Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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    Gap analysis - potatoes occurrences
    Castaneda-Alvarez, N.P. ; Haan, S. de; Juarez, H. ; Khoury, C.K. ; Achicanoy, H.A. ; Sosa, C.C. ; Bernau, V. ; Salas, A. ; Heider, B. ; Simon, R. ; Maxted, N. ; Spooner, D.M. - \ 2015
    Wageningen UR
    animal breeding and genetics - pigs
    Records (with and without coordinates) representing germplasm accessions and sightings of the wild relatives of potato. These records were used as input to assess the ex situ conservation urgency of 73 wild relatives of potato
    Ex Situ Conservation Priorities for the Wild Relatives of Potato (Solanum L. Section Petota)
    Castaneda-Alvarez, N.P. ; Haan, S. de; Juarez, H. ; Khoury, C.K. ; Achicanoy, H.A. ; Sosa, C.C. ; Bernau, V. ; Salas, A. ; Heider, B. ; Simon, R. ; Maxted, N. ; Spooner, D.M. - \ 2015
    PLoS ONE 10 (2015)4. - ISSN 1932-6203 - 19 p.
    globodera-pallida stone - late blight resistance - tuber-bearing solanum - somatic hybrids - cultivated potato - phytophthora-infestans - ralstonia-solanacearum - species distributions - ortholog sequences - genetic-resources
    Crop wild relatives have a long history of use in potato breeding, particularly for pest and disease resistance, and are expected to be increasingly used in the search for tolerance to biotic and abiotic stresses. Their current and future use in crop improvement depends on their availability in ex situ germplasm collections. As these plants are impacted in the wild by habitat destruction and climate change, actions to ensure their conservation ex situ become ever more urgent. We analyzed the state of ex situ conservation of 73 of the closest wild relatives of potato (Solanum section Petota) with the aim of establishing priorities for further collecting to fill important gaps in germplasm collections. A total of 32 species (43.8%), were assigned high priority for further collecting due to severe gaps in their ex situ collections. Such gaps are most pronounced in the geographic center of diversity of the wild relatives in Peru. A total of 20 and 18 species were assessed as medium and low priority for further collecting, respectively, with only three species determined to be sufficiently represented currently. Priorities for further collecting include: (i) species completely lacking representation in germplasm collections; (ii) other high priority taxa, with geographic emphasis on the center of species diversity; (iii) medium priority species. Such collecting efforts combined with further emphasis on improving ex situ conservation technologies and methods, performing genotypic and phenotypic characterization of wild relative diversity, monitoring wild populations in situ, and making conserved wild relatives and their associated data accessible to the global research community, represent key steps in ensuring the long-term availability of the wild genetic resources of this important crop.
    The Rhoptry Proteins ROP18 and ROP5 Mediate Toxoplasma gondii Evasion of the Murine, But Not the Human, Interferon-Gamma Response
    Niedelman, W. ; Gold, D.A. ; Rosowski, E.E. ; Sprokholt, J.K. ; Lim, D. ; Arenas, A.F. ; Melo, M.B. ; Spooner, E. ; Yaffe, M.B. ; Saeij, J.P.J. - \ 2012
    PLoS Pathogens 8 (2012)6. - ISSN 1553-7366
    parasitophorous vacuole - population-structure - human-fibroblasts - host-resistance - surface-antigen - ifn-gamma - virulence - mice - infection - parasite
    The obligate intracellular parasite Toxoplasma gondii secretes effector proteins into the host cell that manipulate the immune response allowing it to establish a chronic infection. Crosses between the types I, II and III strains, which are prevalent in North America and Europe, have identified several secreted effectors that determine strain differences in mouse virulence. The polymorphic rhoptry protein kinase ROP18 was recently shown to determine the difference in virulence between type I and III strains by phosphorylating and inactivating the interferon-gamma (IFN gamma)-induced immunity-related GTPases (IRGs) that promote killing by disrupting the parasitophorous vacuole membrane (PVM) in murine cells. The polymorphic pseudokinase ROP5 determines strain differences in virulence through an unknown mechanism. Here we report that ROP18 can only inhibit accumulation of the IRGs on the PVM of strains that also express virulent ROP5 alleles. In contrast, specific ROP5 alleles can reduce IRG coating even in the absence of ROP18 expression and can directly interact with one or more IRGs. We further show that the allelic combination of ROP18 and ROP5 also determines IRG evasion and virulence of strains belonging to other lineages besides types I, II and III. However, neither ROP18 nor ROP5 markedly affect survival in IFN gamma-activated human cells, which lack the multitude of IRGs present in murine cells. These findings suggest that ROP18 and ROP5 have specifically evolved to block the IRGs and are unlikely to have effects in species that do not have the IRG system, such as humans.
    Histological and molecular investigation of the basis for variation in tomato fruit size in response to fruit load and genotype
    Fanwoua, J. ; Visser, P.H.B. de; Heuvelink, E. ; Angenent, G.C. ; Yin, X. ; Marcelis, L.F.M. ; Struik, P.C. - \ 2012
    Functional Plant Biology 39 (2012)9. - ISSN 1445-4408 - p. 754 - 763.
    plant-cell cycle - dna endoreduplication - carbon availability - gene-expression - hormone levels - growth - number - proliferation - carbohydrate - metabolism
    Understanding the molecular mechanisms and cellular dynamics that cause variation in fruit size is critical for the control of fruit growth. The aim of this study was to investigate how both genotypic factors and carbohydrate limitation cause variation in fruit size. We grew a parental line (Solanum lycopersicum L.) and two inbred lines from Solanum chmielewskii (C.M.Rick et al.; D.M.Spooner et al.) producing small or large fruits under three fruit loads (FL): continuously two fruits/truss (2&2F) or five fruits/truss (5&5F) and a switch from five to two fruits/truss (5&2F) 7 days after anthesis (DAA). Final fruit size, sugar content and cell phenotypes were measured. The expression of major cell cycle genes 7 DAA was investigated using quantitative PCR. The 5&5F treatment resulted in significantly smaller fruits than the 5&2F and 2&2F treatments. In the 5&5F treatment, cell number and cell volume contributed equally to the genotypic variation in final fruit size. In the 5&2F and 2&2F treatment, cell number contributed twice as much to the genotypic variation in final fruit size than cell volume did. FL treatments resulted in only subtle variations in gene expression. Genotypic differences were detected in transcript levels of CycD3 (cyclin) and CDKB1 (cyclin-dependent-kinase), but not CycB2. Genotypic variation in fruit FW, pericarp volume and cell volume was linked to pericarp glucose and fructose content (R2 = 0.41, R2 = 0.48, R2 = 0.11 respectively). Genotypic variation in cell number was positively correlated with pericarp fructose content (R2 = 0.28). These results emphasise the role of sugar content and of the timing of assimilate supply in the variation of cell and fruit phenotypes
    AFLP analysis reveals a lack of phylogenetic structure within Solanum section Petota
    Jacobs, M.M.J. ; Berg, R.G. van den; Vleeshouwers, V. ; Visser, M.E. ; Mank, R. ; Sengers, M. ; Hoekstra, R. ; Vosman, B. - \ 2008
    BMC Evolutionary Biology 8 (2008). - ISSN 1471-2148 - 12 p.
    restriction site variation - wild potatoes - series relationships - solanaceae - reexamination - germplasm - taxonomy - complex
    Background The secondary genepool of our modern cultivated potato (Solanum tuberosum L.) consists of a large number of tuber-bearing wild Solanum species under Solanum section Petota. One of the major taxonomic problems in section Petota is that the series classification (as put forward by Hawkes) is problematic and the boundaries of some series are unclear. In addition, the classification has received only partial cladistic support in all molecular studies carried out to date. The aim of the present study is to describe the structure present in section Petota. When possible, at least 5 accessions from each available species and 5 individual plants per accession (totally approx. 5000 plants) were genotyped using over 200 AFLP markers. This resulted in the largest dataset ever constructed for Solanum section Petota. The data obtained are used to evaluate the 21 series hypothesis put forward by Hawkes and the 4 clade hypothesis of Spooner and co-workers. Results We constructed a NJ tree for 4929 genotypes. For the other analyses, due to practical reasons, a condensed dataset was created consisting of one representative genotype from each available accession. We show a NJ jackknife and a MP jackknife tree. A large part of both trees consists of a polytomy. Some structure is still visible in both trees, supported by jackknife values above 69. We use these branches with >69 jackknife support in the NJ jackknife tree as a basis for informal species groups. The informal species groups recognized are: Mexican diploids, Acaulia, Iopetala, Longipedicellata, polyploid Conicibaccata, diploid Conicibaccata, Circaeifolia, diploid Piurana and tetraploid Piurana. Conclusion Most of the series that Hawkes and his predecessors designated can not be accepted as natural groups, based on our study. Neither do we find proof for the 4 clades proposed by Spooner and co-workers. A few species groups have high support and their inner structure displays also supported subdivisions, while a large part of the species cannot be structured at all. We believe that the lack of structure is not due to any methodological problem but represents the real biological situation within section Petota.
    Molecular markers for genebank management
    Spooner, D. ; Treuren, R. van; Vicente, M.C. de - \ 2005
    Rome, Italy : IPGRI (IPGRI Technical Bulletins 10) - ISBN 9789290436843
    genenbanken - moleculaire merkers - genetische bronnen van plantensoorten - gene banks - molecular markers - plant genetic resources
    Wild potatoes (Solanum section Petota; Solanaceae) of North and Central America
    Spooner, D.M. ; Berg, R.G. van den; Rodrigues, A. ; Bamberg, J.B. ; Hijmans, R.J. ; Lara-Cabrera, S. - \ 2004
    [S.l.] : The American Society of Plant Taxonomists (Systematic botany monographs 68) - ISBN 9780912861685 - 209
    aardappelen - solanum - solanaceae - wilde verwanten - plantengeografie - soorten - taxonomie - noord-amerika - centraal-amerika - potatoes - solanum - solanaceae - wild relatives - phytogeography - species - taxonomy - north america - central america
    Solanum section Petota, the potato and its wild relatives, contains about 200 wild species distributed from the southwestern United States, to central Argentina and adjacent Chile. Although most species occur in South America, a secondary center of diversity peaks at 20 degrees north in the central Mexican highlands, including diploids (2n = 2x = 24), tetraploids (2n = 4x = 48), hexaploids (2n = 6x = 72), and triploid and pentaploid nothospecies. This treatment covers the wild potatoes of North and Central America (United States to Panama). It is a summary of recent morphological and molecular studies of species limits and their interrelationships. We collected herbarium and germplasm samples from all countries harboring wild potatoes in this region and now have access to germplasm of every species. A comprehensive treatment in 1990 recognized 33 species, 12 subspecies, and five nothospecies from the region, partitioned into eight formal taxonomic series. We recognize 25 species and four nothospecies from the region, partitioned into eleven informal species groups. It provides the first formal typification of many of these names, an extensive list of georeferenced localities, a geographic information systems based diversity analysis, and illustrations and maps of all the species.
    Frost tolerance in wild potatoes : Assessing the predictivity of taxonomic, geographic and ecological factors
    Hijmans, R.J. ; Jacobs, M. ; Bamberg, J.B. ; Spooner, D.M. - \ 2003
    Euphytica 130 (2003). - ISSN 0014-2336 - p. 47 - 59.
    restriction site variation - solanum sect petota - series relationships - insect resistance - reexamination - associations - solanaceae
    The use of genetic resources could be more effective and efficient if we were able to predict the presence or absence of useful traits in different populations or accessions. We analyzed the extent to which taxonomic, geographic and ecological factors can predict the presence of frost tolerance in wild potatoes. We used screening data for 1646 samples from 87 species that had been collected in 12 countries in the Americas. There was a strong association of frost tolerance with species and to a lesser extent with taxonomic series. There was significant geographic clustering of areas with wild potatoes with similar levels of frost tolerance. Areas with a high level of frost tolerance are the central and southern Peruvian Andes, the lowlands of Argentina and adjacent areas, and a small area in the central Chilean Andes. There is a greater chance of finding wild potatoes with high levels of frost tolerance in areas with a yearly mean minimum temperature below 3 C than there is in warmer areas. However, temperature is only a weak predictor of frost tolerance. Temperature data alone did not predict observed frost tolerance in eastern Argentina/Uruguay and falsely predicted it in the southwestern United States. Because many wild potato species occur over small areas, taxonomic, ecological, and geographical factors are difficult to disentangle.
    Plant nomenclature and taxonomy : an horticultural and agronomic perspective
    Spooner, D.M. ; Hetterscheid, W.L.A. ; Berg, R.G. van den; Brandenburg, W.A. - \ 2003
    Horticultural Reviews 28 (2003). - ISSN 0163-7851 - p. 1 - 60.
    Species concepts and relationships in wild and cultivated potatoes
    Spooner, D.M. ; Bryan, G.J. ; Berg, R.G. van den; Brandenburg, W.A. - \ 2002
    In: Potatoes, Healthy Food for Humanity: International Developments in Breeding, Production, Protection and Utilization.. - - p. 63 - 75.
    Wild and cultivated potatoes (Solanum section Petota) present challenges to taxonomists arising from lack of clearly defined morphological character differences among many species, phenotypic plasticity, a range of ploidy levels from diploid to hexaploid, and hybrid speciation and introgression. Taxonomic treatments of the group have differed greatly regarding numbers of species and hypotheses of their interrelationships at the series level. Recent morphological phenetic studies and molecular studies have confirmed the general lack of clearly defined species, have shown the need to use a number of character states with overlapping ranges for species delimitation (polythetic support), and have suggested the need for the reduction of species in section Petota. Molecular studies have sometimes confirmed hypotheses of hybridization and sometimes have failed to support them. Molecular studies have suggested the need for a reconsideration of the traditionally held series concepts. Currently, section Petota contains 196 wild species and a single cultivated species, Solanum tuberosum, with eight landrace cultivar groups, exclusive of the modern cultivars that are not yet classified into cultivar groups. The number of wild species likely will decrease with future study. These points are here illustrated by (1) a discussion of published species level studies in Solanum series Longipedicellata, the Solanum brevicaule complex, and the cultivated landrace populations of potatoes; (2) reinvestigations of hybridization in S. chacoense, S. raphanifolium and S. xrechei; and (3) studies of ingroup and outgroup relationships of section Petota.
    Reduction of species in the wild potato Solanum section Petota series Longipedicellata : AFLP, RAPD and chloroplast SSR data
    Berg, R.G. van den; Bryan, G.J. ; Rio, A. del; Spooner, D.M. - \ 2002
    Theoretical and Applied Genetics 105 (2002). - ISSN 0040-5752 - p. 1109 - 1114.
    Species boundaries were assessed with three molecular markers [AFLPs, RAPDs and chloroplast simple sequence repeats (cpSSRs)] for all six species of wild potatoes (Solanum section Petota) assigned to ser. Longipedicellata: Solanum fendleri, S. hjertingii, S. matehualae, S. papita, S. polytrichon and S. stoloniferum. These tetraploid (2n = 4x = 48) species grow in the southeastern United States (S. fendleri) and Mexico (all six species), and a recent morphological analysis supported only three species: (1) S. polytrichon, (2) S. hjertingii (including S. matehualae) and (3) S. stoloniferum (including S. fendleri and S. papita). We analyzed all six species of ser. Longipedicellata (tetraploid) and also analyzed diploids in ser. Bulbocastana, ser. Pinnatisecta, ser. Polyadenia and ser. Tuberosa; tetraploids in ser. Acaulia and hexaploids in ser. Demissa. Concordant with morphological data, AFLP and RAPD results support the synonymy of S. hjertingii and S. matehualae, and completely intermix S. papita and S. fendleri. However, accessions of S. stoloniferum have a tendency to cluster but with exceptions, and S. polytrichon is completely intermixed with S. fendleri and S. papita. The cpSSRs fail to distinguish any of the species in ser. Longipedicellata. Combined morphological and molecular data support only two species in ser. Longipedicellata: S. hjertingii and S. stoloniferum.
    Taxonomy and new collections of wild potato species in Central and Southern Peru in 1999
    Salas, A.R. ; Spooner, D.M. ; Huamán, Z. ; Torres Maita, R.V. ; Hoekstra, R. ; Schüler, K. ; Hijmans, R.J. - \ 2001
    American Journal of Potato Research 78 (2001)3. - ISSN 1099-209X - p. 197 - 207.
    Peru contains about half of the described wild potato taxa, and many of these are not yet preserved in genebanks. This paper reports results of the second of a series of five planned collecting expeditions to Peru. Collections were made in the central Peruvian departments of Ancash, Huancavelica, La Libertad, and Lima, from March 8 to April 25,1999. They follow collections in 1998 in the southern Peruvian departments of Apurimac, Arequipa, Cusco, Moquegua, Puno, and Tacna. We collected 101 germplasm accessions, including first germplasm collections of the following 22Solanum taxa:Solanum amayanum, S. anamatophilum, S. arahuayum (lost in germplasm increase),S. augustii, S. bill- hookeri, S. cantense, S. chavinense, S. chomatophilum var. subnivale, S. chrysoflorum, S. gracilifrons, S. hapalos um, S. huarochiriense, S. hypacrarthrum, S.jalcae, S. moniliforme, S. multiinterruptum f. longipilosum, S. multiinterruptum var. machaytambinum, S. peloquinianum, S. rhombilanceolatum, S. simplicissimum, S. taulisense (lost in germplasm increase), andS. wittmackii. In addition, new collections were made of the under-collected speciesS. hastiforme (three collections). The above taxonomy is that used in planning our expedition, that we compare to a new treatment of Peruvian wild potatoes published by C. Ochoa in 1999. This paper reports the collection and new species identifications of the 1999 collections, and germplasm conservation and survival of the 1998 and 1999 collections. In addition, chromosome counts are provided for 134 accessions from the 1998 and 1999 expeditions, including first reports forS. chomatophilum var. subnivale (2n = 2x = 24),S. megistacrolobum subsp.purpureum (2n = 2x = 24), andS. multiinterruptum var.multiinterruptum f.albiflorum (2n = 2x = 24); we also report the first triploid count of an accession ofS. immite.
    Solarium sectionPetota in Costa Rica: taxonomy and genetic resources
    Spooner, D.M. ; Hoekstra, R. ; Vilchez, B. - \ 2001
    American Journal of Potato Research 78 (2001)2. - ISSN 1099-209X - p. 91 - 98.
    Prior to 1996, worldwide holdings of germplasm of wild potatoes from Costa Rica amounted to just two collections; this country therefore formed a priority for collecting. We mapped all localities of wild potatoes from herbarium specimen data from Costa Rica and collected throughout the country. We made 13 collections, 10 of these with botanical seeds. These collections considerably extend the numbers of accessions and geographic range of the germplasm available from Costa Rica. The taxonomic identity of the species of wild potatoes (Solanum sect. Petota) in Costa Rica was previously unresolved. Our fieldwork supports the concept that Costa Rican wild potatoes belong to a single species,S. longiconicum.
    Geographic distribution of wild potato species
    Hijmans, R.J. ; Spooner, D.M. - \ 2001
    American Journal of Botany 88 (2001). - ISSN 0002-9122 - p. 2101 - 2112.
    The geographic distribution of wild potatoes (Solanaceae sect. Petota) was analyzed using a database of 6073 georeferenced observations. Wild potatoes occur in 16 countries, but 88% of the observations are from Argentina, Bolivia, Mexico, and Peru. Most species are rare and narrowly endemic: for 77 species the largest distance between two observations of the same species is <100 km. Peru has the highest number of species (93), followed by Bolivia (39). A grid of 50 x 50 km cells and a circular neighborhood with a radius of 50 km to assign points to grid cells was used to map species richness. High species richness occurs in northern Argentina, central Bolivia, central Ecuador, central Mexico, and south and north-central Peru. The highest number of species in a grid cell (22) occurs in southern Peru. To include all species at least once, 59 grid cells need to be selected (out of 1317 cells with observations). Wild potatoes occur between 38° N and 41° S, with more species in the southern hemisphere. Species richness is highest between 8° and 20° S and around 20° N. Wild potatoes typically occur between 2000 and 4000 m altitude.
    Taxonomy of Mexican and Central American Members of Solanum series Conicibaccata (sect. Petota).
    Spooner, D.M. ; Berg, R.G. van den; Rivera-Pena, A. ; Velguth, P. ; Rio, A. del; Salas-Lopez, A. - \ 2001
    Systematic Botany 26 (2001)4. - ISSN 0363-6445 - p. 743 - 756.
    Members of Solanum series Conicibaccata in Mexico and Central America are very similar. All are tetraploids (2n = 4x = 48). Recent authors have recognized three or four species: S. agrimonifolium, S. woodsonii, S. longiconicum (sometimes included in the next), and S. oxycarpum. We had difficulty distinguishing these species in the herbarium, and needed to resolve species boundaries for ongoing floristic studies. We studied this group in the field throughout Mexico, Guatemala, Costa Rica, and Panama, grew collections in the greenhouse, studied herbarium specimens, determined ploidy levels through flow cytometry, and generated molecular data using Random Amplified Polymorphic DNA. Molecular data distinguish S. agrimonifolium, S. longiconicum, and S. oxycarpum. Solanum woodsonii was not available for molecular analysis. All four species can be distinguished morphologically, but only by leaf character states that overlap in range, by pubescence differences that are best observed in living specimens, and by a seed spot character that is only evident on living or recently gathered specimens.
    Molecular systematics of Solanum series Circaeifolia using AFLP and RAPD markers
    Berg, R.G. van den; Groendijk-Wilders, N. ; Zevenbergen, M.J. ; Spooner, D.M. - \ 2001
    In: Solanaceae V: Advances in taxonomy and utilization : Vth International Solanaceae Conference, Nijmegen, 23-29 July 2000 / van den Berg, R.G., Barendse, G.W.M., van der Weerden, G.M., Mariani, C., Nijmegen : Nijmegen University Press - p. 73 - 84.
    Quantitative assessment of corolla shape variation in Mexican Solanum sect. Petota
    Spooner, D.M. ; Berg, R.G. van den - \ 2001
    In: Solanaceae V: Advances in taxonomy and utilization : Vth International Solanaceae Conference, Nijmegen, 23-29 July 2000 / R.G. van den Berg, G.W.M. Barendse, G.M. van der Weerden and C. Mariani. - Nijmegen : Nijmegen University Press, 2001 - p. 61 - 71.
    Molecular systematics of Solanum series Circaeifolia (Solanum section Petota) based on AFLP and RAPD markers
    Berg, R.G. van den; Groendijk-Wilders, N. ; Zevenbergen, M.J. ; Spooner, D.M. - \ 2000
    In: Fifth International Solanaceae Conference : Fifth International Conference , Nijmegen, 23-29 July 2000 Nijmegen : - p. 12 - 12.
    Quantitative assessment of corolla shape variation in Mexican Solanum sect. Petota
    Spooner, D.M. ; Berg, R.G. van den - \ 2000
    In: Fifth International Solanaceae Conference : Fifth International Solanaceae Conference, Nijmegen, 23-29 juli Nijmegen : - p. 53 - 53.
    Potato germplasm collecting expedition to Mexico in 1997 : taxonomy and new germplasm resources
    Spooner, D.M. ; Rivera-Pena, A. ; Berg, R.G. van den; Schueler, K. - \ 2000
    American Journal of Potato Research 77 (2000). - ISSN 1099-209X - p. 261 - 270.
    Wild potato (Solanum sect. Petota) germplasm has been collected in Mexico on nine major expeditions, as determined by 20 collections or more from each expedition currently at the United States potato genebank, the National Research Support Program-6 (NRSP-6). These have resulted in 609 accessions with good collection data. In addition, NRSP-6 has germplasm of approximately 90 other Mexican collections that are unspecific regarding date or place of collection. This expedition was funded to collect those remaining collections with no or little germplasm: Solanum clarum, S. x edinense, S. hintonii, S. hjertingii var. physaloides, S. leptosepalum, S. lesteri, S. macropilosum, S. x michoacanum, S. x sambucinum, and S. stenophyllidium. In addition, some species and species groups (species groups indicated in parentheses) have unresolved taxonomic problems that needed clarification by additional field collections. These are (S. agrimonifolium and S. oxycarpum), (S. brachycarpum, S. guerreroense, S. hougasii, and S. iopetalum - the S. brachycarpum complex), (S. fendleri, S. papita, S. stoloniferum - the S. stoloniferum complex), S. leptosepalum, and S. macropilosum. We conducted a wild potato germplasm collecting expedition in Mexico from August 22 to October 31, 1997. Our 103 collections, 71 as germplasm collections, provide the first germplasm samples for S. hjertingii var. physaloides, S. leptosepalum, and S. macropilosum. They provide additional germplasm of the rare species S. clarum, S. x edinense, S. lesteri, S. x michoacanum, S. x sambucinum, and S. stenophyllidium. We additionally gathered germplasm and field data to help resolve taxonomic difficulties in S. agrimonifolium and S. oxycarpum, the S. brachycarpum complex, and the S. stoloniferum complex.
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