scholarly journals Exploring Plant Genetic Variations with Morphometric and Molecular Markers

2021 ◽  
Author(s):  
Bushra Sadia ◽  
Faisal Saeed Awan ◽  
Fozia Saleem ◽  
Javaria Altaf ◽  
Abdullah Bin Umar ◽  
...  

For centuries, crop improvement has served as the basis of food security of ever increasing human population. Though vast germplasm collections are available; their exploitation for crop improvement still depends upon efficient assessment of genetic diversity. Genetic variability is the key element in adaptation of plants to varying climates. While crops with narrow genetic diversity are vulnerable to stresses. The estimation of extent and pattern of genetic variability is a prerequisite for generating superior varieties. Genetic diversity analysis generates key information to dissect genetic variations in crop germplasm with the help of morphometrical, biochemical and molecular tools. Among these, DNA markers provide a reliable and detailed insight into the similarities and differences among crops. In this chapter, we discuss the applications of phenotypic and molecular markers to probe genetic divergence in crops and present case studies that describe the significance of these tools to characterize sorghum germplasm. Furthermore, we spotlight sorghum biodiversity exploration efforts worldwide and propose future directions.

2021 ◽  
Author(s):  
Luis Augusto Becerra Lopez-Lavalle ◽  
Adriana Bohorquez-Chaux ◽  
Xiaofei Zhang

The identification of cassava cultivars is important for understanding the crop’s production system, enabling crop improvement practitioners to design and deliver tailored solutions with which farmers can secure high yields and sustainable production. Across the lowland tropics today, a large number improved varieties and landraces of cassava are under cultivation, making it inefficient for breeders and geneticists to set improvement goals for the crop. The identification and characterization of cassava genotypes is currently based on either morphological characters or molecular features. The major aim of cultivar identification is to catalog the crop’s genetic diversity, but a consensus approach has still not been established. Of the two approaches to the identification of variety, morphological characters seem to account for most of the genetic variability reported in cassava. However, these characters must be treated with caution, as phenotypic changes can be due to environmental and climatic conditions as well as to the segregation of new highly heterozygous populations, thus, making the accurate identification of varieties difficult. The use of molecular markers has allowed researchers to establish accurate relationships between genotypes, and to measure and track their heterozygous status. Since the early 1990’s, molecular geneticists working with cassava have been developing and deploying DNA-based tools for the identification and characterization of landraces or improved varieties. Hence, in the last five years, economists and social scientists have adopted DNA-based variety identification to measure the adoption rates of varieties, and to support the legal protection of breeder’s rights. Despite the advances made in the deployment of molecular markers for cassava, multiple platform adoption, as well as their costs and variable throughput, has limited their use by practitioners of crop improvement of cassava. The post-genomic era has produced a large number of genome and transcriptome sequencing tools, and has increased our capacity to develop and deploy genome-based tools to account for the crop’s genetic variability by accurately measuring and tracking allele diversity. These technologies allow the creation of haplotype catalogs that can be widely shared across the cassava crop improvement community. Low-density genome-wide SNP markers might be the solution for the wide adoption of molecular tools for the identification of cultivars or varieties of cassava. In this review we survey the efforts made in the past 30 years to establish the tools for cultivar identification of cassava in farmer’s fields and gene banks. We also emphasize the need for a global picture of the genetic diversity of this crop, at its center of origin in South America.


2016 ◽  
Vol 141 (1) ◽  
pp. 62-65 ◽  
Author(s):  
Michael J. Havey ◽  
Yul-Kyun Ahn

Garlic (Allium sativum) is cultivated worldwide and appreciated for its culinary uses. In spite of primarily being asexually propagated, garlic shows great morphological variation and adaptability to diverse production environments. Molecular markers and phenotypic characteristics have been used to assess the genetic diversity among garlics. In this study, we undertook transcriptome sequencing from a single garlic plant to identify molecular markers in expressed regions of the garlic genome. Garlic sequences were assembled and selected if they were similar to monomorphic sequences from a doubled haploid (DH) of onion (Allium cepa). Single nucleotide polymorphisms (SNPs) and insertion–deletion (indel) events were identified in 4355 independent garlic assemblies. A sample of the indels was verified using the original complementary DNA (cDNA) library and genomics DNAs from diverse garlics, and segregations confirmed by sexual progenies of garlic. These molecular markers from the garlic transcriptome should be useful for estimates of genetic diversity, identification and removal of duplicate accessions from germplasm collections, and the development of a detailed genetic map of this important vegetable crop.


2018 ◽  
Vol 16 (5) ◽  
pp. 469-477 ◽  
Author(s):  
Georgios F. Tsanakas ◽  
Photini V. Mylona ◽  
Katerina Koura ◽  
Anthoula Gleridou ◽  
Alexios N. Polidoros

AbstractThe Greek lentil landrace ‘Eglouvis’ is cultivated continuously at the Lefkada island for more than 400 years. It has great taste, high nutritional value and high market price. In the present study, we used morphological and molecular markers to estimate genetic diversity within the landrace. Morphological analysis was based on characteristics of the seed. Molecular analysis was performed using simple sequence repeat (SSR) molecular markers in a high-resolution melting (HRM) approach. ‘Samos’ and ‘Demetra’, two of the most widely cultivated commercial lentil varieties in Greece, were used for comparisons. Morphological analysis was performed with 584 seeds randomly selected from a lot. Analysis of seed dimensions and colour distributed the samples in different categories and highlighted the phenotypic variability in ‘Eglouvis’ lentil seeds. Genetic variability was estimated from 91 individual DNA samples with 11 SSR markers using HRM analysis. Genotyping was based upon the shape of the melting curves and the difference plots; all polymerase chain reaction products were also run on agarose gels. Genetic distances of individuals and principal coordinates analysis suggested that ‘Eglouvis’ landrace has a unique genetic background that significantly differs from ‘Samos’ and ‘Demetra’ and no overlapping could be detected. Genetic variability within the ‘Eglouvis’ landrace can be considered in targeted breeding programs as a significant phytogenetic resource of lentils in Greece.


2017 ◽  
Vol 5 (1) ◽  
pp. 50-57
Author(s):  
Rupsanatan Mandal ◽  
Suprakash Pal ◽  
Nonigopal Shit

Proficiency and organization of the genetic variability in cultivated and wild relatives are pivotal for a particular crop improvement program. In the present scenario there has been noteworthy improvement in the development of novel genetic tools such as DNA or molecular markers and genetic maps profiling techniques. In this study, seven chickpea (Cicer arietinum L.) genotypes including some cultivars were considered (Collection Id of the seven genotypes are TZCP-1, TZCP-2, TZCP-3, TZCP-4, TZCP-5, TZCP-6 and TZCP-7). The experiment was conducted out in Random Complete Block Design (RCBD) having three replications. All the quantitative characters were collected for assessing the diversity and to find key characters in chickpea cultivars. The statistical analysis was done for all the quantitative character (viz. plant height, number of branches per plant, number of pod per plant, number of seeds per pod, test weight, seed length, seed width, days to 50% flowering, days to 50% maturity and grain yield). Analysis of variance divulged significant differences among the genotypes for all the 10 characters. An extensive range of diversity was displayed by most of the characters under study. The magnitude of phenotypic coefficient of variation (1.23% - 33.71%) in the present study was slightly wider than genotypic coefficient of variation (1.13% - 33.02%) suggesting that environmental factors have high contribution to the observed variation among chickpea accessions. The first four PC axes from the principal component analysis accounted for 91.63% of the multivariate variation among entries indicating a moderate degree of correlation among characters for these entries. The genotypic data generated through RAPD profiling of seven chickpea genotypes were used to study genetic diversity or interrelationship. The pair wise Jaccard’s similarity coefficient ranged from 0.47 (TZCP-3 and TZCP-5) to 0.87 (TZCP-2 and TZCP-4). Finally, this research work helped with the analysis of genetic diversity in chickpea by using different approaches such as morphological and molecular marker system.


2009 ◽  
Vol 69 (2) ◽  
pp. 447-453 ◽  
Author(s):  
AJ. Mossi ◽  
RL. Cansian ◽  
O. Leontiev-Orlov ◽  
JL. Cechet ◽  
AZ. Carvalho ◽  
...  

The aim of this work was to analyze genetic variability in 18 populations of Maytenus ilicifolia, and representatives of Maytenus aquifolia and Maytenus evonymoidis, collected in the states of Mato Grosso do Sul, Paraná, Santa Catarina and Rio Grande do Sul, using RAPD molecular markers. Considering total samples of the three species, 263 amplified fragments were identified, of which 72.2% showed to be polymorphous. The index of similarity (Jaccard coefficient) was on average 0.64 between M. ilicifolia and M. aquifolia; 0.47 between M. ilicifolia and M. evonymoidis; and 0.44 between M. aquifolia and M. evonymoidis. The analysis of groupings by the UPGMA algorithm allowed to clearly separate the three analyzed species. In determining the variability in M. ilicifolia, 222 bands were identified, on average 11.1 bands per primer, being 43.2% polymorphous. The index of similarity (Jaccard coefficient) in the bulks of each population in M. ilicifolia was, on average, 0.92 and the index of similarities among the populations was 0.83. The analysis of groupings with the UPGMA algorithm and the analysis of the main coordination (PCO), allowed the separation of the analyzed populations into three groups, the populations from the south of Rio Grande do Sul and the population from Mato Grosso do Sul standing out. A relation between the groupings found and the edaphoclimatic conditions of the collecting places was observed.


HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 692c-692
Author(s):  
Charles J. Simon ◽  
Richard C. Johnson

Maintenance of genetic resources within the National Plant Germplasm System includes preserving the genetic constituency of accessions as close to the original sample as possible. Genetic changes that can arise during seed regeneration include both an overall loss of genetic diversity within heterogenous accessions and changes in the gene frequencies within accessions. Two germplasm collections are being examined with molecular methods at the Western Regional Plant Introduction Station (WRPIS) for evidence of such genetic change. In the case of pea, gross observation of seed and plant characters indicate that vigorous plant culling during a comprehensive Pea Seedbourne Mosaic Virus eradication program a decade ago resulted in the overall loss of genetic diversity in some heterogenous accessions. Isozyme data has corroborated these observations. Molecular markers are beginning to be used, both to quantify possible genetic changes in accessions as a result of the eradication process, and to document success in reintroducing diversity by repeating the eradication process with additional seed from archival seedlots. In the case of ryegrass, the practice of bulking the seed harvested from regeneration plots may bias the seedlot toward genotypes that are more fruitful. Isozyme analysis after two regeneration cycles showed that balanced sampling (equal seed no./plant) maintained allele frequencies close to the original seed sample. A bulk harvest sample and a sample with an equal number of spikes harvested from each plant showed some significant change in allele frequency, but no significant changes were seen in the allelic richness of accessions, or in the level of an accession's overall heterozygosity. A regeneration sample with an equal number of seed/plant will therefore best preserve gene frequencies within accessions, but loss of an accessions overall diversity will not diminish as a result of less than ideal sampling methods in ryegrass.


2021 ◽  
Author(s):  
Shiraz Mehmood ◽  
Israr Ud Din ◽  
Izhar Ullah ◽  
Heba I. Mohamed ◽  
Abdul Basit ◽  
...  

Abstract Knowledge of the genetic diversity and population structure of germplasm collections is an important foundation for crop improvement. Rice production across a broad range of rice-growing environments results in a diverse array of local rice varieties. Many rice varieties have been lost as a result of biodiversity loss and are now grown in Pakistan. To protect the biodiversity of rice varieties, an experiment was carried out to check the genetic and morphological variations between 8 exotic and 7 local rice genotypes, using 5 different SSR markers, i.e, RM3, RM259, RM341, RM520, and RM11943. The analysis of morphological and quality traits of rice observed significant variation across genotypes. The results revealed that genotype Irri-Pak attained the highest plant height and primary branch plant-1, while genotype Mushkan produced a higher number of productive tillers and obtained a higher fertility factor (%). Similarly, the highest value for panicle length was observed for genotype Faker-e-Malakand, 1000-grains weight in genotype Calmochi, and maximum days to maturity was noticed in genotype Swati-2014. Moreover, the genotype Brio attained the highest value of stem diameter, while maximum seed length was noted in genotype Sug Dasi. The highest number of primary branches plant-1 in genotype Ibge-I and secondary branches plant-1 in genotype Calmochi were noticed. A higher concentration of sodium and potassium was observed for the genotype Marte, while the genotype Muskan attained the maximum content of copper. Moreover, the highest concentration of iron in genotype Originario, zinc in genotype JP-5, and cadmium content were noticed in genotype Ibge. Similarly, the dendrogram analysis for quantitative parameters showed three clusters at 74.13 % similarities. Whereas all the genotypes of European origin formed a separate cluster. A set of 5 SSR primers, covering four chromosomes, amplified a total of 14 alleles and showed 100% polymorphism with an average PIC value ranging from 0.39 to 0.91. The UPGMA cluster analysis separated the 15 rice genotypes into 3 main groups based on 32.5% similarities and the highest genetic distance (45.1%) was observed between two genotypes (Fakher-e-malakand and Musa), having different geographical origins. There was no genetic distance between genotype Marte and Brio, irrespective of having the same origin.


2018 ◽  
Vol 10 (2) ◽  
pp. 193-198 ◽  
Author(s):  
Carmen Florentina POPESCU ◽  
Manna CRESPAN

Aiming to investigate the correspondence of phenotypic variability and molecular markers, 50 varieties of Vitis vinifera ssp. vinifera, ancient grapevine varieties grown on Romanian territory, were selected to be analysed. All varieties were subjected to ampelographic analyses with OIV descriptors and also to molecular analyses with 13 microsatellites. The morphology description with recommended methods corresponded with the reference literature, proving the correct registration of the varieties at the moment of acquisition. Markers efficiency for assessing the genetic diversity among studied varieties was evaluated by computation of statistic parameters referring to the polymorphisms found. Among the internationally recommended SSR markers, ISV4 and VMCNG4b9 markers displayed interesting PIC and PI values. By comparing the SSR profiles of the 50 Romanian grapevine varieties with those in the Eu database, the following can be concluded: confirmation of 10 synonymies mentioned in old documents, while 3 synonymies mentioned in old reference literature were not confirmed, new synonyms were found for 4 accessions, additional synonyms were found for 4 accessions, which are to be added to the previous ones already mentioned in the literature, the synonymies in three groups of accessions were documented for the first time in  the specialised literature, the unicity of three Romanian accessions was proved (ʻMoroştinăʼ, ʻNegru mareʼ and ʻRomânieʼ) and the genetic profiles of 15 varieties were identical to those already recorded in the investigated databases


2021 ◽  
Vol 89 (1) ◽  
Author(s):  
Wiwit Budi WIDYASARI ◽  
. DAMANHURI

and is a cross-pollinator, so information about the genetic relationship between the accessions in germplasm collections is very important for selecting the prospective parent in crossbreeding. This research aims to determine the phylogenetic relationship of 24 Saccharum complex accessions and to verify the grouping of accessions using 37 morphological and three microsatellite molecular markers. Interpretation of morphological and molecular data was obtained from the analysis using the NTYSYpc-2.02i program. The results show that within the 24 accessions analyzed using morphological markers, some accessions did not cluster as the classification at the conservation time. This difference is due to the morphological markers, descriptions of characters that do not appear are considered as the same variables though in different morphological characters, so this increases the value of genetic similarity among accessions analyzed. In contrast, the grouping of molecular markers shows that each accession was grouped according to the classification at the conservation time. These accessions had a low genetic similarity of 0.20 with a broad genetic distance of 0.80. This broad genetic distance indicates that the twenty-four accessions have a distant genetic relationship with one another, so that the genetic diversity of these accessions is relatively high. The high genetic diversity in germplasm collections improves its potential as a crossing parent to obtain a high heterosis effect.


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