Genetic structure of introduced European fallow deer (<Emphasis Type="Italic">Dama dama dama</Emphasis>) in Tasmania,Australia

European fallow deer are an introduced species classified as partly protected wildlife in Tasmania, Australia. Current management practices are primarily governed under the Quality Deer Management regime, in which animals are harvested during designated hunting seasons. Among populations, prominent morphological differences have been reported; however, the genetic relationship of these populations has until now been poorly understood. Representative animals were sampled from three key areas across their range and genotyped at ten polymorphic microsatellite loci to investigate genetic diversity, population structure, and genetic bottlenecks. Allelic richness was low in all three populations and ranged between 2.20 and 2.49 alleles/locus. A genetic bottleneck was detected in two of the three populations (P < 0.001). Population differentiation was evident between Lake Echo and Benham (q = 0.122; P < 0.001) and Benham and Connorville (q = 0.110; P < 0.001), but not between Lake Echo and Connorville (q = 0.0235), with individuals being identified as belonging to two genetic clusters. The pattern of population differentiation from the three study populations suggests that deer from the western region of their range are genetically distinct to those from the eastern region. This correlates with morphological variation within Tasmanian fallow deer, in which differences between the regions maybe attributable to geographical barriers.     

Genetic Diversity and Geographical Differentiation of <Emphasis Type="Italic">Desmodium triflorum</Emphasis> (L.) DC. in South China Revealed by AFLP Markers

High levels of genetic variation enable species to adapt to changing environments and provide plant breeders with the raw materials necessary for artificial selection. In the present study, six AFLP primer pairs were used to assess the genetic diversity of Desmodium triflorum (L.) DC. from 12 populations in South China. A high percentage of polymorphic loci (P = 76.16%) and high total gene diversity (H _T = 0.310) were found, indicating that the genetic diversity of D. triflorum is high at the species level. Genetic diversity was also relatively high at the population level (P = 55.85%, H _e = 0.230). The coefficient of gene differentiation among populations (G _ST) was 0.255, indicating that while most genetic diversity resided within populations, there was also considerable differentiation among populations. AMOVA also indicated 24.29% of the total variation to be partitioned among populations (Φ_ST = 0.243). UPGMA clustering analysis based on genetic distances showed that the 12 populations could be separated into three subgroups: an eastern, a western, and a central-southern subgroup. However, a Mantel test revealed no significant correlation (r = 0.286, p = 0.983) between the geographical distances and genetic distances separating these populations; mountain barriers to gene flow and human disturbance may have confounded these correlations. The present study has provided some fundamental genetic data that will be of use in the exploitation of D. triflorum.     

Genetic variability and structure of the remnant natural populations of <Emphasis Type="Italic">Cedrus libani</Emphasis> (Pinaceae) of Lebanon

Cedrus libani of Lebanon is a valuable natural resource and the dominant species in its natural ecosystem. Intense and diverse anthropogenic pressures over historical times raised concerns about its genetic vigor and continued survival. Our investigation of the genetic diversity included samples from all remnant natural populations. Assessment of the genetic diversity using random amplified polymorphic DNA markers revealed the persistence of considerable variation distributed within populations with low population differentiation corroborated by Bayesian and analysis of molecular variance estimates (G _ST = 0.07, Φ _ST = 0.09). Individual assignment tests were carried out to investigate measures of gene flow. Inferences concluded that this natural heritage is not currently threatened by inbreeding or by random genetic drift. Correlation studies investigated possible effects of spatial distribution and environmental conditions on genetic structure. A climatic trend corresponding to a temperature–humidity gradient correlated significantly with the level of genetic diversity, while the edaphic variation did not.     

Local genetic differentiation in Proteopsis argentea (Asteraceae), a perennial herb endemic in Brazil

 Proteopsis argentea (Asteraceae, Vernonieae) is a perennial herb endemic to the “campos rupestres” of the Espinha?o Range in Minas Gerais, Brazil, with fragmented populational distribution. Eleven populations were sampled, throughout the entire distribution of the species, and assayed for isozyme variation. Low intra-population genetic diversity was found (P = 19.2; A = 1.30; He = 0.058) whereas species level diversity was higher (P = 55.5, A = 2.0, He = 0.093). The most geographically isolated population showed exclusive alleles at two loci, whereas two populations less than 2 km apart from each other showed inverted frequencies for two alleles. Mean genetic identity was high (I = 0.974), but the large Fst (0.30) indicates that the species could lose an important part of its genetic variation with the extinction of a single population. Our findings indicate that geographic isolation alone cannot explain population differentiation: localized pollinator behaviour and selection, for example, may be contributing to the patterns observed. Received February 18, 2000 Accepted November 1, 2000     

Population Genetic Structure of the Endangered <Emphasis Type="Italic">Brasenia schreberi</Emphasis> in South Korea Based on Nuclear Ribosomal Spacer and Chloroplast DNA Sequences

Genetic variation of nuclear ribosomal ITS (nrITS) and chloroplast DNA (cpDNA) regions was investigated in Brasenia schreberi (Cabombaceae) to assess the population structure and to infer the evolutionary relationship among 12 populations distributed in South Korea. The combined sequence of the two regions was aligned to 2,069 bp, of which 28 sites were variable. In total, 20 genotypes were identified from 240 individuals of B. schreberi. Genotype diversity (Gd) and nucleotide diversity (Pi) on Jeju Island (Gd = 0.2511, Pi = 0.00012) were higher than those of the mainland of South Korea (Gd = 0.1358, Pi = 0.00005). The relatively low level of genetic variation of the mainland populations is associated with its higher genetic differentiation (G _ST = 0.095 on mainland and 0.039 on Jeju Island) and human activities. Minimum spanning network analysis demonstrated that the investigated populations of B. schreberi were subdivided into two geographical groups: the mainland of South Korea and Jeju Island. In addition, analysis of molecular variation showed that a large proportion (73.55%) of genetic differentiation existed between the two regions. These results strongly suggest the presence of significant barriers to gene flow between regions. Thus, the management unit for B. schreberi should be carefully designed to avoid the potential risk that can results from the admixture of individuals from the mainland and Jeju Island regions.     

Mitochondrial DNA reveals low population differentiation in elongate loach, <Emphasis Type="Italic">Leptobotia elongata</Emphasis> (Bleeker): implications for conservation

Elongate loach (Leptobotia elongata (Bleeker)), an endemic fish species to China, is a famous ornamental freshwater fish. Here, a comparative study of mtDNA control region (D-loop) (835 bp) sequences was performed to analyze its wild population structure and evaluate the genetic diversity for 110 individuals from five locations in the upper reaches of the Yangtze River, China. A total of 49 polymorphic sites and 45 haplotypes yielded high haplotype diversity (h = 0.952), but low nucleotide diversity (π = 0.00454) as that of many fish species. Sequence divergences between haplotypes ranged from 0.0033 ± 0.0011 to 0.0050 ± 0.0012 in intra-groups, and from 0.0037 ± 0.0.0011 to 0.0050 ± 0.0012 between groups. Significant values of Tajima’s D (−1.86383, P < 0.01) and Fu’s F _S (−25.93, P < 0.01), together with uni-modal mismatch distribution, indicated a recent genetic bottleneck or population expansion of the species. Analysis of molecular variance (AMOVA) indicated a small amount of differentiation among groups (1.7%); most of the total variation occurred within groups (98.3%). Also, there was no significant population structure (F _ST = 0.017, P > 0.05), and estimates of gene flows among groups were extremely high (Nm = 28.88), suggesting low genetic divergence between populations in the species. The lack of genetic differentiation among groups is most likely due to the combined gene flow from the downstream movement of eggs and larvae with currents and the upstream or downstream migration of adults throughout the distribution. These groups of L. elongata distributed in upper reaches of the Yangtze River should be considered as a single management unit.     

Genetic structure analysis of natural <Emphasis Type="Italic">Sargassum muticum</Emphasis> (Fucales,Phaeophyta) populations using RAPD and ISSR markers

Sargassum muticum is important in maintaining the structure and function of littoral ecosystems, and is used in aquaculture and alginate production, however, little is known about its population genetic attributes. In this study, random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers were used to investigate the genetic structure of four populations of S. muticum and one outgroup of S. fusiforme (Harv.) Setchell from Shandong peninsula of China. The selected 24 RAPD primers and 19 ISSR primers amplified 164 loci and 122 loci, respectively. Estimates of genetic diversity with different indicators (P%, percentage of polymorphic loci; H, the expected heterozygosity; I, Shannon’s information index) revealed low or moderate level of genetic variations within each S. muticum population, and a high level of genetic differentiations were determined with pairwise unbiased genetic distance (D) and fixation index (F _ST ) among the populations. The Mantel test showed that two types of matrices of D and F _ST were highly correlated whether from RAPD (r = 0.9706, P = 0.009) or ISSR data (r = 0.9161, P = 0.009). Analysis of molecular variance (AMOVA) was conducted to apportion the variations among and within the S. muticum populations. It indicated that variations among populations were higher than those within populations, being 55.82% verse 44.18% by RAPD and 55.21% verse 44.79% by ISSR, respectively. Furthermore, the Mantel test suggested that genetic differentiations among populations were related to the geographical distances (r > 0.6), namely, conformed to the IBD (isolation by distance) model, as expected from UPGMA (unweighted pair group method with arithmetic averages) cluster analysis. On the whole, the high genetic structuring among the four S. muticum populations along the distant locations was clearly indicated in RAPD and ISSR analyses (r > 0.9, P < 0.05) in our study.     

Karyology and cytotaxonomy of the genus Passiflora L. (Passifloraceae)

 The chromosomes of 31 species of Passiflora, distributed throughout the subgenera Astrophea, Calopathanthus, Distephana, Dysosmia, Passiflora, Plectostemma and Tacsonia were analysed. Three different karyotypes were observed: 2n = 12, 24, 36; 2n = 18, 72 and 2n = 20. The karyotype of these species was almost always constituted of metacentric and submetacentric chromosomes with variable karyotype symmetry. In the group with x = 6, represented by the subgenus Plectostemma, six diploid species with 2n = 12, one tetraploid with 2n = 24 (P. suberosa) and an intraspecific polyploid with 2n = 12, 36 (P. misera) were analysed. P. pentagona (subgenus Astrophea) may also be included in this karyological group since it presents 2n = 24 and may be of polyploid origin, with x = 6. The interphase nuclei in this group were areticulate, except those of P. morifolia and P. pentagona with semi-reticulate characteristics. Two small terminal heterochromatic blocks, positive for chromomycin A₃, were identified in the largest chromosome pair of P. capsularis and P. rubra, species very closely related, while P. tricuspis displayed four chromosomes with proximal blocks. In the group with x = 9, represented mainly by subgenus Passiflora, 20 species with 2n = 18 and one with 2n = 72 were studied. They presented chromosomes larger than those species with x = 6 and interphase nuclei of semi-reticulate type, except for P. mixta with areticulate nuclei. Four terminal CMA⁺ blocks were observed in P. edulis, six blocks in P. caerulea and P. racemosa, while five blocks were observed in the single P. amethystina plant analysed. P. foetida (subgenus Dysosmia), the only species with 2n = 20, exhibited six chromosomes with CMA⁺ blocks and interphase nuclei of the areticulate type. The meiotic analysis of representatives of the three groups (P. foetida, P. suberosa, P. cincinnata and P. racemosa) always presented regular pairing and regular chromosome segregation, except in P. jilekii where a tetravalent was observed. The analysis of the chromosome variation within the genus and the family suggests that the base number of Passiflora may be x₁ = 6 or x₁ = 12, whereas x₂ = 9 is only an important secondary base number. Received April 11, 2000 Accepted October 5, 2000     

Maintenance of genetic diversity in Cordia africana Lam., a declining forest tree species in Ethiopia

We assessed genetic variation in a total of 22 populations of the tree species Cordia africana Lam. in Ethiopia and analyzed the country-wide impact of population history, forest disturbance and alteration of land use on extant intraspecific diversity. Amplified Fragment Length Polymorphisms (AFLPs) and chloroplast microsatellite markers were investigated. The analyses of the AFLP data revealed high diversity in all investigated populations: the percentage of polymorphic loci (PPL) ranged from 62.2% to 92.2% and Nei's gene diversity from 0.220 to 0.320 within the populations. The mean PPL and the mean diversity within populations were 85.7% and 0.287, respectively. The analysis of molecular variance revealed a moderate level of differentiation (Φ_ST = 0.07, p < 0.001) among the populations. The Mantel test proved a significant but low correlation (r = 0.31, p < 0.001) between the geographic distance and the genetic differentiation matrices. Only three different cpDNA haplotypes were observed; no more than two haplotypes were found in any population. The dominant haplotype with an overall frequency of 81% was observed in all populations. The level of differentiation among the populations was comparatively low at chloroplast DNA (G _ST = 0.18, R _ST, N _ST = 0.22). The observed patterns and levels of genetic variation within and among the populations indicate that efficient gene flow via pollen and seed is likely to be the main factor contributing to the maintenance of genetic diversity in natural and disturbed conditions.     

Population genetic structure of <Emphasis Type="Italic">Sargassum thunbergii</Emphasis> (Fucales,Phaeophyta) detected by RAPD and ISSR markers

Genetic variation of four populations of Sargassum thunbergii (Mert.) O. Kuntze and one outgroup of S. fusiforme (Harv.) Setchell from Shandong peninsula of China was studied with random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) markers. A total of 28 RAPD primers and 19 ISSR primers were amplified, showing 174 loci and 125 loci, respectively. Calculation of genetic diversity with different indicators (P%, percentage of polymorphic loci; H, the expected heterozygosity; I, Shannon’s information index) revealed low or moderate levels of genetic variations within each S. thunbergii population. High genetic differentiations were determined with pairwise Nei’s unbiased genetic distance (D) and fixation index (F _ST ) between the populations. The Mantel test showed that two types of matrices of D and F _ST were highly correlated, whether from RAPD or ISSR data, r = 0.9310 (P  = 0.008) and 0.9313 (P = 0.009) respectively. Analysis of molecular variance (AMOVA) was used to apportion the variations between and within the S. thunbergii populations. It indicated that the variations among populations were higher than those within populations, being 57.57% versus 42.43% by RAPD and 59.52% versus 40.08% by ISSR, respectively. Furthermore, the Mantel test suggested that the genetic differentiations between the four populations were related to the geographical distances (r > 0.5), i.e., they conformed to the IBD (isolation by distance) model, as expected from UPGMA (unweighted pair group method with arithmetic averages) cluster analysis. As a whole, the high genetic structuring between the four S. thunbergii populations along distant locations was clearly indicated in the RAPD and ISSR analyses (r > 0.8) in our study.     

Wild genetic diversity preservation in a small-sized first generation breeding population of <Emphasis Type="Italic">Allanblackia floribunda</Emphasis> (Clusiaceae)

Founder group size is of prime importance in tree breeding programs. We determined whether sampling 20-plus trees for breeding in Allanblackia floribunda, a tropical forest tree species that has been recently enrolled in tree improvement program for fruit and seed production, would affect neutral genetic diversity and inbreeding level in both breeding and production populations. Using eight informative microsatellite loci, we: (a) assessed the nuclear genetic diversity of ten natural populations, and of the breeding population in the humid forest zone of Cameroon; (b) investigated temporal effective-size fluctuations in A. floribunda natural populations, with a view to identifying the role of past demographic events in the genetic structure of the studied species; and (c) tested the hypothesis that genetic diversity in a founder group of 20 individuals is not different from that existing in the wild. The eight loci were variable. High levels of genetic diversity (A = 4.96; H _E = 0.59) and moderate differentiation (R _ST = 0.061) were found within and among populations in wild stands. High genetic distances existed between populations ( \textaverage chord distance = 0.\text2769 ±0.00\text554 ) \left( {{\text{average chord distance}} = 0.{\text{2769}} \pm 0.00{\text{554}}} \right) . Eight of the ten surveyed populations showed signs of deviation from mutation-drift equilibrium, suggesting Pleistocene population bottlenecks and fluctuations in effective population size. Mantel tests did not reveal any relationships between genetic and geographic distances. A neighbor-joining dendrogram showed a population structure that could be explained by historical factors. The hypothesis tested has been accepted. However, a slight increase in inbreeding was observed in the breeding population.     

Genetic diversity and population differentiation in the endangered Siberian flying squirrel (<Emphasis Type="Italic">Pteromys volans</Emphasis>) in a fragmented landscape

Siberian flying squirrel (Pteromys volans) has declined in Finland and it is considered an endangered species. We studied microsatellite variation in four flying squirrel populations in a fragmented landscape in Finland to determine the amount of gene flow and genetic diversity in the populations. Demographic data from these areas suggest that the populations are declining. All the populations are significantly differentiated (F _ST = 0.23). The most notable result is the high degree of differentiation between two adjacent populations (F _ST = 0.11) and low genetic variability (number of alleles 3.0) in one of the populations. These findings suggest problems in dispersal and possible fragmentation effects in the landscape where only 10–20% of habitat favorable for the flying squirrel is left. Conservation ensuring dispersal should be urgently considered. Future studies should concentrate on the modeling of the population viability and on the effects of inbreeding in these small populations. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Chromosome numbers are not fixed in Agaonidae (Hymenoptera: Chalcidoidea)

Agaonidae (the pollinators of fig trees, Ficus spp., Moraceae) are a distinctive family of chalcid wasps with uncertain affinities within the Chalcidoidea. Chromosome numbers have only been described previously for one species (Blastophaga psenes, 2n = 12, the pollinator of F. carica, of subgenus Ficus). In this paper, we used a modified technique to analyze the karyology of three Ceratosolen species, Ceratosolen solmsi, C. graveli and C. emarginatus which are associated with figs of Ficus subgenus Sycomorus. Their karyotypes are 2n = 10. All the chromosomes are metacentric (NF = 20) with little difference in relative lengths, making them hard to distinguish. The variation in chromosome numbers that we have detected suggests that karyology can usefully complement molecular-based studies of the phylogeny of fig wasps.     

Observations on the division characterization of diploid nuclear in <Emphasis Type="Italic">Porphyra</Emphasis> (Bangiales,Rhodophyta)

Nuclear divisions of carpospores, conchocelis and conchospores of Porphyra yezoensis, P. haitanensis, P. katadai var. hemiphylla and P. oligospermatangia from China were investigated. The observations showed diploid chromosome numbers of 2n = 6 for P. yezoensis and P. oligospermatangia, and 2n = 10 for P. haitanensis and P. katadai var. hemiphylla. For all four species, somatic pairing of chromosome sets was observed in late prophase. Sister chromosomes separated at anaphase as mitosis took place in carpospores, conchocelis filamentous cells, conchosporangial branch cells and sporangial cells (conchospore formation). Chromosome configurations of tetrad and ring-shaped in conchospore germination were observed, demonstrating the occurrence of meiosis. The characteristics of diploid nuclear division in 2n = 6 species are the same as those of 2n = 10 species. The influence of somatic pairing on nuclear division of diploid cells in Porphyra was discussed.     

A rapid PCR-based diagnostic test for the identification of subspecies of <Emphasis Type="Italic">Acacia saligna</Emphasis>

Subspecific taxa of species complexes can display cryptic morphological variation, and individuals and populations can often be difficult to identify with certainty. However, accurate population identification is required for comprehensive conservation and breeding strategies and for studies of invasiveness and gene flow. Using five informative microsatellite markers and a Bayesian statistical approach, we developed an efficient polymerase chain reaction-based diagnostic tool for the rapid identification of individuals and populations of the Acacia saligna species complex of Western Australia. We genotyped 189 individuals from 14 reference populations previously characterised based on morphology and used these data to investigate population structure in the species complex. High total genetic diversity (H _T = 0.729) and high population differentiation (θ = 0.355) indicated strong intraspecific structuring. With the provision of prior population information, the reference data set was optimally resolved into four clusters, each corresponding to one of the four main proposed subspecies, with very high membership values (Q > 97%). The reference data set was then used to assign individuals and test populations to one of the four subspecies. Assignment was unequivocal for all test individuals from two populations of subsp. lindleyi and for all but one individual of subsp. stolonifera. Individuals from populations of subsp. saligna and subsp. pruinescens showed a degree of genetic affinity for the two subspecies in their assignments, although the majority of individuals were correctly assigned to subspecies. The diagnostic tool will assist in characterising populations of A. saligna, especially naturalised and invasive populations of unknown origin.     

Effects of population size on genetic diversity and seed production in the rare <Emphasis Type="Italic">Dictamnus albus</Emphasis>(Rutaceae) in central Germany

It is widely assumed that population size significantly affects the dynamics of plant populations. Smaller populations are threatened by genetic drift and inbreeding depression, both of which may result in a decrease of genetic variation and a resulting negative impact on plant fitness. In our study we analysed the patterns of random amplified polymorphic DNA (RAPD) variation among 10 Dictamnus albuspopulations of varying size. The aim was to examine local differentiation in relation to spatial isolation resulting from limited population size and geographical distancing between populations. Significant correlations were noted between population size and both percentage of polymorphic loci (P <0.01) and genetic diversity (P<0.01). The matrix correlation between genetic and geographical distances revealed that geographical differentiation was reflected in the RAPD profile (Mantel test: r²=0.34, P<0.001). We found the highest level of molecular variance of RAPD patterns among individuals within the populations (72.6%), whereas among-population variation accounted for only 21.6% of variation. These results were highly significant in that they indicated a restricted population differentiation, as would be expected from outcrossing species. An additional analysis of seed production showed that there was significant variation among populations in terms of mean seed number per flower and mean seed mass per population which could be attributed to differences in population size as well as levels of genetic variation.     

Impact of Mapped SSR Markers on the Genetic Diversity of Apricot (<Emphasis Type="Italic">Prunus armeniaca</Emphasis> L.) in Tunisia

The impact of mapped microsatellites on the study of genetic diversity of Tunisian apricot accessions was assessed. The genetic variability of 47 traditional apricot cultivars originating from several areas in Tunisia was investigated with 32 polymorphic microsatellite loci selected for their location throughout the eight linkage groups of Prunus genome. The higher polymorphism and greater transportability of these markers among Prunus species were proved by the expected heterozygosity (He = 0.56) and Shannon’s index of diversity (I = 1.05), indicating that Tunisian apricot germplasm maintained a substantial level of genetic diversity. According to their geographical origin, the genetic differentiation among groups (north, center, and south; Fst = 0.04) was lower, while the gene flow among groups was consequent (Nm = 4.79), attesting a narrow genetic background of apricot in the country. Both unweighted pair-group method with arithmetic mean dendrogram, based on Nei’s genetic distances and factorial correspondence analysis, separated northern cultivars from central and southern cultivars, revealing the same molecular basis of apricot material in the Center and the South of Tunisia. These results revealed the efficiency of mapped markers for genetic variability measurements compared to randomly ones, however, no advantage was observed considering the genetic relationships among studied accessions.     

A new karyotype for <Emphasis Type="Italic">Cavia magna</Emphasis> (Rodentia: Caviidae) from an estuarine island and <Emphasis Type="Italic">C. aperea</Emphasis> from adjacent mainland

We describe a new karyotype for Cavia magna Ximenez, 1980 from an estuarine island and the karyotype of Cavia aperea Erxleben, 1777 from an adjacent mainland. The species have differences in diploid number (2n), autosomal fundamental number, quantity, and distribution of heterochromatin as dissimilar distributions of the nucleolus-organizing regions (Ag-NORs). The C. aperea karyotype has a diploid number of 64 as previously reported for C. aperea and most other Cavia species. In contrast, this new C. magna karyotype exhibits a variant diploid number of 2n = 62, considering that previous work reported a karyotype of 2n = 64 for C. magna. The discovery of a distinct diploid number within C. magna represents the first record of intra-specific chromosomal variation in a species of Caviidae. The diploid number of 2n = 62, heterochromatin quantity, Ag-NOR distributions, and inversed X chromosome from this population of C. magna are as seen in the geographically proximate (Cavia intermedia Cherem Olimpio and Ximenez; intermediate Cavy). These data provide further evidence supporting C. magna as the sister species of C. intermedia.     

Development of informative genic SSR markers for genetic diversity analysis of Picrorhiza kurroa

Picrorhiza kurroa is a medicinal perennial herb of economic importance due to its hepatoprotective properties mainly accounted by picroside I and picroside II. To fulfill the current demand of the market indiscriminate collection from its natural habitat pose a great threat to this endangered species. To strategize the conservation of natural populations, a set of 20 highly informative novel genic SSR markers were identified. The utility of these makers was successfully tested for the genetic diversity characterization of P. kurroa populations (n = 28) from three geographical locations. These markers produced 136 alleles (average of 6.8) with mean observed heterozygosity, expected heterozygosity, Shannon’s information index, and PIC value of 0.971, 0.798, 1.681, and 0.737 respectively, revealing a higher extent of genetic diversity in P. kurroa. Further, clustering of all the individuals according to their geographical locations indicates at a spatial population structure in P. kurroa. The current study suggests that informative SSR makers identified here can be potentially used for diversity characterization targeting wider geographical locations for selection of elite/quality genotypes for commercial cultivation and genetic rescue of this endangered species.     

High levels of genetic divergence and inbreeding in populations of cupuassu (Theobroma grandiflorum)

Theobroma grandiflorum (cupuassu) is an important fruit tree native to the Brazilian Amazon. Establishing the genetic diversity and structure of populations is critical to define long-term strategies for cupuassu conservation presently threatened by rapid deforestation. Three natural populations collected at the putative center of diversity, three groups of accessions established at a germplasm collection, and one derived from commercial plantings were analyzed. The genetic diversity was assessed using 21 polymorphic microsatellite loci originally developed for Theobroma cacao, disclosing a total of 113 alleles. The estimated genetic diversity parameters averaged over cupuassu populations (A = 3.53 alleles per locus; H _e = 0.426; H _o = 0.346) were lower than the values reported for other Neotropical tree species. The three natural populations presented a positive and significant fixation index (f), ranging from 0.133 to 0.234. Cupuassu apparently adhered to a general pattern of genetic diversity structure of some Neotropical tree species occurring at low densities, with a low intrapopulation genetic diversity and important levels of endogamy, possibly due to biparental inbreeding derived from the presence of spatial genetic structure in the populations. A high level of genetic divergence was detected among the natural populations (θ _p = 0.301), a strong differentiation caused by limited gene flow, and suggesting that human interference in spreading and/or stimulating plantings might have had a smaller effect than expected. The approximate location of the T. grandiflorum center of diversity could not be confirmed by analyzing natural populations from the putative region.