Inter-simple Sequence Repeat Markers Research Articles

Morphological and genetic characterization of mutants of Gladiolus cultivar prince of orange for two successive vegetative generations

Gladiolus mutants developed using gamma irradiations and EMS treatments were characterized using morphological, genetic and Polymerase Chain Reactions (PCR) based Inter-Simple Sequence Repeats (ISSR) for designing future breeding strategies. As many as 7 mutants based on phenotypic variations such as colour and shape modifications were subjected to molecular characterization using 11 ISSR primers that confirmed variations. ISSR markers showed 13.88 to 36.00 percent polymorphism among the mutants was recorded, signifying variability among different mutants. UPGMA (unweighted pair group method with arithmetic mean) based analysis of cluster separated gladiolus variety prince of orange mutants into four clusters. ISSR markers were subjected for comparative analysis like effective multiplex ratio, marker index, polymorphic information content and resolving power wherein, highest EMR (3.24), MI (1.32) were found for UBC 810, Rp (4.37) values were found for UBC 827, and maximum PIC value (0.46) for ISSR 22218 UBC 812. The results clearly indicated the reproducibility of ISSRs and their ability to detect variability among the mutants. A significant level of genetic variation was depicted by ANOVA which suggested the usefulness of studies in gladiolus breeding and unique bands obtained could be utilized for mutant/ varietal identification.

Micropropagation, micromorphological evaluation and genetic homogeneity validation of Cucumis collosus (Rottl.) Cogn.: A wild progenitor of melon

Cucumis collosus (Rottl.) Cogn., a wild ancestor of melon cultivars, is an underutilized cucurbit of arid horticulture having nutraceutical and therapeutic significance. C. collosus has great potential for enhancing the genetic base of cultivated melon and other cucurbits. This investigation is the first report on a robust and reliable micropropagation system for C. collosus (var. AHK-119) using nodal explants, followed by micromorphological and genetic stability assessment. More than 95% explants showed axillary shoot-bud induction on MS (Murashige and Skoog, 1962) medium containing 0.5 mg L−1 BAP and developed a maximum of 3.2 ± 0.6 shoots measuring 3.2 ± 0.1 cm length. After evaluating the various parameters, the best shoot multiplication (Shoot Number 34.9 ± 1.7, Shoot Length 6.7 ± 0.9 cm) was achieved on MS medium having half-strength of nitrates (825 mg L−1 NH4NO3 and 950 mg L−1 KNO3) + 0.25 mg L−1 6-benzylaminopurine (BAP) + 0.1 mg L−1 Kinetin (Kin) + 0.1 mg L−1 Indole-3-acetic acid (IAA) + additives (50 mg L−1 ascorbic acid and 25 mg L−1 each of adenine sulfate, L-arginine and citric acid), after 4 weeks. Micro-shoots were rooted using three approaches: In Vitro Continuous Treatment (IVCT), In Vitro Pulse-Treatment (IVPT) and Ex Vitro Pulse Treatment (EVPT). Of these, EVPT approach proved to be most successful in terms of rooting response (80%), root number (6.4 ± 0.9) and root length (5.7 ± 0.7 cm). The foliar micro-morphology analysis of in vitro leaves (IVL), ex vitro leaves (EVL) and mother plant leaves (MPL) demonstrated notable adaptive alterations during the transitional stages and produced structurally stable plants similar to the mother plant. Furthermore, the validation of genetic homogeneity using Start Codon Targeted (SCoT) and Inter Simple Sequence Repeats (ISSR) markers revealed monomorphic banding patterns among the micropropagated and the mother plant. The discussed method can be applied for large-scale commercial production of C. collosus for arid horticulture, urban/vertical farming, breeding purposes and improvement of other cucurbits.

Production of genetically stable and Odontoglossum ringspot virus-free Cymbidium orchid ‘New True’ plants via meristem-derived protocorm-like body (PLB) subcultures

BackgroundThis study aimed to produce Odontoglossum ringspot virus (ORSV)-free Cymbidium orchid ‘New True’ plants from ORSV-infected mother plants by culturing their meristems and successively repeating subcultures of protocorm-like bodies (PLBs) derived from the meristems.ResultsInitially, ORSV was confirmed as the causative agent of viral symptoms in orchid leaves via reverse transcription-polymerase chain reaction (RT-PCR) analysis. Meristems from infected plants were cultured to generate PLBs, which in sequence were repeatedly subcultured up to four times. RT-PCR and quantitative RT-PCR analyses revealed that while ORSV was undetectable in shoots derived from the first subculture, complete elimination of the virus required at least a second subculture. Genetic analysis using inter-simple sequence repeat markers indicated no somaclonal variation between regenerated plants and the mother plant, suggesting that genetic consistency was maintained.ConclusionOverall, our findings demonstrate that subculturing PLBs for a second time is ideal for producing genetically stable, ORSV-free Cymbidium orchids, thus offering a practical means of generating genetically stable, virus-free plants and enhancing plant health and quality in the orchid industry.

Assessing genetic diversity of indigenous turmeric (Curcuma longa L.) through inter-simple sequence repeat (ISSR) markers

Assessing genetic diversity of indigenous turmeric (Curcuma longa L.) through inter-simple sequence repeat (ISSR) markers

Genetic Diversity and Population Genetic Structure of Jatropha curcas L. Accessions from Different Provenances Revealed by Amplified Fragment-Length Polymorphism and Inter-Simple Sequence Repeat Markers

The genetic diversity and structure of 17 populations of J. curcas, including 92 accessions from different provenances (tropical and subtropical), were investigated and effectively evaluated using twelve inter-simple sequence repeats (ISSRs) and seven pairs of florescence-amplified fragment-length polymorphism (AFLP) primers. Genetic diversity, at the overall level among populations of J. curcas based on the ISSR markers, showed that the observed number of alleles (Na) was 1.593, the effective number of alleles (Ne) was 1.330, Nei’s gene diversity (H) was 0.200, Shannon’s information index (I) was 0.303, and the percentage of polymorphic loci was 59.29%, indicating moderate genetic diversity between and within the different populations of J. curcas. Based on the genetic diversity analysis of AFLP markers, there were 1.464 (Na) and 1.216 (Ne) alleles, Nei’s gene diversity (H) was 0.132, Shannon’s information index (I) was 0.204, and the percentage of polymorphic loci was 46.40%. The AMOVA analysis showed that this large variance was due to differences within the populations, with genetic distinctions and limited gene flow among those from varied regions. The 17 populations were clustered into five main groups via UPGMA clustering analysis based on Nei’s genetic distance, and the genetic relationships among the populations exhibited no significant correlations with geographical provenances. The genetic variation among Chinese populations of J. curcas distributed in dry-hot valley areas was remarkable, and the American germplasm presented with distinct genetic differentiation.

Genetic characterization of white onion genotypes (Allium cepa L.) using ISSR markers

Understanding the genetic characteristics is crucial for preserving and developing Moroccan's white onion genotypes, with increased yield and quality as well as improved tolerance to biotic and abiotic stresses. In the present paper, inter simple sequence repeat (ISSR) markers were used to assess the genetic diversity and characteristics of white onion genotypes (Allium cepa L.) of Morocco. Based on the ISSR markers bands, 28 white onion genotypes were divided into four distinguished subgroups, with a genetic similarity value of 0.46 based on Jaccard index. Molecular markers analysis revealed that all ISSR markers were 100 % polymorphic with the white onions genotypes. Concerning markers performance, polymorphic information content (PIC) ranges from 0.051 to 0.39 with a mean of 0.301; however, the effective multiplex ratio (EMR) and marker index (MI) vary between 3–17 and 0.35–5.04, respectively. Based on resolving power (RP), it appears that the marker UBC825 has an efficient discriminatory power with an RP = 15.67. In contrast, the lowest RP value was detected with the marker UBC815 (RP = 1.58). Based on their high performance, markers UBC825, UBC835, UBC826, UBC840, and UBC811 ISSR seem to be specific and efficient for the identification of Moroccan white onion genotypes. Thus, given the genetic diversity shown by ISSR markers, the abundant resources of white onion genotypes in Morocco could be exploited in more valuable ways.

Phenotypic and Molecular-Markers-Based Assessment of Jamun (Syzygium cumini) Genotypes from Pakistan

Jamun plant displays enormous diversity throughout Pakistan, which necessitates its screening, evaluation, and validation to document elite genotypes having better traits for the benefit of the fruit industry and farmers. Surveys were made in natural Jamun habitats across Punjab, Pakistan, and genotypes were marked based on visual diversity of trees and fruits. In total, 60 Jamun genotypes were selected for characterization based on phenotypic and genetic markers. Phenotypic characters related to trees, leaf, and flower along with fruit qualitative traits were assessed in situ. Results revealed significant diversity with high (>25%) coefficient of variance values and the first two components of correspondence analysis exhibited 41.71% variation among genotypes. A strong association was observed among traits like upright tree and round fruit shape (0.74), bluish-colored fruit and pinkish pulp (0.85), and elliptic-shaped fruit with low fruit waxiness (−0.72). Leaves of phenotypically characterized plants were brought to Wheat Biotechnology Lab., University of Agriculture, Faisalabad, Pakistan, where Jamun genotypes were investigated genetically using Random Amplified Polymorphic DNA (RAPD) and Inter Simple Sequence Repeat (ISSR) markers. A total of 132 bands were scored, of which 108 were polymorphic, corresponding to almost 81% polymorphism among collected genotypes. High polymorphism information content values were observed against RAPD (0.389) and ISSR (0.457) markers. Genotypes were compared in relation to genetic markers, which exhibited that almost 86% of genetic variability was attributed to differences among accessions, while 14% of variation was due to differences between collections of different areas. Findings of this study confirmed wide phenotypic and genetic distinctness of Jamun in Pakistan that can aid breeders for marker-assisted selection and germplasm enhancement for future crop improvement programs.

Analysis of Fluorescently Labeled ISSR Markers to Reveal the Genetic Diversity of Cassava Varieties (Manihot esculenta Crantz) in the Kerala’s Tribal Area of India

The study Inter Simple Sequence Repeat (ISSR) molecular markers to genotype distinct cassava (Manihot esculenta Crantz) cultivars within tribal communities in Kerala, India. Fluorescent ISSR primers were labelled with 6-carboxyfluorescein and used for PCR amplification. The total number of bands produced was 72, of which 49 were found to be polymorphic markers; an average of 17 polymorphic bands was obtained per primer. The manuscript is a scientific validation of the traditional knowledge of tribal people regarding the diversity and wealth of cassava crops in the region, and this validation can therefore help in protecting the farmers right on a particular landrace that they cultivate. The technique used in the diversity analysis is a time-saving process as compared to conventional breeding programs for crop improvement. The data in the manuscript also supports similarity and differences of each variety to one another, which is analysed statistically with the molecular marker-based data generated. By examining genetic diversity at a high resolution, ISSR markers can provide valuable insights into the evolutionary dynamics of these cassava populations. This research contributes to the broader goal of enhancing agricultural sustainability and food security in tribal communities.

Molecular diversity of rice germplasms from Thailand characterized by different pericarp colors using Inter Simple Sequence Repeat (ISSR) markers

Abstract. Saengprajak J, Phetsom J, Sangdee A, Atichart P, Theerakulpisut P. 2024. Molecular diversity of rice germplasms from Thailand characterized by different pericarp colors using Inter Simple Sequence Repeat (ISSR) markers. Biodiversitas 25: 2839-2848. Studying genetic diversity in rice using molecular markers is necessary for varietal identification, better understanding of relationships and evolution, and conserving genetic resources. This study aimed to evaluate the genetic diversity of rice germplasms from Thailand characterized by different pericarp colors using ISSR markers. Thirty-two white and colored rice genotypes were assessed using 16 selected ISSR markers, which generated 179 alleles ranging from 210 to 1,374 bp, averaging 11.19 alleles per locus. The polymorphism percentage ranged from 40% to 100%, averaging 80%. The genetic similarity coefficient ranged from 0.458 to 0.855, while PIC values varied between 0.15 and 0.45, averaging 0.31. ISSR markers show a high Resolving Power (RP) of 12.15 and a Marker Index (MI) of 3.20, indicating their significant discriminatory power and effectiveness in detecting genetic diversity. The dendrogram grouped genotypes into five clusters: Cluster I included 5 red pericarp genotypes, Cluster II had 6 purple-black pericarp genotypes, Cluster III had 2 mixed white and purple-black pericarp genotypes, Cluster IV included 18 white pericarp genotypes, and Cluster V comprised 1 white pericarp genotype. PCA results corresponded to seed coat traits, forming eight grouping patterns similar to dendrogram clusters. These findings show that ISSR markers effectively assess genetic diversity and relationships in rice germplasms, providing valuable information for managing germplasm resources, developing variety-specific markers, and supporting rice breeding programs.

Genetic structure and gene flow among populations of willow (Salix species)

The newly developed Salix hybrids were assessed for genetic diversity using ISSR (Inter Simple Sequence Repeats) molecular markers. The results revealed 88.08 polymorphism, 0.53 polymorphism information content, 4.70 effective multiplex ratio, 2.54 marker index, and 7.18 resolving power from the amplified primers. Clones of the Salix matsudana (MAT) population recorded a maximum mean number of effective alleles (1.42), Shannon information index (0.38), gene diversity (0.25), and percentage of polymorphic loci (82.24 %). The AMOVA (Analysis of molecular variance) results revealed a moderate genetic divergence with a genetic variation of 88 per cent within populations and 12 per cent among the populations. The highest value of total diversity (0.28) and gene diversity (0.24) was recorded between S. matsudana (MAT) and S. tetrasperma (TETRA) populations, while there was more gene flow between S. matsudana (MAT) and S. tetrasperma (TETRA) populations (5.86). The clustering pattern obtained through STRUCTURE software showed two main gene pools and a mixture of 6–7 gene pools to confirm the hybrids based on ISSR marker data. S. matsudana and S. tetrasperma clones showed the highest gene diversity due to their proximity from their original locations, resulting in the least amount of gene exchange among populations. Molecular characterization using ISSR markers was extremely useful for studying the genetic diversity among the willow hybrids and high genetic variability should be utilized for breeding purposes in the future.

Assessment of Genetic Relationship among Rhynchostylis Species based on Inter-Simple Sequence Repeat (ISSR) Markers

Assessment of Genetic Relationship among <i>Rhynchostylis</i> Species based on Inter-Simple Sequence Repeat (ISSR) Markers

Curcuma species DNA fingerprinting of wild and cultivated genotypes from different agroclimatic zones

IntroductionCurcuma isolates from different agroclimatic zones in Chhattisgarh have been found to possess a varied spectrum of Curcumin, we set out to learn more about their genetic diversity by molecular fingerprinting in the present study. MethodsUsing SSR primers, the genetic variability of 25 Curcuma genotypes has been analyzed. These included the fingerprints of Curcuma longa, Curcuma aromatica, and Curcuma caesia. 13 inter simple sequence repeat (ISSR) primers amplified 107 unique fragments across all kinds, whereas 11 simple sequence repeat (SSR) primers amplified 51 unique fragments across all varieties, with 97 % and 86 % showing polymorphism, respectively. ResultsA total of 1080 ISSR and 567 SSR loci were amplified across all genotypes; among these, 5 monomorphic and 102 polymorphic alleles were produced in ISSR primers. However, SSR data showed 47 polymorphic and 4 monomorphic alleles. A panel of ISSR and SSR markers calculated DNA fingerprinting, genetic similarity, and distance estimates between Curcuma genotypes. In order to examine the diversity in different Curcuma genotypes, UPGMA data scoring methods were used. DiscussionCurcuma species demonstrate significant genetic variability, which is essential for breeding initiatives focused on creating better cultivars with desirable characteristics such as increased productivity, resistance to diseases, and improved medicinal capabilities.

Genetic diversity, chemical constituents and anatomical analysis of eight popular Olive (Olea europaea L.) cultivars in Al-Jouf region, Saudi Arabia

In light of the multitude of olive trees cultivated and the lack of the genetic diversity of available genotypes to select varieties and lines that are characterized by high diversity and better performance under the corresponding conditions, A comparison analysis of the genotyping and morphological characteristics of eight olive cultivars growing in Saudi Arabia’s Al-Jouf region was conducted and analyzed. Morpho-anatomical and chemical characteristics along with both inter-simple-sequence repeats (ISSRs) and start-codon-targeted (SCoT) markers were used to evaluate the genetic diversity among eight olive varieties in Al-Jouf, Saudi Arabia. Analyses of 27 morphological, chemical, and anatomical characteristics concluded the existence of genetic differences among the studied varieties. Moreover, six ISSR and eight SCoT primer combinations produced a total of 48 loci, of which 18 (10 ISSR and 8 SCoT) were polymorphic. The average polymorphism information content (PIC values of 0.48 and 0.44, respectively) and marker index (MI of 0.79 and 0.48, respectively) detected for ISSR and SCoT markers revealed the prevalence of high genetic diversity among the studied olive varieties. Based on chemical and anatomical characteristics and the selected molecular markers, the eight olive cultivars were grouped into two distinct clusters. Clusters in the adjacent joint dendrogram produced using ISSR, SCoT and combined data were similar, and grouped all individuals into two groups. However, the dendrogram generated on the basis of SCoT separated individuals into subgroups containing at least two varieties. The findings showed that both methods were effective in assessing diversity, and that SCoT markers can be used as a reliable and informative method for assessing genetic diversity and relationships among olive varieties and can serve as a complementary tool to provide a more complete understanding of the genetic diversity available in Olea europaea populations in Saudi Arabia.

GENETIC VARIATION IN TWO PHENOTYPES OF BALI CATTLE (Bos javanicus) INFERRED BY (AG)9C ISSR MARKER

&lt;p class="Abstract"&gt;&lt;strong&gt;Background.&lt;/strong&gt; Bali cattle (&lt;em&gt;Bos javanicus&lt;/em&gt;) are Indonesian native cattle that are kept as beef cattle. Among Bali cattle, however, there are white Bali cattle, called Taro cattle which are found in small numbers of the population and used only for religious ceremony needs. &lt;strong&gt;Objective. &lt;/strong&gt;To quantify the genetic variation in two phenotypes of Bali cattle (wildtype and white colors) with inter-simple sequence repeat (ISSR) primer of (AG)&lt;sub&gt;9&lt;/sub&gt;C. &lt;strong&gt;Methodology. &lt;/strong&gt;Forty Bali cattle, 20 wildtype bulls, and 20 white Bali cows were used. The blood samples were taken from the jugular vein of each animal using venoject vacutainer tube containing EDTA. The DNA extraction was performed using DNA extraction kit following the manufacturer’s protocol. Number of DNA fragments, number of effective alleles (n&lt;sub&gt;e&lt;/sub&gt;), and polymorphic informative content (PIC) were calculated to describe the genetic diversity in animals under study. &lt;strong&gt;Result&lt;/strong&gt;&lt;strong&gt;s&lt;/strong&gt;: Results showed that three haplotype (H) types were observed in the animals under this study based on the ISSR fragments. The polymorphic informative content (PIC) in the white animals was higher than in the wild-type animals (0.62 vs 0.18). According to (AG)&lt;sub&gt;9&lt;/sub&gt;C ISSR marker, mostly white (50%) and wildtype (90%) animals were classified into H2 type. Therefore, a total of 25% of white and 10% of wild-type animals were classified into H3 type. While 25% of white animals were classified into H1 type. &lt;strong&gt;Implications. &lt;/strong&gt;the information generated in this study can be used as early information to investigate the molecular genetics of Taro cattle. &lt;strong&gt;Conclusion&lt;/strong&gt;&lt;strong&gt;s&lt;/strong&gt;: This study suggests that many white animals have a specific locus which is absent in wild-type animals. &lt;/p&gt;

Genetic Diversity and Relationships among Indian Jujube (Ziziphus mauritiana Lamk.) Cultivars Using Morphometric Characteristics, matK Barcoding, and ISSR Markers

Indian jujube displays genetic diversity and does not prominently display minute morphometric variations, and this makes correct identification a difficult and long-term task. However, little work has been conducted to bring jujube cultivars into domestication. So, the present study aimed to evaluate eleven cultivars of Indian jujube in terms of the fruit’s morphometric characteristics, as well as molecular marker studies by plastidial megakaryocyte-associated tyrosine kinase (matK) barcoding and inter-simple sequence repeats (ISSR) markers for species differentiation, identification, and relationships among Indian jujube cultivars. The results of the morphometric characteristics showed that the mean geometric diameter, surface area, sphericity, sphericity ratio, shape index, fruit length, fruit diameter, fruit weight, and seed weight varied among cultivars. The results also showed that the color values of L*, a*, and b* for fruits differed in different cultivars. In addition, the results showed a discrepancy in the genetic diversity parameters related to the matK barcoding, ISSR markers, and relationships among Indian jujube cultivars. Substantially, hierarchical clustering by heatmap revealed that ‘Zytoni’ and ‘Um-Sulaem’ with spines seem to be mono-clades distinct from other cultivars, which related to variations in the expression levels of genes. Therefore, they should be relied upon together to distinguish and identify cultivars in order to maximize the effectiveness of local germplasm conservation and exploitation.

Investigation of genetic diversity using molecular and biochemical markers associated with powdery mildew resistance in different flax (Linum usitatissimum L.) genotypes

Under greenhouse conditions, the resistance of 18 different genotypes of flax to powdery mildew was evaluated. To investigate genetic diversity and identify the molecular and biochemical markers linked to powdery mildew resistance in the tested genotypes, two molecular marker systems—start codon targeted (SCoT) and inter-simple sequence repeat (ISSR)—as well as a biochemical marker (protein profiles, antioxidant enzyme activity, and secondary metabolites) were used. Based on the results, the genotypes were classified into four categories: highly susceptible, susceptible, moderately susceptible, and moderately resistant. The genotypes differed significantly in powdery mildew severity: Polk had a severity of 92.03% and Leona had a severity of 18.10%. Compared to the other genotypes, the moderately resistant genotypes had higher levels of flavonoids, antioxidant enzymes, phenolics, and straw yield; nevertheless, their hydrogen peroxide and malondialdehyde levels were lower. Protein profiles revealed 93.75% polymorphism, although the ISSR marker displayed more polymorphism (78.4%) than the SCoT marker (59.7%). Specific molecular and biochemical markers associated with powdery mildew resistance were identified. The 18 genotypes of flax were divided into two major clusters by the dendrogram based on the combined data of molecular markers. The first main cluster included Leona (genotype number 7), considered moderate resistance to powdery mildew and a separate phenetic line. The second main cluster included the other 17 genotypes, which are grouped together in a sub-cluster. This means that, besides SCoT, ISSR markers can be a useful supplementary technique for molecular flax characterization and for identifying genetic associations between flax genotypes under powdery mildew infection.

Molecular Identification of Genetic Diversity and Population Structure in Moroccan Male Date Palm (Phoenix dactylifera L.) Using Inter-Simple Sequence Repeat, Direct Amplification of Minisatellite DNA, and Simple Sequence Repeat Markers

Understanding genetic diversity and population structure plays a vital role in the efficient use of available material in plant-breeding programs and in germplasm conservation strategies. In the present study, we aim to evaluate the genetic variations and population structure of male date palms from Morocco. The genetic diversity of 100 date palm (Phoenix dactylifera L.) genotypes was investigated using the performance of three types of molecular markers: inter-simple sequence repeats (ISSRs), direct amplification of minisatellite DNA (DAMD), and simple sequence repeats (SSRs). On the basis of their polymorphic information content (PIC) (ISSRs = 0.38; DAMD = 0.4; SSRs = 0.33), effective multiplex ratio (EMR) (ISSRs = 27.34; DAMD = 52.31; SSRs = 22.20), Resolving power Rp (ISSR = 13.81; DAMD = 28.73; SSR = 14.6), and marker index (MI) (ISSRs = 9.22; DAMD = 20.23; SSRs = 7.54) values, all markers used in our study are considered informative markers. Among them, DAMD markers demonstrated slightly higher informativeness compared to ISSR and SSR markers. A total of 216, 438, and 248 bands were, respectively, detected using ISSRs, DAMD, and SSRs, with 95%, 98% and 94% of polymorphism, respectively. The AMOVA results revealed considerable diversity within date palms. The PCOa results showed that males of Tinghir and Errachidia were regrouped into the same cluster, while males of Goulmima were separated into another group. A cluster and structure analysis separated the studied genotypes into three groups. One group comprises genotypes of males from Zagora with some female varieties scattered in this group. The second group includes male genotypes from Goulmima along with accessions of female and male varieties. The third group contains males of Errachidia, Tata and Tinghir populations. The cluster and structure analysis separated the studied genotypes according to their origin.

Microsatellite marker-based analysis of the genetic diversity and population structure of three Arnebiae Radix in western China

Arnebiae Radix is an important medicinal and perennial herb found in Western China, particularly in the Xinjiang region. However, the assessment, utilization and conservation of Arnebiae Radix resources are still unexplored. In this study, we evaluated the genetic diversity of three Arnebiae Radix populations across 47 regions (Ae = 16, Ag = 16, Ad = 15) in Xinjiang, China, using inter-simple sequence repeat (ISSR) molecular markers. In total, 48 alleles were amplified by six pairs of primers screened with ISSR markers. The average number of effective alleles (Ne) was 1.5770. The percentage of interspecific genetic polymorphisms in A. guttata (Ag = 89.58 %) was greater than that in A. euchroma. and A. decumbens (Ae = Ad = 87.50 %). Intraspecific genetic polymorphisms, Bo Le (BL) population of A. euchroma exhibited the highest percentage of polymorphic bands (PPB% =58.33 %, Na = 1.313, Ne = 1.467, I = 0.0.366, H = 0.255), which indicated high genetic diversity. In contrast, the Tuo Li (TL) population of A. guttata had the lowest values for these parameters (PPB% =0.00 %, Na = 0.313, Ne = 1,000, I = 0.000, H = 0.000). The Arnebiae Radix germplasms were classified into two major groups (I and II) based on UPGMA cluster analysis (Fig. 8a) and principal coordinate analysis (PCOA). In addition, A. decumbens is placed in a separate category due to its high differentiation coefficient. The AMOVA and genetic differentiation coefficient results indicated that the genetic variation in Arnebiae Radix was predominantly due to intrapopulation differences (78 %). Additionally, the gene flow index (Nm) between populations was 2.4128, which further indicated that the genetic diversity of Arnebiae Radix was greater at the intrapopulation level. The destruction of the ecological environment leads to the continuous reduction and degradation of the genetic diversity of Arnebiae Radix germplasm resources. In this study, we used ISSR molecular markers to analyze the genetic diversity and relatedness of Arnebiae Radix, which revealed the genetic relationship of Arnebiae Radix germplasm resources at the molecular level and provided a scientific basis for future research on selecting and breeding good varieties, evaluating the quality of Arnebiae Radix, and conserving and utilizing its resources.

Thymus algeriensis Boiss. et Reut., a north African endemic plant species: genetic diversity and population structure as assessed by molecular markers, a pioneer step for conservation implications.

Thymus algeriensis Boiss. et Reut. is one of the most widespread North African species of the genus Thymus L. The species is subshrub growing primarily in subtropical biome of Morocco, Algeria, Tunisia and Libya. In Tunisia, the plant species is under high pressure of anthropogenic activities including over-collecting. The assessment of genetic diversity and population structure of T. algeriensis is a pioneer step to retrace its evolutionary history and to perform appropriate conservation strategies of the plant species. Seven wild populations growing, widely, in different bioclimatic zones were selected and analysed using two molecular markers systems. Fifteen Simple Sequence Repeats (SSRs) and fifteen Inter-Simple Sequence Repeats (ISSRs) were used to characterize genetically 140 different genotypes. The results showed a high molecular variation within populations and among the studied genotypes. The intra-populations genetic diversity revealed by SSRs was higher (P = 80.95%, Na = 2.143 and He = 0.364) than that based on ISSRs (P = 78.12%, Na = 1.632, He = 0.265 and I = 0.398). As demonstrated by inbreeding coefficients, a significant level of differentiation and a low level of gene flow were detected among studied populations (FST = 0.161 for SSRs and ΦST = 0.197 for ISSRs). Furthermore, the results of ISSRs marker suggest land strips as barriers in population genetic structure. While SSRs marker reflects a relatively structured bioclimatic patterns of studied populations. The Bayesian analysis showed a specific adaptation of populations to local environments. The used molecular markers (ISSRs and SSRs) seem to be effective in deciphering genetic polymorphism of Tunisian genotypes of T. algeriensis. Therefore, the genetic structure of the studied genotypes could constitute a starting point for further conservation, characterization and breeding programs.

Genetic diversity and morpho-physiological assessment of drought tolerance in rapeseed (Brassica napus L.) cultivars

AbstractWater deficit is one of the most important abiotic stresses constraining crop production in rapeseed. Understanding the mechanisms of adaptation to this stress is essential for the development and production of drought-tolerant genotypes. For this reason, this research study aims to investigate the importance of genetic diversity in identifying genotypes with a high degree of drought tolerance through assessing effectiveness of inter simple sequence repeat (ISSR) markers on 14 genotypes of rapeseed in a factorial design. Morphological and physiological characteristics were studied after the early stages of growth; in order to evaluate the genetic diversity among genotypes, 18 different ISSR markers were used. A total of 106 clear and scalable loci were amplified, of which 60 bands (56.6%) were polymorphic. The highest polymorphism information content belonged to marker number 9 with the amount of 0.365 (85.7%). Gene variation ranged from 0.081 to 0.365 and the rapeseed genotypes were divided into three groups by cluster analysis (unweighted pair group method with arithmetic mean method). The analysis of molecular variance showed that 70% of the total variation was observed within populations and 30% of this variation occurred among populations. In addition, t-test was used for comparing oil content percentage among different genotypes in control and stress levels. Adriana had the highest amount of seed oil with 36.47%, whereas Karaj 2 had the lowest amount with 27.28 and Cooper had the highest decrease in oil content percentage under stress conditions. Overall, the genotypes Likord, Hyola 401 and Sarigol 32 were identified as the most drought-tolerant.