Mean Polymorphism Information Content Research Articles

Genotyping-by-Sequencing Based Molecular Genetic Diversity of Pakistani Bread Wheat (Triticum aestivum L.) Accessions.

Spring wheat (Triticum aestivum L.) is one of the most imperative staple food crops, with an annual production of 765 million tons globally to feed ∼40% world population. Genetic diversity in available germplasm is crucial for sustainable wheat improvement to ensure global food security. A diversity panel of 184 Pakistani wheat accessions was genotyped using 123,596 high-quality single nucleotide polymorphism (SNP) markers generated by genotyping-by-sequencing with 42% of the SNPs mapped on B, 36% on A, and 22% on D sub-genomes of wheat. Chromosome 2B contains the most SNPs (9,126), whereas 4D has the least (2,660) markers. The mean polymorphic information content, genetic diversity, and major allele frequency of the population were 0.157, 0.1844, and 0.87, respectively. Analysis of molecular variance revealed a higher genetic diversity (80%) within the sub-population than among the sub-populations (20%). The genome-wide linkage disequilibrium was 0.34 Mbp for the whole wheat genome. Among the three subgenomes, A has the highest LD decay value (0.29 Mbp), followed by B (0.2 Mbp) and D (0.07 Mbp) genomes, respectively. The results of population structure, principal coordinate analysis, phylogenetic tree, and kinship analysis also divided the whole population into three clusters comprising 31, 33, and 120 accessions in group 1, group 2, and group 3, respectively. All groups were dominated by the local wheat accessions. Estimation of genetic diversity will be a baseline for the selection of breeding parents for mutations and the genome-wide association and marker-assisted selection studies.

Genetic diversity of Greek grapevine (Vitis viniferaL.) cultivars using ampelographic and microsatellite markers

AbstractGrapevine (Vitis viniferaL.) is a major worldwide crop of high economic importance, tightly interwoven with the traditions and the culture of many civilizations. The Greek vineyard is one of the oldest in the world composed of an ample number of highly diverse indigenous landraces. However, over the last decades the local cultivated grapevine germplasm has undergone a drastic reduction of diversity, due to the established market preferences for international varieties. In the current work a combined approach involving both, ampelographic traits and microsatellite markers has been undertaken, to study the genetic diversity within and among 96 grapevine genotypes belonging to 36V. viniferasubsp.viniferacultivars, predominantly representing autochthonous Greek landraces. Results revealed high genetic diversity for the Greek cultivars yielding a mean number of alleles per locus 14.69 and mean polymorphic information content 0.848. Hierarchical cluster analysis, employing both, ampelographic and microsatellite data, showed a clear distinction based on the origin of the germplasm; Anatolian versus Mediterranean. Principal component analysis, based on the most informative ampelographic traits, coupled to the results from genetic structure analysis further corroborated the proposal of germplasm differentiation on the basis of geographic origin. This information can be further utilized for the reconstitution of the Greek vineyard and can significantly contribute towards a rational conservation and utilization strategy for breeding or for direct cultivation of the Greek indigenous grapevine germplasm.

Analyses of genetic diversity and population structure of sesame (Sesamum indicum L.) germplasm collections through seed oil and fatty acid compositions and SSR markers

Knowledge of the genetic profiles of diverse germplasm collections of sesame using seed oil, fatty acid contents, and molecular markers is a prerequisite to develop market-preferred cultivars with quantity and quality oil. The objective of this study was to determine the genetic diversity and relationships among Ethiopia’s sesame germplasm collections using seed oil content and fatty acid compositions and diagnostic simple sequence repeat (SSR) markers to select genetically complementary and promising parental lines for breeding. The contents of the seed oil and fatty acids of 100 lines grown under field conditions were determined using the near-infrared reflectance spectrometry. Twenty-seven polymorphic SSR markers were used to assess the genetic profile of the test lines and complement the seed oil and fatty acid data. The SSR markers revealed that the mean gene diversity and polymorphic information content were 0.30 and 0.25, respectively. Population structure analysis identified four major heterotic groups. Based on higher oil content and desirable fatty acid compositions and SSR markers the following superior and complementary lines such as: Hirhir Kebabo Hairless Sel-6 (from sub-cluster I-b), Hirhir Humera Sel-8 and NN0058–2 (sub-cluster II-a) and Bawnji Fiyel Kolet (sub-cluster II-b) are identified for sesame breeding programs or production globally.

Morphometric and Microsatellite Diversity in Seabuckthorn (Hippophae rhamnoides L.) Natural Populations Originating from the Different Geographical Regions of the Indian Himalayas.

Seabuckthorn (Hippophae rhamnoides L.), an upcoming superfood plant, has attracted researchers’ attention worldwide for its medicinal, nutritional, and socio-economic value, along with its characteristic features to sustain extreme climatic conditions. We have studied microsatellite marker–based genetic and morphometric diversity in 93 collections of H. rhamnoides from different geographic sites representing two regions, namely Leh and Lahaul of the Indian Himalayas. Microsatellite markers were isolated using two different approaches, including screening of microsatellite-enriched genomic library, and in silico screening of in-house developed seabuckthorn EST database and whole transcriptome assembly. In Leh and Lahaul collections, 32 and 30 microsatellite markers were found polymorphic, respectively. All the markers developed for H. rhamnoides showed cross-species transferability to H. salicifolia and H. tibetana. Two to six alleles were recorded in the two sets of collections with an average of 3.71 and 3.53 alleles per locus in Leh and Lahaul collections, respectively. Mean polymorphic information content (PIC) values for microsatellite markers were 0.39 and 0.41 for Leh and Lahaul collections, respectively. The average expected heterozygosity was less than the observed heterozygosity. Wright’s fixation index (FIS) varied from (−)0.2045 to 1.0 and (−)0.1688 to 1.0 for Leh and Lahaul collections, respectively. Shannon’s informative index (I) remained in the range of 0.6745 to 1.8621, and 0.6824 to 1.6308 for Leh and Lahaul collections, respectively. The UPGMA-based combined dendrogram showed clear demarcation between Leh and Lahaul collections, although a few ecotypes were regrouped with collections from the other region. No significant relationship was observed between the morphological distance matrix and molecular marker distance matrix. The findings of the present study may prove helpful in future breeding and conservation strategies aiming for seabuckthorn improvement.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11105-022-01338-6.

Genetic variation for grain phytate and molecular characterization of low phytic acid‐2 (lpa2) gene‐based maize (Zea mays) inbreds

AbstractMaize possesses higher concentration of phytic acid (PA) compared with other cereals, reducing bioavailability of iron and zinc. Reduction of PA in maize grains thus assumes significance to alleviate micronutrient malnutrition. Here, a set of 24 inbreds possessing mutant lpa2‐1 gene and seven inbreds with wild‐type LPA2 gene was field evaluated at Delhi and Hyderabad. The performance of lpa2‐1‐based inbreds was at par with wild‐type inbreds for grain yield (P = .09645) and key agronomic traits (P > .54100). Mutant inbreds possessed significantly low mean PA (1.90 mg/g) over wild‐type inbreds (2.56 mg/g) (P < .00001), with average reduction of 26% PA among lpa2‐1 mutants. Mean inorganic phosphorous (iP) was 0.81 mg/g in lpa2‐1 mutants and 0.27 mg/g in wild types, revealing significantly (P < .00001) higher increment (three‐fold) of iP in mutants compared with wild‐type inbreds. Characterization using 61 simple sequence repeats (SSRs) generated 181 alleles with mean polymorphism information content of 0.40 and mean gene diversity of 0.46. Cluster analyses grouped lpa2‐1 inbreds into three‐major clusters. The study identified potential cross combinations for development of low phytate maize with higher bioavailability of iron and zinc.

Systematic Evaluation of a Novel 6-dye Direct and Multiplex PCR-CE-Based InDel Typing System for Forensic Purposes.

Insertion/deletion (InDel) polymorphisms, combined desirable characteristics of both short tandem repeats (STRs) and single nucleotide polymorphisms (SNPs), are considerable potential in the fields of forensic practices and population genetics. However, most commercial InDel kits designed based on non-Asians limited extensive forensic applications in East Asian (EAS) populations. Recently, a novel 6-dye direct and multiplex PCR-CE-based typing system was designed on the basis of genome-wide EAS population data, which could amplify 60 molecular genetic markers, consisting of 57 autosomal InDels (A-InDels), 2 Y-chromosomal InDels (Y-InDels), and Amelogenin in a single PCR reaction and detect by capillary electrophoresis, simultaneously. In the present study, the DNA profiles of 279 unrelated individuals from the Hainan Li group were generated by the novel typing system. In addition, we collected two A-InDel sets to evaluate the forensic performances of the novel system in the 1,000 Genomes Project (1KG) populations and Hainan Li group. For the Universal A-InDel set (UAIS, containing 44 A-InDels) the cumulative power of discrimination (CPD) ranged from 1–1.03 × 10–14 to 1–1.27 × 10–18, and the cumulative power of exclusion (CPE) varied from 0.993634 to 0.999908 in the 1KG populations. For the East Asia-based A-InDel set (EAIS, containing 57 A-InDels) the CPD spanned from 1–1.32 × 10–23 to 1–9.42 × 10–24, and the CPE ranged from 0.999965 to 0.999997. In the Hainan Li group, the average heterozygote (He) was 0.4666 (0.2366–0.5448), and the polymorphism information content (PIC) spanned from 0.2116 to 0.3750 (mean PIC: 0.3563 ± 0.0291). In total, the CPD and CPE of 57 A-InDels were 1–1.32 × 10–23 and 0.999965, respectively. Consequently, the novel 6-dye direct and multiplex PCR-CE-based typing system could be considered as the reliable and robust tool for human identification and intercontinental population differentiation, and supplied additional information for kinship analysis in the 1KG populations and Hainan Li group.

Genetic diversity, population structure and core collection analysis of Hunan tea plant germplasm through genotyping-by-sequencing

Tea is considered to be a well-known and widely consumed beverage and Hunan province is rich in tea plant germplasm. In order to better conserve and utilize Hunan tea plant resources, 110 tea accessions from seven geographical origins were used to assess genetic diversity of Hunan tea plant germplasm through genotyping by sequencing (GBS) technology. As a result, a total of 311,044 high-quality single nucleotide polymorphism (SNP) markers were obtained. Population structure, phylogenetic relationships and principal component analysis (PCA) divided the entire accessions into three groups. The genetic diversity and population differentiation analysis showed that the mean observed heterozygosity (Ho) ranged from 0.16 to 0.24, while the mean polymorphic information content (PIC) ranged from 0.14 to 0.17, and mean minor allele frequency (MAF) ranged from 0.11 to 0.14. Analysis of molecular variance (AMOVA) indicated that 81.38% of the total variance was derived from within populations, which suggested a rich genetic diversity in Hunan tea germplasms. Furthermore, a core tea germplasm set was developed, which was comprised of 22 tea plant accessions and maintained the whole genetic diversity of the entire collection. This work should be valuable for conservation and utilization of tea germplasm in Hunan.

Development and application of a duplex simple sequence repeat panel for outcrossing fertility evaluation in red clover (Trifolium pratense) under open-pollination conditions†

Context Red clover (Trifolium pratense L.) is an important legume forage in temperate agricultural zones. Evaluation of self- and cross-pollination fertility is important for setting up an effective breeding-program scale. However, the outcrossing rate of red clover under open-pollination conditions is not certain. Development of a reliable and time-saving marker system is needed to quantify and characterise outcrossing rates. Aim We aimed to develop a duplex PCR-based protocol based on a genome-wide simple sequence repeat (SSR) screen, and to determine the outcrossing rate of red clover under open-pollination environments. Methods We screened 209 SSR markers with pooled DNA samples of 60 plants from 20 red clover accessions, and selected 185 SSR markers that produced clear scorable bands for testing with 24 individual DNA samples to determine polymorphism. We selected 70 primer pairs, and then assembled a core set of 24 loci into 12 sets of duplex markers, which were used for outcrossing behaviour analysis of 60 maternal parents and their respective 22 half-sib progenies. Key results Mean polymorphic information content (PIC) for the 70 markers was 0.490 (range 0.117–0.878). Minimum, mean and maximum PIC values for the 24 markers constituting the 12 duplexes were 0.226, 0.594 and 0.781, respectively. The outcrossing rate was identified as 99.4% for red clover in a natural environment. Conclusion We successfully developed a duplex SSR-based PCR protocol consisting of 24 markers. This SSR system was applied to determine the outcrossing rate of red clover in a natural environment.

Genetic Diversity and Population Structure of Didymellarabiei Affecting Chickpea in Ethiopia.

Ascochyta blight, also known as chickpea blight, which is caused by the fungal pathogen, Didymella rabiei, is an important disease affecting chickpea (Cicer arietinum L.) in many countries. We studied the genetic diversity and population structure of 96 D. rabiei isolates collected from three geographic populations in Ethiopia using simple sequence repeat (SSR) markers. We confirmed the genetic identity of 89 of the D. rabiei isolates by sequencing their rRNA internal transcribed spacer region genes. The chickpea blight pathogen isolates were genetically diverse, with a total of 51 alleles identified across 6 polymorphic SSR loci, which varied from 3 to 18 (average 8.5) alleles per SSR marker. The observed heterozygosity and expected heterozygosity ranged from 0.01 to 0.92 and 0.19 to 0.86, respectively. The mean polymorphic information content value of the D. rabiei populations was 0.58, with a mean gene diversity of 0.61 among loci. Gene flow (Nm = number of migrants) for the three populations of D. rabiei isolates ranged from 1.51 to 24.10 (average 6.2) migrants/cluster. However, the genetic variation between the D. rabiei populations was small (8%), with most of the variation occurring within populations (92%). Principal component analysis to visualize genetic variation showed that the D. rabiei isolates obtained from most of the chickpea samples formed roughly three groups on a two-dimensional coordinate plane. Similarly, the clustering of individuals into populations based on multi-locus genotypes (using Clumpak) grouped isolates into three clusters but with individual isolate admixtures. Hence, no clear geographic origin-based structuring of populations could be identified. To our knowledge, this is the first report of D. rabiei diversity in Ethiopia. Virulence studies should be conducted to develop chickpea varieties that are resistant to more aggressive pathogen populations.

Eco-Geographical, Morphological and Molecular Characterization of a Collection of the Perennial Endemic Species Medicago tunetana (Murb.) A.W. Hill (Fabaceae) from Tunisia.

In order to characterize and conserve the endemic pastoral species Medicago tunetana, many prospecting missions were carried out in mountainous regions of the Tunisian ridge. Twenty-seven eco-geographical and morphological traits were studied for six M. tunetana accessions and followed by molecular analysis using seven Simple Sequence Repeat (SSR). Only five markers were polymorphic and reproductible in the six M. tunetana populations. A total of 54 alleles were observed with an average of 10.8 bands/primer/genotype. Mean Polymorphism Information Content (PIC), Nei gene diversity (h) Shannon’s information index (I) indicated the high level of polymorphism. The generated dendrogram with hierarchical UPGMA cluster analysis grouped accessions into two main groups with various degree of subclustring. All the studied accessions shared 57% of genetic similarity. Analysis of variance showed high significant difference between morphological traits among M. tunetana populations where MT3 from Kesra showed different morphological patterns regarding leaf, pod and seeds traits. Canonical correspondence analysis (CCA) showed two principal groups of M. tunetana populations based on potassium, total and active lime contents in soil. Our results suggest that SSR markers developed in M. truncatula could be a valuable tool to detect polymorphism in M. tunetana. Furthermore, the studied morphological markers showed a large genetic diversity among M. tunetana populations. This approach may be applicable for the analysis of intra specific variability in M. tunetana accessions. Our study could help in the implementation of an effective and integrated conservation programs of perennial endemic Medicago.

ISSR analysis of Tulipa suaveolens (Liliaceae) populations from throughout the European part of the species range reveal genetic patterns shaped by Pleistocene transgressions of the Caspian Sea

Tulipa suaveolens Roth is a decorative bulbous, polycarpic species in the Liliaceae family. Currently, the species populations are declining due to the degradation of natural steppes. In the present article, we evaluated the genetic diversity of 216 specimens from 22 natural T. suaveolens localities in the European part of the species range using 10 inter simple sequence repeat (ISSR) markers. The polymerase chain reaction (PCR) yielded 250 unambiguous and reproducible polymorphic bands with a mean polymorphism information content (PIC) value of 0.27. Neither the principal component analysis nor the clustering method split the dataset. However, the Bayesian model‐based STRUCTURE analysis detected two genetic clusters of T. suaveolens. The analysis of the biogeographical distributional pattern of the revealed genetic groups confirmed our hypothesis that the evolution and distribution of T. suaveolens were likely affected by the Early Khvalynian transgression of the Caspian Sea and the following Enotayevsk regression. Furthermore, this hypothesis was supported by the results of the NEW HYBRIDS analysis identifying the specimens from the populations located outside the Early Khvalynian flooding limit as pure parents, while the specimens of the populations within the flooding limit were classified as backcrosses and second generation hybrids.

Genetic and molecular characterisation of subtropically adapted low-phytate genotypes for utilisation in mineral biofortification of maize (

Phytic acid (PA) is a major anti-nutritional factor in maize grains and significantly reduces the bioavailability of minerals such as iron and zinc in humans. Reduction of PA in maize (Zea mays L.) thus assumes great significance. Despite the availability of low phytic-acid (lpa) mutants in maize, their utilisation in breeding has been limited because of non-availability of well adapted lpa-based inbreds. A set of 24 subtropically adapted lpa1-1-based maize inbreds derived through molecular breeding was evaluated along with seven wild-type inbreds at multilocation. The lpa1-1 inbreds possessed 35.8% lower PA (1.68 mg/g) than the wild-type inbreds (2.61 mg/g). Mean proportion of PA was lower in the lpa1-1-based inbreds (62.8%) than in the wild-type inbreds (91.6%). The lpa1-1 inbreds showed similar performance for plant- and ear-height besides flowering behaviour as did wild types. Average grain yield among lpa1-1 inbreds (2735.9 kg/ha) was at par with the original versions (2907.3 kg/ha). Molecular profiling of these lpa1-1 inbreds using 60 genome-wide single-sequence repeats generated 172 alleles, with a mean of 2.87 alleles per locus. Mean polymorphism information content and mean gene diversity were 0.41 and 0.48 respectively. Genetic dissimilarity ranged from 0.23 to 0.81, with an average of 0.64. Cluster analyses grouped 24 lpa1-1 genotypes into three major clusters, and principal-coordinate analysis depicted the diverse nature of genotypes. The study also identified a set of potential hybrid combinations with low PA for their direct utilisation in biofortification program. This is the first study on comprehensive characterisation of lpa1-1-based inbreds adapted to subtropical conditions.

The Genetic Diversity and Population Structure of Different Geographical Populations of Bottle Gourd (Lagenaria siceraria) Accessions Based on Genotyping-by-Sequencing

Lagenaria siceraria (Molina) Standl is an important horticultural and medicinal crop grown worldwide in the food and pharmaceutical industries. The crop exhibits extensive phenotypic and genetic variation useful for cultivar development targeting economic traits; however, limited genomic resources are available for effective germplasm characterization into breeding and conservation strategies. This study determined the genetic relationships and population structure in a collection of different accessions of bottle gourd derived from Chile, Asia, and South Africa by using single-nucleotide polymorphism (SNP) markers and mining of simple sequence repeat (SSR) loci derived from genotyping-by-sequencing (GBS) data. The GBS resulted in 12,766 SNPs classified as moderate to highly informative, with a mean polymorphic information content of 0.29. The mean gene diversity of 0.16 indicated a low genetic differentiation of the accessions. Analysis of molecular variance revealed less differentiation between (36%) as compared to within (48%) bottle gourd accessions, suggesting that a random mating system dominates inbreeding. Population structure revealed two genetically differentiated groups comprising South African accessions and an admixed group with accessions of Asian and Chilean origin. The results of SSR loci mining from GBS data should be developed and validated before being used in diverse bottle gourd accessions. The SNPs markers developed in the present study are useful genomic resources in bottle gourd breeding programs for assessing the extent of genetic diversity for effective parental selection and breeding.

Genome-Wide Assessment of Population Structure and Genetic Diversity of the Global Finger Millet Germplasm Panel Conserved at the ICRISAT Genebank.

Finger millet [Eleusine coracana (L.) Gaertn.] is an important climate-resilient nutrient-dense crop grown as a staple food grain in Asia and Africa. Utilizing the full potential of the crop mainly depends on an in-depth exploration of the vast diversity in its germplasm. In this study, the global finger millet germplasm diversity panel of 314 accessions was genotyped, using the DArTseq approach to assess genetic diversity and population structure. We obtained 33,884 high-quality single nucleotide polymorphism (SNP) markers on 306 accessions after filtering. Finger millet germplasm showed considerable genetic diversity, and the mean polymorphic information content, gene diversity, and Shannon Index were 0.110, 0.114, and 0.194, respectively. The average genetic distance of the entire set was 0.301 (range 0.040 – 0.450). The accessions of the race elongata (0.326) showed the highest average genetic distance, and the least was in the race plana (0.275); and higher genetic divergence was observed between elongata and vulgaris (0.320), while the least was between compacta and plana (0.281). An average, landrace accessions had higher gene diversity (0.144) and genetic distance (0.299) than the breeding lines (0.117 and 0.267, respectively). A similar average gene diversity was observed in the accessions of Asia (0.132) and Africa (0.129), but Asia had slightly higher genetic distance (0.286) than African accessions (0.276), and the distance between these two regions was 0.327. This was also confirmed by a model-based STRUCTURE analysis, genetic distance-based clustering, and principal coordinate analysis, which revealed two major populations representing Asia and Africa. Analysis of molecular variance suggests that the significant population differentiation was mainly due to within individuals between regions or between populations while races had a negligible impact on population structure. Finger millet diversity is structured based on a geographical region of origin, while the racial structure made negligible contribution to population structure. The information generated from this study can provide greater insights into the population structure and genetic diversity within and among regions and races, and an understanding of genomic-assisted finger millet improvement.

Screening for drought tolerance and molecular variability among some sugar beet cultivars

Drought is one of the significant abiotic stress factors that affect plant development and productivity. Screening and producing of more tolerant genotypes with higher yield capacity is the breeders' principal purpose. Therefore, this work was carried out to evaluate the performance of four sugar beet cultivars (Top, Hossam, Hercules and Kawamera) under water limitation. The drought stress experiment was applied based on three water regimes, 25%, 50% and 75% (severe, moderate and non-stress conditions, respectively) of relative water capacity (RWC). The study incorporated some productivity and quality traits. The results showed that drought stress has a significant effect on all studied traits. Whereas, increasing of water deficiency led to decrease of the productivity traits and increasing of quality parameters. Kawamera cultivar has superior performance in all the studied traits under all three different levels of water regime. Besides, the four cultivars were assessed by both SSR and ISSR molecular markers. SSR marker exhibited a higher polymorphism percentage (71.43%) than ISSR marker (44.26%). In addition, the mean polymorphism information content (PIC) value was higher for the SSR marker (0.25) than the ISSR marker (0.18) too. Moreover, the constructed dendrograms revealed that the SSR marker was able to separate the cultivars according to their drought-tolerance, where the highest drought-tolerant cultivar (Kawamera) was classified alone in the main cluster. However, the superiority of Kawamera cultivar under drought stress indicated that it could be utilized in breeding programs for developing more drought-tolerant sugar beet cultivars.

Exploring the genetic diversity and population structure of scarlet eggplant germplasm from Rwanda through iPBS-retrotransposon markers.

Scarlet eggplant (Solanum aethiopicum gr. gilo) is a part of African indigenous vegetables and acknowledged as a source of variations in the breeding of Brinjal. Since its genetic diversity is still largely unexplored, therefore genetic diversity and population structure of this plant were investigated in this study. Scarlet eggplant germplasm made of fifty-two accessions originated from two districts of Rwanda was assessed by employing the iPBS-retrotransposon markers system. Twelve most polymorphic primers were employed for molecular characterization and they yielded 329 total bands whereupon 85.03% were polymorphic. The recorded mean polymorphism information content was 0.363 and other diversity indices such as; mean the effective number of alleles, mean Shannon's information index and gene diversity with the following values; 1.298, 0.300 and 0.187 respectively. A superior level of diversity was noticed among accessions from Musanze district. The model-based structure, neighbor-joining, and principal coordinate analysis (PCoA) gathered scarlet germplasm in a divergence manner to their collection district. Analysis of molecular variance (AMOVA) displayed that the utmost variations (81%) in scarlet eggplant germplasm are resulting in differences within populations. The extensive diversity of scarlet eggplant in Rwanda might be used to form the base and genetic resource of an exhaustive breeding program of this economically important African indigenous vegetable. For instance, accessions MZE53 and GKE11 might be proposed as parent candidates due to their high relative genetic distance (0.6781).

Genetic diversity and population structure assessment using molecular markers and SPAR approach in Illicium griffithii, a medicinally important endangered species of Northeast India

BackgroundIllicium griffithii is an aromatic medicinal tree species that has been listed in the IUCN Red List as an endangered species. Dried seed pods of I. griffithii have a good market potential in the spices and pharmaceutical industries. Fruits are the potential source of shikimic acid and used for the production of oseltamivir (a drug against bird flu). However, in recent years, unscientific harvesting and rampant exploitation of the species has caused a negative and adverse effect on its natural population. Proper knowledge of genetic diversity and population structure is crucial to understand the population dynamics, adaptation, and evolutionary pattern of a particular species for conservation. It was from this view point that the present study was undertaken so as to compare the various types of DNA-based molecular markers namely RAPD, ISSR, DAMD, and SCoT by their efficiency and SPAR approach to evaluate the genetic diversity of I. griffithii as well as to analyze population genetic structure for conservation purpose. ResultA total of 250 discernible bands were generated with 246 bands (98.40 %) being polymorphic in nature. All the primers in combination gave a mean polymorphic information content (PIC) of 0.81 and Rp value (resolving power) of 4.32. Nei’s, Gst, and AMOVA analysis showed similar values of genetic differentiation among populations (Gst = 0.396, FST = 0.30, respectively), revealing a low level of genetic differentiation among the eight sampled populations. I. griffithii with an estimated gene flow value of Nm = 0.761 was significantly low among populations. Clustering pattern obtained with Bayesian structure and PCoA diagram revealed that intermixing of genetic material across populations is only possible when the populations lie close to each other. This is further validated with UPGMA clustering method where a positive correlation of genetic variability with geographical distance among closely related populations could be clearly seen. ConclusionThe result aids in the identification, collection, and preservation of diverse germplasm of I. griffithii from Arunachal Pradesh and Meghalaya of Northeast India. This would further help in understanding the population structure and genetic diversity among other Illicium species in order to formulate effective conservation strategies for the improvement of this endangered taxa.

Assessment of genetic diversity among wild populations of the striped catfish (Pangasianodon hypophthalmus) by 20 novel microsatellite markers

The striped catfish, Pangasianodon hypophthalmus, is one of the most economically important aquaculture species in Vietnam. This study developed 26 novel microsatellite markers from the draft genome of the striped catfish to assess the genetic diversity of three wild populations of the striped catfish (Bien Ho, Cuu Long, and Kratie) for establishing the breeding program. The study exhibited that 6 out of 26 loci had significantly high null allele frequency and deviated from Hardy - Weinberg equilibrium; thus, they were eliminated for further analysis. Across 20 loci without null alleles, a total of 255 different alleles was identified, ranging from 7 to 21 alleles per locus, with many unique alleles for each population. The results based on 20 loci revealed the mean polymorphic information content PIC=0.783; the mean observed heterozygosity Ho=0.809; the mean expected heterozygosity He=0.812; inbreeding coefficient Fis=-0.0147 (Fis<0). The results indicated that the striped catfish populations have high genetic diversity and are suitable for selective breeding. The Analysis of Molecular Variance (AMOVA) and comparison of genetic distances showed significant genetic differentiation among three populations while the Kratie population was distant from the others.

Genetic Diversity of Ancient Camellia sinensis (L.) O.Kuntze in Sandu County of Guizhou Province in China

The ancient tea plant germplasm is an important resource for breeding new tea plant varieties and has great economic value. However, due to man-made and natural disturbances, it has become endangered. In order to have a better management of the conserved tea plant germplasm, it is a requirement to understand the genetic and phenotypic diversity. The aim of this study was to evaluate the genetic and phenotypic diversity of 145 ancient tea plant germplasm resources from five populations in Sandu County of Guizhou province in China. To explore the population genetics of tea plant, we successfully identified 15 simple sequence repeat (SSR) markers, which were highly polymorphic. Additionally, we applied traditional phenotypic methods to evaluate the tea plant diversity. The results suggested that the genetic and phenotypic diversity were relatively high. A total of 96 alleles were identified, and the mean polymorphic information content (PIC) value was found to be 0.66. The analysis of molecular variance (AMOVA) showed that genetic variation within the populations was greater than among the populations. Overall, our results are the valuable baseline data in developing more efficient management and breeding plans for one of the most popular non-alcoholic beverage crops, the tea plant species.

Genetic Diversity among Some Walnut (Juglans regia L.) Genotypes by SSR Markers

The food needs for increasing population, climatic changes, urbanization and industrialization, along with the destruction of forests, are the main challenges of modern life. Therefore, it is very important to evaluate plant genetic resources in order to cope with these problems. Therefore, in this study, a set of ninety-one walnut (Juglans regia L.) accessions from Central Anatolia region, composed of seventy-four accessions and eight commercial cultivars from Turkey, and nine international reference cultivars, was analyzed using 45 SSR (Simple Sequence Repeats) markers to reveal the genetic diversity. SSR analysis identified 390 alleles for 91 accessions. The number of alleles per locus ranged from 3 to 19 alleles with a mean value of 9 alleles per locus. Genetic dissimilarity coefficients ranged from 0.03 to 0.68. The highest number of alleles was obtained from CUJRA212 locus (Na = 19). The values of polymorphism information content (PIC) ranged from 0.42 (JRHR222528) to 0.86 (CUJRA212) with a mean PIC value of 0.68. Genetic distances were estimated according to the UPGMA (Unweighted Pair Group Method with Arithmetic Average), Principal Coordinates (PCoA), and the Structure-based clustering. The UPGMA and Structure clustering of the accessions depicted five major clusters supporting the PCoA results. The dendrogram revealed the similarities and dissimilarities among the accessions by identifying five major clusters. Based on this study, SSR analyses indicate that Yozgat province has an important genetic diversity pool and rich genetic variance of walnuts.