Genetic variation between and within two populations of Trifolium glomeratum (cluster clover) in Western Australia

1997 ◽  
Vol 48 (7) ◽  
pp. 969 ◽  
Author(s):  
Sarita Jane Bennett
Keyword(s):  
Cluster Analysis ◽  
Genetic Variation ◽  
Western Australia ◽  
Morphological Characters ◽  
Field Station ◽  
Site Variation ◽  
Components Analysis ◽  
And Cluster Analysis ◽  
The University ◽  
Two Populations

Genetic variation between and within populations of Trifolium glomeratum (cluster clover) was studied using seed collected from 2 sites in Western Australia: Mount Barker in the south and Kwelkan in the wheatbelt. Seed was collected at 64 subplots within each site and the material was grown at the University Field Station at Shenton Park, Perth. Seventeen morphological characters were scored and the results were analysed using analysis of variance, principal components analysis, and cluster analysis. Within-site variation was much greater than had previously been shown, and a considerable amount of between-site variation was present. It is suggested that within-site variation is due to a small amount of heterozygosity, as a result of limited outbreeding, being present in each population. The 2 populations are shown to be distinct from each other, with the population from Mount Barker containing more within-site variation. It is suggested that this is a result of climatic stress influencing and reducing the amount of variation being maintained in the Kwelkan population.

The use of spatial analysis to measure the effect of environmental heterogeneity on genetic variation in Trifolium species from Sardinia

2002 ◽  
Vol 139 (3) ◽  
pp. 283-294 ◽  
Author(s):  
S. J. BENNETT ◽  
N. W. GALWEY
Keyword(s):  
Genetic Variation ◽  
Spatial Analysis ◽  
Western Australia ◽  
Acid Soils ◽  
Morphological Characters ◽  
Alkaline Soils ◽  
Field Station ◽  
Stressful Environment ◽  
Outcrossing Species ◽  
The University

Trifolium species are native to the Mediterranean Basin where they are an important component of permanent pastures. A number of species have become naturalized in Australia and are agriculturally important in annual pastures. To understand the importance of genetic and ecotypic variation in the adaptation of Trifolium species to a new environment, seeds of three predominantly inbreeding and two predominantly outcrossing species of Trifolium were collected from 12 sites in Sardinia in 1998. Detailed ecogeographic information was collected at each site. The progeny were grown at the University of Western Australia Field Station at Shenton Park, Western Australia in 1999, and were scored for 10 morphological characters. Spatial analysis was applied to the data to improve the estimation of accession means, and to investigate the relationship with environmental variables that characterized the sites of collection. The spatially adjusted means were used as the basis for a principal components analysis. Ecogeographical factors at the sites of collection, particularly soil pH, are suggested to be more important than breeding system in determining the extent of genetic variation within the species. The species that showed the greatest genetic variation between accessions were the predominantly inbreeding species T. glomeratum and T. subterraneum, and the predominantly outcrossing species T. nigrescens. It is suggested that the wide genetic variation of these three species is largely due to their being in an ecogeographic environment close to their optimum, and to the possession of a mating system that is neither completely outcrossing nor completely self-fertilizing. The remaining two species, T. tomentosum and T. resupinatum, both occur more frequently on alkaline soils, and it is suggested that for the collected accessions of these two species the acid soils of Sardinia are a stressful environment that does not promote high levels of genetic variation.

Genetic variation in five populations of strawberry clover (Trifolium fragiferum cv. Palestine) in Western Australia

2005 ◽  
Vol 45 (11) ◽  
pp. 1445 ◽  
Author(s):  
K. S. McDonald ◽  
P. S. Cocks ◽  
M. A. Ewing
Keyword(s):  
Genetic Variation ◽  
Total Variation ◽  
Western Australia ◽  
Principal Components ◽  
Plant Traits ◽  
Population Variation ◽  
Field Station ◽  
The North ◽  
Perennial Legume ◽  
The University

Genetic variation within and among populations of an outcrossing stoloniferous perennial legume, strawberry clover (Trifolium fragiferum L.), was studied using seed collected from 5 different locations in Western Australia. The sites ranged from Badgingarra to the north of the wheatbelt to Karridale in the southwest of the state. Seed was collected randomly at each site and was grown out at the University of Western Australia Field Station at Shenton Park, Perth. Thirteen morphological plant traits were measured and analysed. Results show that within-population variation was extremely high. In contrast, among-population variation was generally low with most characters showing only 8–15% of the total variation. Despite this, all but 1 of the measured plant traits differed among populations. Principal components analysis highlighted the large amount of variation within the populations with the first 3 principal components accounting for only 59% of the total variation. We suggest that the populations have begun to differentiate into ecotypes more suited to those habitats into which they have been sown but that within-population variation remains high due to the outcrossing nature of strawberry clover.

Significant population genetic structure detected for a new and highly restricted species of Atriplex (Chenopodiaceae) from Western Australia, and implications for conservation management

2012 ◽  
Vol 60 (1) ◽  
pp. 32 ◽  
Author(s):  
Laurence J. Clarke ◽  
Duncan I. Jardine ◽  
Margaret Byrne ◽  
Kelly Shepherd ◽  
Andrew J. Lowe
Keyword(s):  
Genetic Variation ◽  
New Species ◽  
Genetic Structure ◽  
Western Australia ◽  
Sequence Data ◽  
Isolation By Distance ◽  
Conservation Strategies ◽  
New Taxon ◽  
Near Surface ◽  
Two Populations

Atriplex sp. Yeelirrie Station (L. Trotter & A. Douglas LCH 25025) is a highly restricted, potentially new species of saltbush, known from only two sites ~30 km apart in central Western Australia. Knowledge of genetic structure within the species is required to inform conservation strategies as both populations occur within a palaeovalley that contains significant near-surface uranium mineralisation. We investigate the structure of genetic variation within populations and subpopulations of this taxon using nuclear microsatellites. Internal transcribed spacer sequence data places this new taxon within a clade of polyploid Atriplex species, and the maximum number of alleles per locus suggests it is hexaploid. The two populations possessed similar levels of genetic diversity, but exhibited a surprising level of genetic differentiation given their proximity. Significant isolation by distance over scales of less than 5 km suggests dispersal is highly restricted. In addition, the proportion of variation between the populations (12%) is similar to that among A. nummularia populations sampled at a continent-wide scale (several thousand kilometres), and only marginally less than that between distinct A. nummularia subspecies. Additional work is required to further clarify the exact taxonomic status of the two populations. We propose management recommendations for this potentially new species in light of its highly structured genetic variation.

scholarly journals Use of Highly Discriminating Morphological Characters and Isozymes in the Study of Spanish Chestnut Cultivars

2006 ◽  
Vol 131 (6) ◽  
pp. 770-779 ◽  
Author(s):  
Santiago Pereira-Lorenzo ◽  
María Belén Díaz-Hernández ◽  
Ana María Ramos-Cabrer
Keyword(s):  
Principal Component Analysis ◽  
Cluster Analysis ◽  
Multivariate Analysis ◽  
Castanea Sativa ◽  
Principal Component ◽  
Market Value ◽  
Morphological Characters ◽  
Minor Importance ◽  
Breeding Programs ◽  
And Cluster Analysis

Morphological characters (six traits) and isozymes (four systems, five loci) were used to discriminate between Spanish chestnut cultivars (Castanea sativa Mill.) from the Iberian Peninsula. A total of 701 accessions (representing 168 local cultivars) were analyzed from collections made between 1989 and 2003 in the main chestnut growing areas: 31 were from Andalucía (12 cultivars), 293 from Asturias (65 cultivars), 25 from Castilla-León (nine cultivars), four from Extremadura (two cultivars) and 348 from Galicia (80 cultivars). Data were synthesized using multivariate analysis, principal component analysis, and cluster analysis. A total of 152 Spanish cultivars were verified: 58 cultivars of major importance and 94 of minor importance, of which 18 had high intracultivar variation. Thirty-seven cultivars were clustered into 14 synonymous groups. Six of these were from Galicia, one from Castilla-León (El Bierzo), four from Asturias, one from Asturias and Castilla-León (El Bierzo), and two from Asturias, Castilla-León (El Bierzo), and Galicia. The chestnut cultivars from Galicia and Asturias were undifferentiated in genetic terms, indicating that they are not genetically isolated. Overall, chestnut cultivars from southern Spain showed the least variation. Many (58%) of Spanish cultivars produced more than 100 nuts/kg; removing this low market-value character will be a high priority. The data obtained will be of use in chestnut breeding programs in Spain and elsewhere.

scholarly journals Pathways and Patterns of Cell Loss in Verified Alzheimer’s Disease: A Factor and Cluster Analysis of Clinico-Pathological Subgroups

1994 ◽  
Vol 7 (3-4) ◽  
pp. 175-180 ◽  
Author(s):  
H. Förstl ◽  
R. Levy ◽  
A. Burns ◽  
P. Luthert ◽  
N. Cairns
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cluster Analysis ◽  
Cell Loss ◽  
Cell Numbers ◽  
Cell Counts ◽  
Patient Groups ◽  
Components Analysis ◽  
Factor And Cluster Analysis ◽  
And Cluster Analysis

Thirty-seven patients with neuropathologically verified Alzheimer's disease (AD) have been studied prospectively. A principal components analysis of neuron numbers in cortical and subcortical areas revealed two variables: Variable I with high loadings for the hippocampo-parahippocampo-parietal neuron counts and Variable II with high loadings for coeruleo-frontal cell numbers. Both may reflect functional neuroanatomical connections which may act as pathways of neurodegeneration in AD. A cluster analysis based on these neuron numbers yielded three groups of patients: Cluster A with low hippocampo-parahippocampo-parietal cell counts, Cluster B with well-preserved neuron numbers, and Cluster C with low coeruleo-frontal neuron numbers. Differences in clinical features between these patient groups indicated the potential clinical relevance of these clusters.

Phenetic analysis of the complex Senna fabrisii—S. trichosepala (Leguminosae, Caesalpiniodeae, Aphyllae) based on morphological characters and seed protein electrophoretic profiles

Phytotaxa ◽  
2013 ◽  
Vol 145 (1) ◽  
pp. 1 ◽  
Author(s):  
Federico O. Robbiati ◽  
Alícia Lamarque ◽  
Ana M. Anton ◽  
Renée H. Fortunato
Keyword(s):  
Cluster Analysis ◽  
Seed Protein ◽  
Principal Component ◽  
Taxonomic Status ◽  
Electrophoretic Analysis ◽  
Morphological Characters ◽  
Herbarium Specimens ◽  
And Cluster Analysis ◽  
High Degree ◽  
Univariate Analyses

Multivariate and univariate analyses based on morphological characters and seed soluble protein electrophoretic profiles were carried out in order to understand the taxonomic status within the complex S. fabrisii-S. trichosepala. Twenty morphological characters from herbarium specimens were recorded and analyzed by ANOVA, principal component and cluster analysis. The seed protein electrophoretic analysis including cluster analysis was based on three populations: one of S. fabrisii and two of S. trichosepala. The results showed that both taxa differed only by three morphological features; in parallel, the CPA and CA demonstrate that no clearly separated group can be recognized. The seed protein electrophoretic profiles show a high degree of similarity. Based on these results, and due to the variability observed, the inclusion of S. fabrisii in the synonymy of S. trichosepala is proposed.

scholarly journals Multivariable Analysis Methods On Identifying Factors and Groups of Students in the Environment of the Discovery Learning/Constructivistic Approach Using Cognitive Tools

2019 ◽  
pp. 7-12
Author(s):  
Konstantinos Korres
Keyword(s):  
Cluster Analysis ◽  
Data Analysis ◽  
Multivariable Analysis ◽  
Discovery Learning ◽  
Cognitive Tools ◽  
Analysis Methods ◽  
Multiple Variables ◽  
Students Attitudes ◽  
And Cluster Analysis ◽  
The University

This paper studies the environment of the discovery learning/constructivistic approach using cognitive tools regarding students’ performance in tests involving different kinds of learning and in the final formal examinations and students’ attitudes towards the approach in Mathematics’ higher education. In particular the paper aims in identifying factors regarding students’ scores and attitudes affected by the approach and groups of students with similar characteristics based on these factors. Data was obtained by a study realized at the Department of Statistics and Insurance Sciences of the University of Piraeus, concerning the application of the discovery learning/constructivistic approach using Mathematica on the course Calculus (Functions of multiple variables). Multivariable analysis methods are used in the data analysis, in particular factor analysis in identifying factors and cluster analysis in identifying groups of students with similar characteristics, in combination with inferential statistics’ methods. The statistical package SPSS was used for the data analysis.

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