Simple Sequence Repeat Markers Research Articles

First report of Phytophthora infestans genotype US17 causing late blight on potato and tomato in British Columbia, Canada

Potato and tomato are grown in all Canadian provinces and contribute billions of dollars in exports and sales. Late blight, caused by Phytophthora infestans, is a destructive disease of potato and tomato worldwide and is responsible for millions of dollars in losses annually. Changes in pathogen strains were reported to be associated with late blight epidemics in several regions and pose challenges to late blight management. In British Columbia (BC), diverse strains of P. infestans were reported. Using multiplex microsatellite or simple sequence repeat (SSR) markers, we identified the new genotype US17 of P. infestans from samples of potato and tomato with late blight in BC. All isolates were of the A1 mating type. One, five, and one isolates were sensitive, moderately resistant, and highly resistant to metalaxyl-m, respectively. This is the first report of the occurrence of the US17 genotype in BC and Canada. The US17 strain was also able to cause tuber rot and foliar blight symptoms in potato in pathogen-inoculated assays.

Genetic dissection of green pod yield in dolichos bean, an orphan vegetable legume, using new molecular markers.

In the era of genomic-assisted breeding for crop improvement, developing new molecular markers and validating them for use in breeding programs are the prelude. Dolichos bean is one of the most important vegetable legume crops owing to its nutrient-rich green pods used as vegetables. Limitations in genomic resources, including molecular markers, restrict the accelerated improvement of the crop. In the present investigation, a set of 430 new simple sequence repeat markers was developed from sequence information of a reference variety. These markers included di- and tri-nucleotide repeats. The markers were assayed on an association panel, which was evaluated for green pod yield over 5years. A multi-locus model, FarmCPU, was used to assess the marker-trait association analysis. A total of 106 marker-trait associations were identified using an efficient mixed-model approach. Tri-nucleotide repeats were more informative and predominantly associated with trait. Among these markers, 17 were associated with a high level of significance. Markers LP-D-68 and LP-D-14 were identified with a high level of significance in 5-year pooled data and explained 12.70% and 12% of the phenotypic variance, respectively. These markers associated with a high level of confidence have significant scope for use in marker-assisted selection programmes. Other associated markers may be utilized for improving parents through marker-assisted recurrent selection or genomic selection programs.

Characterization of genetic diversity of greens‐type hybrid bermudagrass selections through SSR markers and morphological analysis

AbstractThe development of Tifgreen bermudagrass, and the subsequent mutations of this cultivar, has revolutionized the game of golf in the southern United States as superintendents have access to high‐quality putting surface capable of withstanding hot summers. However, the lack of genetic diversity may make them vulnerable to various pests and the low tolerance to freeze temperatures may make them susceptible to winterkill. In recent years, Oklahoma State University and other universities have begun to create new interspecific F1 hybrids between common (Cynodon dactylon) and African bermudagrasses (C. transvaalensis) for putting greens. The objectives of this study were to investigate the genetic diversity and variation among 14 experimental genotypes and two standard cultivars (TifEagle and Tifdwarf). Simple sequence repeat (SSR) markers and morphological characteristics were used to evaluate the genetic relationships and variation among the 16 genotypes. Results showed significant variation for 11 vegetative traits and two reproductive traits. The phenotypic coefficient of variation was greatest for the third internode length and the least for the first leaf angle for both the field and greenhouse trials. The morphological cluster analysis also showed variation between the two trial environments. The SSR marker cluster analysis showed the 16 genotypes were grouped into four major groups, with a similarity coefficient ranging from 0.44 to 1. The highest similarity was found among the two commercial standards and an experimental ultradwarf from Florida. Several new genotypes (OKC3920, 5 × 23, 11 × 2, 19 × 19, and 34 × 20) were also grouped with the ultradwarf genotypes in the morphological cluster analysis, showing the possibility of achieving similar morphological traits with new genetics. Further field evaluations are needed to determine the performance of these genotypes under low mowing heights.

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

Abstract Water 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.

Directional Breeding Generates Distinct Genetic Diversity in Hybrid Turf Bermudagrass as Probed with Simple Sequence Repeat Markers

Bermudagrass (Cynodon spp.) is a drought-resistant warm-season turfgrass adapted to the southern and transitional zones in the United States. Multiple hybrid cultivars have been developed and released for use as turfgrass, and others are still undergoing development. Increasing genetic diversity of commercial cultivars is vital to stress tolerance. A DNA profiling study of 21 experimental selections from the Oklahoma State University turfgrass breeding program and 11 cultivars was conducted using 51 simple sequence repeat primer pairs across the bermudagrass genome. A pairwise genetic relationship analysis of the genotypes using 352 polymorphic bands showed genetic similarity coefficients ranging from 0.59 to 0.89. The average pairwise population differentiation values were 0.012 for the 11 cultivars and 0.169 for the 21 selections. A cluster analysis using the unweighted paired group with the arithmetic average method grouped the entries into six clusters. A correlation analysis identified different levels of pairwise genetic relationships among the entries that largely reflected parental relationship. Directional breeding and selection for cold hardiness or drought resistance created progeny that had distinct genetic diversity in the tested bermudagrasses. It is evident that an increase in genetic diversity of the existing cultivar pool with the release of one or more experimental selections for commercial use will strengthen and improve bermudagrass systems.

Genetic diversity of Sinapis arvensis L. (wild mustard) in Türkiye determined by microsatellite markers

Wild mustard (Sinapis arvensis L.) is a self-fertilizing weed species that exerts negative impacts on wheat production and herbicides are intensively used to manage it. Cross-fertilization may lead to genetic differentiation in this species. Therefore, this study investigated genetic diversity among wild mustard populations collected from wheat fields across various regions in Türkiye. Genetic variation was evaluated using 5 simple sequence repeat (SSR) markers in populations collected from 30 different locations. Populations were analyzed using UPGMA (unweighted pair group method with arithmetic mean) and principal component analysis (PCA). The mean genetic diversity (GD) and polymorphism information content (PIC) values were 0.752 and 0.844, respectively. High genetic variability was recorded among populations within geographic locations. The populations were categorized into two major groups by UPGMA. There was no apparent geographic isolation among tested populations, which displayed a high degree of variability. The primary source of this variability is thought to be the adaptability of wild mustard seeds dispersed through various methods across diverse locations. Despite being a predominantly self-pollinating species, wild mustard may also employ some cross-pollination mechanisms. In conclusion, SSR markers proved useful in determining genetic diversity in outcrossing species, especially where no prior genotypic information is available. The study suggests that genetic diversity is maintained in wild mustard populations even with rotational farming practices and intensive use of herbicides.

Genetic Structure of Macrophomina phaseolina Populations, the Causal Agent of Sesame Charcoal Rot Disease in Iran

Charcoal rot disease, caused by the fungus <i>Macrophomina phaseolina</i>, is one of the most important diseases of Sesame (<i>Sesamum indicum</i>) all over the world. However, the population biology of <i>M. phaseolina</i> is poorly understood. In this study, <i>M. phaseolina</i> isolates from five different regions of Iran (Khuzestan, Fars, Bushehr, Hormozgan, and Kohgiluyeh & Boyer-Ahmad provinces) (n=200) were analyzed for genetic variation using inter simple sequence repeats marker. In total, 152 unique haplotypes were identified among the 200 <i>M. phaseolina</i> isolates, and gene diversity (H=0.46–0.84) and genotypic diversity were high in each of the regions. The structure analysis clustered five Iranian populations into two distinct groups, the individuals from group 1 were assigned to the Bushehr population and the individuals from Khuzestan, Fars, Hormozgan and Kohgiluyeh & Boyer-Ahmad were aggregated and formed group 2. The results matched with genetic differentiation and gene flow among regions. Analyses of the distribution of gene diversity within and among five Iranian populations were 61% and 39%, respectively. Our results showed that infected seeds are thought to be the dominant mechanism responsible for the spreading of the pathogen in southern parts of Iran. In summary, it is essential to have local quarantine and prevent seed exchanges between geographical populations to restrict the dispersal of pathogen over long distances and provide certified seeds in Iran.

Development of Novel Genomewide Simple Sequence Repeat Markers for Acer truncatum Bunge and Assessment of Their Transferability to Other Closely Related Species

Acer truncatum Bunge is a versatile woody tree species with high economic and medicinal value in the production of bioactive substances and unsaturated fatty acids (especially nervonic acid). However, the exploitation and evaluation of A. truncatum germplasm resources are limited owing to a lack of sound molecular marker systems. In this study, a large set of genomewide simple sequence repeat (SSR) markers of A. truncatum was developed based on its whole-genome sequences. A total of 462,331 SSR loci were identified in the genome sequences, 99.3% (459,193) of which were located on 13 chromosomes. The chromosome length was significantly positively correlated with the number of SSR loci on the chromosome (r = 0.977, p < 0.001). The (A/T)n, (AT/TA)n, and (AAT/ATT/TAA/TTA/TAT/ATA)n were the most frequent motifs for mono-, di-, and trinucleotide repeat motifs, respectively, showing A/T-base bias. After BLASTN and electronic polymerase chain reaction (PCR) analyses, 199,990 loci with specific physical positions were screened. Most of the SSR loci were located in the intergenic regions and fewest in the coding sequences (CDSs). The frequency of loci with tri- and hexanucleotide repeat motifs was the highest in the CDSs, potentially serving to maintain the stability of gene function and structure. In randomly selected 105 SSR markers, 82 (78.1%) showed allelic polymorphism, with polymorphism information content (PIC) values of 0.032–0.926 (0.481 on average). The SSRs in the noncoding regions exhibited significantly higher PIC values than those in the CDSs. The transferability of the 105 markers was 48.6%–59.0% to seven other Acer species. The large set of valid SSR markers provides a powerful tool for studies on population genetics, conservation genetics, linkage mapping, comparative genomics, and marker-assisted breeding of the genus Acer.

Analysis of Genetic Variability of Potato Induced Mutants Using Simple Sequence Repeat (SSR) Markers

Aims: Potato (Solanum tuberosum L.) is ranked fourth amongst the world’s major stable food crop and second in Kenya after maize and thus plays a vital role in food and nutrition security and sustainable development. Despite its importance, potato production in Kenya is still low due to abiotic and biotic constraints. Traditional breeding and improvement have been difficult due to the narrow genetic diversity of the crop owed to the complex tetrasomic inheritance patterns. Induced mutation has been used to generate genetic variations in potato from which desired putative mutants are selected. In most cases the level of genetic variability is not known. The objective of this study was to determine the genetic variability of potato mutants using SSR markers. Study Design: The study involved three potato varieties; Asante, Kenya Mpya and Kenya Sherekea which are high yielding and commercially grown varieties in Kenya. Place and Duration of Study: Sample: They were irradiated at different dose rates of gamma rays at Co60 source at FAO/IAEA laboratories, Seiberdorf Austria in 2014. A total of 163 mutants were advanced to M1V4 generation at the University of Eldoret between 2015 and 2018. Methodology: Genomic DNA was extracted to assess the diversity with 20 SSRs markers. Results: All the 20 SSR primers were polymorphic with 6-19 bands amplified per primer and marker STM5127 showed the highest allele number (19) using PowerMarker software. The STRUCTURE analysis suggested that the potato mutants were clustered into six sub-populations based on the unweighted pair-group method of arithmetic averages (UPGMA) thus, the accessions were divided into three major clusters. Analysis of molecular variance (AMOVA) indicated that 8.6% of total molecular variance was attributed to diversity among sub-populations, while 91.4% of variance was associated with differences within sub-populations. Conclusion: This study highlights the most comprehensive investigation of the genetic diversity and population structure of potato mutants, and provides valuable information for genetic improvement, and systematic utilization.

Material Selection for Restoration of Genetic Diversity of Abies koreana on Mt. Jirisan in South Korea

: A strategy is required for selecting appropriate materials for the restoration of Abies koreana on Mt. Jirisan, where the habitat of A. koreana is continuously shrinking. The current study aimed to analyze the genetic characteristics of A. koreana in three subpopulations (Banyabong, Byeoksoryeng, and Cheonwangbong) on Mt. Jirisan using 10 nuclear simple sequence repeat (nSSR) markers and calculate the sampling distance for each subpopulation for avoiding genetically similar samples. Based on the calculated sampling distance, we proposed the size of a sample containing more than 95% of the alleles at a frequency greater than 0.05. AMOVA showed that the difference in genetic variation across subpopulations of A. koreana on Mt. Jirisan was small, approximately 3% of the total. Spatial genetic structure analysis results suggested that it would be appropriate to collect samples of the Banyabong subpopulation at intervals of 10 m or more, when sampling A. koreana, whereas for the Byeoksoryeong and Cheonwangbong subpopulations, samples should be collected at intervals of 20 m or more. Results of random sampling of 5 to 30 individuals indicated that, by applying a 10 m distance within the Banyabong subpopulation, more than 95% of the total alleles with a frequency ≥ 0.05 were secured when more than 25 individuals were extracted. Therefore, as a restoration strategy for A. koreana on Mt. Jirisan, we proposed the collection of more than 25 samples, keeping 10 m distance within the Banyabong subpopulation, which has a relatively high genetic diversity.

Contradistinctive floral attributes, pollination guilds and their consequence on the outcrossing rate in two elevational morphs of Rhododendron arboreum Sm.

Infraspecific floral trait variations may appear in response to elevational differences in alpine plant species. There is enormous information on the selection of such morphs mediated by biotic and/or abiotic variables. Whether such differences contribute to differences in reproductive strategy and mating outcomes is rarely investigated. We investigated these aspects in two distinct elevational floral morphs (Red and Pink) of Rhododendron arboreum Sm. in Western Himalaya. The red morphs occupy the lower elevations while pink morphs the higher elevations. The two morphs differ in floral traits like phenology, dimension, display, quality of floral rewards, and pollinators that happen to influence interaction with available pollinator pool at each elevation. The pink morph exhibits entomophily, while the red ones show ornithophily. Although experimental pollinations established that both the morphs are self-compatible, selfing results in significantly lower fruit-set than either cross- or open-pollinations. The outcrossing rate in the red morph, as determined by using simple sequence repeat (SSR) markers, was higher (tm=0.82) than that in the pink morph (tm=0.76), with a tendency of the latter to be shifting towards mixed-mating strategy. However, the extent of biparental inbreeding was comparable among the two morphs. It is inferred that the differences in the mating outcomes among the morphs in the tree species are linked to those emerging from floral traits and the pollination by different functional groups of floral visitors.

Population genetic analyses highlight an eastward dispersal of Puccinia striiformis f. sp. tritici from the Shaanxi province to the North China Plain

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a common airborne wheat disease. The frequent occurrence at a large scale in China has caused significant yield losses and poses a considerable threat to food security. To effectively manage and forecast the disease, a comprehensive understanding of the long-distance migration patterns of Pst is essential. Shaanxi province, situated in close proximity to the northwestern epidemic areas in China, plays a crucial role as a key overwintering region for Pst. However, it remains uncertain whether Pst, after winter reproduction in Shaanxi province, can extend its spread to the primary wheat regions in the North China Plain. In this study, during February and June 2022, a total of 302 Pst samples were collected from Shaanxi province and the North China Plain. Thirteen pairs of simple sequence repeat (SSR) markers were adopted to analyze the population genetic structure. It was observed that both genetic and genotypic diversities exhibited a discernible decline from the Shaanxi to the North China Plain. Moreover, Shaanxi displayed a close genetic relationship with Henan and Shandong, whereas Henan exhibited the most substantial population exchange with Shaanxi. Further analysis revealed that Shaanxi served as the primary inoculum of Pst in the investigated region, and the spread of Pst to Henan and Shandong originated from Shaanxi. As a result, the epidemics in Shandong further led to the prevailing of the disease in Hebei. Our study enhances the understanding of the epidemiological patterns of wheat stripe rust in the springtime prevalent regions of China, and it provides insights for future disease management.

Molecular marker-assisted genetic diversity analysis in soybean cultivars from Himalayan region of Uttarakhand, India

‘Bhat’ is the soybean variety highly valued in the traditional food and therapeutic system of Uttarakhand state in the Indian Himalayan region. It is available in diverse colors, shapes, and sizes, often linked to their nutritional parameters. The present investigation was conducted to assess the diversity and genetic relatedness in ‘bhat’ genotype indigenous to the Garhwal division of Uttarakhand. 25 polymorphic simple sequence repeats (SSR) markers were used to determine the genetic diversity and varietal identification among the 45 genotypes collected from the different villages of Uttarakhand. Out of the different markers assessed only 13 primers showed amplification with the maximum of 2–4 alleles obtained with each primer with the molecular weight ranging between 80 and 400 kb. The highest band amplification was observed in Satt 257 and Satt 197. The allelic frequencies of amplified primers ranged from 0.5 to 0.833 with a mean value of 0.645 and the mean gene diversity and PIC value was found to be 0.43 and 0.33. Satt 183, Satt 288, and Satt 389 showed the highest polymorphism, while Satt257 and Satt245 exhibited the presence of unique alleles in some samples. The phylogenetic analysis grouped the genotypes into 4 major clusters having visually distinct phenotypes in each group, indicating the mixing of population and loss of authenticity also confirming that phenotypic attributes are not indicative of genetic relatedness among the genotype under study. The results indicate the need for the development of novel ‘bhat’ specific markers for more accurate genetic identification of the nutritionally rich indigenous soybean variety.

Development of NBS-LRR gene-specific microsatellite markers for passion fruit Passiflora edulis Sims

The chromosome-level genome assembly of passion fruit (Passiflora edulis Sims) has facilitated computational analyses in developing novel informative SSR markers for genetics and breeding research. In this study, in-silico analysis was conducted to discover potential microsatellite loci and to design specific primers from the sequences of the characterised nucleotide-binding site - leucine-rich repeats (NBS-LRR) gene family of passion fruit, and a genotyping experiment was performed to validate the novel simple sequence repeat (SSR) markers.In total, 497 microsatellite loci were detected from 161 passion fruit NBS-LRR genes, of which 383 loci were qualified for primer generation. Forty-six SSR markers were selected for polymorphism verification, targeting 35 NBS-LRR genes that showed potential gene expression in response to biotic and abiotic stresses. From that, 25 SSR markers showed consistent polymorphic alleles among different passion fruit genotypes via PCR-PAGE analysis. These novel NBS-LRR-specific SSR markers might provide valuable tools for fortifying research on germplasm evaluation, genetic mapping, and molecular breeding for disease-resistant passion fruit varieties.

SSR Marker–Based Genetic Diversity and Relationship Analyses of Stephania tetrandra S. Moore

AbstractStephania tetrandra S. Moore (family: Menispermaceae), a dioecious herbaceous vine and the only species in the subgenus Botryodiscia of the genus Stephania of the family Menispermaceae, is mainly distributed in hilly areas south of the Huaihe River in China and found in many provinces of China, showing a high genetic diversity. This paper aimed to study genetic diversity of and genetic relationship among individuals of S. tetrandra within China to provide a basis for evaluation, exploitation, and utilization of S. tetrandra by using simple sequence repeat (SSR) molecular markers. Our results show that effective products were amplified from the 26 screened SSR gene loci, a total of 183 alleles amplified (2–16 alleles amplified by each pair of primers). Among the 26 loci, 16 had a PIC value higher than 0.5, indicating a high level of polymorphism. For most of the loci, the number of effective alleles was lower than that of the observed alleles, and the observed heterozygosity was lower than the expected heterozygosity. The genetic differentiation coefficient (0.021–0.547) was lower than 0.05 (low level of genetic differentiation) for 7 loci and higher than 0.25 (very high level of genetic differentiation) for 2 loci, and had a value representing a medium level of genetic differentiation for the remaining 17 loci. The intra-population inbreeding coefficient had a positive value for 21 loci, suggesting the presence of inbreeding and homozygous excess. The gene flow value was bigger than 1, indicating that genetic drift and natural selection played an unimportant role in population genetic differentiation of S. tetrandra. Based on discriminant analysis of principal components and Bayesian Information Criterion, K-means clustering was performed on 620 samples. These samples were divided into 9 genetic clusters, whose similarity coefficients and genetic distances were 0.755–0.918 and 0.067–0.280, respectively, indicating that these clusters were highly similar and short-distanced. The Bayesian clustering analysis was implemented in the STRUCTURE software to analyze the genetic structure of S. tetrandra and it was found that the 620 samples could be clustered into 5 ancestor groups; the 9 clusters and 40 natural populations inherited genes from the 5 groups to varying degrees, but the proportion of genes inherited from the 5 groups by each cluster and natural population differed. S. tetrandra was characterized by the presence of population structure and pronounced genetic subdivision, which, together with the presence of gene flow, may indicate a relatively stable recent state of these populations.

Assessing the Genetic Variation of Swarna rice (Oryza sativa L.) Cultivars using SSR marker

Swarna rice cultivars (Indian cultivar) are widely grown in the northern part of Bangladesh because of their higher yield, drought tolerance, higher quality of grain and good plant appearance. Therefore, a study was conducted to observe genetic diversity among eight Swarna cultivars grown in Bangladesh. The genetic diversity of the cultivars was assessed by one hundred SSR (simple sequence repeat) markers. Among these, forty-four primers were polymorphic. In total, 188 alleles from eight rice genotypes with an average of 4.27 alleles per locus were identified. Allele numbers varied from 2 to 11. The average polymorphism information content (PIC) was 0.533, with a range of 0.195 to 0.889. The most suitable markers found were RM149, RM232, and RM3421, which provided the highest PIC value of 0.889. Genetic dissimilarity coefficient values between pairs indicated that the Guti Swarna and Nepali Swarna cultivars along with the Guti Swarna and Deshi Guti Swarna cultivars were the most genetically distant (0.818) cultivars whereas the Nepali Swarna and Nironjon Swarna cultivars were the closest (0.091). A dendrogram constructed based on polymorphism indicated five major groups. It was observed that the Guti Swarna and Sumon Swarna cultivars formed two different solitary groups, I and II whereas the Nepali Swarna and Nironjon Swarna formed group III, the Lal Swarna and Swarna5 constructed group IV, and the Deshi Guti Swarna and Tiger Indian Swarna were in group V. Our findings may help in designing appropriate cross combinations for further improvement of Swarna cultivars.

Genetic Diversity Analysis of Anisogramma anomala in the Pacific Northwest and New Jersey.

Anisogramma anomala, a biotrophic ascomycete, causes eastern filbert blight (EFB) of hazelnuts (Corylus spp.). EFB is endemic in eastern North America, preventing the commercial production of European hazelnut (C. avellana L.). In contrast, the historic absence of A. anomala in the Pacific Northwest (PNW) supported the development of a robust hazelnut industry. Circa 1960, A. anomala was inadvertently introduced into southwestern Washington causing orchard devastation. Distribution of the pathogen in the PNW has been hypothesized to be the result of a single-point introduction. This study aimed to investigate the single-point introduction hypothesis of A. anomala by comparing the genetic diversity of A. anomala samples from the PNW and New Jersey (NJ). Specimens from the main PNW production region [n=60] and an area within the pathogen's native range, NJ [n=151], were genotyped using 15 simple sequence repeat (SSR) markers. The following were used to assess genetic diversity and population structure: allelic summary statistics, discriminant analysis of principal components, network median-joining tree, analysis of multilocus genotypes, and allelic population diversity analysis. Analyses separated the samples into one cluster containing all the PNW isolates, and five clusters of NJ isolates. The PNW samples were nearly genetically uniform, and the NJ isolates were diverse. These findings support the hypothesis that A. anomala in the PNW was derived from a single-point introduction and corroborate previous studies that have shown A. anomala is very diverse in NJ. This indicates that maintaining restrictions on the movement of Corylus into the PNW is important to prevent the introduction of new populations of A. anomala, thus protecting the PNW hazelnut industry.

Population genetic variation and geographic distribution of suitable areas of Coptis species in China.

The rhizomes of Coptis plants have been used in traditional Chinese medicine over 2000 years. Due to increasing market demand, the overexploitation of wild populations, habitat degradation and indiscriminate artificial cultivation of Coptis species have severely damaged the native germplasms of species in China. Genome-wide simple-sequence repeat (SSR) markers were developed using the genomic data of C. chinensis. Population genetic diversity and structure of 345 Coptis accessions collected from 32 different populations were performed based on these SSRs. The distribution of suitable areas for three taxa in China was predicted and the effects of environmental variables on genetic diversity in relation to different population distributions were further analyzed. 22 primer pairs were selected as clear, stable, and polymorphic SSR markers. These had an average of 16.41 alleles and an average polymorphism information content (PIC) value of 0.664. In the neighbor-joining (N-J) clustering analysis, the 345 individuals clustered into three groups, with C. chinensis, C. chinensis var. brevisepala and C. teeta being clearly separated. All C. chinensis accessions were further divided into four subgroups in the population structure analysis. The predicted distributions of suitable areas and the environmental variables shaping these distributions varied considerably among the three species. Overall, the amount of solar radiation, precipitation and altitude were the most important environmental variables influencing the distribution and genetic variation of three species. The findings will provide key information to guide the conservation of genetic resources and construction of a core reserve for species.

Assessment of genetic diversity of Camellia yuhsienensis based on leaf structure and inter simple sequence repeat (ISSR) markers

Assessment of genetic diversity of Camellia yuhsienensis based on leaf structure and inter simple sequence repeat (ISSR) markers

Genetic diversity and distinctness of flax (Linum usitatissimum L.) based on morphological and simple sequence repeat (SSR) markers

Genetic diversity and distinctness of flax (Linum usitatissimum L.) based on morphological and simple sequence repeat (SSR) markers