Average Polymorphism Information Content Value Research Articles

Population structure and genetic diversity of Tamarix chinensis as revealed with microsatellite markers in two estuarine flats.

Tamarix chinensis Lour. is a 3-6-meter-tall small tree with high salt- and alkali- tolerance and aggressive invasiveness, mainly distributed in the eastern part of China in warm-temperate and subtropical climate zones, yet there is little information available regarding genetic diversity and population structure. A total of 204 individuals of nine T. chinensis populations were investigated for genetic diversity and population structure using a set of 12 highly polymorphic microsatellite markers. The total number of alleles detected was 162, the average number of effective allele was 4.607, the average polymorphism information content (PIC) value of the 12 loci was 0.685, and the mean observed heterozygosity (Ho) and the mean expected heterozygosity (He) was 0.653 and 0.711, respectively. Analysis of molecular variance (AMOVA) showed a 5.32% genetic variation among T. chinensis populations. Despite a low population differentiation, Bayesian clustering analysis, discriminant analysis of principal components (DAPC) and the unweighted pair group method with arithmetic mean (UPGMA) clearly identified three genetic clusters correlated to the populations' geographic origin: the northern populations including those from Yellow River Delta, the Fangshan (FS) population from Beijing, the Changyi (CY) population from Bohai Bay, the Huanjiabu (HHJ) population from Hangzhou Bay, and the remaining two populations from Hangzhou Bay. There was a significant relationship between the genetic distance and geographical distance of the paired populations. Gene flow (Nm) was 4.254 estimated from FST. T. chinensis possessed high genetic diversity comparable to tree species, and although the population differentiation is shallow, our results classified the sampled populations according to sampling localities, suggesting the different origins of the study populations.

Genetic diversity and population structure analysis in cultivated soybean (Glycine max [L.] Merr.) using SSR and EST-SSR markers.

Soybean (Glycine max) is an important legume that is used to fulfill the need of protein and oil of large number of population across the world. There are large numbers of soybean germplasm present in the USDA germplasm resources. Finding and understanding genetically diverse germplasm is a top priority for crop improvement programs. The current study used 20 functional EST-SSR and 80 SSR markers to characterize 96 soybean accessions from diverse geographic backgrounds. Ninety-six of the 100 markers were polymorphic, with 262 alleles (average 2.79 per locus). The molecular markers had an average polymorphic information content (PIC) value of 0.44, with 28 markers ≥ 0.50. The average major allele frequency was 0.57. The observed heterozygosity of the population ranged from 0-0.184 (average 0.02), while the expected heterozygosity ranged from 0.20-0.73 (average 0.51). The lower value for observed heterozygosity than expected heterozygosity suggests the likelihood of a population structure among the germplasm. The phylogenetic analysis and principal coordinate analysis (PCoA) divided the total population into two major groups (G1 and G2), with G1 comprising most of the USA lines and the Australian and Brazilian lines. Furthermore, the phylogenetic analysis and PCoA divided the USA lines into three major clusters without any specific differentiation, supported by the model-based STRUCTURE analysis. Analysis of molecular variance (AMOVA) showed 94% variation among individuals in the total population, with 2% among the populations. For the USA lines, 93% of the variation occurred among individuals, with only 2% among lines from different US states. Pairwise population distance indicated more similarity between the lines from continental America and Australia (189.371) than Asia (199.518). Overall, the 96 soybean lines had a high degree of genetic diversity.

Evaluation of Genetic Diversity in Indian Mustard (Brassica juncea var. rugosa) Employing SSR Molecular Markers

Indian mustard (Brassica juncea var. rugosa) constitutes an authoritative group of mustard crops in India. Evaluation of genetic diversity is a vivacious component of mustard breeding programmes for efficient utilization of plant genetic resources. In present study, 77 microsatellite markers were employed to assess the genetic diversity of 75 Indian mustard genotypes. Results revealed positive amplification for all SSRs, with 21 SSRs exhibiting polymorphic amplicons. A total of 99 alleles, ranging from 3 to 5 with an average of 4.71 alleles per SSR marker were obtained. The major allele frequency varied between 0.26 (cnu/m616) and 0.56 (ENA28F) with an average value of 0.36. The average polymorphic information content (PIC) value was 0.67 and ranged between 0.43 (ENA28F) and 0.76 (gi258660710gbGT071338.1). Mean value of 0.72 was detected for each pair of SSR primers, with the gene diversity per locus ranging between 0.53 (ENA28F) and 0.79 (gi258660710gbGT071338.1). The dendrogram grouped the 75 genotypes into three main clusters or subpopulations based on Unweighted Neighbour-Joining technique. The study revealed better understanding of the genetic diversity among different Indian mustard genotypes using genomic-SSR markers that could be exploited for the genetic improvement of the crop.

Morphological and molecular characterization of flax (Linum usitatissimum L.) accessions obtained from different locations in Turkey

Flax (Linum usitatissimum L.) is one of the most significant industrial crops due to its oil and fiber, which have a plethora of uses. Because of this, the characterization and introduction/adaptation of flax crops are of great interest. For this reason, we aimed to investigate the genetic diversity and patterns of flax cultivars/genotypes (a 63-cultivar/genotype was used) employing single sequence repeat microsatellite markers via 16 strong amplicon loci, and by estimating their morphological attributes. We determined the quality of the flax, in terms of oil content and composition, and its fiber quality using scanning electron microscopy and strength-linked attributes. For assessment, a series of statistical analyses were carried out in order to cluster and scatter the relevant parameters corresponding to the cultivars/genotypes. Of the assayed flax cultivar/genotypes, Eckendorfi was found to have promising agromorphological values. The average polymorphic information content values were recorded (= 0.689), and the smallest and largest loci with allele dimensions were Lu9(2) and Lu19-Lua613(6) respectively. Overall, the agromorphological attributes were consistent with the microsatellite-based markers in decoding the genetic diversity and population structure of the flax germplasm.

Exploring genetic diversity and population structure of a large grapevine (Vitis vinifera L.) germplasm collection in Türkiye.

Grapevine (Vitis Vinifera L.) has been one of the significant perennial crops in widespread temperate climate regions since its domestication around 6000 years ago. Grapevine and its products, particularly wine, table grapes, and raisins, have significant economic importance not only in grapevine-growing countries but also worldwide. Grapevine cultivation in Türkiye dates back to ancient times, and Anatolia is considered one of the main grapevine migration routes around the Mediterranean basin. Turkish germplasm collection, conserved at the Turkish Viticulture Research Institutes, includes cultivars and wild relatives mainly collected in Türkiye, breeding lines, rootstock varieties, and mutants, but also cultivars of international origin. Genotyping with high-throughput markers enables the investigation of genetic diversity, population structure, and linkage disequilibrium, which are crucial for applying genomic-assisted breeding. Here, we present the results of a high-throughput genotyping-by-sequencing (GBS) study of 341 genotypes from grapevine germplasm collection at Manisa Viticulture Research Institute. A total of 272,962 high-quality single nucleotide polymorphisms (SNP) markers on the nineteen chromosomes were identified using genotyping-by-sequencing (GBS) technology. The high-density coverage of SNPs resulted in an average of 14,366 markers per chromosome, an average polymorphism information content (PIC) value of 0.23 and an expected heterozygosity (He) value of 0.28 indicating the genetic diversity within 341 genotypes. LD decayed very fast when r2 was between 0.45 and 0.2 and became flat when r2 was 0.05. The average LD decay for the entire genome was 30 kb when r2=0.2. The PCA and structure analysis did not distinguish the grapevine genotypes based on different origins, highlighting the occurrence of gene flow and a high amount of admixture. Analysis of molecular variance (AMOVA) results indicated a high level of genetic differentiation within populations, while variation among populations was extremely low. This study provides comprehensive information on the genetic diversity and population structure of Turkish grapevine genotypes.

Genome-Wide Development of Polymorphic Microsatellite Markers and Genetic Diversity Analysis for the Halophyte Suaeda aralocaspica (Amaranthaceae).

Suaeda aralocaspica, which is an annual halophyte, grows in saline deserts in Central Asia with potential use in saline soil reclamation and salt tolerance breeding. Studying its genetic diversity is critical for effective conservation and breeding programs. In this study, we aimed to develop a set of polymorphic microsatellite markers to analyze the genetic diversity of S. aralocaspica. We identified 177,805 SSRs from the S. aralocaspica genome, with an average length of 19.49 bp, which were present at a density of 393.37 SSR/Mb. Trinucleotide repeats dominated (75.74%) different types of motifs, and the main motif was CAA/TTG (44.25%). We successfully developed 38 SSR markers that exhibited substantial polymorphism, displaying an average of 6.18 alleles with accompanying average polymorphism information content (PIC) value of 0.516. The markers were used to evaluate the genetic diversity of 52 individuals collected from three populations of S. aralocaspica in Xinjiang, China. The results showed that the genetic diversity was moderate to high, with a mean expected heterozygosity (He) of 0.614, a mean Shannon's information index (I) of 1.23, and a mean genetic differentiation index (Fst) of 0.263. The SSR markers developed in this study provide a valuable resource for future genetic studies and breeding programs of S. aralocaspica, and even other species in Suaeda.

Development of Chloroplast Microsatellite Markers and Evaluation of Genetic Diversity and Population Structure of Cutleaf Groundcherry (Physalis angulata L.) in China.

Cutleaf groundcherry (Physalis angulata L.), an annual plant containing a variety of active ingredients, has great medicinal value. However, studies on the genetic diversity and population structure of P. angulata are limited. In this study, we developed chloroplast microsatellite (cpSSR) markers and applied them to evaluate the genetic diversity and population structure of P. angulata. A total of 57 cpSSRs were identified from the chloroplast genome of P. angulata. Among all cpSSR loci, mononucleotide markers were the most abundant (68.24%), followed by tetranucleotide (12.28%), dinucleotide (10.53%), and trinucleotide (8.77%) markers. In total, 30 newly developed cpSSR markers with rich polymorphism and good stability were selected for further genetic diversity and population structure analyses. These cpSSRs amplified a total of 156 alleles, 132 (84.62%) of which were polymorphic. The percentage of polymorphic alleles and the average polymorphic information content (PIC) value of the cpSSRs were 81.29% and 0.830, respectively. Population genetic diversity analysis indicated that the average observed number of alleles (Na), number of effective alleles (He), Nei's gene diversity (h), and Shannon information indices (I) of 16 P. angulata populations were 1.3161, 1.1754, 0.1023, and 0.1538, respectively. Moreover, unweighted group arithmetic mean, neighbor-joining, principal coordinate, and STRUCTURE analyses indicated that 203 P. angulata individuals from 16 populations were grouped into four clusters. A molecular variance analysis (AMOVA) illustrated the considerable genetic variation among populations, while the gene flow (Nm) value (0.2324) indicated a low level of gene flow among populations. Our study not only provided a batch of efficient genetic markers for research on P. angulata but also laid an important foundation for the protection and genetic breeding of P. angulata resources.

Genetic Profile of Local Buffalo (Bubalus bubalis) Populations in Pacitan and Tuban, East Java, Indonesia Measured by the Molecular Marker of INRA032 Locus

This study focused on the application of microsatellite markers at the INRA032 locus for genetic diversity assessment in buffalo (Bubalus bubalis) populations in Pacitan and Tuban Regencies, East Java, Indonesia. The total number of samples used was 16, each population represented by 8 samples. Genetic diversity assessment parameters include allele frequency, the Polymorphism Information Content (PIC) and heterozygosity. The results showed that based on the INRA032 locus, the Tuban buffalo population had a higher allele frequency range (0.08 to 0.33) than the Pacitan population (0.18 to 0.31). The average PIC value in both populations was 0.39, so it can be concluded that the INRA032 locus is informative enough to detect polymorphisms in both populations. The percentage heterozygosity of the Pacitan buffalo population is 88%, which is higher than the Tuban population at 50%, suggesting that the genetic diversity of the two populations is still quite high despite the decreasing trend in population numbers.

Population genetic characteristics of Aedes aegypti in 2019 and 2020 under the distinct circumstances of dengue outbreak and the COVID-19 pandemic in Yunnan Province, China.

Introduction: Since Aedes aegypti invaded Yunnan Province in 2002, its total population has continued to expand. Shi et al. used microsatellite and mitochondrial molecular markers to study the Ae. aegypti populations in Yunnan Province in 2015 and 2016, found that it showed high genetic diversity and genetic structure. However, there are few studies on the population genetic characteristics of Ae. aegypti in Yunnan Province under different levels of human intervention. This study mainly used two common types of molecular markers to analyze the genetic characteristics of Ae. aegypti, revealing the influence of different input, prevention and control pressures on the genetic diversity and structure of this species. Understanding the genetic characteristics of Ae. aegypti populations and clarifying the diversity, spread status, and source of invasion are essential for the prevention, control and elimination of this disease vector. Methods: We analyzed the genetic diversity and genetic structure of 22 populations sampled in Yunnan Province in 2019 and 17 populations sampled in 2020 through nine microsatellite loci and COI and ND4 fragments of mitochondrial DNA. In 2019, a total of 22 natural populations were obtained, each containing 30 samples, a total of 660 samples. In 2020, a total of 17 natural populations were obtained. Similarly, each population had 30 samples, and a total of 510 samples were obtained. Results: Analysis of Ae. aegypti populations in 2019 and 2020 based on microsatellite markers revealed 67 and 72 alleles, respectively. The average allelic richness of the populations in 2019 was 3.659, while that in 2020 was 3.965. The HWE analysis of the 22 populations sampled in 2019 revealed significant departure only in the QSH-2 population. The 17 populations sampled in 2020 were all in HWE. The average polymorphic information content (PIC) values were 0.546 and 0.545, respectively, showing high polymorphism. The average observed heterozygosity of the 2019 and 2020 populations was 0.538 and 0.514, respectively, and the expected average heterozygosity was 0.517 and 0.519, showing high genetic diversity in all mosquito populations. By analyzing the COI and ND4 fragments in the mitochondrial DNA of Ae. aegypti, the populations sampled in 2019 had a total of 10 COI haplotypes and 17 ND4 haplotypes. A total of 20 COI haplotypes were found in the populations sampled in 2020, and a total of 24 ND4 haplotypes were obtained. STRUCTURE, UPGMA and DAPC cluster analyses and a network diagram constructed based on COI and ND4 fragments showed that the populations of Ae. aegypti in Yunnan Province sampled in 2019 and 2020 could be divided into two clusters. At the beginning of 2020, due to the impact of COVID-19, the flow of goods between the port areas of Yunnan Province and neighboring countries was reduced, and the sterilization was more effective when goods enter the customs, leading to different immigration pressures on Ae. aegypti population in Yunnan Province between 2019 and 2020, the source populations of the 2019 and 2020 populations changed. Mantel test is generally used to detect the correlation between genetic distance and geographical distance, the analysis indicated that population geographic distance and genetic distance had a moderately significant correlation in 2019 and 2020 (2019: p < 0.05 R2 = 0.4807, 2020: p < 0.05 R2 = 0.4233). Conclusion: Ae. aegypti in Yunnan Province maintains a high degree of genetic diversity. Human interference is one reason for the changes in the genetic characteristics of this disease vector.

Genetic Variability of Small Horse Populations from Greek Islands

In this study, we analyzed microsatellite variation in DNA obtained from hair samples collected from 46 local Greek horse populations originating from the islands of Skyros (Skyros Small Horse; n=9), Rhodes (Rodos Small Horse; n=6), Lesvos (with the traditional miniature Midili Small Horse (n=2) and the larger Lesvos Gaiter (n=22)) and Crete (Messara) (n=7). We used 15 autosomal microsatellite markers (VHL20, HTG4, AHT4, HMS7, HTG6, AHT5, HMS6, ASB2, HTG10, HTG7, HMS3, HMS2, ASB17, ASB23 and LEX33) for the genetic characterization of the above populations and exploration of their genetic structure and diversity levels. A total of 120 alleles were detected across the 15 loci with a minimum of 4 alleles in HTG7 locus and a maximum of 13 alleles in ASB17 locus. Τhe total per population number of alleles was 42 (Skyros Small Horse), 20 (Rodos Small Horse), 71 (Lesvos Gaiter), 52 (Messara breed) and 21 (Midili Small Horse). The effective number of alleles (Ne) per locus ranged from 1.47±0.13 (Rodos Small Horse) to 4.67±0.31 (Lesvos Gaiter). The allelic richness (Ar) was between 1.50±0.12 (Rodos Small Horse) and 2.93±0.08 (Lesvos Gaiter) and the average Polymorphism Information Content (PIC) values varied from 0.200±0.035 (Rodos Small Horse) to 0.733±0.026 (Lesvos Gaiter). No significant deviations from H-W equilibrium were found except for three loci (ASB2, HTG10 and LEX33) in Messara and one locus (ASB23) in Lesvos Gaiter. Τhe inbreeding coefficient (Fis) ranged from -0.130 (Rodos Small Horse) to 0.042 (Lesvos Gaiter). The observed (Ho) and expected (He) multilocus heterozygosity mean estimations were highest in Lesvos Gaiter (0.764±0.027 and 0.783±0.024, respectively) and smallest in Rodos Small Horse (0.300±0.075 and 0.269±0.064, respectively). Across loci, the total genetic diversity HT was 0.741, the diversity among subpopulations HS was 0.621 and the multilocus genetic differentiation GST was 0.161, which was rather high. The population of Rodos Small Horse separated from the remaining horses as shown by factorial correspondence analysis, population assignment and metric multidimensional scaling diagrams. This study highlights the loss of genetic diversity in small isolated horse populations and the urgent need to take protective measures to preserve them.

Avena sterilis L.’in Mikrosatellit İşaretleyicileri ile Genetik Çeşitlilik Analizi

Avena sterilis is an important grassy weed that causes a problem in wheat cultivation areas, and intensive herbicides are used to control it. Genetic diversity study is important to have information how on the effect weed species of the environmental factors and herbicides. The high level of genetic diversity within the species is a guarantee for adaptation to changing environmental conditions. This study was conducted based on complaints of the loss of effectiveness during the chemical control. Analyses were carried out on 27 selected populations collected from wheat cultivation areas in Turkey's Middle Black Sea region. Seventy-seven alleles from microsatellite loci were detected, and the average number of alleles per locus was determined as five using 17 microsatellite primers. The average gene diversity (GD) and polymorphism information content (PIC) values were 0.894 and 0.732, respectively. According to the UPGMA dendrogram generated using Average Linkage, the populations were clustered into two main groups. A high degree of diversity was found among the studied steril oat genotypes, and it is seen that there is no geographical isolation. It is understood that this situation primarily provides adaptation to those geographical areas by transporting weed seeds from other provinces in various ways. According to these findings, issues such as crop rotation, cultural control methods, encouraging the use of certified seeds, and the use of herbicides with different mechanisms of action can be listed among the measures that can be taken to control the high genetic diversity, which is an indicator of herbicide resistance.

A Set of Highly Polymorphic Microsatellite Markers for Genetic Diversity Studies in the Genus Origanum

This study reports the development of a set of 20 highly polymorphic genomic SSR markers which can be used for both cultivar identification and genetic diversity studies in several Origanum species, including some of the most popular ones like Greek oregano (Origanum vulgare L. ssp. hirtum), common oregano (O. vulgare L. ssp. vulgare), and sweet marjoram (O. majorana L.). Analysis of the polymorphic information content (PIC) showed an average PIC value of 0.75 with a minimum of 0.41 and a maximum of 0.89, where 17 of the markers showed PIC values above 0.73. Comparative analysis of the genetic diversity of eight natural populations of Greek oregano in Bulgaria showed that six of the genomic SSR markers revealed significantly higher portions of genetic diversity in the populations, compared to 12 EST SSR markers used in our previous study. We also compared the performance of the same six genomic SSR markers with the results for eight SRAP primer combinations, which showed that SRAP markers captured more precisely the genetic structure in natural populations. The developed highly polymorphic genomic SSR markers can be successfully applied to evaluation of the genetic diversity in the genus Origanum, based on the expected and observed heterozygosity in the populations as well as for easy identification of breeding lines and cultivars based on unique SSR fingerprints.

Development of Diagnostic Markers and Applied for Genetic Diversity Study and Population Structure of Bipolaris sorokiniana Associated with Leaf Blight Complex of Wheat

Bipolaris sorokiniana, a key pathogenic fungus in the wheat leaf blight complex, was the subject of research that resulted in the development of fifty-five polymorphic microsatellite markers. These markers were then used to examine genetic diversity and population structure in Indian geographical regions. The simple sequence repeat (SSR) like trinucleotides, dinucleotides, and tetranucleotides accounted for 43.37% (1256), 23.86% (691), and 16.54% (479) of the 2896 microsatellite repeats, respectively. There were 109 alleles produced by these loci overall, averaging 2.36 alleles per microsatellite marker. The average polymorphism information content value was 0.3451, with values ranging from 0.1319 to 0.5932. The loci's Shannon diversity varied from 0.2712 to 1.2415. These 36 isolates were divided into two main groups using population structure analysis and unweighted neighbour joining. The groupings were not based on where the isolates came from geographically. Only 7% of the overall variation was found to be between populations, according to an analysis of molecular variance. The high amount of gene flow estimate (NM = 3.261 per generation) among populations demonstrated low genetic differentiation in the entire populations (FST = 0.071). The findings indicate that genetic diversity is often minimal. In order to examine the genetic diversity and population structure of the B. sorokiniana populations, the recently produced microsatellite markers will be helpful. This study's findings may serve as a foundation for developing improved management plans for the leaf blight complex and spot blotch of wheat diseases in India.

English

Fungal diseases are one of the major causes of losses on wheat yield in the world. Recent studies on plant defense mechanisms have highlighted the role of amino acids and total polyphenols in disease tolerance. Thus, with the objective of identifying on the basis of morphological and physiological variables the high-performance wheat accessions in high and low altitude, we characterized sixteen wheat accessions via quantification of polyphenols (TPP) and amino acids (AA) and identified fungal diseases affecting wheat in Centre Cameroon. Using the set of the three hexaploid wheat cultivars where the 11 microsatellite markers data was available, a total of 29 alleles were detected among cultivars and the number of alleles per locus ranged from 2 to 3 with an average of 2.64. Gene diversity ranged from 0.44 to 0.67 with an average of 0.59, increasing with the number of alleles. Microsatellites markers used had an average Polymorphic Information Content (PIC) value of 0.50, indicating that these markers are useful and will make a contribution to the studies in hexaploid wheat. The assessment of wheat plant to disease tolerance permitted to identify Septoria, Fusarium wilt; tanned spot and powdery mildew in high and low altitude. Analyzes of TPP and AA have made it possible to discriminate accessions that are tolerant to diseases. Hence, accession Atilla 1 was highly tolerant and had high levels of TPP (3.5 &plusmn; 0.36 &mu;g/mg) and AA (40.1 &plusmn; 1.21 &mu;g/mg) while the accession Sup 152 highly susceptible to disease had low levels (2.3 &plusmn; 0.1 and 2.1 &plusmn; 0.36 &mu;g/mg, respectively). This study will contribute to the extension of wheat in areas where conditions similar to the study sites will be localized. &nbsp; Key words: Amino acids, bread wheat, high and low altitude, fungal diseases, polyphenols.

Genetic Diversity and Differences among Three F1 Families and Two Wild Populations of Genus Scylla Using Microsatellite Markers

Genetic diversity is the determinant of the allocation of germplasm resources in the genetic improvement of aquaculture species. In this study, three F1 families, including a hybrid Scylla family (S. paramamosain ♂ × S. serrata ♀), a paternal family of S. paramamosain, a maternal family of S. serrata, and two wild populations, including a paternal population of S. paramamosain and a maternal population of S. serrata, were used to investigate the genetic diversity and genetic difference. The results indicated that 98 alleles of nine microsatellites loci were observed in five Scylla populations. The highest average value of Ho (observed heterozygosity), He (expected heterozygosity), and PIC (polymorphic information content) of the wild S. paramamosain population were 0.790, 0.799, and 0.771, respectively, suggesting the wild paternal population has high genetic diversity. The comparative analysis of PIC, Fst (fixation index), and HWE (Hardy–Weinberg equilibrium) indicated that the paternal S. paramamosain may be more suitable for artificial breeding than the maternal S. serrata from the perspective of allele frequency. Analysis of molecular variance analysis (AMOVA) showed that the total genetic variation mainly occurred within populations (73.28%), demonstrating that artificial breeding may induce genetic differentiation of the family groups of Scylla. The results of the analysis of Fst value, UPGMA (unweighted pair-group mean analysis) dendrogram, and genetic diversity indicated that the F1 hybrid offspring had a close genetic distance and high genetic identity with the paternal S. paramamosain populations. It indicated that the F1 hybrid offspring showed potential paternal genetic affinities and a similar potential for artificial breeding with S. paramamosain. The study will provide valuable information to evaluate the difference in the genetic diversity and population structure between hybrid offspring and distinct parental populations of Scylla.

Evaluating genetic diversity of geographically diverse populations of Embelia ribes Burm f., a highly medicinal woody liana from the Western Ghats of India, using random amplified polymorphic DNA (RAPD) and intersimple sequence repeats (ISSR) markers.

Embelia ribes Burm f. (Primulaceae) is a medicinal and vulnerable woody liana distributed throughout India. Embelin, a well-recognized active phytoconstituents in berries, is commonly used in ayurvedic formulations. Due to over-exploitation, the status of the plant is vulnerable. Previous studies on this species mainly focused on its phytochemical analysis, which led to overexploitation and loss of the germplasm. In the present study, 20 RAPD and 18 ISSR markers were employed to assess genetic divergence in 40 genotypes of E. ribes collected from different parts of the Western Ghats of India. In RAPD analysis, all 40 accessions with 20 RAPD primers amplified 282 fragments, with 83.91% average polymorphism and with an average of 14.10 bands per primer. The size of amplicons varied from 200 to 2500bp. While, ISSR primers produced 203 fragments of which 161 were polymorphic with an average of 11.28 bands per primer with 73.25% average polymorphism. The size of amplicons ranges from 200 to 2500bp. RAPD and ISSR markers were also assessed by calculating polymorphic information content (PIC) to discriminate the genotypes; the average PIC value for RAPD, ISSR, and combined RAPD + ISSR markers obtained was more than 0.50 suggesting the informativeness of markers. UPGMA analysis based on Jaccard's similarity coefficient for RAPD, ISSR, and RAPD + ISSR data reveals that 40 accessions of E. ribes were depicted in four clusters. The clustering pattern of all individuals in PCoA analysis agreed with the UPGMA dendrograms, which further confirms the genetic relationships explained by cluster analysis. AMOVA analysis of RAPD, ISSR, and combined marker system revealed variation within the population, ranging from 41 to 44%, and among the population, it ranged from 56 to 59%. The present study provides an optimized method for evaluating the genetic diversity of Embelia ribes using RAPD and ISSR markers which are useful for further sustainable utilization and conservation of natural populations in the Western Ghats of India.

Genetic Characterization and Population Structure of Pea (Pisum sativum L.) by Molecular Markers against Rust (Uromyces viciae-fabae) in Newly Developed Genotypes

The understanding of the genetic diversity of germplasm of any crop is necessary for genetic improvement. Pea (Pisum sativum L.) is a very important legume crop that provides protein and several essential vitamins, carbohydrates, and minerals. The genetic diversity and population structure of pea germplasm consisted of 115 entries of Australian accessions and 4 entries of Indian varieties used as checks with varying responses and severities of rust, which were analysed using 31 polymorphic SSR (Simple Sequence Repeats) markers. The combination of the markers revealed that 78 alleles were present at 32 loci. It was also observed that each marker had three alleles with an average PIC (Polymorphic Information Content) value of 0.272. The population structure analysis showed the genetic differentiation of the entries. The model-based population structure grouped the entries into three sub-populations of SP1, SP2, and SP3 having 37, 35, and 32 entries, respectively with 15 entries as admixtures. AMOVA (Analysis of Molecular Variance) disclosed that there was 56% variation among the individuals and 20% within the population. A mean fixation index (Fst) of 0.240 among the pea entries exhibited relatively significant variation in population. This study provides basic information to select parental lines for developing rust resistant varieties to meet the ultimate goal of sustainable agriculture.

Assessment of Genetic Diversity among Wild Ruta chalepensis L. from the North of Jordan

Ruta chalepensis, known as Fringed Rue, is a small shrub of the Rutaceae family. To date, there is no record of its natural distribution across Jordan, a country located in the eastern part of the Mediterranean basin, and there are no previous studies on its genetic diversity in the region. Therefore, this study was conducted to assess the genetic diversity of R. chalepensis in the northern parts of Jordan using morphological trait and amplified fragment length polymorphism (AFLP) analyses. For the morphological traits, the analysis of variance indicated that there were significant differences between the identified populations. The Shannon diversity indices showed relatively high values, indicating the existence of a high variability among the identified populations. The principal component analysis explained 82% of the variation between the collected plants, and a clear separation of the collected individuals from the Jarash-A, Jarash-B and Ajloun-B populations from the rest of the populations was observed. The heatmap clustering was in general agreement with the results of the principal component analysis, with the plant height, rachis length and plant width considered as the discriminative traits. The AFLP analysis using eight different primer combinations generated 59 polymorphic bands, with an average polymorphism information content value of 0.32. The phylogenetic analysis identified three main clusters, with the first cluster including 65% of the individuals collected from the Jarash and Ajloun provinces, with a clear separation of the Jarash-B population. The AMOVA revealed that the genetic variation between the populations contributed 30% of the total genetic variation, while the variation within the populations explained 70%. In conclusion, morphological traits and molecular markers were used successfully to assess the genetic diversity among wild R. chalepensis from the north of Jordan, and such data can be used for future conservation plans and utilization purposes.

Development of the maize 5.5K loci panel for genomic prediction through genotyping by target sequencing.

Genotyping platforms are important for genetic research and molecular breeding. In this study, a low-density genotyping platform containing 5.5K SNP markers was successfully developed in maize using genotyping by target sequencing (GBTS) technology with capture-in-solution. Two maize populations (Pop1 and Pop2) were used to validate the GBTS panel for genetic and molecular breeding studies. Pop1 comprised 942 hybrids derived from 250 inbred lines and four testers, and Pop2 contained 540 hybrids which were generated from 123 new-developed inbred lines and eight testers. The genetic analyses showed that the average polymorphic information content and genetic diversity values ranged from 0.27 to 0.38 in both populations using all filtered genotyping data. The mean missing rate was 1.23% across populations. The Structure and UPGMA tree analyses revealed similar genetic divergences (76-89%) in both populations. Genomic prediction analyses showed that the prediction accuracy of reproducing kernel Hilbert space (RKHS) was slightly lower than that of genomic best linear unbiased prediction (GBLUP) and three Bayesian methods for general combining ability of grain yield per plant and three yield-related traits in both populations, whereas RKHS with additive effects showed superior advantages over the other four methods in Pop1. In Pop1, the GBLUP and three Bayesian methods with additive-dominance model improved the prediction accuracies by 4.89-134.52% for the four traits in comparison to the additive model. In Pop2, the inclusion of dominance did not improve the accuracy in most cases. In general, low accuracies (0.33-0.43) were achieved for general combing ability of the four traits in Pop1, whereas moderate-to-high accuracies (0.52-0.65) were observed in Pop2. For hybrid performance prediction, the accuracies were moderate to high (0.51-0.75) for the four traits in both populations using the additive-dominance model. This study suggests a reliable genotyping platform that can be implemented in genomic selection-assisted breeding to accelerate maize new cultivar development and improvement.

Genetic diversity and population structure of the USDA collection of Brassica juncea L.

The success of plant biofuels relies on finding inexpensive feedstocks that do not compete with food crops and can be cultivated economically in diverse geographical regions and agricultural production systems. Brassica juncea L. is a native crop of the western and central Asia, is considered a good biodiesel candidate due to its high oil content with high unsaturated fatty acids that can be refined into biofuels that equal petroleum-based fuels characteristics. To build genomic resources for B.juncea, a diversity panel consisting of 340 of accessions, were collected from 22 countries and stored at the USDA repository, and were genotyped to explore genetic diversity, relatedness, and population structure. A total of 99030 high-quality single nucleotide polymorphisms (SNP) markers were identified using genotyping-by-sequencing (GBS) technology. Those SNP were distributed over the 18 chromosomes with an average of 5000 SNP per chromosome, an average polymorphism information content (PIC) value of 0.23 and an expected heterozygosity (He) value of 0.281 indicating the genetic diversity within the USDA collection of B. juncea. Population structure and principal components analyses (PCA) based on identified SNPs revealed five distinct subpopulations, with the largest subpopulation containing accessions traced back to Pakistan and India. Analysis of molecular variance (AMOVA) revealed that 40% of the variation in USDA collection was among the five subpopulations, while 49% of the variation was due to the variation among accessions used in the analysis. High fixation index (FST) among distinguished subpopulations indicates a wide genetic diversity and high genetic differentiation among subpopulations. The results explored the genetic diversity in the USDA collection of B. juncea that could be used to genetically improve the crop. This information and accessions provide tools to enhance genetic gain in B. juncea breeding programs through genome-wide association analysis studies (GWAS) and marker-assisted selection (MAS) approaches.