Commercial scale fingerprinting of potato cultivars is made difficult by the need for speed, reliability and the ability to distinguish between large numbers of genotypes. In the present study the potentiality of ISSR-PCR for fingerprinting was evaluated using 11 multi loci ISSR markers on 47 commercial Indian potato cultivars. The complex band profiles generated were highly reproducible. A total of 68 distinct alleles were obtained with number varying from 3 (ISSR UBC079) to 9 (ISSR 827). The average fragments per (AM) marker and per genotype (AG) were 6.1 and 1.43 respectively with a total of 47 polymorphic fragments. Rp value varied from 4.17 (ISSR UBC079) to 12.26 (ISSRHB-10). The average RP was 7.60 per ISSR primer. The dendrogram analysis showed that Indian potato cultivars placed into three broad clusters which were in concordance with the Principle Component (PCO) analysis. Similarity coefficient varied from 0.82 to as high as 0.98 and PIC value of the markers ranged from 0.16 (ISSR UBC079) to 0.35 (ISSR 7). ISSR 827 and ISSR ACAa were able to distinguish maximum cultivars 21 and 10 respectively. But, no single primer was sufficient to distinguish all the cultivars. Furthermore, use of these markers in combination need to be checked for distinguishing all cultivars. The study revealed that ISSR-PCR technique seems to have potential for the large-scale and systematic fingerprinting of potato cultivars with added number of ISSR markers and high resolving techniques to unearth the diversity present in the Indian potato cultivars

A considerable number of highly diverse species exist in genus Solanum. Because they can adapt to a broad range of habitats, potato wild relatives are promising sources of desirable agricultural traits. Potato taxonomy is quite complex because of introgression, interspecific hybridization, auto- and allopolyploidy, sexual compatibility among many species, a mixture of sexual and asexual reproduction, possible recent species divergence, phenotypic plasticity, and the consequent high morphological similarity among species. Recent researchers using molecular tools have contributed to the identification of genes controlling several types of resistance as well as to the revision of taxonomical relationships among potato species. Historically, primitive forms of cultivated potato and its wild relatives have been used in breeding programs and there is still an enormous and unimaginable potential for discovering desirable characteristics, particularly in wild species Different methods have been developed to incorporate useful alleles from these wild species into the improved cultivars. Potato germplasm comprising of useful alleles for different breeding objectives is preserved in various gene banks worldwide. These materials, with their invaluable information, are accessible for research and breeding purposes. Precise identification of species base on the new taxonomy is essential for effective use of the germplasm collection.

China is the world’s leading country for potato production but potato is not native to China. To gain insights into the genetic diversity of potato germplasm various studies have been performed but no study has been reported for potato landraces in China. To improve the available genepool for future potato breeding programs, a diverse population containing 292 genotypes (including foreign elite lines, local landraces and cultivars) was developed and genotyped using 30 SSR markers covering the entire potato genome. A total of 174 alleles were detected with an average of 5.5 alleles per locus. The model-based structure analysis discriminated the population into two main sub-groups, which can be further subdivided into seven groups based on collection sites. One sub-group (P1) revealed less genetic diversity than other (P2) and contained a higher number of commercial cultivars possibly indicating a slight reduction in diversity due to selection in breeding programs. The P2 sub-group showed a wider range of genetic diversity with more new and unique alleles attained from wild relatives. The potato landraces, clustered in sub-population P1 may be derived from historical population imported from ancient European and International Potato Center genotypes while sub-population P2 may be derived from modern populations from International Potato Center and European genotypes. It is proposed that in the first step, the potato genotypes were introduced from Europe to China, domesticated as landraces, and then hybridized for modern cultivars.

Morphology has long provided key data to assess diversity in landrace collections in genebanks worldwide. We explored, through an F2 cross between two inbred diploid potato clones, the utility of tuber morphology to assess diversity of potato landraces. We assessed the F2 population created by self-pollinating an F1 clone from a cross between two diploid (2n = 2x = 24) potato clones: DM, a completely homozygous clone derived from somatically doubling an androgenic monoploid of a cultivated potato, and M6, a highly inbred clone derived from seven generations of self-pollination of the wild diploid potato relative Solanum chacoense. We evaluated the F2 population for tuber size, shape and eye depth; skin and flesh colors; and dry matter content. Phenotypic segregation in this F2 population is astonishing. This single cross displayed a range of tuber traits approaching the entire diversity of potato landraces. Morphological characterization of potato used to classify accessions in genebanks is not representative of underlying genetic diversity. This is in agreement with other studies that have shown a lack of correlation between morphological/taxonomic classification and neutral genetic diversity, and a lack of correlation between either morphology or neutral genetic diversity and functional, trait-related genetic diversity in several species. We need better strategies for combining phenotypic and genetic characterization of accessions to develop predictive models that plant breeders can use to identify promising accessions for traits of interest.

Abstract China is the world’s largest producer of sweet potato (Ipomoea batatas (L.) Lam.). Considering that there are numerous sweet potato-producing regions in China and sweet potato is a vegetatively propagated crop, the genetic diversity of sweet potato viruses could be high in the country. However, studies on species and genetic variabilities of sweet potato viruses in China are limited, making it difficult to prevent and control viral diseases in this crop. During 2014–2019, sweet potato samples with viral disease-like symptoms were randomly collected from sweet potato fields in 25 provinces in China. Twenty-one virus species, including 12 DNA and 9 RNA viruses, were identified in the samples using next-generation sequencing, polymerase chain reaction and rolling-circle amplification methods. One novel sweepovirus species, Sweet potato leaf curl Hubei virus (SPLCHbV), was identified. Two species, Sweet potato collusive virus and Tobacco mosaic virus, were identified for the first time in sweet potato in China. Full-length or nearly full-length genomic sequences of 111 isolates belonging to 18 viral species were obtained. Genome sequence comparisons of potyvirus isolates obtained in this study indicate that the genome of sweet potato virus 2 is highly conserved, whereas the other four potyviruses, sweet potato feathery mottle virus, sweet potato virus G, sweet potato latent virus and sweet potato virus C, exhibited a high genetic variability. The similarities among the 40 sweepovirus genomic sequences obtained from eight sweepovirus species are 67.0–99.8%. The eight sweepoviruses include 14 strains, of which 4 novel strains were identified from SPLCHbV and 1 from sweet potato leaf curl Guangxi virus. Five sweet potato chlorotic stunt virus (SPCSV) isolates obtained belong to the WA strain, and the genome sequences of SPCSV are highly conserved. Together, this study for the first time comprehensively reports the variability of sweet potato viruses in China.

Potato (<i>Solanum tuberosum</i> L.) is an important staple food and economic crop in many countries. It is of critical importance to understand the genetic diversity and population structure for effective collection, conservation, and utilization of potato germplasm. Thus, the objective of the present study was to investigate the genetic diversity and population structure of potato germplasm conserved in the National Agrobiodiversity Center (NAC) of South Korea to provide basic data for future preservation and breeding of potato genetic resources. A total of 24 simple sequence repeat (SSR) markers were used to assess the genetic diversity and population structure of 482 potato accessions. A total of 257 alleles were detected, with an average of 10.71 alleles per locus. Analysis of molecular variance showed that 97% of allelic diversity was attributed to individual accessions within the population, while only 3% was distributed among populations. Results of genetic structure analysis based on STRUCTURE and discriminant analysis of principal components revealed that 482 potato accessions could be divided into two main subpopulations. Accessions of subpopulation 1 mainly belonged to cultivars and breeding lines. Accessions of subpopulations 2 basically corresponded to wild relatives of potatoes. Results of this study provide useful information for potato improvement and conservation programs, although further studies are needed for a more accurate evaluation of genetic diversity and phenotypic traits of potatoes.

Potato, tomato, pepper, and eggplant or aubergine are key food security and commercial crops. Making their genetic diversity more widely available will support the livelihoods of farmers and other enterprises around the world. This project aims to streamline access to the extensive genetic resources of these crops | International Potato Center, 'Sharing the genetic diversity of solanaceous food crops. Project profile', p.2, International Potato Center, 2019

Abstract Background China is the largest producer of sweet potato in the world, accounting for 57.0% of the global output. Germplasm resources are the basis for promoting innovations in the seed industry and ensuring food security. Individual and accurate identification of sweet potato germplasm is an important part of conservation and efficient utilization. Results In this study, nine pairs of simple sequence repeat molecular markers and 16 morphological markers were used to construct genetic fingerprints for sweet potato individual identification. Combined with basic information, typical phenotypic photographs, genotype peak graphs, and a two-dimensional code for detection and identification were generated. Finally, a genetic fingerprint database containing 1021 sweet potato germplasm resources in the “National Germplasm Guangzhou Sweet Potato Nursery Genebank in China” was constructed. Genetic diversity analysis of the 1021 sweet potato genotypes using the nine pairs of simple sequence repeat markers revealed a narrow genetic variation range of Chinese native sweet potato germplasm resources, and Chinese germplasm was close to that from Japan and the United States, far from that from the Philippines and Thailand, and the furthest from that from Peru. Sweet potato germplasm resources from Peru had the richest genetic diversity, supporting the view that Peru is the center of origin and domestication of sweet potato varieties. Conclusions Overall, this study provides scientific guidance for the conservation, identification, and utilization of sweet potato germplasm resources and offers a reference to facilitate the discovery of important genes to boost sweet potato breeding.