The hybrid nature of Lycium ciliatum × cestroides (Solanaceae): experimental, anatomical, and cytological evidence

1995 ◽  
Vol 73 (12) ◽  
pp. 1995-2005 ◽  
Author(s):  
Luis Bernardello ◽  
Ivana Rodriguez ◽  
Laura Stiefkens ◽  
Leonardo Galetto
Keyword(s):  
Parental Species ◽  
Germination Rate ◽  
Principal Component ◽  
Putative Hybrid ◽  
Herbarium Specimens ◽  
Similar Data ◽  
Hybrid Breakdown ◽  
Cytological Evidence ◽  
Living Plant ◽  
Hybrid Nature

The hybrid nature of Lycium ciliatum × cestroides Hieron. is supported through experimental crosses. Using L. ciliatum Schlecht. as a female parent, 57% of crosses set fruit with hybrid seeds, whereas reciprocal crosses were unsuccessful. Seeds had a high germination rate (76%). F1 plants obtained agree with the herbarium specimens previously cited as putative hybrid and with a living plant we found in Córdoba (Argentina). Leaf, stem, and flower anatomy, karyotype composition, and chemical nectar composition were analyzed in the artificial and the natural hybrid. Results were compared with similar data on the parental species. Most of the studied features were intermediate between those of the parental species, as supported by principal component analysis. The origin of this hybrid may be due to pollen transfer mediated by bumblebees that occasionally visit both parental species. The distribution of the parental species overlaps in a wide Chaco region showing no spatial, environmental, or external reproductive isolating mechanisms. Results indicate there is a hybrid breakdown in the progeny of the hybrid that would restrict the natural interspecific gene flow. Key words: Lycium ciliatum × cestroides, hybrid, karyotype, anatomy, crosses, flower visitors.

Hybridization Between Eucalyptus obliqua L'hérit. And E. pulchella Desf

1983 ◽  
Vol 31 (3) ◽  
pp. 211 ◽  
Author(s):  
BM Potts ◽  
JB Reid
Keyword(s):  
Hybrid System ◽  
Parental Species ◽  
Principal Component ◽  
Pollen Parent ◽  
Putative Hybrid ◽  
Hybrid Progeny ◽  
Hybrid Swarm ◽  
Long Distance ◽  
Or Gene ◽  
Tasmanian Endemic

The present study provides the first evidence for the occurrence of natural hybrids between the wide- ranging species E. obliqua (series Obliquae) and the restricted Tasmanian endemic E. pulchella (series Piperitae). The progeny from one putative hybrid is shown to be intermediate between the progeny from the two parental species for virtually all characters examined. Principal component and likelihood analyses support this intermediacy of the hybrid progeny and suggest that no other species are involved in this hybrid system. The hybrid progeny shows greater variability than progeny from either parental species. Further, the hybrid tree has a lower seed output per capsule than trees of either parental species and therefore the hybrid tree appears to be at an evolutionary disadvantage. The two adult hybrids were found on the edge of shallow gullies on E. pulchella-dominated, north- facing slopes away from pure stands of E. obliqua. Some natural saplings outside the phenotypic range of either species were also found in the gullies. These results are most easily interpreted as suggesting that the intermediate trees examined originated from recent hybridization (possibly F1) following the migration of E. obliqua pollen into the range of E. pulchella. It is suggested that long-distance pollen migration of this type may be of evolutionary importance in allowing the colonization of suitable sites (in this case, small gullies) by advantageous genes or gene combinations from a distant species. The gene combinations of the pollen parent may be reselected from a segregating hybrid swarm.

An Accurate, Robust and Low Dimensionality Deep Learning Localization Approach in DM-MIMO Systems Based on RSS

2021 ◽  
Author(s):  
Seyedeh Samira Moosavi ◽  
Paul Fortier
Keyword(s):  
Massive Mimo ◽  
Clustering Algorithm ◽  
Mean Squared Error ◽  
Mimo Systems ◽  
Principal Component ◽  
Base Station ◽  
Location Estimation ◽  
Similar Data ◽  
High Coverage ◽  
Single Antenna

Abstract Currently, localization in distributed massive MIMO (DM-MIMO) systems based on the fingerprinting (FP) approach has attracted great interest. However, this method suffers from severe multipath and signal degradation such that its accuracy is deteriorated in complex propagation environments, which results in variable received signal strength (RSS). Therefore, providing robust and accurate localization is the goal of this work. In this paper, we propose an FP-based approach to improve the accuracy of localization by reducing the noise and the dimensions of the RSS data. In the proposed approach, the fingerprints rely solely on the RSS from the single-antenna MT collected at each of the receive antenna elements of the massive MIMO base station. After creating a radio map, principal component analysis (PCA) is performed to reduce the noise and redundancy. PCA reduces the data dimension which leads to the selection of the appropriate antennas and reduces complexity. A clustering algorithm based on K-means and affinity propagation clustering (APC) is employed to divide the whole area into several regions which improves positioning precision and reduces complexity and latency. Finally, in order to have high precise localization estimation, all similar data in each cluster are modeled using a well-designed deep neural network (DNN) regression. Simulation results show that the proposed scheme improves positioning accuracy significantly. This approach has high coverage and improves average root-mean-squared error (RMSE) performance to a few meters, which is expected in 5G and beyond networks. Consequently, it also proves the superiority of the proposed method over the previous location estimation schemes.

scholarly journals The efficacy of different seed priming agents for promoting sorghum germination under salt stress

PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245505
Author(s):  
Xiaofei Chen ◽  
Ruidong Zhang ◽  
Yifan Xing ◽  
Bing Jiang ◽  
Bang Li ◽  
...  
Keyword(s):  
Salt Stress ◽  
Seed Germination ◽  
Germination Rate ◽  
Principal Component ◽  
Dry Weight ◽  
Seed Priming ◽  
Nacl Stress ◽  
Future Research ◽  
Fresh Weight ◽  
Positive Effects

Sorghum [Sorghum bicolor (L.) Moench] seed germination is sensitive to salinity, and seed priming is an effective method for alleviating the negative effects of salt stress on seed germination. However, few studies have compared the effects of different priming agents on sorghum germination under salt stress. In this study, we quantified the effects of priming with distilled water (HP), sodium chloride (NaCl), potassium chloride (KCl), calcium chloride (CaCl2), and polyethylene glycol (PEG) on sorghum seed germination under 150 mM NaCl stress. The germination potential, germination rate, germination index, vigor index, root length, shoot length, root fresh weight, shoot fresh weight, root dry weight, and shoot dry weight were significantly reduced by salt stress. Different priming treatments alleviated the germination inhibition caused by salt stress to varying degrees, and 50 mM CaCl2 was the most effective treatment. In addition, the mitigation effect of priming was stronger on root traits than on shoot traits. Mitigation efficacy was closely related to both the type of agent and the concentration of the solution. Principal component analysis showed that all concentrations of CaCl2 had higher scores and were clearly distinguished from other treatments based on their positive effects on all germination traits. The effects of the other agents varied with concentration. The priming treatments were divided into three categories based on their priming efficacy, and the 50, 100, and 150 mM CaCl2 treatments were placed in the first category. The 150 mM KCl, 10% PEG, HP, 150 mM NaCl, 30% PEG, and 50 mM KCl treatments were placed in the second category, and the 100 mM NaCl, 100 mM KCl, 20% PEG, and 50 mM NaCl treatments were least effective and were placed in the third category. Choosing appropriate priming agents and methods for future research and applications can ensure that crop seeds germinate healthily under saline conditions.

scholarly journals Propagation of Dry Habitat Fern Species Using Spore Collections from Historic Herbarium Specimens

2011 ◽  
pp. 43-54
Author(s):  
Gunnar Ovstebo
Keyword(s):  
Royal Botanic Garden ◽  
Herbarium Specimens ◽  
Botanic Garden ◽  
Spore Viability ◽  
Living Plant ◽  
Herbarium Material ◽  
Plant Collection ◽  
Fern Species ◽  
Herbarium Collections ◽  
Horticultural Research

Spores sourced from historic herbarium specimens have been used to introduce wild-collected material to the Royal Botanic Garden Edinburgh (RBGE) living plant collection. The ability of dry habitat ferns to maintain spore viability for prolonged periods makes it possible to grow plants from the historically important RBGE herbarium collections. The factors that affect the ability of spores to germinate from herbarium collections are described. Three fern species from the Pteridaceae – Actiniopteris semiflabellata, Anogramma leptophylla and Aleuritopteris scioana – which were not previously in cultivation at RBGE were germinated from herbarium material of different ages. Germination was observed from all three species. Plants produced in this experiment were accessed into the RBGE living plant collection for future horticultural research and germination trials.

scholarly journals Testing hypotheses of hybrid origins for two seashore species of Carex section Phacocystis (Cyperaceae)

2020 ◽  
Vol 194 (1) ◽  
pp. 100-117
Author(s):  
Michael D Nowak ◽  
A Tiril M Pedersen ◽  
Anne K Brysting ◽  
Audun Schrøder-Nielsen ◽  
Reidar Elven ◽  
...  
Keyword(s):  
Clonal Propagation ◽  
Parental Species ◽  
Sequence Data ◽  
Genomic Data ◽  
Putative Hybrid ◽  
Genetic Structuring ◽  
Hybrid Species ◽  
Testing Hypotheses ◽  
Future Studies ◽  
Analytical Approaches

Abstract Taxonomists have proposed numerous hybrid species in plants, but to gain a better understanding of the role that hybridization may play in plant diversification, such taxonomic hypotheses must be tested using genomic data. In this study, we employ ddRAD sequence data to test taxonomic hypotheses of hybrid origins in Carex salina and C. ramenskii (Carex section Phacocystis). Sequence data from multiple Norwegian and Icelandic populations of the putative hybrid and parental species were generated for hundreds of ddRAD loci. These data were used to estimate geographical structuring of genetic diversity and admixture and to explicitly test for hybrid origins using several analytical approaches. Our results indicate recurrent hybrid origins for the populations of C. salina and C. ramenskii sampled in our study and show that these populations are characterized by high interspecific heterozygosity. Our results support the idea that hybridization may indeed play an important role in the diversification of lineages of Carex and highlight the important role that clonal propagation might play in maintaining hybrid populations. Future studies focusing on a broader geographical sampling would be needed to assess if the genetic structuring in these Nordic populations reflects range-wide patterns in these hybrid lineages.

scholarly journals IMPROVED ESTIMATION OF COVARIANCE MATRIX IN HOTELLING’S T2 FOR MICROARRAY DATA

2016 ◽  
Vol 8 (2) ◽  
pp. 26 ◽  
Author(s):  
Suryaefiza Karjanto ◽  
Norazan Mohamed Ramli ◽  
Nor Azura Md Ghaninor Azura Md Ghani
Keyword(s):  
Covariance Matrix ◽  
Microarray Data ◽  
Simulated Data ◽  
Principal Component ◽  
Data Sets ◽  
Similar Data ◽  
Shrinkage Methods ◽  
Differential Gene ◽  
The Relationship ◽  
Simulated Data Sets

<p class="lead">The relationship between genes in gene set analysis in microarray data is analyzed using Hotelling’s <em>T</em><sup>2</sup> but the test cannot be applied when the number of samples is larger than the number of variables which is uncommon in the microarray. Thus, in this study, we proposed shrinkage approaches to estimating the covariance matrix in Hotelling’s <em>T<sup>2</sup></em> particularly to cater high dimensionality problem in microarray data. Three shrinkage covariance methods were proposed in this study and are referred as Shrink A, Shrink B and Shrink C. The analysis of the three proposed shrinkage methods was compared with the Regularized Covariance Matrix Approach and Kong’s Principal Component Analysis. The performances of the proposed methods were assessed using several cases of simulated data sets. In many cases, the Shrink A method performed the best, followed by the Shrink C and RCMAT methods. In contrast, both the Shrink B and KPCA methods showed relatively poor results. The study contributes to an establishment of modified multivariate approach to differential gene expression analysis and expected to be applied in other areas with similar data characteristics.</p>

scholarly journals Chromosomal Pairing and Pollen Viability in Rhizophora mangle and Rhizophora stylosa Hybrids

2002 ◽  
Vol 20 (1) ◽  
pp. 1 ◽  
Author(s):  
Anand P. Tyagi
Keyword(s):  
Diploid Number ◽  
Parental Species ◽  
Pollen Viability ◽  
Rhizophora Mangle ◽  
Staining Technique ◽  
Putative Hybrid ◽  
Mangrove Species ◽  
Rhizophora Stylosa ◽  
Chromosomal Pairing ◽  
Very High

Two prominent mangrove species of Fiji, Rhizophora mangle, Linn. Rhizophora stylosa Griff and their puative hyubrid (R x selala) were analysed for chromosome number and pairing. Both parental species and their hybrid possess a diploid number of (2n) = 36 chromosomes. Regular 18 bivalents were observed in two species but the hybrid lacked proper chromosome pairing during meiosis. Analysis of tetrads showed normal tetrad and microspores development in parental species but very high abnormality in the hybrid. Pollen fertility determined by staining technique and pollen germination technique showed very high pollen viability in both parental species but very low pollen viability in the putative hybrid. Lack of chromosomal homology appears to be contributing to high percentage of non-viable pollen resulting in complete sterility in the putative hybrid.

scholarly journals Morphometry and Distribution of Senecio Nemorensis agg. Species (Asteraceae) in Poland

2014 ◽  
Vol 59 (1) ◽  
pp. 37-54
Author(s):  
Kaja Rola
Keyword(s):  
Principal Component Analysis ◽  
Principal Component ◽  
Involucral Bract ◽  
Canonical Discriminant Analysis ◽  
Herbarium Specimens ◽  
Distribution Map ◽  
Pca Analysis ◽  
Leaf Base ◽  
Quantitative Characters ◽  
Base Width

Abstract A morphometric analysis based on 316 herbarium specimens of Senecio nemorensis agg. indicated the occurrence of the following four species in Poland: S. germanicus Wallr., S. hercynicus Herborg, S. ovatus (G. Gaertn. et al.) Willd. and S. ucranicus Hodálová. Principal component analysis (PCA), analysis of variance (ANOVA)/Kruskal-Wallis test and canonical discriminant analysis (CDA) were applied. Quantitative characters such as supplementary bract length, leaf base width, ligule length and the supplementary/involucral bract length ratio clearly discriminated taxa within S. nemorensis agg. Included is a distribution map of the investigated species based on the examined material, with particular emphasis on the course of the northeastern boundary of S. hercynicus and the northwestern boundary of S. ucranicus. Also given is a determination key for species within S. nemorensis agg. in Poland, together with morphological descriptions of particular species

AFLP markers and cytotaxonomic analysis reveal hybridisation in the genus Schoenus (Cyperaceae)

Genome ◽  
2002 ◽  
Vol 45 (2) ◽  
pp. 222-228 ◽  
Author(s):  
Ivan Scotti ◽  
Anna Mariani ◽  
Valentino Verona ◽  
Alberto Candolini ◽  
Carlo A Cenci ◽  
...  
Keyword(s):  
Pollen Grains ◽  
Aflp Markers ◽  
Morphological Data ◽  
Hybrid Population ◽  
Putative Hybrid ◽  
Cytological Evidence ◽  
Northeastern Italy ◽  
Natural Range ◽  
The Alps ◽  
Schoenus Nigricans

Molecular, cytological, and morphological data support the existence of a hybrid population between Schoenus nigricans and Schoenus ferrugineus. This population was found in northeastern Italy, where S. nigricans is central with respect to its natural range and S. ferrugineus is marginal, being most common in the Alps and in central and northern Europe. Molecular marker data show that the putative hybrid population is genetically intermediate between nearby populations of the parent species. Cytological evidence confirmed the hybrid nature of this population, as does the almost complete sterility of plants within the population. Although no seeds were produced by the hybrid population, some possibly fertile pollen grains were produced; this suggests that the possibility of introgression between the two species through the hybrids cannot completely be excluded.Key words: Schoenus, AFLP markers, chromosome behaviour, introgression.

Multivariate morphometric relationships between Hordeum jubatum and Hordeum brachyantherum in Canada and Alaska

1980 ◽  
Vol 58 (6) ◽  
pp. 604-623 ◽  
Author(s):  
Bernard R. Baum
Keyword(s):  
Field Data ◽  
Principal Component ◽  
Herbarium Specimens ◽  
Morphometric Characters ◽  
Herbarium Material ◽  
Repeated Observations ◽  
Hordeum Jubatum ◽  
Discriminant Analyses ◽  
The One

Scoring for morphometric characters was conducted on both herbarium material (including artificially produced hybrids) and specimens collected across Canada and Alaska and studied in situ. The data from herbarium material were analysed by means of various principal component analyses and by a series of discriminant analyses. The morphometric data from field material were obtained by repeated observations of every spikelet along the one side of each spike selected for analysis. A representative sample of spikes was collected from every population visited, with emphasis on hybrid populations. These repeated observations within spikes were also made in order to evaluate the reliability, representability, and taxonomic value of every spikelet and the degree of homologization within a spike. The field data were analysed by means of discriminant analyses and various cluster analyses.The conclusion reached is the recognition of three species for Canada and Alaska, H. jubatum L., H. caespitosum Scribn., H. brachyantherum Nevski, and a hybrid H. jubatum × brachyantherum representing F1 and F1-like phenotypes. Classification function coefficients were computed and are provided in this paper in order to effect both the identification of the three taxa and the hybrid and their circumscription.All the herbarium specimens were identified by means of these coefficients and, as a result, previously unsuspected hybrids were revealed. This study indicated that an analysis of herbarium specimens alone can be misleading and, consequently, that field data are necessary. It is also demonstrated that the spikelets within a spike are not uniform enough for taxonomic reliance to be placed on observations made on one spikelet alone.

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