DNA markers and pollen morphology reveal that <Emphasis Type="Italic">Praecitrullus fistulosus</Emphasis> is more closely related to <Emphasis Type="Italic">Benincasa hispida</Emphasis> than to <Emphasis Type="Italic">Citrullus</Emphasis> spp.

The round melon Praecitrullus fistulosus (Stocks) Pangalo has been cultivated in Asia since ancient times and has been considered an underexploited crop in the western world. In the USA, there is an increased interest in using P. fistulosus as a commercial vegetable, and possibly as a rootstock for grafting watermelon, melon, or cucumber. However, the taxonomic classification of P. fistulosus is incomplete and for many years it has been considered a close relative of watermelon [Citrullus lanatus subsp. vulgaris (Schrad. ex Eckl. et Zeyh.) Fursa] and was previously classified as Citrullus lanatus subsp. fistulosus (Stocks) Duthie et J.B. Fuller. Here, we used two sets of DNA markers to assess the genetic similarity of P. fistulosus in relation to Citrullus spp. {including Citrullus lanatus subsp. vulgaris, C. lanatus subsp. lanatus, Citroides group [also known as C. lanatus (Thunb.) Matsum. et Nakai subsp. lanatus var. citroides (Bailey) Mansf. ex Greb.], and C. colocynthis (L.) Schrad.}, Cucumis spp. (including C. melo, C. sativus, C. anguria, C. meeusei, C. zeyheri), Benincasa hispida (Thunb.) Cogn., Lagenaria siceraria (Mol.) Standl. and Cucurbita spp. (including C. moschata Duchesne and the winter squash C. maxima Duchesne). The first marker set comprised 501 markers that were produced by 38 primer pairs derived from watermelon expressed sequenced tags (ESTs) containing simple sequence repeat (SSR) motifs (designated as EST-SSR primers; produced 311 markers), and by 18 primer pairs derived from ESTs that do not contain SSR motives (designated here as EST-PCR primers; produced 190 markers). The second marker set comprised 628 markers that were produced by 18 sequence related amplified polymorphism (SRAP) primer pairs. The phylogenetic data indicated that among these cucurbit species, the wax gourd B. hispida is the closest to the P. fistulosus. Pollen observations, using light microscopy, indicated that each of the cucurbit genera examined here has unique pollen morphology. The Cucurbita spp. have globular pollen grains with a stigmatic surface. The L. siceraria has polygonal pollen grains with symmetrical boundaries, while the Citrullus spp. and Cucumis spp. have ovular (conical) and triangular shaped pollen grains (respectively). The B. hispida and P. fistulosus have spherical or semispherical pollen grains. These pollen features appear to be in agreement with the phylogenetic relationships of these two species based on DNA markers. Analysis with 12 SRAP primer pairs revealed low genetic diversity among 18 United States Plant Introductions (PIs) of P. fistulosus, indicating the need to expand the germplasm collection of this cucurbit crop.     

Polymorphisms Among Chloroplast and Mitochondrial Genomes of <Emphasis Type="Italic">Citrullus</Emphasis> Species and Subspecies

Twelve and six DNA clones representing various parts of chloroplast and mitochondrial genomes, respectively, were used to detect polymorphism among five watermelon cultivars and 21 U.S. Plant Introductions (PIs) collected from diverse geographical locations and representing major groups of Citrullus species. Cluster analysis based on 20 chloroplast DNA (cpDNA) and 10 mitochondrial DNA (mtDNA) restriction fragment length polymorphism (RFLP) markers differentiated the accessions into three major phenetic groups: PIs and watermelon cultivars of Citrullus lanatus subsp. vulgaris (Schrad. ex Eckl. et Zeyh.) Fursa (also designated as C. lanatus var. lanatus) (group I), PIs of C. lanatus var. citroides (of C. lanatus subsp. lanatus Schrad. ex Eckl. et Zeyh.)(group II), and C. colocynthis (L.) Schrad. PIs (group III). The chloroplast and mitochondrial genomes of watermelon cultivars are distinct, but closely related to those of the C. lanatus var. lanatus PIs. On the other hand, the chloroplast and mitochondrial genomes of the wild species C. colocynthis are more similar to those of C. lanatus var. citroides. Polymorphic cpDNA and mtDNA markers identified in this study can complement isozyme and nuclear DNA data used in earlier phylogenetic and phenetic classifications of Citrullus PIs. These cpDNA and mtDNA markers are being used in experiments designed to enhance watermelon cultivars by replacing the chloroplast and mitochondrial genome of cultivated watermelon with those of the wild species C. colocynthis.     

The genetic characterization of Turkish watermelon (<Emphasis Type="Italic">Citrullus lanatus</Emphasis>) accessions using RAPD markers

Genetic diversity of the Turkish watermelon genetic resources was evaluated using different Citrullus species, wild relatives, foreign landraces, open pollinated (OP) and commercial hybrid cultivars by RAPD markers. The germplasm was consisted of 303 accessions collected from various geographical regions. Twenty-two of 35 RAPD primers generated a total of 241 reproducible bands, 146 (60.6%) of which were polymorphic. Based on the RAPD data the genetic similarity coefficients were calculated and the dendrogram was constructed using UPGMA (Unweighted pair-group method with arithmetic average). Cluster analysis of the 303 accessions employing RAPD data resulted in a multi-branched dendrogram indicating that most of the Turkish accessions belonging to var. lanatus of Citrullus lanatus (Thunb.) Matsum et Nakai were grouped together. Accessions of different Citrullus species and Praecitrullus fistulosus (Stocks) Pangalo formed distant clusters from C. lanatus var. lanatus. Among 303 accessions, a subset of 56 accessions was selected representing different groups and a second dendrogram was constructed. The genetic similarity coefficients (GS) within the Turkish accessions were ranged from 0.76 to 1.00 with 0.94 average indicating that they are closely related. Taken together, our results indicated that low genetic variability exist among the watermelon genetic resources collected from Turkey contrary to their remarkable phenotypic diversity.     

Exploitation of <Emphasis Type="Italic">Malus</Emphasis> EST-SSRs and the utility in evaluation of genetic diversity in <Emphasis Type="Italic">Malus</Emphasis> and <Emphasis Type="Italic">Pyrus</Emphasis>

A total of 8117 suitable SSR-contaning ESTs were acquired by screening from a Malus EST database, among which dinudeotide SSRs were the most abundant repeat motif, within which, CT/TC followed by AG/GA were predominant. Based on the suitable sequences, we developed 147 SSR primer pairs, of which 94 pairs gave amplifications within the expected size range while 65 pairs were found to be polymorphic after a preliminary test. Eighteen primer pairs selected randomly were further used to assess genetic relationship among 20 Malus species or cultivars. As a result, these primers displayed high level of polymorphism with a mean of 6.94 alleles per locus and UPGMA cluster analysis grouped twenty Malus accessions into five groups at the similarity level of 0.6800 that were largely congruent to the traditional taxonomy. Subsequently, all of the 94 primer pairs were tested on four accessions of Pyrus to evaluate the transferability of the markers, and 40 of 72 functional SSRs produced polymorphic amplicons from which 8 SSR loci selected randomly were employed to analyze genetic diversity and relationship among a collection of Pyrus. The 8 primer pairs produced expected bands with the similar size in apples with an average of 7.375 alleles per locus. The observed heterozygosity of different loci ranged from 0.29 (MES₉₆) to 0.83 (MES₁₃₈), with a mean of 0.55 which is lower than 0.63 reported in genome-derived SSR marker analysis in Pyrus. The UPGMA dendrogram was similar to the previous results obtained by using RAPD and AFLP markers. Our results showed that these EST-SSR markers displayed reliable amplification and considerable polymorphism in both Malus and Pyrus, and will contribute to the knowledge of genetic study of Malus and genetically closed genera.     

Analysis based on RAPD and ISSR Markers Reveals Closer Similarities among <Emphasis Type="Italic">Citrullus</Emphasis> and <Emphasis Type="Italic"> Cucumis</Emphasis> Species than with <Emphasis Type="Italic">Praecitrullus fistulosus</Emphasis> (Stocks) Pangalo

A cucurbit species named Praecitrullus fistulosus (Stocks) Pangalo, which thrives in India, is considered to be a distant relative of watermelon. Recent experiments indicated that it has mild resistance to whiteflies (Bemisia tabaci). However, our attempts to cross various US plant introductions (PIs) of P. fistulosus with watermelon or other Citrullus PIs have not been successful. Thus, to determine genetic relatedness among those species, phylogenetic analysis [based on simple sequence repeat (SSR)–anchored (also termed ISSR), and randomly amplified polymorphic DNA (RAPD) markers] was conducted among PIs of P. fistulosus, Citrullus lanatus var. lanatus (watermelon), C. lanatus var. citroides and the wild Citrullus colocynthis. Phylogenetic relationships were also examined with Cucumis melo (melon), Cucumis sativus (cucumber), and wild Cucumis species including C. africanus, C. metuliferus, C. anguria, C. meeusei, and C. zeyheri. Wide genetic distance exists between Citrullus and Cucumis groups (8% genetic similarity). Phylogenetic relationships among Citrullus species and subspecies are closer (25–55% genetic similarity) as compared with those among most Cucumis species (14–68% genetic similarity). P. fistulosus appeared to be distant from both Cucumis and Citrullus species (genetic similarity between P. fistulosus and Cucumis or Citrullus groups is less than 3%). Although wide genetic differences and reproductive barriers exist among cucurbit species examined in this study, they are still considered as potential germplasm source for enhancing watermelon and melon crops using traditional breeding and biotechnology procedures.     

Diversity and origin of cultivated and citron type watermelon (<Emphasis Type="Italic">Citrullus lanatus)</Emphasis>

Cultivated (Citrullus lanatus var. lanatus) and citron type (var. citroides) watermelon collected from different areas on the African continent are remarkably diverse in fruit and seed morphology. Chloroplast DNA investigations using PCR-RFLP and sequencing analysis of several non-coding regions were conducted to infer their biogeographic and evolutionary relationships, origin and domestication history. Variability within C. lanatus was observed at regions of high A + T content, resulting in indels and transversions mainly. Distinct chlorotype lineages were identified separating the cultivated and egusi-type watermelon from var. citroides accessions. This suggests an ancient split from a common ancestor and haplotype fixation. Three haplotypes as a result of relatively recent indel events were detected within var. citroides. The geographical range of two of the main citroides haplotypes is relatively similar across southern Africa. Accessions with the most ancient citroides haplotype originated in Swaziland and South Africa resulting in colonization routes from this area all over the world. Chloroplast divergence is not associated with morphological divergence. The cultivated and wild watermelon appear to have diverged independently from a common ancestor, possibly C. ecirrhosus from Namibia.     

Genetic diversity of Swiss maize (<Emphasis Type="Italic">Zea mays</Emphasis> L. ssp. <Emphasis Type="Italic">mays</Emphasis>) assessed with individuals and bulks on agarose gels

About 65 years ago, more than 150 Swiss maize landraces (Zea mays L. ssp. mays) of the flint type were collected and conserved ex situ. Due to the climatically and culturally diverse environment of the Alps, a considerable genetic diversity of this material was assumed. To prove this, an efficient method was required to carry out genetic profiling of all the accessions in the Swiss Gene Bank. Simple sequence repeat marker (SSR) profiling in combination with the visualization of the polymerase chain reaction (PCR) products on agarose gels was chosen. Here a set of 19 different landrace accessions was analyzed to: (i) investigate their genetic diversity, (ii) investigate and display the population structure and (iii) determine whether DNA bulks rather than single plants can be used for such analyses. Four repeated samples of one accession were found to be much closer to one another than to the rest of accessions. Furthermore, specific alleles were identified for several accessions. The PCR products of the bulked DNA samples represented only a small part of the variation revealed by the analysis of individuals. Loci with four base repeat motifs performed better in the analysis of bulks than loci with other repeat motifs. The correlation between genetic distance matrices, based on the analysis of individuals and bulks, respectively, was significant. Thus, the single plant approach allowed for sufficient differentiation of accessions, and DNA bulks visualized on agarose gels led to correlated genetic distances although a limited number of alleles were detected. Although the limited resolution of agarose gels likely causes some bias, profiling of larger sets with the individual plant approach appears feasible and more informative compared to the bulk analysis we conducted.     

Development and utilization of diagnostic DAMD-PCR markers for <Emphasis Type="Italic">Capsicum</Emphasis> accessions

A polymerase chain reaction (PCR) based approach involving the directed amplification of minisatellite DNA region (DAMD-PCR) was used to identify accession specific DNA markers and study genetic relationships between and within 15 accessions corresponding to 11 species in genus Capsicum. A touch down PCR profile and unique chemical concentration of ingredients resulted in reproducible and reliable DNA amplifications. The number of amplified products varied from 1 to 12 fragments depending on the template DNA and the primers. The DAMD-PCR technique provided a total of 38 accession specific DNA markers (diagnostic DAMD-PCR) which can be utilized in accession identification, preservation and genetic studies of Capsicum germplasm. Based on 1,292 polymorphic and monomorphic DNA markers directed with 22 minisatellite specific primers, accessions were divided into four major groups, three of which corresponded to the three distinct Capsicum complexes. Capsicum chacoense was found to be the most distinct species.     

PCR Marker-based Analysis of Wild and Cultivated Yams (<Emphasis Type="Italic">Dioscorea</Emphasis> spp.) in Nigeria: Genetic Relationships and Implications for <Emphasis Type="Italic">ex situ</Emphasis> Conservation

Reliable characterization of the variation among wild and cultivated yams in Nigeria is essential for improved management and efficient utilization of yam genetic resources. RAPD and double stringency PCR (DS-PCR) analyses were used to investigate genetic relationships and the extent of redundancy among 30 accessions of two cultivated, and 35 accessions of four wild yam species collected from Nigeria. Twenty-five selected random decamer and two microsatellite primers were used individually and in combination to generate DNA profiles for each accession of the six Dioscorea species. The number of amplified fragments varied from 7 to 18 fragments per primer/primer combination. Different levels of intraspecific genetic diversity were found, with Dioscorea rotundata Poir. being the most variable. Based on identical profiles for the RAPD and DS-PCR primers, 12 duplication groups consisting of a total number of 37 accessions were observed in the present study. An UPGMA analysis grouped the majority of plants according to the species. Cultivated yams belonging to the D. cayenensis–rotundata species complex, which were classified into seven morphotypes/varietal groups, could be clearly separated into two major groups corresponding to D. rotundata Poir. and D. cayenensis Lam. D. cayenensis cultivars exhibited a low level of intraspecific variation and were genetically close to the wild species Dioscorea burkilliana J. Miège. D. rotundata cultivars classified into six varietal groups showed a high degree of DNA polymorphism and were separated into two major groups that appeared most closely related to Dioscorea praehensilis Benth. and Dioscorea liebrechtsiana de Wild. We propose, based on these results, that cultivars classified into D. cayenensis should be considered as a taxon separate from D. rotundata. The implications of intraspecific variability for the ex situ conservation of wild and cultivated yam germplasm in Nigeria are discussed.     

Exploring genetic diversity and disease response of cultivated rice accessions (<Emphasis Type="Italic">Oryza</Emphasis> spp.) against <Emphasis Type="Italic">Pyricularia oryzae</Emphasis> under rainfed upland conditions in Benin

The main goal of this study is to gain insight into the relationship between the genetic profile of cultivated rice (Oryza spp.) accessions and their resistance to rice blast. Therefore, the genetic and phenotypic variability of a set of 350 cultivated rice accessions originating from Africa (Benin, Mali and Nigeria, Ivory Coast etc.) was examined. Seventy-seven fluorescent amplified fragment polymorphism (AFLP) markers were used to gain insight into the genetic variation and to classify the germplasm collection. In addition, the rice germplasm was assessed for its resistance to blast disease caused by Pyricularia oryzae in upland field conditions. Huge differences in responses of rice accessions to P. oryzae were observed, ranging from highly susceptible to highly resistant. Twelve percent of all accessions were highly resistant to P. oryzae. Based on their AFLP marker profile these highly resistant accessions could be separated from the other accessions. Stepwise regression revealed that the best prediction of the blast resistance level was achieved with a maximum number of 13 AFLP markers. Marker CTA22 was the most important for accurate prediction of blast resistance, this marker was present in all highly resistant accessions. It can be concluded that AFLP markers are a valuable tool to screen rice accessions for their susceptibility towards blast disease and that, based on a subset of markers, it is possible to predict the resistance to rice blast.     

Biodiversity of <Emphasis Type="Italic">Secale strictum</Emphasis> in Iran measured using microsatellites

The mountain rye Secale strictum is native to the Middle East and is the progenitor of the cultivated rye. Regarding lack of information about the genetic diversity of this species in Iran, this study was aimed to evaluate its genetic variation and to examine the patterns of diversity related to the varieties and geography. Fifteen wheat and rye derived microsatellite markers were used to achieve this aim. High levels of diversity, with an average number of 6.1 alleles per locus (ranging up to 11) and high level polymorphism with polymorphism rate averaging 0.624 (between populations) and 0.357 (within populations) were observed among 125 individuals from 19 populations collected from various regions of Iran. The Northwestern populations showed the highest and the Northern populations showed the lowest polymorphism and diversity. One population of the Northwest of the country was notably closer in its allele range to the S. cereale accessions used as outgroup. No taxon or geographic specific marker was detected, suggesting high gene flow between the populations, however some groupings which can be related to the geographic regions and varieties, were evident. The analysis of molecular variance attributed same portions of genetic diversity to the within and between populations with no significant variation among different geographic regions. The results of this study indicated that the Iranian genepool of Secale strictum is valuable to search for new useful alleles for crop improvement.     

EST <Emphasis Type="Italic">versus</Emphasis> Genomic Derived Microsatellite Markers for Genotyping Wild and Cultivated Barley

Genetic variation present in wild and cultivated barley populations was investigated using two sources of microsatellite also known as simple sequence repeat (SSR) markers. EST-SSRs are derived from expressed sequences and genomic SSRs are isolated from genomic DNA. Genomic SSR markers detected a higher level of polymorphism than those derived from ESTs. Polymorphism information content was higher in genomic SSRs than EST-derived SSRs. This study showed that the EST-SSR markers developed in cultivated barley are polymorphic in wild and cultivated varieties and produced high quality markers. Ten of these functional markers were polymorphic across the accessions studied. EST markers indicated clearer separation between wild and cultivated barley than genomic SSRs. The EST-SSRs are a valuable source of new polymorphic markers and should be highly applicable to barley genetic resources, providing a direct estimate of functional biodiversity.     

Genetic Characterization of Brazilian Annual <Emphasis Type="Italic">Arachis</Emphasis> Species from Sections <Emphasis Type="Italic">Arachis</Emphasis> and <Emphasis Type="Italic">Heteranthae</Emphasis> using RAPD Markers

The genus Arachis is divided into nine taxonomic sections. Section Arachis is composed of annual and perennial species, while section Heteranthae has only annual species. The objective of this study was to investigate the genetic relationships among 15 Brazilian annual accessions from Arachis and Heteranthae using RAPD markers. Twenty-seven primers were tested, of which nine produced unique fingerprintings for all the accessions studied. A total of 88 polymorphic fragments were scored and the number of fragments per primer varied from 6 to 17 with a mean of 9.8. Two specific markers were identified for species with 2n = 18 chromosomes. The phenogram derived from the RAPD data corroborated the morphological classification. The bootstrap analysis divided the genotypes into two significant clusters. The first cluster contained all the section Arachis species, and the accessions within it were grouped based upon the presence or absence of the ‘A’ pair and the number of chromosomes. The second cluster grouped all accessions belonging to section Heteranthae.     

Characterization of a world collection of <Emphasis Type="Italic">Agropyron cristatum</Emphasis> accessions

The genetic diversity was studied of 115 Agropyron cristatum accessions from 17 countries. Tetraploids were the most common (74.8%), followed by diploid (16.3%) and hexaploid (6.9%). We observed a relation between geographic distribution and ploidy level. The tetraploids, the most widespread, were found from Europe through Russia to East Asia. The diploids appeared over the same general range, except in Turkey, Iran and Georgia where no diploid accessions were found. Hexaploid accessions mainly came from a region comprising the east of Turkey, the north of Iran and Georgia. A selection of 71 accessions, including all three ploidy levels, were analyzed by capillary electrophoresis using six wheat simple sequence repeat (SSR) markers. All markers presented high levels of polymorphism, generating 166 different alleles ranging in size between 84 and 256 bp. Based on polymorphic information content values obtained (0.579–0.968), all the SSRs were classified as informative markers (values?>?0.5). According to the dendrogram generated, all the A. cristatum accessions were distinctly classified. Diploid, tetraploid and hexaploid accessions are not clearly differentiated from each other on the basis of SSR markers. A field experiment was conducted to morphologically characterize 18 accessions including the three ploidy levels. Significant differences were found between the accessions in spike length, spike width and number of spikelets per spike. All the cytological, molecular, and morphological data demonstrate the high genetic diversity present in A. cristatum, making it a valuable resource for future breeding programs.     

Genetic Diversity of the Greater Yam (<Emphasis Type="Italic">Dioscorea alata</Emphasis> L.) and Relatedness to <Emphasis Type="Italic">D. nummularia</Emphasis> Lam. and <Emphasis Type="Italic">D. transversa</Emphasis> Br. as Revealed with AFLP Markers

Amplified fragment length polymorphism markers were used to assess the genetic relatedness between Dioscorea alata and nine other edible Dioscorea. These species include D. abyssinica Hoch., D. bulbifera L., D. cayenensis-rotundata Lamk. et Poir., D. esculenta Burk., D. nummularia Lam., D. pentaphylla L., D. persimilis Prain. et Burk., D. transversa Br. and D. trifida L. Four successive studies were conducted with emphasis on the genetic relationship within D. alata and among species of the Enantiophyllum section from Vanuatu. Study 1 was carried out to select a set of polymorphic primer pairs using 11 combinations and eight species belonging to five distinct sections. The four most polymorphic primer pairs were used in study 2 among six species of the Enantiophyllum section. Study 3 focussed mainly on the genetic relationship among 83 accessions of D. alata, mostly from Vanuatu (78 acc.) but also from Benin, Guadeloupe, New Caledonia and Vietnam. The ploidy level of 53 accessions was determined and results indicated the presence of tetraploid, hexaploid and octoploid cultivars. Study 4, included 35 accessions of D. alata, D. nummularia and D. transversa and was conducted using two primer pairs to verify the taxonomical identity of the cultivars `langlang', `maro' and `netsar' from Vanuatu. The overall results indicated that each accession can be fingerprinted uniquely with AFLP. D. alata is an heterogeneous species which shares a common genetic background with D. nummularia and `langlang', `maro' and `netsar'. UPGMA cluster analysis revealed the existence of three major groups of genotypes within D. alata, each assembling accessions from distant geographical origins and different ploidy levels. The analysis also revealed that `langlang', `maro' and `netsar' clustered together with the cultivar `wael' (D. transversa) from New Caledonia. Results are discussed in the paper.     

<Emphasis Type="Italic">In situ</Emphasis> conservation and genetic diversity of three populations of <Emphasis Type="Italic">Gossypium mustelinum</Emphasis> Miers ex Watt

Gossypium mustelinum Miers ex Watt is a native from Northeastern Brazil and belongs to the primary gene pool of the cultivated cotton. The unique places where the species was known to occur were visited to plan ex situ and in situ preservation. Two populations at Caicó became extinct, and only eleven individuals were found. At Jaguarari, although one population became extinct, a new one was localized with approximately 500 adult plants, where a fence avoided cattle feeding. The population from Macururé consisted of 28 plants protected from animals by thorns of Bromelia laciniosa Mart. ex Schult. f. Thirteen SSR primer pairs amplified 40 alleles, among which 30% were exclusive of one of the populations. The genetic differences between populations represented 58.3% of the total genetic variation observed. The high genetic distances are likely to be caused by geographical isolation as well as by the small number of individuals which contribute to new generations, and consequential genetic drift.     

Characterization of European hazelnut (<Emphasis Type="Italic">Corylus avellana</Emphasis>) cultivars using SSR markers

World hazelnut production is based primarily on selections from the wild. In this study, we used 21 pairs of simple sequence repeat (SSR) primers to investigate genetic diversity in 270 clonal accessions of European hazelnut (Corylus avellana) representing a wide geographic range. Of the 270 accessions, 198 had unique fingerprints while 72 were duplicates. Based on the 198 unique accessions, the number of detected alleles per locus averaged 9.81 and observed heterozygosity (H_o) averaged 0.67. Of the 206 total alleles amplified, 20 were unique to a single accession. A genetic similarity matrix was constructed and the resulting dendrogram revealed four major geographical groups: Central European, Black Sea, English and Spanish-Italian. SSR alleles indicated the parentage of 31 accessions. The fingerprints are publicly available through the Germplasm Resources Information Network (GRIN) database. The identification of duplicate and mislabeled accessions will improve management of hazelnut genebanks, and information on genetic variation in hazelnut will assist the international research community. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

EST-SSR cross-amplification and genetic similarity in <Emphasis Type="Italic">Onobrychis</Emphasis> genus

EST-SSR from Medicago truncatula Gaertn. and Glycine max (L.) Merr. were tested for transferability in various species of Onobrychis (O. pyrenaica Sennen, O. argentea Boiss. and O. viciifolia Scop.). Repeatable amplification was obtained for 81% of the microsatellites and 52% were polymorphic. Six selected SSRs from M. truncatula were used to fingerprint and estimate the genetic similarity of a set of 23 accessions of O. viciifolia. PCA analysis discriminated among the different Onobrychis species and the sainfoin accessions were clustered in a single major group. This grouping is discussed in terms of the history of cultivation of sainfoin in Spain. The selected SSRs will allow fingerprinting and genetic studies in Onobrychis species, solving the lack of available SSR markers in this species.