Diversity In Sesame Research Articles

Assessment of Genetic Diversity in Sesame (Sesamum indicum L.) for Yield and its Components

A field experiment was conducted to assess the diversity among sesame genotypes for yield and yield component traits during late kharif, 2017 (August-November) at Seed Research and Technology Centre, Rajendranagar, Hyderabad, Telangana State, India. Genetic diversity among the genotypes were estimated based on the data recorded for eight yield and yield attributing characters in 51 genotypes using Mahalanobis’s D2 statistics. The percent contribution of characters towards divergence showed that the character days to 50% flowering contributed maximum followed by seed yield plant-1, capsule length and number of seeds capsule-1. Selection of parents based on these traits would be useful to achieve a wide range of genetic variability in crop improvement programmes. The 51 genotypes were grouped into ten clusters and out of them, cluster I was the largest comprising of eighteen genotypes followed by cluster III with fifteen genotypes, cluster IV with seven genotypes, cluster II with five genotypes. The clusters viz., V, VI, VII, VIII, IX and X represented by single genotype indicating high degree of diversity among the genotypes. The maximum inter cluster distance was observed between cluster IX and cluster X (219.39) followed by cluster VII and cluster VIII (190.41). Among the ten clusters, the cluster X had highest mean value for capsule length, number of capsules plant-1, number of seeds capsule-1 and seed yield plant-1. The genotypes from these divergent clusters with favourable mean values for different traits could be used as parents in hybridization programme to get superior transgressive segregants.

Analysis of genetic diversity in sesame (Sesamum indicum L.) germplasm for yield and its attributing traits

The  genetic diversity of 50 sesame genotypes was studied by Mahalanobis D2 statistics. By using Tocher’s method, genotypes were grouped into nine clusters based on 10 economically important traits viz., days to flowering, days to 50% flowering, days to maturity, plant height, the number of primary branches, the number of secondary branches, the number of capsules per plant, the number of seeds per capsules, thousand seed weight and single plant yield. The largest intercluster distance among the nine clusters was found between clusters I and VIII, indicated that they were significantly more diverse and clusters IV and VI showed the lowest intercluster distance indicating that the genotypes under these clusters are closely related. The cluster with the highest cluster mean was found in cluster VIII for the number of capsules per plant, the number of primary and secondary branches, the number of seeds per capsule and single plant yield and cluster V for plant height and cluster VII for thousand seed weight. Taking into account the highest cluster mean for a trait, genotypes could be selected as parents in the hybridization program to create superior cross combinations. Keywords : Genetic diversity, Cluster, Germplasm, Sesame, D2 analysis

Studies on genetic diversity in sesame (Sesamum indicum L.) over seasons

D2 analysis of the sixty genotypes based on sixteen characters confirmed the presence of high diversity. Genotypes of different eco-geographic origins were grouped in a single cluster as well as in different clusters. Out of these twelve genotypes only five genotypes viz., G27, G32, G35, G39 and G40 showed high mean seed yield.

Line × tester analysis for seed yield, protein and oil content and SSR based diversity in sesame (Sesamum indicum L.)

Abstract The present investigation was conducted in sesame (Sesamum indicum L.) to estimate heterosis, combining ability using line × tester mating design and genetic variability of parents through molecular markers. Five lines and seven testers were crossed to produce 35 F1 hybrids. The heterobeltiosis for seed yield per plant ranged from −39.76 to 68.28%, while the standard heterosis ranged from −61.82 to 1.57% over better check variety; G. Til 10. Analysis of variance for combining ability revealed that the mean squares due to lines × testers interaction showed significant for all characters. GJT-5 and G. Til-4 displayed high gca effects and good per se performance for seed yield per plant and should be utilized in multiple crossing programmes. The sca effect of the crosses indicated that eight hybrids manifested significant and positive sca effects for seed yield per plant. Among these, the best three specific combiners were Keriya-7 × G. Til-2, AT-319 × GJT-5 and ABT-33 × G. Til-1. A set of eleven polymorphic SSR primers could generate 36 alleles among 12 parents. The average number of allele per locus was 3.27 with a range of 2–4. Neighbour- Joining (NJ) clustering grouped 12 genotypes into three main clusters A, B and C with 4, 6 and 2 genotypes, respectively. The highest genetic distance (0.86) was observed between AKT 64 and G. Til-4 genotypes while it was lowest (0.23) between Keriya-7 and NIC-17274.

Root diversity in sesame (Sesamum indicum L.): insights into the morphological, anatomical and gene expression profiles.

Sesame harbors a large diversity in root morphological and anatomical traits and a high root biomass improves the plant aboveground biomass as well as the seed yield. Sesame provides one of the most nutritious and healthy vegetable oils, sparking an increasing demand of its seeds. However, with the low yield and productivity of sesame, there is still a huge gap between the seed demand and supply. Improving the root system has a high potential to increase crop productivity, but information on the diversity of the sesame root systems is still lacking. In this study, 40 diverse sesame varieties were grown in soil and hydroponics systems and the diversity of the root system was investigated. The results showed that sesame holds a large root morphological and anatomical diversity, which can be harnessed in breeding programmes. Based on the clustering of the genotypes in hydroponics and soil culture systems, we found that similar genotypes were commonly clustered either in the small-root or in the big-root group, indicating that the hydroponics system can be employed for a large-scale root phenotyping. Our results further revealed that the root biomass positively contributes to increased seed yield in sesame, based on multi-environmental trials. By comparing the root transcriptome of two contrasting genotypes, 2897 differentially expressed genes were detected and they were enriched in phenylpropanoid biosynthesis, starch and sucrose metabolism, stilbenoid, diarylheptanoid and gingerol biosynthesis, flavonoid biosynthesis, suggesting that these pathways are crucial for sesame root growth and development. Overall, this study sheds light on the diversity of sesame root system and offers the basis for improving root traits and increasing sesame seed yield.

Analysis of genetic diversity in sesame (Sesamum indicum L.) advanced breeding lines and varieties collected from major breeding centers in India

Genetic diversity study was carried out among 41 sesame genotypes using seed yield and its component characters. Based on the present investigation the 41sesame genotypes were grouped into seven clusters suggesting that considerable amount of genetic diversity present across genotypes. The maximum diversity was contributed by capsules per plant followed by number of branches per plant, plant height and days to maturity. Cluster II was the largest one comprising of 17 genotypes followed by cluster I with 12 genotypes, cluster IV with five genotypes, cluster III with four genotypes, cluster V, VI, and VII, were represented by each single genotype indicating high degree of heterogeneity among the genotypes. The maximum inter cluster distance was observed between IV and VI clusters followed by clusters IV and V and clusters VI and VII while it was low between clusters V and VI, followed by clusters I and V, clusters II and VII. Maximum intra cluster distance was observed in cluster VI, followed by cluster IV, cluster III, cluster II and cluster I. The inter cluster distance in most of the cases were higher than the intra-cluster distance indicating wider genetic diversity among the genotypes of different groups. Four characters viz., capsules per plant, followed by number of branches, plant height and days to maturity contributed more than 90% towards genetic divergence. Hence, these four characters are very important for selection indices.

Utility of some floral characters in the assessment of genetic diversity in sesame (Sesamum indicum L.)

Sesame collections were evaluated for quantitative floral characters and data obtained were subjected to various statistical analyses. Result showed narrow diversity in most of the quantitative floral characters with moderate variability in length of flower (2.03-3.27 cm), length of style (1.10-1.40 cm), length of capsule (2.33-2.98 cm) and number of seeds per capsule (38.67 – 57.67). Correlation study revealed significantly (p < 0.01) positive correlations for length of ovary versus length of flower (r= 0.70) and length of capsule versus length of style (r= 0.77). The first two principal components accounted for 61.59 % of which the first component had 34.13 % and the second was 27.46 %. Dendrogram divided the seventeen accessions/landraces into two major groups (A and B). Group A had only one cluster with five members whilegroup B had three clusters (Cluster II, III and IV) with seven, three and two members respectively. Each accession within a cluster could be employed as baseline parent in crossbreeding for improvement of yield in Nigerian sesame.

Genomic Simple Sequence Repeat Markers Reveal Patterns of Genetic Relatedness and Diversity in Sesame.

Sesame (Sesamum indicum L. syn. Sesamum orientale L.) is an orphan crop species with most molecular genetic research work done in the last decade. In this study, we used a pyrosequencing approach for the development of genomic simple-sequence repeat (SSR) markers in sesame. Our approach proved successful in identifying 19,816 nonredundant SSRs, 5727 of which were identified in a contig assembly that covers 19.29% of the sesame genome. Mononucleotide repeats were the most abundant SSR type identified in the sesame genome (48.5% of all SSRs), followed by dinucleotide SSRs (45.0%). Adenine-thymine-rich motifs were predominant, representing 81.7, 51.7, 66.5, and 22.1% of the mononucleotide, dinucleotide, trinucleotide, and tetranucleotide SSRs, respectively. As a result of this work, we introduce 933 experimentally validated sesame specific markers, 849 of which are also applicable in Sesamum mulayanum (syn. Sesamum orientale var. malabaricum Nar.), the wild progenitor of cultivated sesame. Using a subset of the newly identified SSR markers, we analyzed molecular genetic diversity and population structure of a collection of world accessions. Results of the two analyses almost overlapped and suggested correlation between genetic similarity and geographical proximity. Indeed, a pattern of gene flow among sesame diversity centers was apparent, with levels of variability in some regions similar to that seen in the domestication origin of the crop. Taken together with the high rate of genomic marker transferability detected between S. indicum and S. mulayanum, our results represent additional molecular genetic evidence for designating the two taxa as cultivated and wild forms of the same species.

Sesame (<i>Sesame indicum L</i>.) Crop Production in Ethiopia: Trends, Challenges and Future Prospects

The Aim of this paper is to review the importance of sesame (Sesamum indicum L.) oil crop, production status in Ethiopia, constraints, potentials and future opportunities. Sesame is one of the most important high value oil crops in Ethiopia contributing high foreign currency. Sesame oil is useful edible oil and has wide applications. Different reports indicate that the sesame production is increasing from year to year which is mainly driven by high current market demand and suitability of environmental factors.For instance, the recent five years data indicated that the production is growing at the rate of about 54% in parallel with an increased area coverage of about 45% during the same years indicating a yield gain from extensive farming system. The production is concentrated in South western and north western parts of Ethiopian. The three commonly used sesame commercial varieties in these areas are known by their brand name as Humera, Gondar and Wollega types. The presence of genetic diversity insesame genetic resources, proximity of Ethiopia to the international market, an increased demand for Ethiopian sesame, the presence of relatively high oil content of sesame cultivars and suitability of environmental condition for sesame growth will give high opportunity for Ethiopia to improve the crop. Therefore, to increase yield potential and quality of sesame crop and achieve better profit requires the collaborative efforts of all stake holders in capacity building on sesame crop improvement and post harvest handling of the crop, development of high yielding widely adapted cultivars with better resistance to diseases and pests, development of improved agronomic and managemental practices, environmental clustering for high oil quality and creating a capacity to process the sesame and/or oil seeds in the country.

Assessment of genetic diversity in sesame (Sesamum indicum L.) genotypes, using EST-derived SSR markers

A total of 16,619 ESTs sequences (SSRs) of sesame (Sesamum indicum L.) were mined from Genbank. From sequences, 156 primer pairs were designed and characterized to determine the diversity among 49 sesame accessions. Twenty SSRs were found to be polymorphic and the number of alleles ranged from two to five per locus. The allele size varied from 101 to 399 bp. The average PIC value of the 20 SSR loci was 0.72 ranging from 0.49 (SEM-12-68) to 0.90 (SEM-12-27). Dendrogram analysis grouped the 49 genotypes into five separate clusters exhibiting a genetic similarity coefficient from 0.59 to 1.0. Hence, these EST-derived SSRs markers could be useful in assessing the diversity of sesame accessions and could also help in identifying diverse parents for sesame improvement programs.

Genetic diversity in cultivated sesame (Sesamum indicum L.) and related wild species in East Africa

Genetic diversity of traditional sesame landraces and related wild species in East Africa remains largely unexplored. Knowing what fraction of the available genetic diversity is actually used by the farmers is of central importance for understanding how cultivation shapes the genetic structure of a crop and for the management of biodiversity preservation. Genetic diversity in cultivated sesame and related wild species in East Africa was determined using inter-simple sequence repeats (ISSR). Six reliable ISSR primers generated 51 amplification fragments of which 36 (70.6%) were polymorphic. The number of amplified fragments ranged from 7 to 12 with a mean of 8.5 fragments per primer. The overall gene diversity and Shannon’s index were 0.28 and 0.34, Jaccard’s similarity coefficient ranged from 0.26 to 0.96, with an average of 0.67. Forty-six accessions of sesame were divided into six clusters, although the clustering did not indicate any clear division among sesame accessions based on their geographical locations. Each wild species was more distant from cultivated sesame than from other wild species, indicating that no cross-pollination with these wild species occurred during sesame domestication. These results showed a relatively high genetic diversity in sesame and related wild species. Indian-1 and Indian-2 accessions showed a good amount of genetic divergence. The genetic diversity data uncovered in this study can be exploited to improve traditional landraces of sesame in East Africa.

Analysis of genotypic diversity in sesame (Sesamum indicum L.) based on some physiological characters

Genetic diversity among 30 sesame genotypes, collected from different parts of India, was studied using measurements of leaf area index (LAI) obtained 30, 45, 60 and 75 days after sowing (DAS), crop growth rates (CGR) estimated between the above leaf area measurements (i.e. 30 to 45 DAS, 45 to 60 DAS and 60 to 75 DAS), days to peak flowering, duration of flowering, duration from peak flowering to maturity and oil yield per plant. The normalised Euclidean distance was calculated from the data, and, independently, the Mahalanobis D<sup>2</sup> statistics was calculated after dimensionality was reduced by pivotal condensation. The clustering pattern obtained by D<sup>2</sup> analysis agreed closely with the dendrogram constructed from the Euclidean distance matrix. In general, the distribution pattern of genotypes in different clusters indicated that genetic divergence was not related to geographical differentiation. However, it was evident that a certain degree of genotypic divergence resulted from the geographic origin of the cultivars. Duration from peak flowering to maturity contributed most to the observed diversity, followed by days to peak flowering, duration of flowering, LAI at 30 DAS and 75 DAS, oil yield per plant and LAI at 60 DAS. Therefore, a greater emphasis should be laid on these characters in the selection of parents for further breeding programmes.

Relationship between metabolic and genomic diversity in sesame (Sesamum indicum L.)

BackgroundDiversity estimates in cultivated plants provide a rationale for conservation strategies and support the selection of starting material for breeding programs. Diversity measures applied to crops usually have been limited to the assessment of genome polymorphism at the DNA level. Occasionally, selected morphological features are recorded and the content of key chemical constituents determined, but unbiased and comprehensive chemical phenotypes have not been included systematically in diversity surveys. Our objective in this study was to assess metabolic diversity in sesame by nontargeted metabolic profiling and elucidate the relationship between metabolic and genome diversity in this crop.ResultsTen sesame accessions were selected that represent most of the genome diversity of sesame grown in India, Western Asia, Sudan and Venezuela based on previous AFLP studies. Ethanolic seed extracts were separated by HPLC, metabolites were ionized by positive and negative electrospray and ions were detected with an ion trap mass spectrometer in full-scan mode for m/z from 50 to 1000. Genome diversity was determined by Amplified Fragment Length Polymorphism (AFLP) using eight primer pair combinations. The relationship between biodiversity at the genome and at the metabolome levels was assessed by correlation analysis and multivariate statistics.ConclusionPatterns of diversity at the genomic and metabolic levels differed, indicating that selection played a significant role in the evolution of metabolic diversity in sesame. This result implies that when used for the selection of genotypes in breeding and conservation, diversity assessment based on neutral DNA markers should be complemented with metabolic profiles. We hypothesize that this applies to all crops with a long history of domestication that possess commercially relevant traits affected by chemical phenotypes.

Assessment of genetic diversity in sesame (Sesamum indicum L.) detected by Amplified Fragment Length Polymorphism (AFLP) markers

Is an international scientific electronic journal which publishes paper from all areas related to biotechnology. It covers from molecular biology and the chemistry of biological process to aquatic and earth enviromental aspects, as well as computational applications and policy issues directly related to biotechnology. Papers concerning multidisciplinary research are particulary welcomed. EJB Electronic Journal of Biotechnology provide and effective way to publish research papers and solicited review articles. Publication is free of charge.

Assessment of genetic diversity in sesame (Sesamum indicum L.) detected by Amplified Fragment Length Polymorphism markers

Sesame ( Sesamum indicum L.) is one of the oldest oil crops and is widely cultivated in Asia and Africa. To determine the level of genetic diversity in relation to geographical origins and morphological characteristics, a total of 96 accessions have been collected from different parts of the world and were analyzed using AFLP techniques. Twenty-one primer pairs generated a total of 445 bands and among them 157 (35%) were polymorphic. Using UPGMA clustering analysis method based on the similarity coefficient, accessions were separated into two major groups. The first group mostly consists of Eastern Asian origin and another group consists of South Asian origin. Sub-clusters separated the accessions and form distinct diversity among groups. Considering the relatednessof accessions, geographical origin and their morphological characteristics are reflected to the similarity of AFLP pattern.

Genetic relationship and diversity in a sesame (Sesamum indicum L.) germplasm collection using amplified fragment length polymorphism (AFLP)

BackgroundSesame is an important oil crop in tropical and subtropical areas. Despite its nutritional value and historic and cultural importance, the research on sesame has been scarce, particularly as far as its genetic diversity is concerned. The aims of the present study were to clarify genetic relationships among 32 sesame accessions from the Venezuelan Germplasm Collection, which represents genotypes from five diversity centres (India, Africa, China-Korea-Japan, Central Asia and Western Asia), and to determine the association between geographical origin and genetic diversity using amplified fragment length polymorphism (AFLP).ResultsLarge genetic variability was found within the germplasm collection. A total of 457 AFLP markers were recorded, 93 % of them being polymorphic. The Jaccard similarity coefficient ranged from 0.38 to 0.85 between pairs of accessions. The UPGMA dendrogram grouped 25 of 32 accessions in two robust clusters, but it has not revealed any association between genotype and geographical origin. Indian, African and Chinese-Korean-Japanese accessions were distributed throughout the dendrogram. A similar pattern was obtained using principal coordinates analysis. Genetic diversity studies considering five groups of accessions according to the geographic origin detected that only 20 % of the total diversity was due to diversity among groups using Nei's coefficient of population differentiation. Similarly, only 5% of the total diversity was attributed to differences among groups by the analysis of molecular variance (AMOVA). This small but significant difference was explained by the fact that the Central Asia group had a lower genetic variation than the other diversity centres studied.ConclusionWe found that our sesame collection was genetically very variable and did not show an association between geographical origin and AFLP patterns. This result suggests that there was considerable gene flow among diversity centres. Future germplasm collection strategies should focus on sampling a large number of plants. Covering many diversity centres is less important because each centre represents a major part of the total diversity in sesame, Central Asia centre being the only exception. The same recommendation holds for the choice of parents for segregant populations used in breeding projects. The traditional assumption that selecting genotypes of different geographical origin will maximize the diversity available to a breeding project does not hold in sesame.