Moderate Genetic Diversity Research Articles

Coping With Dynamism: Phylogenetics and Phylogeographic Analyses Reveal Cryptic Diversity in Heleobia Snails of Atacama Saltpan, Chile

The species that inhabit systems highly affected by anthropic activities usually exhibit this external influence in their gene pool. In this study, we investigated the genetic patterns of populations of Heleobia atacamensis, a freshwater microgastropod endemic to the Atacama Saltpan, a system historically exposed to environmental changes, and currently subjected to conditions associated with metallic and non-metallic mining and other anthropic activities. Molecular analyses based on nuclear and mitochondrial sequences indicate that the saltpan populations are highly fragmented and that the genetic structure is mainly explained by historical geographic isolation, with little influence of contemporary factors. The microsatellite results suggest a moderate genetic diversity and sharp differentiation mediated by isolation by distance. Additionally, despite the high environmental heterogeneity detected and the marked historical dynamism of the region, our data reveal no signs of demographic instability. The patterns of contemporary gene flow suggest a change in the current genetic structure, based on the geographic proximity and specific environmental conditions for each population. Our results, highlight the role of fragmentation as a modulator of genetic diversity, but also suggest that the historical persistence of isolated populations in naturally dynamic environments could explain the apparent demographic stability detected.

Genetic variation and population structure analysis of Leymus chinensis (Trin.) Tzvelev from Eurasian steppes using SSR makers

Leymus chinensis (Trin.) Tzvelev is an important perennial grass species extensively dispersed in the typical grassland communities of the Eurasian steppe region. It is relished by livestock due to its high quality and being a nutritionally valuable forage crop. L. chinensis has recently gained extensive consideration on its genetic diversity. However, genetic diversity studies on L. chinensis using SSR markers is currently limited. In the present study, we investigate the genetic variation and population structure analysis of L. chinensis from Eurasian steppes using SSR makers. For the genetic diversity, nineteen SSR markers were used and a total of 133 alleles were identified across the 166 L. chinensis plants. Our findings illustrated that the polymorphic rate for all SSR markers was greater than 80%, with the exception of SSR12i and SSR6c, which had polymorphism rates of 50% and 75%, respectively. The gene diversity (H) ranged from 0.0545 for SSR12i to 0.4720 for SSR25v, and the average was 0.3136. Furthermore, genetic diversity analysis indicated that the 166 samples could be grouped into five main population clusters based on their maximum membership coefficients which were assigned as Pop1 to Pop5. Among the five populations, the largest values of allele (total number of detected alleles), Ne (effective number of alleles) and Na (observed mean number of alleles) was found to be higher in Pop1, with values of 61, 1.461, and 1.977, respectively. Additionally, AMOVA showed that 13% of the total genetic variation occurred among the population and 87% genetic variation within the populations of the species. Whereas, the pairwise Fst specified the moderate genetic variation ranging from 0.0336 to 0.0731. Finally, the principal coordinate analysis revealed that the x-axis and y-axis explained 5.72% and 4.86% of the variation in molecular data, respectively. Taken together, these SSR markers provide new insights for a more precise understanding of the genetic diversity of L. chinensis germplasm and could potentially enhance the breeding program of L. chinensis.

A genetic analysis of grey squirrel (Sciurus carolinensis) populations in Ireland

The grey squirrel (Sciurus carolinensis) is an invasive rodent in Ireland that has had detrimental impacts on the native Irish red squirrel (S. vulgaris) as well as on silviculture. This invasive species spread rapidly throughout Ireland, but in recent years appears to be declining in certain areas of the country. This study analysed the genetic profile of grey squirrel populations in Ireland to gain insight into their introduction, evolutionary history in Ireland, and vulnerability to management strategies. The genetic diversity and population structure of eight grey squirrel populations in Ireland was assessed using 11 species-specific microsatellite loci, and was compared to a small population from Tennessee, U.S.A., part of the native range of the grey squirrel. This is the first time these microsatellite markers developed specifically for grey squirrels have been used to study the species in Ireland. We found low to moderate genetic diversity overall across Irish populations as well as the presence of inbreeding. One population in particular, (in Co. Kildare), was differentiated from all other populations, which could indicate genetic isolation between Irish populations or a secondary introduction of S. carolinensis to Ireland.

Gamma Irradiation Induced High Yield Mutant Genotype Samosir Local Shallot in the Third Generation

The gamma irradiation can promote the agronomic characters of plant. This study aims to obtain putative mutant genotype of the 3rd generation Samosir local shallot (M1V3), which highly yields. The study used the augmented design in which 8 mutant genotypes of Samosir local shallot from the 2nd generation after gamma (γ)-ray treatment were planted along with untreated. The differences between the irradiation plants and untreated were tested by t-test: Similarity distance and dendrogram were analyzed using the hierarchical cluster. The results showed that almost all the mean values made by all quantitative agronomic character changes in the M1V3 populations were higher than those made in M1V2. The expected high heritability value with a broad coefficient of genetic diversity was found in the character of fresh and dried bulb’s weight resulted from genotype populations treated with γ rays irradiation with doses 3, 4 and 5 Gy. High heritability values were also found in the fresh weight and dry weight of bulb in genotype populations treated with doses 1 and 2 Gy with moderate genetic diversity coefficients. Selection based on the dried bulb’s weight from each mutant genotype population with a selection intensity of 30 % was obtained 39 genotypes that showed the highest selection index. The highest number of genotypes were selected from the application of γ-rays with a dose of 1 to 2 Gy, each of 10 genotypes. Therefore, application at the dose of 1 - 2 Gy in M1V3-generation for Samosir local shallot can still improve the yielding character through breeding to archive shallot in national.
 HIGHLIGHTS
 
 The low doses (1 to 5 Gy) of gamma rays increased the growth and yield of shallots in the third generation
 The dose at 2 Gy of gamma ray resulted in the highest plant length, number of tillers, number of bulbs, fresh- and dry weight of bulbs in mutant M1V3 of Samosir local shallot
 The results found that 38 of 39 shallot mutants had greater characters compared to the control
 The application of 1 - 2 Gy gamma rays on local shallots in the third generation can be used as an effort to increase the yield character
 
 GRAPHICAL ABSTRACT

Diversity of Tidal Swamp Rice (Oryza sativa) Cultivars Indigenously from South Kalimantan, Indonesia

Studies on genetic diversity and relationships are necessary for breeders and scientists to increase the effectiveness of future breeding programs. The tidal swamp rice (Oryza sativa L.) is one of the potential germplasms which has a prominent opportunity to be incorporated in the rice breeding program. This study aimed to investigate and reveal the genetic diversity and relationship of tidal swamp rice germplasms indigenously from South Kalimantan, Indonesia, using Random Amplified Polymorphic DNA (RAPD) markers. A total of ten rice samples, consisting of nine from this region and one from South Sumatera (an outgroup), and five selected RAPD markers, i.e., OPB-06, OPAJ-01, OPAB-17, OPAL-09, and OPAL-08, were used in this study. DNA amplifications were performed and programmed for one cycle of initial denaturation (5 min, 94ºC), 45 cycles of denaturation (30 sec, 94ºC), annealing (30 sec, 37ºC), and extension (1.5 min, 72ºC), as well as one cycle of final extension (7 min, 72ºC). The genetic similarity was analyzed using Dice’s coefficient method, whereas their relationship (dendrogram) by the UPGMA. The results showed that these germplasms have a moderate genetic diversity level, indicated by the polymorphism degree of 75.64%. The clustering analysis revealed that they are grouped into three main groups at a similarity coefficient of 0.70. In this case, Siam Unus is distantly related to the other cultivars and forms a solitaire group. Siam Unus also shows the farthest relationship with Sardani, an outgroup. It is a new finding for the genetic insight of tidal swamp rice of South Kalimantan, Indonesia, including their diversity and relationship. Thus, the results obtained from this study is useful in supporting future rice conservation and breeding programs.

Genetic Diversity and Population Genetic Structure of Setosphaeria turcica From Sorghum in Three Provinces of China Using Single Nucleotide Polymorphism Markers.

Setosphaeria turcica is a heterothallic fungus that is the causal agent of northern leaf blight (NLB), which is a devastating foliar disease of sorghum and maize. Despite of its adversary to crop production, little is known about the genetic diversity and population genetic structure of this pathogen from sorghum. In this study, we explored the utilization of single nucleotide polymorphism (SNP) molecular markers and three mating type-specific primers to analyze the genetic diversity, population genetic structure, and mating type distribution of 87 S. turcica isolates that had been collected in sorghum production areas from three provinces, including Henan, Shaanxi, and Shanxi in China. The populations are featured with moderate genetic diversity and relatively equal mating type distribution of MAT1-1 and MAT1-2. The genetic differentiation was significant (p < 0.05) among different populations except those from Henan and Shanxi provinces that showed particularly frequent gene flow between them. Neither the maxinum likelihood phylogenetic tree, nor principal coordinate analysis, nor genetic structure analysis was able to completely separate the three populations. The relatively low genetic distance and high genetic identification were also observed among the three populations. Nevertheless, the genetic variation within populations was the major source of variation as revealed by AMOVA analysis. The findings of this study have improved our current understanding about the genetic diversity, population genetic structure, and the distribution of mating type of S. turcica, which are useful for unraveling the epidemiology of NLB and developing effective disease management strategies.

Evolution and conservation genetics of an insular hemiparasitic plant lineage at the limit of survival: the case of Thesium sect. Kunkeliella in the Canary Islands.

PremiseThe diversification of island flora has been widely studied. However, the role of environmental niches in insular radiation processes has been less investigated. We combined population genetic analyses with species distribution modelling to clarify the genetic relationships, diversification patterns, species niche requirements, and conservation of Thesium sect. Kunkeliella, a clade of rare hemiparasitic plants endemic to the Canaries.MethodsWe studied the three extant Thesium species and a new taxon from La Palma Island. We developed 12 microsatellites and performed population genetic analysis and studied the demographic history of the group. To evaluate the role of niche conservatism in the diversification of the group, we performed species distribution modelling (ESM) with four algorithms.ResultsAll species presented moderate genetic diversity values for rare endemics. Thesium canariense (Gran Canaria) showed high differentiation, whereas T. subsucculentum, T. retamoides (Tenerife), and La Palma populations are closely related. The lineage may have undergone a recent diversification with colonization proceeding east to west, with T. canariense as sister to the others. We detected a climatic niche shift, as taxa showed different distributions across the temperature gradient. There is enough evidence to describe La Palma populations as a new species.ConclusionsWe characterized the evolutionary history of Thesium sect. Kunkeliella by integrating genetic and ecological assessments. Our results indicate that this clade has undergone a recent radiation process with niche differentiation among species. The results increase our knowledge about insular radiations and will inform the conservation management of the study species.

Linkage disequilibrium and population structure in a core collection of Brassica napus (L.).

Estimation of genetic diversity in rapeseed is important for sustainable breeding program to provide an option for the development of new breeding lines. The objective of this study was to elucidate the patterns of genetic diversity within and among different structural groups, and measure the extent of linkage disequilibrium (LD) of 383 globally distributed rapeseed germplasm using 8,502 single nucleotide polymorphism (SNP) markers. We divided the germplasm collection into five subpopulations (P1 to P5) according to geographic and growth habit-related patterns. All subpopulations showed moderate genetic diversity (average H = 0.22 and I = 0.34). The pairwise Fst comparison revealed a great degree of divergence (Fst > 0.24) between most of the combinations. The rutabaga type showed highest divergence with spring and winter types. Higher divergence was also found between winter and spring types. Admixture model based structure analysis, principal component and neighbor-joining tree analysis placed all subpopulations into three distinct clusters. Admixed genotype constituted 29.24% of total genotypes, while remaining 70.76% belongs to identified clusters. Overall, mean linkage disequilibrium was 0.03 and it decayed to its half maximum within < 45 kb distance for whole genome. The LD decay was slower in C genome (< 93 kb); relative to the A genome (< 21 kb) which was confirmed by availability of larger haplotype blocks in C genome than A genome. The findings regarding LD pattern and population structure will help to utilize the collection as an important resource for association mapping efforts to identify genes useful in crop improvement as well as for selection of parents for hybrid breeding.

Genetic diversity analysis among 123 accessions of castor (Ricinus communis L.) using SSR marker and its association to agronomic traits

Abstract. Anggraeni TDA, Waluyo B, Sugiharto AN, Kuswanto. 2022. Genetic diversity analysis among 123 accessions of castor (Ricinus communisL.) using SSR marker and its association to agronomic traits. Biodiversitas 23: 1211-1221. Castor (Ricinus communis L.) breeding program targets to create dwarf-type plants suitable for mechanical harvesting. Characterization of plantsusing morphological and molecular markers can enhance the successful breeding program. This studyaimed to investigate the diversity of castor accessionsusing Simple Sequence Repeat (SSR) markers and find the SSR markers that are significantly associated with the agronomic traits. The castor germplasm collection consisting of 123 accessions from the islands throughout Indonesia, breeding lines, and introducedaccessions displayed a moderate genetic diversity. The germplasm collection showed high variation in plant height, node length average, number of nodes, 100 seed weight, and oil content. The association analysis using GLM (General Linear Model) and MLM (Mixed Linear Model) could detect six associations between SSR marker alleles and agronomic traits. Among the marker alleles, two marker alleles had an overlap association. RcSSR-12_175 had an association with plant height and flowering day, RcSSR-23_113 had an association with node length average and branch number, and RcSSR-4_125 had an association with seed weight/raceme. This finding could provide information on Indonesia’s castor accession status. The linked-trait SSR markers are useful in marker-assisted selection for breeding high yield dwarf type-castor.

Metabolomic Fingerprinting and Molecular Characterization of the Rock Samphire Germplasm Collection from the Balkan Botanic Garden of Kroussia, Northern Greece

The traditionally edible aerial parts of rock samphire (Crithmum maritimum L.) could be a valuable functional food or feed ingredient due to their high antioxidant capacity, ascorbic acid content, and rich content in secondary metabolites such as phenolics and flavonoids. The first objective of this study was to evaluate eighteen genotypes derived from different regions of Greece regarding the phytochemical contents of their soluble extracts in total phenolics, total flavonoids, and individual polyphenols as determined by LC-MS analysis, as well as ascorbic acid content and their antioxidant capacity as determined by different assays, including ABTS (2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid), DPPH (2,2-diphenyl-1-picrylhydrazyl radical scavenging activity), and FRAP (ferric reducing antioxidant power) assays. The second objective of the study was the molecular characterization of native Greek C. maritimum genotypes. Great variation among genotypes was observed in terms of the antioxidant capacity, ascorbic acid content, and phenolic compounds (total phenolic content and total flavonoid content), as well as in caffeolquinic acids and flavonoids. The principal component analysis highlighted genotypes with a higher potential in antioxidants and polyphenolics. The most promising genotypes were G9 from Kefalonia, followed by G4 from Ikaria, where both clearly exhibited a similar response with high values of evaluated traits. The molecular characterization of genotypes revealed low variability and low to moderate genetic diversity between populations. Our data indicated that the rock samphire germplasm collection from the Balkan Botanic Garden of Kroussia could serve as an important source of documented genetic material and, thus, it is suggested for further investigation to provide insight regarding cultivation and agro-processing aspects, artificial selection, or plant breeding aimed at developing C. maritimum genotypes of high-bioactive value.

Resistance traits and molecular characterization of multidrug-resistant Acinetobacter baumannii isolates from an intensive care unit of a tertiary hospital in Guangdong, southern China.

This study aims to characterize antimicrobial resistance (AMR) of all the non-duplicated Acinetobacter baumannii strains isolated from an intensive care unit in a tertiary hospital during the period of January 1 to December 31, 2015. A. baumannii (n = 95 strains) isolated from patients was subjected to antimicrobial susceptibility test (AST) by Vitek 2 Compact system to determine minimum inhibitory concentrations, followed by genotyping by enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR). Resistance genes of interest were PCR amplified and sequenced. All isolates were qualified as MDR, with a resistance rate of > 80% to 8 antimicrobials tested. In terms of beta-lactamase detection, the blaOXA23, blaTEM-1, and armA genes were detected frequently at 92.63%, 9 1.58%, and 88.42%, respectively. The metallo-β-lactamase genes blaIMP and blaVIM were undetected. Aph (3')-I was detected in 82 isolates (86.32%), making it the most prevalent aminoglycoside-modifying enzyme (AMEs) encoding gene. In addition, ant (3″)-I was detected at 30.53%, while 26.32% of the strains harbored an aac (6')-Ib gene. ERIC-PCR typing suggested moderate genetic diversity among the isolates, which might be organized into 10 distinct clusters, with cluster A (n = 86 isolates or 90.53%) being the dominant cluster. All of the A. baumannii strains detected in the ICU were MDR clones exhibiting extremely high resistance to carbapenems and aminoglycosides as monitored throughout the study period. They principally belonged to a single cluster of isolates carrying blaOXA23 and armA co-producing different AMEs genes.

Parental Polymorphic Marker Survey and Genetic Diversity Studies among the Popular Maintainer Lines of Hybrid Rice (Oryza sativa L.) for Stigma Exsertion Trait

Parental polymorphic survey using rice satellite (RM) simple sequence repeats (SSR’S) is a pre-requisite for genotypic screening to identify the loci associated with trait of interest among mapping population. In the present study, eight popularly used rice maintainer lines viz., APMS-6B (Improved for Bacterial leaf blight. [1], IR58025B, IR68897B, IR79156B, DRR-6B, DRR-9B, BF-16B and BF2096B were used to study stigma exsertion trait as a single, double and total stigma exsertion. A total of 630RM markers were used to study parental polymorphism among eight maintainer lines and also to map their association with stigma exsertion trait. Among 630, 253 RM markers showed polymorphism with 635 alleles among the eight maintainers which were distributed across twelve chromosomes of rice. The overall parental survey revealed 40.18 per cent of polymorphism among the maintainer lines with a maximum and minimum frequency of 5 and 2 alleles, respectively. The genetic similarity coefficient for the most number of pairs ranged between of 0.2-0.9 with the average value of 0.60 for all possible combinations, indicating moderate genetic diversity among the chosen genotypes. The genotypes grouped according to their place of origin and represents genetic closeness between them. The identified RM polymorphic markers could be used to construct the linkage map and subsequently, to identify the stigma exsertion related QTLs from mapping population developed from different combinations of the rice maintainer lines.

Defining Management Units for Wild Nile Tilapia Oreochromis niloticus from Nine River Basins in Ghana

Despite the global importance of the Nile tilapia Oreochromis niloticus, especially to aquaculture, knowledge of genetic variability within native populations is still limited. While several studies have assessed genetic differentiation across the major drainage basins of Africa, relatively little effort has focused on characterizing genetic differentiation at finer scales. We assessed genetic variation in O. niloticus within and among nine drainage basins in Ghana using nuclear microsatellite DNA markers as the basis for identifying potential units of conservation among wild populations. We screened 312 wild individuals using eight nuclear microsatellite DNA markers. We found moderate genetic diversity within and differentiation among all wild populations studied, with strong signals of recent demographic bottlenecks in several populations. Genetic structure among 11 populations suggested the presence of up to ten management units (MUs). In particular, the Black Volta and the Tano–Asuhyea populations, which were the most genetically distinct and geographically isolated and may be most at risk of loss of genetic diversity over time, may well represent evolutionary significant units. Therefore, at the minimum, the Black Volta and Tano–Asuhyea populations should be prioritized for conservation actions to sustain them over the long-term.

High genetic differentiation and moderate genetic diversity of the degenerative branching coral Pocillopora verrucosa in the tropical South China Sea

Global warming is causing rapid degradation of coral reefs, among which branching corals are degrading the fastest. An assessment of coral genetic diversity and adaptive potential provides a basis for coral reef protection. In this study, we selected the branching coral Pocillopora verrucosa, a widely distributed species in the tropical South China Sea (SCS), to carry out population genetic studies. To analyze the genetic diversity and structure of 319 P. verrucosa samples from 10 populations in 4 SCS regions, twelve pairs of microsatellite primers and two nuclear markers, ITS and β-tub, were selected. Microsatellite marker results showed moderate genetic diversity for P. verrucosa in the SCS, but relatively low diversity in Dazhou Island and Yongxing Island. The haplotype network showed that P. verrucosa in the SCS was derived from two ancestors, which may be linked to geographical isolation in the Pleistocene glacial period. AMOVA (ΦST = 0.3375) and FST pairwise analysis results based on β-tub showed that the populations were highly differentiated, with most FST values (21/45) > 0.25. Yongxing and Qilianyu Islands populations were significantly different from those in the Xisha area. Mantel test results showed that genetic differentiation among P. verrucosa populations was significantly and positively correlated with both mean sea surface temperature (SST) and SST variance, and was not correlated with distance, chlorophyll-a, or turbidity. The reproductive mode of brooding planulae was an important factor contributing to high genetic differentiation among populations. The moderate genetic diversity of SCS P. verrucosa indicates that this population has a certain genetic potential in the context of global changes, but the high genetic differentiation between populations increases the risk of local degradation or extinction. This study provides a theoretical basis for the protection and restoration of SCS coral reefs.

Genetic comparison of populations of Piaractus brachypomus and P. orinoquensis (Characiformes: Serrasalmidae) of the Amazon and Orinoco basins

Recently, the large migratory fishes of the family Serrasalmidae (Piaractus brachypomus and P. orinoquensis) were described as restricted to the Orinoco and Amazon basins. Both species provide important ecosystem services. They also are an important fisheries resource, which has caused that their populations have decreased in recent years. National fisheries policies still consider both species as one, which leads to inefficiencies in their management and conservation. The aim of this study was to genetically characterize these two species, using microsatellite and mitochondrial markers, and discuss the implication of these results for conservation and management. We found that both species have moderate genetic diversity and varied patterns of genetic distribution in the fluvial landscape. Piaractus brachypomus presented genetic diversity of A=6.5; He=0.72; Ho=0.67; Ĥ=1.000; ᴫ=0.0092, three management units related to the evolutionary process of the Amazon basin and the effective sizes of local populations were smaller compared to P. orinoquensis, which presented genetic diversity of A=6.1; He=0.66; Ho=0.55; Ĥ=0.968; ᴫ=0.010 and comprises only one management unit. These results demonstrate the need to design management policies that focus on species and geographically restricted populations.

Genetic characterization of remaining populations of paratecoma peroba, an endangered and endemic species of the atlantic forest

Background: The objective of this study was the genetic characterization of remaining populations of the species Paratecoma peroba occurring in fragments of the Atlantic Forest, by estimating parameters of diversity and genetic structure. The study was carried out in two forest fragments, the Atlantic Forest Environmental Education Pole (area 1) and the Pacotuba National Forest (area 2), where 93 adult trees were identified. Results: Ten Inter Simple Sequence Repeats (ISSR) primers were used in genotyping, obtaining 112 amplified bands with 87.5% polymorphism. The genetic diversity estimated for the populations from the Nei (H*) and Shannon (I*) indices was higher for area 1. For the joint data, moderate genetic diversity was observed, referring to the average values of 0.26 and 0.40, obtained for the H* and I* indices, respectively. Molecular variance analysis resulted in moderate differentiation between populations (Φ ST = 0.143), while gene flow analysis (N m = 6.69) revealed the occurrence of similar alleles between them. However, the predominance of a single genetic group in area 2, revealed from Bayesian approach, indicates that its genetic structure, possibly generated by the current scenario of fragmentation of the Atlantic Forest and the distancing of populations, affecting the contemporary gene flow. Conclusion: Despite the moderate genetic diversity of the species for the area 2 population, actions toward inclusion of seedlings obtained from seeds from neighboring fragments, including area 1, and the increase in the connectivity of forest fragments through ecological corridors, could assist in augmenting its genetic variation.

Genetic diversity analysis and parentage verification of Taishu horses using 31 microsatellites.

The Taishu horse in Tsushima is one of eight Japanese native breeds. The breed is on the verge of extinction due to a rapid decrease in numbers since the 1960s owing to motorization in Japan. In this study, we aimed to confirm the pedigree information of 52 horses by genotyping 31 microsatellites in order to avoid inbreeding. Parentage verification failed to identify genetic contradictions among trios (sires, dams, and foals) registered with the Japan Equine Affairs Association (JEAA). Pedigree information registered at the JEAA was obtained and adequately understood. Additionally, the genetic diversity of the Taishu horses was evaluated and compared with those of other Japanese native breeds. The average values for the number of alleles, observed heterozygosity, expected heterozygosity, and inbreeding coefficient were 4.7, 0.643, 0.632, and -0.02, respectively. Using the Structure software, the 52 horses were classified into three subgroups based on the individuals with more than 50% of specific genetic components. The phylogenetic trees created based on neighbor-joining classification tended to be consistent among the stallions. The effective population size was 27.5 and lower than that required for maintaining 90% genetic variation in the source population over a period of 100 years (47.5). Compared with the other Japanese breeds, the Taishu horse population included in the current study exhibited moderate genetic diversity. Our study will contribute to reconsideration of the breeding strategy of Taishu horses.

Analysis of the genetic structure and diversity of a Brazilian macadamia nut (Macadamia integrifolia) germplasm

Macadamia is a nut tree native to Australian rainforest. Due to the small wild populations and the economic interest, studies assessing genetic information are fundamental for use and conservation of this species. Therefore, the present study aimed to assess the structure and genetic diversity of 28 cultivars of macadamia originated from United States, Australia and Brazil, introduced or developed by the Agronomic Institute’s breeding program, using 29 new microsatellite loci. The microsatellite loci showed high genetic diversity (3.65 alleles per locus on average). Our results also suggested the existence of no genetic structure between cultivars, regardless of their geographic origin. The modified Rogers’ distances between cultivars ranged from 0.227 to 0.671. Despite the lack of information about genealogy, the cultivars from this Brazilian germplasm showed moderate genetic diversity, so they can be used as parents in future crosses.

Population genetic study in Epilobium minutiflorum (Onagraceae) in Iran

The genus Epilobium has about 200 species in which taxonomic subdivisions are difficult but possible. Species E. minutiflorum due to its fluffy white inflorescence and small miniature flowers and beaked seeds, it is one of the most prominent species of the genus Epilobium in the region. We have no data on the population genetic structure of this species in the Iran. Therefore a population genetic and morphological investigation was performed through light on genetic and morphological variability in this taxa. We used SCoT molecular markers for population genetic investigation. Genetic diversity analyses revealed a moderate genetic variability between E. minutiflorum populations, while PCoA showed some degree of genetic admixture among populations. AMOVA produced significant genetic difference among populations. Morphometric analysis showed that high degree of overlap among the studied populations. However, the results showed that SCoT marker has a good discrimination power and can differentiate the studied populations. This marker can be used to evaluate genetic diversity and identify genotypes of E. minutiflorum populations.

Genetic-molecular characterization in guava full-sib progeny

Brazil is one of the world’s largest producers of guava (Psidium guajava L.), a very promising fruit in the northern region of the state of Rio de Janeiro. Despite this, no guava cultivar has been developed for the region. Thus, this study proposed to examine a population of guava full sibs using microsatellite markers and to identify which genotypes are the most divergent for future crosses, to select cultivars better adapted to the soil and climatic conditions of northern Rio Janeiro. Ninety-six superior genotypes were selected according to their agronomic traits, which were characterized using 45 microsatellite markers. The genetic distance between the analyzed genotypes, their clustering pattern and the genetic structure of the population were estimated. Hierarchical cluster analysis by the neighbor joining method indicated the formation of three distinct groups. The use of molecular information revealed the existence of moderate genetic variability between the genotypes of the full-sib families. Bayesian analysis separated the genotypes into only two groups, as the individuals shared most of the analyzed genomic regions. The most genetically divergent guava genotypes, that is, those allocated to different groups, such as genotypes 5 and 85, should be recommended for future crosses to obtain segregating populations, thus giving continuity to the guava breeding program.