Nuclear SSR Loci Research Articles

Dissecting Taxonomic Variants within Ulmus spp. Complex in Natural Forests with the Aid of Microsatellite and Morphometric Markers

Spontaneous hybrids between the native elms (genus Ulmus L.) have been observed in the forests of Europe. Gene conservation raises questions regarding the genetic background for the complex morphology and taxonomy of elms. Our objective was to dissect morphological and genetic variation in the natural swamps of Ulmus species groups in Lithuanian forests with the aid of leaf morphology and microsatellite (SSR) markers. We sampled leaves from 189 elms at 26 locations to grasp the phenotypic diversity in variable natural habitats in Lithuanian forests. We assigned the elms into six taxonomic and genetics groups based on 31 leaf morphology parameters and tested the genetic differentiation between these six groups at six nuclear SSR loci by using Bayesian and genetic distance-based clustering. The genetic and leaf morphometric analyses of putative elm hybrid swamps indicated a low genetic exchange between U. laevis Pall. and the other Ulmus groups. The genetic and morphometric data supported the differentiation of U. glabra Huds. and U. glabra (female) × U. minor Mill. (male) spontaneous hybrids. In addition, the results of the genetic analysis also confirmed the high level of genome sharing among U. minor and U. minor subsp. minor Richens., where leaf morphology failed to differentiate genetically discrete groups. For gene conservation, we would suggest considering separate gene conservation units selected based on leaf and stem morphology for U. laevis, U. glabra, U. glabra × minor, and the U. minor species complex.

Genetic diversity of scots pine trees of different selection categories in plus stands of Karelia

BACKGROUND: Genetic control is necessary at all stages of forest selection for the effective use of objects of unified genetic-selection complex (UGSC). This is particularly important for performing a breeding inventory. The aim of the present study was to evaluate the genetic variability of trees of different selection categories in several plus stands of Scots pine.
 MATERIALS AND METHODS: 116 trees of Scots pine of various selection categories have been selected from four plus stands within the middle taiga subzone of Karelia. The analysis of the pine samples had been performed using four nuclear SSR loci tests. DNA fragments were separated on a sequencer CEQ 8000. The main criteria of the genetic diversity and F-statistics were calculated. The genetic structure of the selection groups was evaluated using the coefficient of genetic originality (CGO).
 RESULTS: All the selection groups evaluated with CGO were characterized by a low content of alleles, which are rare for this part of the Scots pine areal. The plus trees were characterized by a reduced level of genetic diversity (Ho = 0.480.59; He = 0.470.59) as compared to minus (Ho = 0.460.64; He = 0.490.65) and normal trees (Ho = 0.500.69; He = 0.490.65). However, the observed differences between the breeding groups were not statistically significant.
 CONCLUSION: The absence of significant differences between the selection groups indicates the need of a separate assessment of the genetic and economic value of plus trees according to their phenotype. The obtained data is necessary for the organization of objects of UGSC, testing of clonal and seed offspring of plus trees, certification of clones, etc.

The state of gene pool of the basic forest-forming species of the white sea watershed (on the example of a Picea × fennica (Regel) kom. And Pinus sylvestris L.)

Background. The genetic diversity of forest tree species populations is a key factor contributing to their resistance against negative effects of human activity, and the global climate change. The aim of the present study was to evaluate the state of gene pools of the main forest-forming species in the White Sea watershed.
 Materials and methods. Five populations of Norway spruce and seven populations of Scotch pine have been selected within the Arctic zone of the European part of Russia (the western part of the White Sea watershed), along with two boundary ones located near the northern borders of the abovementioned species areas. The analysis of the spruce samples had been performed using five nuclear SSR loci, while for the pine samples it was four. DNA fragments were separated on a sequencer CEQ 8000. The main criteria of the genetic diversity (A99%, Ho, He) and F-statistics were calculated.
 Results. The marginal spruce populations were characterized by the largest magnitude of the genetic diversity (Ho = 0.46; He = 0.47) and isolation (FST = 0.33) compared to other populations of the same species. The differences were statistically significant. All pine populations studied demonstrated a higher level of genetic diversity (Ho = 0.50, He = 0.63) compared to spruce populations. The differences between the boundary and in-area populations were not statistically reliable (FST = 0.04).
 Conclusion. Our investigation revealed a sufficiently high level of spruce and pine northern populations genetic diversity making them able to withstand expected negative effects of anthropogenic activity and global climate change.

Contrasting evolutionary processes drive morphological and genetic differentiation in a subtropical fir (Abies, Pinaceae) species complex

AbstractInteracting stochastic and selective forces drive population and species divergence. Such interaction may generate contrasting clines between genetic and phenotypic factors, which can be related to either geographical or environmental variation depending on the predominant evolutionary force (which in its turn is partly determined by population size). Here, we investigated whether the morphological and genetic differentiation across a species complex in Abies in central Mexico fits isolation by distance (IBD) or isolation-by-adaptation (IBA) frameworks. This complex includes two species (A. religiosa and A. flinckii) with discernible morphological and environmental differences and dissimilar range sizes. After comparing variation at nuclear SSR loci and diagnostic morphological traits of needles with the climate variables contributing to ecological differentiation, we found that the widely distributed A. religiosa has more genetic diversity and is morphologically more heterogeneous than the geographically restricted A. flinckii. Morphological differentiation at three physiologically important traits (needle thickness, number of stomata rows and location of the resin duct) is significantly correlated with geography in A. flinckii (indicative of IBD), but is significantly associated with climate variation in A. religiosa (suggesting IBA). In agreement with quantitative genetics theory, PST (phenotypic differentiation)-G’ST (genetic differentiation) comparisons indicate contrasting contributions of putatively adaptive (A. religiosa) and stochastic (A. flinckii) factors to the morphological differentiation of species related to their population size. The integration of such quantitative genetic/evolutionary aspects may reinforce species descriptions and help in disentangling resilient taxonomic discordance.

Multiple founder events explain the genetic diversity and structure of the model allopolyploid grass Brachypodium hybridum in the Iberian Peninsula hotspot.

It is accepted that contemporary allopolyploid species have originated recurrently, but very few cases have been documented using multiple natural formations of the same species. To extend our knowledge, we have investigated the multiple origins, genetic variation and structure of the allotetraploid grass Brachypodium hybridum with respect to its progenitor diploid species B. distachyon (D genome) and B. stacei (S genome). For this, our primary focus is the Iberian Peninsula, an evolutionary hotspot for the genus Brachypodium. We analysed 342 B. hybridum individuals from 36 populations using ten nuclear SSR loci and two plastid loci. The B. hybridum genetic profiles were compared with those previously reported for B. stacei and B. distachyon. In addition, phylogenetic analysis of the plastid data was performed for a reduced subset of individuals. The nuclear simple sequence repeat (SSR) genetic analysis detected medium to high genetic diversity, with a strong south-to-north genetic structure cline, and a high selfing rate in B. hybridum. Comparative genetic analysis showed a close relatedness of current B. hybridum D allelic profiles with those of B. distachyon, but a lack of similarity with those of B. stacei, suggesting another B. stacei source for the B. hybridum S alleles. Plastid analysis detected three different bidirectional allopolyploidization events: two involved distinct B. distachyon-like ancestors and one involved a B. stacei-like ancestor. The south-eastern Iberian Peninsula B. hybridum populations were more genetically diverse and could have originated from at least two hybridization events whereas north-eastern/north-western Iberian Peninsula B. hybridum populations were less diverse and may have derived from at least one hybridization event. The genetic and evolutionary evidence supports the plausible in situ origin of the south-eastern and northern Iberian Peninsula B. hybridum allopolyploids from their respective local B. distachyon and unknown B. stacei ancestors. The untapped multiple origins and genetic variation detected in these B. hybridum populations opens the way to future evolutionary analysis of allopolyploid formation and genomic dominance and expression in the B. hybridum-B. distachyon-B. stacei grass model complex.

Genetic Diversity of Egyptian Date Palms (Phoenix dactylifera L.) Using Morphological and Molecular Markers

Morphological and molecular analyses were conducted to evaluate the genetic diversity among eleven Egyptian date palms (Phoenix dactylifera L.). Ten SSR primer pairs revealed a high percentage of polymorphism (97.4%) among 38 total number of alleles, while 11 SCoT primers produced 48.5% from 171 amplified fragments. SCoTs recorded effective multiplex ratio (EMR) and PIC values of 7.5 and 0.14, respectively, opposing to 3.7 and 0.26 for SSRs, respectively. A similar marker index has thus resulted in both markers. Nei’s gene diversity (h) was generally low for both marker systems indicating homogeneous nature and narrow genetic background for the studied Egyptian date palms, which was also emphasized through their high genetic similarity estimates. The results of UPGMA cluster analysis and PCoA grouped the eleven date palms according to their geographical location and sex. In addition to classical morphological characters, the current study confirmed the importance of using SCoTs as functionally gene-based multi-loci markers besides nuclear SSR loci to assess the genetic variations and cultivar identification among Egyptian date palm genotypes

An inventory of the relic eurasian wild grapevine populational nuclei in huelva province (andalusia, Spain)

This paper is focused on 21 relic wild grapevine populations within province (SW Europe, Spain) prospected between 2015-2017. Position of each population along river-bank forests, types of flower of this dioecious subspecies and morphology of the pollen grains were described. Analyses of five microvinifications were carried out, which indicate that the color intensity of the wines is between 14.6 and 17.6 and the pH between 3.26-3.27, which are suitable values for red wines under Mediterranean climatology. A list of the accompanying vegetation and the cultivated varieties in the Condado de Huelva Registered Appellation Origin Mark were also included. Moreover, the genetic diversity of 23 vines was characterized using 25 nuclear SSR loci, the results showed a slightly higher diversity than the one found in Iberian cultivars. However, the observed heterozygosity was significantly lower than the expected one for wild populations in the province. The inbreeding depression in these wild grape populations is suggested by the positive F values. Therefore, the conservation of this unique germplasm collection should be part of the process of maintaining the genetic diversity in this gene pool, especially, taking into account that no particular legal figure of preservation exists in Spain.

Assessment of genetic diversity of some Siberian and Far Eastern species of the genus Spiraea (Rosaceae) by newly developed multiplex panels of nuclear SSR loci

Taxonomic and population genetic studies of the genus Spiraea (Rosaceae) species require new informative genetic markers. We screened 37 previously published heterologous oligonucleotide primer pairs for nuclear microsatellite loci and selected eight polymorphic and most reproducible of them for PCR multiplexing which substantially increases performance of routine mass genotyping. Three multiplex sets of 3, 3 and 2 loci, respectively, were developed and tested for ability to estimate the parameters of genetic variability and population structure in closely related species Spiraea ussuriensis, S. f lexuosa, S. chamaedryfolia representing seven natural populations of the Russian Far East and Siberia. Allele number ranged among loci from twelve (Spth20) to three. Among 41 alleles found, 7 were unique in some species/populations. Analysis of parameters of genetic variability in Spiraea spp. showed similar values of allele number per locus and observed heterozygosity among populations and slightly greater estimates of expected hete rozygosity in the samples of S. f lexuosa (NA = 2.387; HO = 0.387 ± ± 0.052; HE = 0.540 ± 0.055) as compared to S. ussuriensis (NA = = 2.781; HO = 0.385 ± 0.079; HE = 0.453 ± 0.072) and S. chamaedryfolia (NA = 2.875; HO = 0.331 ± 0.071; HE = 0.505 ± 0.069). The observed values of genetic polymorphism parameters indicate the average level of genetic diversity of the studied species typical to previous studies in Spiraea. About 19 % of the observed variability occurred among populations (FST = 0.191) while 81 % of the total genetic variation concentrated within the populations. The loci VS11, VS12, VS2, and VS6 contributed most to the observed differentiation. Nei genetic distances between populations ranged from 0.049 to 0.585. Genetic differentiation patterns among studied populations based on allele frequencies of nuclear microsatellite loci correspond with their geographical location. Genetic composition of some samples contradicted with their provisional species identification.

Morpho-genetic profiling and phylogenetic relationship of guava (Psidium guajava l.) as genetic resources in Pakistan

Abstract Guava (Psidium guajava L.) is an open-pollinated crop having 25-40% dissimilarity index which promotes heterozygosity and adds new cultivars. Morpho-genetic characterization of 37 guava accessions was carried out for genetic variability and structure of guava germplasm located in Punjab province, Pakistan. Principal Component analysis (PCA) was subjected to analyze the morphological diversity and for genetic analysis we applied cluster analysis, using the PyElph software. PCA distributed thirty one traits into six components and first two components accounted 39.5% of total variation. A dendrogram constructed on the basis of morphological traits which showed 34% dissimilarity index among thirty seven guava accessions and divided them into 6 groups. For genetic characterization 18 microsatellites were used, the size of reproducible and scorable bands ranged from 150 to 320 bp. The 18 primer pairs amplified 85 alleles with an average number of 4.7 alleles per locus and no more than two displayed bands (nuclear SSR loci). The phylogenetic tree based on molecular analysis showed 50% dissimilarity index among selected guava accessions and separated them into 4 groups.

Genetic structure of remnant black poplar (Populus nigra L.) populations along biggest rivers in Serbia assessed by SSR markers

AbstractBlack poplar (Populus nigra L.) is a keystone species of riparian softwood forests along riversides in vast areas of Europe, Western Asia and Northern Africa. Since the end of the 20thcentury, black poplar has been recognized as an endangered species throughout Europe due to the loss of its natural habitat and possible crossbreeding with hybrid poplars. Using twelve nuclear SSR loci, we analysed the genetic structure of four native populations from three river valleys in the northern part of Serbia. All tested loci were highly polymorphic, displaying 8 to 25 alleles per locus, overall 179 detected alleles and an average effective number of alleles 5.87. Observed heterozygosity (overall Ho = 0.703) has been lower than the expected (overallHe= 0.808) in each population, which indicates positive mean of fixation index values (overallFis> 0 (0.132)). An AMOVA analysis revealed that the highest degree of genetic variation occurred within populations (95.33 %) while the genetic variation between populations was really low (4.67 %). High gene flow and no significant loss of allelic diversity have been recorded in the studied populations in Serbia.

Multiple and mass introductions from limited origins: genetic diversity and structure of Solidago altissima in the native and invaded range.

Understanding the origins and diversity of invasive species can reveal introduction and invasion pathways, and inform an effective management of invasive species. Tall goldenrod, Solidago altissima, is a herbaceous perennial plant native to North America and it has become a widespread invasive weed in East Asian countries. We used microsatellite and chloroplast DNA markers to obtain information on neutral processes and on genetic diversity in native and invaded populations of S. altissima and to infer how it invaded and spread in Japan. We found that introduced (n = 12) and native (n = 20) populations had similar levels of genetic diversity at nuclear SSR loci. Genetic structure analysis indicated that at least two independent colonization events gave rise to current S. altissima populations in Japan. The majority (68%) of the Japanese S. altissima were genetically similar and likely shared a common origin from a single or a small number of populations from the southern USA populations, while the populations in Hokkaido were suggested to arise from a different source. Our results suggest that multiple and mass introductions have contributed to the persistence and rapid adaptation of S. altissima promoting its widespread establishment throughout Japan.

Combining conservative and variable markers to infer the evolutionary history of Prunus subgen. Amygdalus s.l. under domestication

The genus Prunus L. is large and economically important. However, phylogenetic relationships within Prunus at low taxonomic level, particularly in the subgenus Amygdalus L. s.l., remain poorly investigated. This paper attempts to document the evolutionary history of Amygdalus s.l. and establishes a temporal framework, by assembling molecular data from conservative and variable molecular markers. The nuclear s6pdh gene in combination with the plastid trnSG spacer are analyzed with bayesian and maximum likelihood methods. Since previous phylogenetic analysis with these markers lacked resolution, we additionally analyzed 13 nuclear SSR loci with the δµ2 distance, followed by an unweighted pair group method using arithmetic averages algorithm. Our phylogenetic analysis with both sequence and SSR loci confirms the split between sections Amygdalus and Persica, comprising almonds and peaches, respectively. This result is in agreement with biogeographic data showing that each of the two sections is naturally distributed on each side of the Central Asian Massif chain. Using coalescent based estimations, divergence times between the two sections strongly varied when considering sequence data only or combined with SSR. The sequence-only based estimate (5 million years ago) was congruent with the Central Asian Massif orogeny and subsequent climate change. Given the low level of differentiation within the two sections using both marker types, the utility of combining microsatellites and data sequences to address phylogenetic relationships at low taxonomic level within Amygdalus is discussed. The recent evolutionary histories of almond and peach are discussed in view of the domestication processes that arose in these two phenotypically-diverging gene pools: almonds and peaches were domesticated from the Amygdalus s.s. and Persica sections, respectively. Such economically important crops may serve as good model to study divergent domestication process in close genetic pool.

Molecular characterisation of Romanian grapevine cultivars using nuclear microsatellite markers.

In the present study we use six nuclear SSR loci (SS2, MD5, MD7, MD27, ZAG 62 and ZAG 79) to characterize four autochthonous grapevine cultivars (BAƒbeasca neagrAƒ, Feteasca regalCŽ, FrA¢ncuAŸa, and Grasa de Cotnari), including four international comparative genotypes (Cabernet Sauvignon, Chardonnay Blanc, Riesling Italian and Merlot Noir). The DNA microsatellite analysis was used to construct a barcode system. The advantage of this mode of grouping data is a visual representation of the number and size of alleles, allowing easy detection of genotypic differences between analysed cultivars. Our results shows that this system of data grouping can be useful for characterisation of Romanian cultivars at molecular level. The integration of such DNA barcodes into nationally and internationally coordinated databases could increase the accuracy with which grapevine genetic resources are managed in Romania.

Genetic structure of endangered wild grapevine Vitis vinifera ssp. sylvestris populations from Tunisia: Implications for conservation and management

Wild grapes, considered as the putative ancestor of the cultivated form, represent the only endemic taxon of the Vitaceae in Europe and the Maghreb. The species has become highly threatened because of habitat loss and intensive forest exploitation.In this work, we analyzed genetic aspects that could shed light on the evolution and conservation of wild grapes that still be found in forests along river banks in Tunisia. We examined the genetic structure of twenty populations using 10 nuclear SSR loci. Vitis sylvestris has a high level of genetic variation with 84.5% of the loci assayed being polymorphic, a mean number of alleles of 10.4, and a mean heterozygosity per population of 0.7546. We calculated Wright’s FST statistic to estimate gene flow indirectly and to evaluate whether or not there was genetic structuring among populations. We found a marked differentiation among populations according to FST values and clustering. AMOVA has shown that most of the variation was partitioned between rather than among populations. A significant pattern of isolation by distance was found which implies that each population would constitute a distinct pool of genetic variation that warrants conservation.Finally, the exponential curve of the relationship between genetic distances and demographic data strongly suggests that due to populations’ small sizes and fragmentation, V. sylvestris is actually at high risk of extinction in Tunisia. Therefore, all studied populations are valuable for conservation.

Multiple introductions and no loss of genetic diversity: invasion history of Japanese Rose, Rosa rugosa, in Europe

The shrub Rosa rugosa (Japanese Rose), native to East Asia, is considered one of the most troublesome invasive plant species in natural or semi- natural habitats of northern Europe and has proven very difficult to control. We aimed at disentangling the species' invasion history in Europe, including deter- mining the number of introductions and their geo- graphic origin, and at investigating whether populations in the introduced and native ranges differ in genetic diversity, structure and degree of differentiation. We found that introduced (n = 16) and native (n = 16) populations had similar levels of genetic diversity at seven nuclear SSR (microsatellite) loci. European populations lack isolation by distance and are less genetically differentiated than are populations in East Asia. Multiple and at least three independent coloniza- tion events, one of which was particularly successful, gave rise to current R. rugosa populations in Europe. The geographic distribution patterns of these three genetic clusters could not be explained by natural dispersal alone, indicating that human mediated sec- ondary dispersal is driving the expansion in Europe. One cluster representing three of the European popu- lations was most likely derived from NW Japan, whereas the origin of the remaining thirteen populations could not clearly be resolved. The introduction and expansion in Europe occurred with no significant loss of genetic diversity. We conclude that high propagule pressure at the primary establishment phase is the most parsimonious explanation for this pattern. A potential for long distance seed dispersal, coastal habitat con- nectivity and an outcrossing breeding system are factors likely to have enabled populations of R. rugosa to avoid detrimental effects of genetic bottlenecks and will further increase the species' range size and abundance in Europe. We recommend that human-mediated dis- persal should be prevented in order to halt the continued expansion.

Genetic diversity of wild grapevine populations in Spain and their genetic relationships with cultivated grapevines

The wild grapevine, Vitis vinifera L. ssp.sylvestris (Gmelin) Hegi, considered as the ancestor of the cultivated grapevine, is native from Eurasia. In Spain, natural populations of V.vinifera ssp.sylvestris can still be found along river banks. In this work, we have performed a wide search of wild grapevine populations in Spain and characterized the amount and distribution of their genetic diversity using 25 nuclear SSR loci. We have also analysed the possible coexistence in the natural habitat of wild grapevines with naturalized grapevine cultivars and rootstocks. In this way, phenotypic and genetic analyses identified 19% of the collected samples as derived from cultivated genotypes, being either naturalized cultivars or hybrid genotypes derived from spontaneous crosses between wild and cultivated grapevines. The genetic diversity of wild grapevine populations was similar than that observed in the cultivated group. The molecular analysis showed that cultivated germplasm and wild germplasm are genetically divergent with low level of introgression. Using a model-based approach implemented in the software structure, we identified four genetic groups, with two of them fundamentally represented among cultivated genotypes and two among wild accessions. The analyses of genetic relationships between wild and cultivated grapevines could suggest a genetic contribution of wild accessions from Spain to current Western cultivars.

Population genetic structure of Sagittaria natans (Alismataceae), an endangered species in China, revealed by nuclear SSR loci analyses

Abstract Sagittaria natans (Alismataceae) is an endangered aquatic herb in China. The nuclear microsatellite (SSR) loci variation of the 11 extant populations of S . natans was investigated in the present study. A relative high level of genetic diversity was found in this species. The Wilcoxon’s signed rank tests did not indicate a recent bottleneck in any of the populations. The Analysis of molecular variance (AMOVA) showed a low level of population differentiation ( F ST = 0.284) among the populations of S . natans . This result was supported by STRUCTURE analysis ( K = 1), the NJ analyses and Mantel test ( r = −0.0221, p > 0.5). The genetic structure could be contributed to an earlier period of more pronounced gene flow when the species had a more continuous distribution. The results of this study could be used as the basis for conservation guidelines for the management of this endangered species in China.

Genetic structure of island populations of Prunus lannesiana var. speciosa revealed by chloroplast DNA, AFLP and nuclear SSR loci analyses

The wild flowering cherry Prunus lannesiana var. speciosa is highly geographically restricted, being confined to the Izu Islands and neighboring peninsulas in Japan. In an attempt to elucidate how populations of this species have established we investigated the genetic diversity and differentiation in seven populations (sampling 408 individuals in total), using three kinds of genetic markers: chloroplast DNA (cpDNA), amplified fragment length polymorphisms (AFLPs), and 11 nuclear SSR polymorphic loci. Eight haplotypes were identified based on the cpDNA sequence variations, 64 polymorphic fragments were scored for the AFLP markers, and a total of 154 alleles were detected at the 11 nuclear SSR loci. Analysis of molecular variance showed that among-population variation accounted for 16.55, 15.04 and 7.45% of the total detected variation at the cpDNA, AFLPs, and SSR loci, respectively. Thus, variation within populations accounted for most of the genetic variance for all types of markers, although the genetic differentiation among populations was also highly significant. For cpDNA variation, no clear structure was found among the populations, except that of the most distant island, although an "isolation by distance" pattern was found for each marker. Both neighbor-joining trees and structure analysis indicate that the genetic relationships between populations reflect geological variations between the peninsula and the islands and among the islands. Furthermore, hybridization with related species may have affected the genetic structure, and some genetic introgression is likely to have occurred.

Genetic structure of Cerasus jamasakura, a Japanese flowering cherry, revealed by nuclear SSRs: implications for conservation

The genetic resources of a particular species of flowering cherry, Cerasus jamasakura, have high conservation priority because of its cultural, ecological and economic value in Japan. Therefore, the genetic structures of 12 natural populations of C. jamasakura were assessed using ten nuclear SSR loci. The population differentiation was relatively low (F (ST), 0.043), reflecting long-distance dispersal of seeds by animals and historical human activities. However, a neighbor-joining tree derived from the acquired data, spatial analysis of molecular variance and STRUCTURE analysis revealed that the populations could be divided into two groups: one located on Kyusyu Island and one on Honshu Island. Genetic diversity parameters such as allelic richness and gene diversity were significantly lower in the Kyushu group than the Honshu group. Furthermore, STRUCTURE analysis revealed that the two lineages were admixed in the western part of Honshu Island. Thus, although the phylogeographical structure of the species and hybridization dynamics among related species need to be evaluated in detail using several marker systems, the Kyusyu Island and Honshu Island populations should be considered as different conservation units, and the islands should be regarded as distinct seed transfer zones for C. jamasakura, especially when rapid assessments are required.

MOROCCAN FIG PRESENTS SPECIFIC GENETIC RESOURCES: A HIGH POTENTIAL OF LOCAL SELECTION

Abstract Molecular characterisation of Moroccan fig germplasm mainly originated from northern areas showed that cultivars are highly local. The few widespread denominations correspond to several distinct genotypes. The lack of widespread homogenous cultivars suggests a local fig selection process and hence local domestication. Were fig natural populations present in the region before domestication? Mitochondrial DNA RFLP data showed that Mediterranean fig populations are structured into three groups: Balearic, West and East Mediterranean. The low genetic diversity and the strong differentiation of Balearic populations support the ancient origin hypothesis and the presence of natural populations in the western Mediterranean region before domestication. Analysis of western populations using nuclear SSR loci showed genetic structuring at the regional scale (South France, Corsica, Balearic islands and northern Morocco) but also at the local scale (Tetouan – Beni Hassan and Akchour – Mokrisset). This study indicates that Moroccan fig populations may constitute indigenous gene pools for fig cultivar selection. Clonal diversity, ancient cultivation, indigenous gene pool and genetic structuring at a local scale suggest a high potential for local selection of cultivars. INTRODUCTION