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Assessment of genetic diversity is crucial for efficient selection genotypes in plant breeding and improvement programs. Studies of genetic diversity of S. persica are rare relative to the large species diversity in Saudi Arabia, despite its valuable importance as one of the most popular medicinal plants. We investigate the genetic variability and genetic differentiation among and within wild Salvadora persica populations distributed in four regions of Saudi Arabia. Twelve sequence-related amplified polymorphism (SRAP) primers combination generated 326 alleles, with an average of 27.2 alleles per primer. All primers showed 100 polymorphism percentage, and higher PIC values exceeded 0.90. Jaccard similarity values varied between 0.04 to 0.43, with an average of 0.31, which showed a weak relationship among the accessions and their origin. Based on UGPMA and principal coordinate analysis, accessions collected from the same region showed less aggregation. Genetic diversity parameters showed that both Aflaj and Joodah populations recorded the highest mean values for the effective number of alleles (1.26 and 1.24). Shannon index and genetic heterozygosity (0.23 and 0.15 for both populations), and percent of polymorphism 45.45% for Aflaj and 43.87 for Joodah population. Most of the genetic variation was because of differences within populations (77%) and 23% among populations. SRAP markers explored the genetic diversity among and within S. persica populations. In this work, genetic diversity within populations was high, and the population structure was weak. We detected no specific geographic structure, which may reveal an active movement of plants among populations.
Asunto(s)
Alelos , Filogenia , Polimorfismo Genético , Salvadoraceae/genética , Arabia SauditaRESUMEN
Apomixis, or asexual seed formation, is of great value for plant breeding and seed production, and is desirable in modern agriculture, but natural apomixis occurs in cassava at very low frequency. In present study, apomixis was induced by the treatments of female flower buds with 1%, 1.5% and 2% (v/v) dimethyl sulfoxide (DMSO) and the results showed that 1.5% DMSO treatment was most effective for the induction of apomictic seed formation in cassava cultivar SC5 with the highest percentages of fruit set and true apomictic seeds. The germinated seedlings resembled their parents and displayed no morphological characteristics of cassava polyploid. Flow cytometry and chromosome counting showed that these plants were uniform diploids. Analysis of 34 DMSO-induced cassava progenies by the expressed sequence tag-simple sequence repeat (EST-SSR) and sequence-related amplified polymorphism (SRAP) markers showed that three true apomictic seeds were obtained from the group of SC5 treated with 1.5% DMSO.
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Rapeseed (Brassica napus L.) and turnip rape (B. rapa L. subsp. campestris (L.)) are important agricultural plants widely used for food, fodder and technical purposes and as green manure. Over the past decades, a large number of perspective varieties that are being currently cultivated in every region of Russia have been developed. To increase the breeding eff iciency and facilitate the seed production, modern molecular-genetic techniques should be introduced as means to estimate species and varietal diversity. The objective of the presented research study was to investigate DNA polymorphism of the rapeseed and turnip rape varieties developed at Federal Williams Research Center of Forage Production and Agroecology and detect informative markers for varietal identif ication and genetic certif ication. To genotype 18 gDNA samples, 42 and 25 combinations of respective SSR and SRAP primers were used. The results obtained demonstrate that SRAP markers were more effective for polymorphism analysis: 36 % of the tested markers revealed genetic polymorphism compared with only 16.7 % of microsatellite loci. Molecular markers to detect differences at interspecif ic and intervarietal levels have also been found. For the investigated set, such microsatellite loci as Na12A02, Ni2C12, Ni02-D08a, Ra02-E01, Ni03H07а and SRAP-marker combinations as F13-R9, Me4- R7, F11-Em2, F10-R7, F9-Em2 and F9-R8 proved to be informative. Application of the two marker techniques made it possible to detect a higher level of DNA polymorphism in plants of different types (spring and winter varieties) if compared against the intervarietal differences within a species or a group. According to Nei's genetic diversity index, in the cluster of winter rapeseed, VIK 2 and Gorizont varieties had the longest genetic distance, and in the spring cluster, these were Novosel and Veles. A high level of similarity was found between Vikros and Bizon winter rapeseed varieties. The results obtained have a high practical value for varietal specif ication of seed material and genetic certif ication of rapeseed and turnip rape varieties.
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We studied the genetic and flower volatile diversity in natural populations of Origanum vulgare subsp. hirtum (Link) Ietsw. in Bulgaria using simple sequence repeat (SSR) and sequence-related amplified polymorphism (SRAP) markers and gas chromatography/mass spectrometry (GC/MS) analysis of flower volatiles from individual plants. Two regions, including the Kresna Gorge and Eastern Rhodopes, typical for the species comprising eight populations and 239 individual plants were included in this study. An analysis with 11 SSR markers and eight SRAP primer combinations showed that SRAP markers were substantially more informative than the SSR markers and were further used for genetic diversity analysis. The results showed low-range to mid-range genetic differentiation between the populations with pairwise fixation index (Fst) values ranging between 0.0047 and 0.11. A total of 10 genetic clusters were identified. An analysis of the flower volatile diversity identified a total of 63 compounds with the vast majority of plants belonging to the carvacrol chemotype and just a single plant to the thymol chemotype. Large deviations were observed for individual compounds within each region as well as within the populations. Hierarchical clustering showed a clear sample grouping based on the two different regions. In addition, an in-depth analysis identified six major and 23 minor metabolite clusters. The overall data set and cluster analysis were further used for the development and testing of a simple and straightforward strategy for the selection of individual plants for the development of a core collection representing the sampled natural populations for this species in Bulgaria. The proposed strategy involves precise genetic clustering of the tested plants followed by the selection of a minimal set from each genetic cluster representing the different metabolite clusters. The selected core set was further compared with a core set extracted by the PowerCore software. A comparison of the genetic and metabolic affiliation of the members of both sets showed that the reported approach selected representatives from each genetic cluster and minor metabolic cluster, whereas some metabolic clusters were unrepresented in the PowerCore set. The feasibility and efficiency of applying the pointed strategy for the development of a core collection representing both the genetic and metabolite diversity of natural populations in aromatic and medicinal plants toward subsequent steps of selection and breeding are discussed.
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Genetic variation and diversity are prerequisites for improvement of buffalograss breeding. To assess the within-population genetic diversity of buffalograss, seven morphological traits were evaluated to confirm the variations at the morphological level. The principal component analysis revealed that leaf length, leaf width and stolon branches had a significant contribution to the total variation. The first three principle components showed 72.55% variation. The DNA analysis performed using SRAP primers was used for deducing the diversity at the DNA level. A total of 125 bands were obtained with 8 selected SRAP primer pairs, of which 119 (95.2%) were polymorphic. The polymorphic information content ranged from 0.94 to 0.97 with a mean of 0.96; the marker index ranged from 10.34 to 18.43 with an average value of 14.28. The individuals were successfully assigned to two major groups according to sex in the PCoA and UPGMA dendrogram based on SRAP data, while the individuals could not be grouped based on morphological traits, and the two markers were not significantly correlated (r = 0.0753, P = 0.8489 > 0.05). The molecular data revealed that sex is a critical factor and that female and monoecious plants could be chosen as parents to breed new varieties.
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BACKGROUND: Simao pine (Pinus kesiya Royle ex Gordon var. langbianensis (A. Chev.) Gaussen) is one of the most important tree species in the production of timber and resin in China. However, the genetic diversity of the natural populations has not been assessed to date. In this study, sequence related amplified polymorphism (SRAP) markers were used to investigate the genetic composition of natural Simao pine populations. METHOD: The SRAP markers were applied and their efficiency was compared using various statistical multivariate methods, including analysis molecular of variance (AMOVA), the unweighted pair group method with arithmetic mean (UPGMA), and Principal coordinate analysis (PCoA). RESULTS: The 11 populations revealed a high level of genetic diversity (PPB = 95.45%, H = 0.4567, I = 0.6484) at the species level. A moderately low level of genetic differentiation (Gst = 0.1701), and a slightly high level of gene flow (Nm = 2.4403) were observed among populations using AMOVA. Eleven populations of Simao pine were gathered into four distinct clusters based on molecular data, and the results of UPGMA and PCoA also illustrated that assignment of populations is not completely consistent with geographic origin. The Mantel test revealed there was no significant correlation between geographic and genetic distance (r = 0.241, p = 0.090). DISCUSSION: The SRAP markers were very effective in the assessment of genetic diversity in Simao pine. Simao pine populations display high levels of genetic diversity and low or moderate levels of genetic differentiation due to frequent gene exchange among populations. The low genetic differentiation among populations implied that conservation efforts should aim to preserve all remaining natural populations of this species. The information derived from this study is useful when identifying populations and categorizing their population origins, making possible the design of long term management program such as genetic improvement by selective breeding.
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Objective: To study the 25 germplasm resources of Coix lacryma-jobi by the technique of SRAP molecular markers. Methods: Taking genome DNA in the leaves of C. lacryma-jobi extracted by modified CTAB method as template. Six ideal primer pairs were selected from 88 primer pairs by using the optimized SRAP-PCR reaction system and the amplification of 25 germplasm resources by SRAP-PCR were carried out. Results: The total 66 clear and repeatable polymorphic bands were obtained, and the polymorphic rate was up to 93%. The coefficient of genetic similarity among each species was calculated by using NTSYPC 2.1 software. The results indicated that the coefficient of genetic similarity of these materials ranged from 0.48 to 0.82. Conclusion: The 25 populations of C. lacryma-jobi could be clustered into four groups.