SNPs were included in the analysis. In addition, data from three important breeding traits – percent dry matter and uniformity of tuber shape and eye – were scored to measure the variation potato cultivars and breeding clones. RESULTS: The genetic diversity among the genotypes was estimated using principal coordinate analysis based on the genetic distance between individuals, as well as by using the software STRUCTURE. Both methods suggest that the collected breeding material and the germplasm from the gene-bank are closely related, with a low degree of population structure between the groups. The phenotypic distribution among the genotypes revealed significant differences, especially between farmer’s cultivars and released cultivars and breeding clones. The percent heterozygosity was similar between the groups, with a mean average of 58–60%. Overall, the breeding germplasm and the accessions from the Nordic genebank seems to be closely related with similar genetic background. CONCLUSION: The genetic potential of available Nordic potato breeding germplasm is low, and for genetic hybridization purposes, genotypes from outside the Nordic region should be employed.

Knowledge of the genetic diversity and genetic relationship is important in crop improvement. The objective of this study was to determine the genetic diversity of 31 sweetpotato genotypes and furthermore to select distantly related individuals for breeding of superior parental clones. The genotypes (sourced from the Agricultural Research Council, South Africa) originating from Africa and American continent were genotyped using eight highly polymorphic SSR markers. The SSR markers generated a total of 83 putative alleles. The polymorphic information content (PIC) of the tested simple sequence markers varied from 0.73 to 0.91, with a mean of 0.85. At least 11 different alleles were found in 8 loci within the population, with 7 effective alleles per locus. Although high diversity was found among the genotypes, genetic distances among the genotypes were relatively low. Cluster analysis revealed the existence of three distinct genetic groups, and the clustering patterns follow to some extent the geographic origin and pedigree of the genotypes. High gene flow was observed among different sweetpotato accessions. The selected SSR markers were found to be highly polymorphic with high discriminatory power for genetic characterization studies and are useful genomic tool to complement phenotyping of sweetpotato genotypes. Two heterotic groups were found in the study. The heterotic group A was composed of 14 genotypes mainly of South African origin, while the heterotic group B consisted of 17 genotypes of American origin. The two distinct groups were important for the selection of breeding clones that were distantly related to be used as parental clones in the advancement of traits of interest.

Knowledge of the genetic diversity and genetic relationship is important in crop improvement. The objective of this study was to determine the genetic diversity of 31 sweetpotato genotypes and furthermore to select distantly related individuals for breeding of superior parental clones. The genotypes (sourced from the Agricultural Research Council, South Africa) originating from Africa and American continent were genotyped using eight highly polymorphic SSR markers. The SSR markers generated a total of 83 putative alleles. The polymorphic information content (PIC) of the tested simple sequence markers varied from 0.73 to 0.91, with a mean of 0.85. At least 11 different alleles were found in 8 loci within the population, with 7 effective alleles per locus. Although high diversity was found among the genotypes, genetic distances among the genotypes were relatively low. Cluster analysis revealed the existence of three distinct genetic groups, and the clustering patterns follow to some extent the geographic origin and pedigree of the genotypes. High gene flow was observed among different sweetpotato accessions. The selected SSR markers were found to be highly polymorphic with high discriminatory power for genetic characterization studies and are useful genomic tool to complement phenotyping of sweetpotato genotypes. Two heterotic groups were found in the study. The heterotic group A was composed of 14 genotypes mainly of South African origin, while the heterotic group B consisted of 17 genotypes of American origin. The two distinct groups were important for the selection of breeding clones that were distantly related to be used as parental clones in the advancement of traits of interest.

Knowledge of the genetic diversity and genetic relationship is important in crop improvement. The objective of this study was to determine the genetic diversity of 31 sweetpotato genotypes and furthermore to select distantly related individuals for breeding of superior parental clones. The genotypes (sourced from the Agricultural Research Council, South Africa) originating from Africa and American continent were genotyped using eight highly polymorphic SSR markers. The SSR markers generated a total of 83 putative alleles. The polymorphic information content (PIC) of the tested simple sequence markers varied from 0.73 to 0.91, with a mean of 0.85. At least 11 different alleles were found in 8 loci within the population, with 7 effective alleles per locus. Although high diversity was found among the genotypes, genetic distances among the genotypes were relatively low. Cluster analysis revealed the existence of three distinct genetic groups, and the clustering patterns follow to some extent the geographic origin and pedigree of the genotypes. High gene flow was observed among different sweetpotato accessions. The selected SSR markers were found to be highly polymorphic with high discriminatory power for genetic characterization studies and are useful genomic tool to complement phenotyping of sweetpotato genotypes. Two heterotic groups were found in the study. The heterotic group A was composed of 14 genotypes mainly of South African origin, while the heterotic group B consisted of 17 genotypes of American origin. The two distinct groups were important for the selection of breeding clones that were distantly related to be used as parental clones in the advancement of traits of interest.

Native potatoes are the most diverse among cultivated potato species and thus constitute a valuable source for identifying genes for potato improvement. Nevertheless, high-density mapping, needed to reveal allelic diversity, has not been performed for native Argentinian potatoes. We present a study of the genetic variability and population structure of 96 Andigena potatoes from Northwestern Argentina performed using a subset of 5035 SNPs with no missing data and full reproducibility. These high-density markers are distributed across the genome and present a good coverage of genomic regions. A Bayesian approach revealed the presence of: (I) a major group comprised of most of the Andean accessions; (II) a smaller group containing the out-group cv. Spunta and the sequenced genotype DM; and (III) a third group containing colored flesh potatoes. This grouping was also consistent when maximum likelihood trees were constructed and further confirmed by a principal coordinate analysis. A group of 19 accessions stored as Andean varieties clustered consistently with group Tuberosum accessions. This was in agreement with previous studies and we hypothesize that they may be reintroductions of European-bred long day-adapted potatoes. The present study constitutes a valuable source for allele mining of genes of interest and thus provides a tool for association mapping studies.

Native potatoes are the most diverse among cultivated potato species and thus constitute a valuable source for identifying genes for potato improvement. Nevertheless, high-density mapping, needed to reveal allelic diversity, has not been performed for native Argentinian potatoes. We present a study of the genetic variability and population structure of 96 Andigena potatoes from Northwestern Argentina performed using a subset of 5035 SNPs with no missing data and full reproducibility. These high-density markers are distributed across the genome and present a good coverage of genomic regions. A Bayesian approach revealed the presence of: (I) a major group comprised of most of the Andean accessions: (II) a smaller group containing the out-group cv. Spunta and the sequenced genotype DM: and (III) a third group containing colored flesh potatoes. This grouping was also consistent when maximum likelihood trees were constructed and further confirmed by a principal coordinate analysis. A group of 19 accessions stored as Andean varieties clustered consistently with group Tuberosum accessions. This was in agreement with previous studies and we hypothesize that they may be reintroductions of European-bred long day-adapted potatoes. The present study constitutes a valuable source for allele mining of genes of interest and thus provides a tool for association mapping studies.

Native potatoes are the most diverse among cultivated potato species and thus constitute a valuable source for identifying genes for potato improvement. Nevertheless, high-density mapping, needed to reveal allelic diversity, has not been performed for native Argentinian potatoes. We present a study of the genetic variability and population structure of 96 Andigena potatoes from Northwestern Argentina performed using a subset of 5035 SNPs with no missing data and full reproducibility. These high-density markers are distributed across the genome and present a good coverage of genomic regions. A Bayesian approach revealed the presence of: (I) a major group comprised of most of the Andean accessions; (II) a smaller group containing the out-group cv. Spunta and the sequenced genotype DM; and (III) a third group containing colored flesh potatoes. This grouping was also consistent when maximum likelihood trees were constructed and further confirmed by a principal coordinate analysis. A group of 19 accessions stored as Andean varieties clustered consistently with group Tuberosum accessions. This was in agreement with previous studies and we hypothesize that they may be reintroductions of European-bred long day-adapted potatoes. The present study constitutes a valuable source for allele mining of genes of interest and thus provides a tool for association mapping studies.

Pectobacterium is a diverse genus which comprises of multiple destructive bacterial species which cause soft rot/blackleg/wilt disease complex in a wide variety of crops by employing high levels of virulence factors. During the 2018, 2019 and 2020 potato growing seasons, numerous outbreaks of bacterial wilt, stem blackleg and tuber soft rot were recorded, and symptomatic plant samples from ten localities in the Province of Vojvodina (Serbia) were collected and analysed. Bacterial soft-rot pathogens were detected in 63 samples using genus and species-specific primers. Through 16S rRNA Sanger sequencing of 19 representative isolates, the identity of P. brasiliense (73.7%), P. punjabense (15.8%), and P. carotovorum (10.5%) species were revealed. To further validate the identification, genotypic profiling of Pectobacterium strains using rep-PCR (ERIC, BOX, REP) was conducted for 25 selected isolates and the phylogenetic assessment based on four selected housekeeping genes (gyrA, recA, rpoA, and rpoS). Physiological and biochemical properties were analysed using basic microbiological tests and VITEK® 2 GN card, and pathogenicity was confirmed on cv. VR808 and cv. Desiree potato tubers and plants. This study confirmed the distinctiveness of the newly described P. punjabense in Serbia as well as the high diversity of Pectobacterium brasiliense and Pectobacterium carotovorum species in Serbia.

<i>Pectobacterium</i> is a diverse genus which comprises of multiple destructive bacterial species which cause soft rot/blackleg/wilt disease complex in a wide variety of crops by employing high levels of virulence factors. During the 2018, 2019 and 2020 potato growing seasons, numerous outbreaks of bacterial wilt, stem blackleg and tuber soft rot were recorded, and symptomatic plant samples from ten localities in the Province of Vojvodina (Serbia) were collected and analysed. Bacterial soft-rot pathogens were detected in 63 samples using genus and species-specific primers. Through 16S rRNA Sanger sequencing of 19 representative isolates, the identity of <i>P. brasiliense</i> (73.7%), <i>P. punjabense</i> (15.8%), and <i>P. carotovorum</i> (10.5%) species were revealed. To further validate the identification, genotypic profiling of <i>Pectobacterium</i> strains using rep-PCR (ERIC, BOX, REP) was conducted for 25 selected isolates and the phylogenetic assessment based on four selected housekeeping genes (<i>gyrA</i>, <i>recA</i>, <i>rpoA</i>, and <i>rpoS)</i>. Physiological and biochemical properties were analysed using basic microbiological tests and VITEK^® 2 GN card, and pathogenicity was confirmed on cv. VR808 and cv. Desiree potato tubers and plants. This study confirmed the distinctiveness of the newly described <i>P. punjabense</i> in Serbia as well as the high diversity of <i>Pectobacterium brasiliense</i> and <i>Pectobacterium carotovorum</i> species in Serbia.

Pectobacterium is a diverse genus which comprises of multiple destructive bacterial species which cause soft rot/blackleg/wilt disease complex in a wide variety of crops by employing high levels of virulence factors. During the 2018, 2019 and 2020 potato growing seasons, numerous outbreaks of bacterial wilt, stem blackleg and tuber soft rot were recorded, and symptomatic plant samples from ten localities in the Province of Vojvodina (Serbia) were collected and analysed. Bacterial soft-rot pathogens were detected in 63 samples using genus and species-specific primers. Through 16S rRNA Sanger sequencing of 19 representative isolates, the identity of P. brasiliense (73.7%), P. punjabense (15.8%), and P. carotovorum (10.5%) species were revealed. To further validate the identification, genotypic profiling of Pectobacterium strains using rep-PCR (ERIC, BOX, REP) was conducted for 25 selected isolates and the phylogenetic assessment based on four selected housekeeping genes (gyrA, recA, rpoA, and rpoS). Physiological and biochemical properties were analysed using basic microbiological tests and VITEK&reg: 2 GN card, and pathogenicity was confirmed on cv. VR808 and cv. Desiree potato tubers and plants. This study confirmed the distinctiveness of the newly described P. punjabense in Serbia as well as the high diversity of Pectobacterium brasiliense and Pectobacterium carotovorum species in Serbia.