Morpho-phenological diversity among Tunisian natural populations of Brachypodium hybridum

2014 ◽  
Vol 153 (6) ◽  
pp. 1006-1016 ◽  
Author(s):  
M. NEJI ◽  
F. GEUNA ◽  
W. TAAMALLI ◽  
Y. IBRAHIM ◽  
M. SMIDA ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Geographic Distribution ◽  
Phenotypic Diversity ◽  
Average Length ◽  
Natural Populations ◽  
Negative Relationship ◽  
Mantel Test ◽  
Population Variation ◽  
Long Distance ◽  
Temperate Cereal

SUMMARYBrachypodium hybridum belongs to the Poaceae grass subfamily. It has a close genetic relationship with temperate cereal crops, which means that it can be used as a model for temperate cereal and grass crops. In order to improve knowledge on the genetic diversity of this species, 145 lines of B. hybridum representative of nine populations and all the ecoregions of Tunisia were characterized on the basis of 18 morpho-phenologic features. The results show a considerable variation between populations and ecoregions in all traits studied. Variation was relatively higher for reproductive than vegetative traits. The majority of traits showed very low to high heritability with low border value for average length of spikelet (ALS) and an average value of 0·64. It is noticeable that high values of heritability were observed for most vegetative descriptors, with low values for reproductive ones. Differentiation between populations (QST) varied from 0·02 for ALS to 0·78 for average length of leaves with a mean value across traits of 0·4, which confirms the wide intra-population variation in Tunisian natural population of B. hybridum. Pairwise QST showed that the greatest differentiation among populations was registered between Ain Drahem and Jbel Zaghouan and the smallest between Haouria and Raoued. Overall, the Ain Draham population showed the largest differentiation from the rest of the populations. To infer the effect of geographic distribution of the species, a Mantel test was applied between observed pairwise differentiation and geographic distance between populations and between ecoregions: the results show a positive, but not significant, relationship. In addition a significant negative relationship was found between phenotypic diversity and altitude, indicating that genetic diversity decreased with increasing altitude. Taken together, the high levels of intra-population variation and the lack of correlation between genetic differentiation and geographic distribution suggest a potentially important rate of long-distance seed dispersal and confirm the role played by natural selection in the population structure of Tunisian natural populations of B. hybridum.

scholarly journals Regional genetic diversity in circadian period in Boechera stricta populations is high relative to the global range of diversity in Arabidopsis

2021 ◽  
Author(s):  
Robby McMinn ◽  
Matti Salmela ◽  
Cynthia Weinig
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Significant Proportion ◽  
Natural Populations ◽  
Elevational Gradient ◽  
Environmental Data ◽  
Population Variation ◽  
Circadian Period ◽  
In The Wild ◽  
Boechera Stricta

Circadian clocks manifest adaptations to predictable 24-h fluctuations in the exogenous environment, but it has yet to be determined why the endogenous circadian period length in the wild varies genetically around the hypothesized optimum of 24 h. We quantified genetic variation in circadian period in leaf movement in 30 natural populations of the Arabidopsis relative Boechera stricta sampled within only 1° of latitude but across an elevational gradient spanning 2460−3300 m in the Rocky Mountains. Measuring over 3800 plants from 473 maternal families (7−20 per population), we found genetic variation that was of similar magnitude among vs. within populations, with population means varying between 21.9−24.9 h and maternal family means within populations varying by up to ~6 h. After statistically factoring out spatial autocorrelation at the habitat extremes, we found that elevation explained a significant proportion of genetic variation in circadian period such that higher-elevation populations had shorter mean period lengths and less within-population variation. Environmental data indicate that these spatial trends could be related to steep regional climatic gradients in temperature, precipitation, and their intra-annual variability. Our findings provide evidence that spatially fine-grained environmental heterogeneity contributes to naturally occurring genetic diversity in circadian traits in wild populations.

scholarly journals Low Divergence Among Natural Populations of Cornus kousa subsp. chinensis Revealed by ISSR Markers

Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1082 ◽  
Author(s):  
Jia-Qiu Yuan ◽  
Qin Fang ◽  
Guo-Hua Liu ◽  
Xiang-Xiang Fu
Keyword(s):  
Genetic Diversity ◽  
Diversity Index ◽  
In Situ Conservation ◽  
Geographic Distance ◽  
Natural Populations ◽  
Issr Markers ◽  
Mantel Test ◽  
Distribution Area ◽  
Genetic Characteristics ◽  
Cornus Kousa

Research Highlights: Taking Chinese dogwood (Cornus kousa subsp. chinensis) as an example, the genetic characteristics of natural populations collected from main a distribution area were evaluated using intersimple sequence repeat (ISSR) markers to reveal the genetic basis for further selection and breeding. Background and Objectives: Chinese dogwood is a small understory tree that is widely distributed in China. Chinese dogwood has attracted interest for its potential horticultural and ornamental values, and its natural resource potential urgently needs to be estimated. Materials and Methods: In this study, the genetic diversity of 12 natural populations collected from six provinces containing 223 individuals was evaluated based on ISSR markers. Results: Relatively high levels of genetic diversity were found at both the population and individual levels. The Shannon’s diversity index (I) among individuals (0.504) was higher than that among populations (0.338). Analysis of molecular variance (AMOVA) revealed that genetic variation mainly existed within populations (61.55%) rather than among populations (38.45%). According to the STRUCTURE analysis, 12 populations were assigned to two groups, i.e., the northern and southern ecological regions, which are separated by the Yangtze River. A Mantel test analysis showed that there was no significant correlation between genetic distance and geographic distance. Conclusions: Considering the breeding system of dogwoods, we speculated that the genetic characteristics of the natural populations of this species would be affected by the dispersal mode of its pollens and seeds; additionally, genetic drift could play an important role in its genetic differentiation. In conclusion, in situ conservation is recommended for Chinese dogwood based on our results.

Cyanogenic polymorphism as an indicator of genetic diversity in the rarespecies Eucalyptus yarraensis (Myrtaceae)

2002 ◽  
Vol 29 (12) ◽  
pp. 1445 ◽  
Author(s):  
Jason Q. D. Goodger ◽  
Ian E. Woodrow
Keyword(s):  
Genetic Diversity ◽  
Effective Means ◽  
Natural Populations ◽  
Population Variation ◽  
Conservation Strategy ◽  
Narrow Sense Heritability ◽  
Specialist Herbivores ◽  
Cyanogenic Plants ◽  
Physical And Chemical ◽  
First Time

The rare Australian tree Eucalyptus yarraensis Maiden & Cambage is cyanogenic, a quantitative trait potentially indicative of genetic diversity. Cyanogenic plants are capable of releasing cyanide from endogenous cyanide-containing compounds. Cyanide is toxic or deterrent to generalist or non-adapted specialist herbivores. Consequently, cyanogenic plants are afforded an effective means of chemical defense. In this paper we characterize quantitative variation in cyanogenic capability, known as cyanogenic polymorphism, in E. yarraensis for the first time. We show that the cyanogenic glucoside prunasin (R-mandelonitrile-β-D-glucoside) is the only cyanogenic compound in E. yarraensis foliage. We also show that two natural populations of E. yarraensis display extensive intra- and inter-population variation in foliar prunasin concentration. The high prunasin concentrations reported in this paper represent the highest yet recorded for mature eucalypt leaves. The cyanogenic variation could not be attributed to measured physical and chemical parameters, supporting the hypothesis that the variation is genetically based. A preliminary progeny trial also supports this hypothesis, with narrow sense heritability estimated at 1.17 from three half-sibling families. The variation in cyanogenic capability may be a useful tool in the development of a conservation strategy for the species.

scholarly journals Assessing the Genetic Diversity and Population Structure of a Tunisian Melon (Cucumis melo L.) Collection Using Phenotypic Traits and SSR Molecular Markers

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1121
Author(s):  
Hela Chikh-Rouhou ◽  
Najla Mezghani ◽  
Sameh Mnasri ◽  
Neila Mezghani ◽  
Ana Garcés-Claver
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Phenotypic Diversity ◽  
Diversity Index ◽  
Polymorphic Information Content ◽  
Crop Improvement ◽  
Molecular Data ◽  
Mantel Test ◽  
Phenotypic Traits ◽  
Genetic Diversity And Structure

The assessment of genetic diversity and structure of a gene pool is a prerequisite for efficient organization, conservation, and utilization for crop improvement. This study evaluated the genetic diversity and population structure of 24 Tunisian melon accessions, by using 24 phenotypic traits and eight microsatellite (SSR) markers. A considerable phenotypic diversity among accessions was observed for many characters including those related to agronomical performance. All the microsatellites were polymorphic and detected 30 distinct alleles with a moderate (0.43) polymorphic information content. Shannon’s diversity index (0.82) showed a high degree of polymorphism between melon genotypes. The observed heterozygosity (0.10) was less than the expected heterozygosity (0.12), displaying a deficit in heterozygosity because of selection pressure. Molecular clustering and structure analyses based on SSRs separated melon accessions into fivegroups and showed an intermixed genetic structure between landraces and breeding lines belonging to the different botanical groups. Phenotypic clustering separated the accessions into two main clusters belonging to sweet and non-sweet melon; however, a more precise clustering among inodorus, cantalupensis, and reticulatus subgroups was obtained using combined phenotypic–molecular data. The discordance between phenotypic and molecular data was confirmed by a negative correlation (r = −0.16, p = 0.06) as revealed by the Mantel test. Despite these differences, both markers provided important information about the diversity of the melon germplasm, allowing the correct use of these accessions in future breeding programs. Together they provide a powerful tool for future agricultural and conservation tasks.

scholarly journals Genetic diversity of natural populations of Taxus wallichiana var. mairei

2021 ◽  
Author(s):  
Qianqian Luo ◽  
Fengqing Li ◽  
Longhua Yu ◽  
Liyun Wang ◽  
Gangbiao Xu ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Diversity Index ◽  
Polymorphic Information Content ◽  
Natural Populations ◽  
Mantel Test ◽  
Jiangxi Province ◽  
Timber Species ◽  
Endangered Tree ◽  
Endangered Tree Species ◽  
Taxus Wallichiana

Abstract Maire yew (Taxus wallichiana var. mairei (Lemée H. Léveillé.) L. K. Fu et Nan Li) is a rare and endangered tree species, and it is also a precious timber species in China. We used 13 microsatellites to assess the genetic diversity and differentiation of 665 Maire yew samples from 18 natural populations. A total of 291 alleles were detected. The average number of alleles (Na=22.39), expected heterozygosity (He=0.74), polymorphic information content (PIC = 0.86) and Shannon diversity index (I = 1.66) of the loci indicated a high level of genetic diversity in natural Maire yew populations. Moreover, gene flow was more active among populations (Nm=1.62) than within populations. Among the 18 populations, the Xinfeng population in Jiangxi Province has the highest genetic diversity. Although each of the studied populations should be protected from further deforestation and agricultural expansion, the Xinfeng population deserves the highest conservation priority. The results based on analysis of molecular variance showed that genetic variation occurred mainly within populations (84.90%; P < 0.001), which indicated that the degree of genetic differentiation of the natural populations of Maire yew was low. Based on UPGMA, the 18 populations were categorized into 4 groups. A Mantel test showed that there was no significant correlation between standard genetic distance and geographical distance or altitude differences among the populations. The genetic clustering results also indicated that the genetic relationship followed a north to south clustered trend. The information presented here forms the basis for the development of genetic guidelines for appropriate conservation programs.

scholarly journals Genetic diversity and population structure in the endangered tree Hopea hainanensis (Dipterocarpaceae) on Hainan Island, China

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0241452
Author(s):  
Chen Wang ◽  
Xiang Ma ◽  
Mingxun Ren ◽  
Liang Tang
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Population Decline ◽  
Hainan Island ◽  
Mantel Test ◽  
Long Distance ◽  
Endangered Tree ◽  
Important Indicator ◽  
Endangered Tree Species ◽  
Model Based Clustering

Hopea hainanensis Merrill & Chun (Dipterocarpaceae) is an endangered tree species restricted to Hainan Island, China and a small part of Northern Vietnam. On Hainan Island, it is an important indicator species for tropical forests. However, because of its highly valued timber, H. hainanensis has suffered from overexploitation, leading to a sharp population decline. To facilitate the conservation of this species, genetic diversity and population structure were assessed using 12 SSR markers for 10 populations sampled across Hainan Island. Compared to non-threatened Hopea species, H. hainanensis exhibited reduced overall genetic diversity and increased population differentiation (AMOVA: FST = 0.23). Bayesian model-based clustering and principal coordinate analysis consistently assigned H. hainanensis individuals into three genetic groups, which were found to be widespread and overlapping geographically. A Mantel test found no correlation between genetic and geographical distances (r = 0.040, p = 0.418). The observed genetic structure suggests that long-distance gene flow occurred among H. hainanensis populations prior to habitat fragmentation. A recent population bottleneck was revealed, which may cause rapid loss of genetic diversity and increased differentiation across populations. Based on these findings, appropriate strategies for the long-term conservation of the endangered species H. hainanensis are proposed.

scholarly journals Genetic Diversity and Population Structure of Chinese Corylus heterophylla and Corylus kweichowensis Using Simple Sequence Repeat Markers

2020 ◽  
Vol 145 (5) ◽  
pp. 289-298
Author(s):  
Tiantian Zhao ◽  
Wenxu Ma ◽  
Qinghua Ma ◽  
Zhen Yang ◽  
Lisong Liang ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Relationships ◽  
In Situ Conservation ◽  
Geographic Distance ◽  
Natural Populations ◽  
Distinct Species ◽  
Mantel Test ◽  
Conservation Of Genetic Resources ◽  
Genetic Clusters

Corylus heterophylla and Corylus kweichowensis are economically and ecologically important nut-producing woody shrubs that are distributed across northern and southern regions of China. However, few studies have examined the genetic diversity and genetic relationships between C. heterophylla and C. kweichowensis, and their taxonomic relationships have been questioned. In this study, 796 individuals collected from 34 natural populations (21 C. heterophylla and 13 C. kweichowensis populations) were investigated to assess the genetic diversity and population structure using 11 microsatellite loci. Analysis of molecular variance revealed that genetic differentiation of C. heterophylla and C. kweichowensis within populations accounted for 93.57% and 88.91% of total variation, respectively. The C. heterophylla and C. kweichowensis populations as a whole group were analyzed by multiple programs, which showed that the 34 populations were divided into two genetic clusters. One cluster included 21 C. heterophylla populations, and the second cluster contained 13 C. kweichowensis populations. We conclude from these results that C. heterophylla and C. kweichowensis are distinct species. The Mantel test showed that the genetic distance was significantly correlated with the geographic distance (r = 0.580, P < 0.001). The populations of C. heterophylla [e.g., populations WC (Weichang), MS (Mishan), and WA (Wu’an)] and C. kweichowensis [e.g., populations YX (Yuexi), ZP (Zhenping), LA (Lin’an), and TB (Taibai)] with high allelic richness are considered suitable for in situ conservation. Our study provides valuable information for breeding and conservation of genetic resources of C. heterophylla, C. kweichowensis, and related species.

Genetic diversity and population genetic structure in fragmented Allocasuarina verticillata (Allocasuarinaceae) – implications for restoration

2011 ◽  
Vol 59 (8) ◽  
pp. 770 ◽  
Author(s):  
Linda M. Broadhurst
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Gene Diversity ◽  
Natural Populations ◽  
Long Distance ◽  
Study Region ◽  
Allocasuarina Verticillata ◽  
Seed Crops

Vegetation restoration in fragmented regions is constrained by limited supplies of high quality seed and an understanding of the scale over which seed can be moved without causing negative outcomes. ‘Local’ seed is often prescribed for restoration but in fragmented landscapes this restricts collecting to small, inbred populations. Six polymorphic microsatellites were used to examine genetic diversity and population genetic structure in seed collected from 18 fragmented natural populations and three restored populations of the wind-pollinated and dispersed tree Allocasuarina verticillata, a key restoration species. Smaller populations produced seed crops with significantly fewer alleles, lower allelic richness and less gene diversity. Most of the populations assessed, including the restored sites, produce genetically diverse seed crops suitable for restoration but smaller populations (<30 plants) should be augmented with seed from larger populations. Principal coordinate analysis, graph-theory and Bayesian analyses found little evidence of spatially predictable genetic structure across the study region, which probably reflects long distance gene dispersal preventing the development of strong spatial structure. The absence of strong spatial patterns suggests that seed can be moved beyond current 5–50-km limits while being mindful of strong selection gradients or conditions that might indicate locally adapted populations.

scholarly journals Genetic polymorphism among natural populations of Anacardium humile A. ST-HIL

2020 ◽  
Vol 42 (1) ◽  
Author(s):  
Silvia Correa Santos ◽  
Raquel dos Santos Carvalho ◽  
Livia Maria Chamma Davide
Keyword(s):  
Genetic Diversity ◽  
Genetic Polymorphism ◽  
Genetic Variability ◽  
Genetic Divergence ◽  
Genomic Dna ◽  
Reproductive Strategies ◽  
Rapd Markers ◽  
Phenotypic Diversity ◽  
Diversity Index ◽  
Natural Populations

Abstract The genus Anacardium presents nine species, of these, three have sub-bush size, common in the Cerrado of the Center-West of Brazil. The objective of this work was to evaluate the genetic variability of the species, collected in eleven provenances, using RAPD markers. Genomic DNA from 122 accessions was extracted and amplified with 25 decamer primers. The results indicated polymorphism, ranging from 77.71% to 96.18%. The distribution of genetic diversity among and within populations shows that 27.14% of the variability is found between populations and 37.44% within the populations, suggesting the existence of genetic variability that may be related to the reproductive strategies adopted by the species throughout its evolution. The index of variation within the provenances (93.36%) was higher than the index found among populations (6.64%). Molecular analysis indicated that there is genetic divergence between and within the studied populations of Anacardium humile A. St. - Hill. The origin of Itajá-GO presented the highest genetic diversity, presenting the highest values of genetic diversity index, phenotypic diversity and higher percentage of polymorphic loci.

scholarly journals Genetic diversity and structure among natural populations of Mytilaria laosensis (Hamamelidaceae) revealed by microsatellite markers

2018 ◽  
Vol 67 (1) ◽  
pp. 93-98 ◽  
Author(s):  
Niu Yu ◽  
Jie Yuan ◽  
Guangtian Yin ◽  
Jinchang Yang ◽  
Rongsheng Li ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Geographic Distance ◽  
Natural Populations ◽  
Magnetic Bead ◽  
Mantel Test ◽  
High Genetic Diversity ◽  
Information Index ◽  
Genetic Diversity And Structure ◽  
High Level ◽  
Mytilaria Laosensis

Abstract Mytilaria laosensis is a fast-growing tropical broadleaf tree that is extensively used for wood production and has significant ecological benefits. To investigate the genetic diversity and population structure of M. laosensis, eight major natural popu­lations in China were analyzed by using simple sequence repeat (SSR) markers. A total of 88 microsatellite-containing fragments were obtained by the method of magnetic bead enrichment, among which 26 pairs of SSR primers were scree­ned out and used to generate a total of 190 alleles among 152 individuals. The average of observed number of alleles, Shannon’s information index and polymorphism information content per locus were 18.3, 1.1577 and 0.7759, respectively, implying a high level of genetic diversity in M. laosensis popu­lations. The variation within populations accounted for 81.74 % of total variation based on analysis of molecular variance. Clus­ter analysis divided the eight populations into four groups, among which five populations from the southern parts of Guangxi province were classified as one major group. Mantel test showed that there was highly significant correlation bet­ween Euclidean genetic distance and geographic distance, suggesting that geographic isolation contribute to the high genetic diversity of M. laosensis. Together, these could provide support for the feasibility of exploration and utilization of M. laosensis in subtropical areas of East Asia including Jiangxi, Hunan and Fujian province of China.

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