The origin of the C-genome and cytoplasm of Avena polyploids

The contribution of C-genome diploid species to the evolution of polyploid oats was studied using C-genome ITS-specific primers. SCAR analysis among Avena accessions confirmed the presence of C-genome ITS1-5.8S-ITS2 sequences in the genome of AACC and AACCDD polyploids. In situ hybridization and screening of more than a thousand rRNA clones in Avena polyploid species containing the C-genome revealed substantial C-genome rRNA sequence elimination. C-genome clones sequenced and Maximum Likelihood Parsimony analysis revealed close proximity to Avena ventricosa ITS1-5.8S-ITS2 sequences, providing strong evidence of the latter's active role in the evolution of tetraploid and hexaploid oats. In addition, cloning and sequencing of the chloroplastic trnL intron among the most representative Avena species verified the maternal origin of A-genome for the AACC interspecific hybrid formation, which was the genetic bridge for the establishment of cultivated hexaploid oats

Examination of the possibilities for the contribution of non-destructive methods of testing in the diagnosis and quality control of building materials with emphasis on sustainable construction

This Doctoral Thesis presents the investigation of the possibilities for the contribution of Non-Destructive methods of Testing in the diagnosis and quality control of building materials with emphasis on Sustainable Construction. Towards this goal, an extensive study was conducted concerning thee building materials examined (concrete samples of five different compositions, each consisting of a different cement constituent, by type and strength category) via both traditional/mainstay (destructive) methods of analysis/testing as well via innovative non-destructive methods of characterization.The holistic method that was developed during the course and framework of this present doctoral research consists and revolves around the combination and synergistic application of the non-destructive techniques of Fiber Optic Microscopy (FOM) and Digital Image Processing (DIP). More specifically, concrete samples were prepared and cured while under study via a suitable observation window which was fitted in the concrete framework; through this window, fiber optic microscopy images were taken in due time increments –in real time– during the initial pouring and setting. Following this stage, these images (“image patterns”) were treated via Digital Image Processing; a suitable tuned algorithm was developed (which was compiled and fine-tuned specifically for the needs of this niche Research and application) in the MatLab® computational environment. Quantitative results were gathered from the information within the images themselves; these characterized the specific image at the corresponding time instances.These experimental results were utilized as real-time automated input and feeded into a specifically designed database & knowledge-based system via which further processing and utilization of the information stored within led to a suitable mathematical correlation model. Furthermore, this semi-empiric mathematical model led to the development of a decision support system (“expert system”) capable to withstand the needs of the construction field (real time, space and scale).The conclusions of the Doctorate Research include both the successfully combination and utilization of non-destructive techniques (Fiber Optic Microscopy and Digital Image Processing) towards the capture of representative surface image patterns at specified time intervals immediately after the start of the concrete placing (start,+ 5, +10, +15, +20, +25, +30, +40, +50, 60minutes). The finalized digitally processed image patters were correlated (via an extensive programme of liner regression study) to the final mechanical strength of the produced concrete samples; the greater impact/relationship of the morphological properties of the “centroid” and the “Euler number” (throughout the time intervals) at a magnification 25x and threshold value of 110 was identified. Besides this, the assessment of the concrete microstructure as per the digital processing of the collected image patters was incorporated successfully in a suitable specialized Knowledge database and this Knowledge was converted (through Artificial Intelligence and more specifically the application of genetic algorithms in a MatLab® environment) to an Expert System designed for Decision Support concerning Sustainability in the Construction Sector.Στην παρούσα Διδακτορική Διατριβή παρουσιάζεται η διερεύνηση των δυνατοτήτων συμβολής μεθόδων μη-καταστρεπτικού ελέγχου στη διάγνωση και στον έλεγχο ποιότητας δομικών υλικών με έμφαση στην Αειφόρο Κατασκευή. Ως προς το παραπάνω σκοπό, πραγματοποιήθηκε εκτενής μελέτη των υπό έρευνα δομικών υλικών (δοκιμίων σκυροδεμάτων 5 συνθέσεων, έκαστη σύνθεση αποτελούμενη από διαφορετικό τύπο, ποιότητα και κατηγορία αντοχών του περιεχόμενου τσιμέντου) μέσω τόσο συμβατικών/παραδοσιακών (καταστρεπτικών) τεχνικών ανάλυσης όσο και καινοτόμων μη-καταστρεπτικών τεχνικών χαρακτηρισμού.Η μέθοδος που αναπτύχθηκε στα πλαίσια της παρούσας Διδακτορικής Διατριβής αφορά την συνδυαστική και συνεργατική εφαρμογή των μη-καταστρεπτικών τεχνικών της Μικροσκοπίας Οπτικών Ινών και της Ψηφιακής Επεξεργασίας Εικόνας. Περισσότερο συγκεκριμένα, παρασκευάσθηκαν δοκίμια σκυροδεμάτων στον ξυλότυπο (“καλούπι”) των οποίων είχε προσαρμοστεί κατάλληλο πλαίσιο (“παράθυρο”) παρατήρησης και λήψης εικόνων μέσω του οποίου εφαρμόστηκε Μικροσκοπία Οπτικών Ινών σε τακτά διαστήματα πραγματικού χρόνου (“real-time”) κατά την διάρκεια της τοποθέτησης/σκυροδέτησης αυτών. Εν συνεχεία, οι εικόνες υφής αυτές επεξεργάστηκαν κατάλληλα μέσω αλγορίθμου Ψηφιακής Επεξεργασίας Εικόνας (ο οποίος αναπτύχθηκε και αριστοποιήθηκε για τις ανάγκες της συγκεκριμένης Έρευνας και εφαρμογής) σε υπολογιστικό περιβάλλον MatLab®, και εξήχθησαν ποσοτικές πληροφορίες χαρακτηρισμού της δεδομένης εικόνας ανά χρονική στιγμή λήψης αυτής.Τα πειραματικά αποτελέσματα αυτά τροφοδοτήθηκαν αυτομάτως (και σε πραγματικό χρόνο - “real-time”) σε κατάλληλη πληροφοριακή γνωσιακή βάση δεδομένων, η οποία αποτέλεσε το έναυσμα για περαιτέρω αξιοποίηση των περιεχόμενων πληροφοριών, υπό την μορφή εύρεσης και έκφρασης κατάλληλου μαθηματικού συσχετισμού (“correlation”). Εν συνεχεία και βάσει του αναπτυχθέντος ημιεμπειρικού μαθηματικού μοντέλου, έλαβε χώρα μετάβαση σε έμπειρο σύστημα υποστήριξης απόφασης (“expert system”), ικανό να ανταποκρίνεται στις ανάγκες της Κατασκευής (σε πραγματικό τόπο, χρόνο και κλίμακα).Στα Συμπεράσματα της παρούσας Διδακτορικής Διατριβής συμπεριλαμβάνεται η επιτυχής συνδυαστική αξιοποίηση μη-καταστρεπτικών τεχνικών Μικροσκοπίας Οπτικών Ινών και Ψηφιακής Επεξεργασίας Εικόνας ως προς την λήψη αντιπροσωπευτικών επιφανειακών εικόνων υφής/μικροδομής (“image patterns”) σε ορισμένες χρονικές στιγμές αμέσως μετά την έναρξη της σκυροδέτησης (αρχή,+ 5, +10, +15, +20, +25, +30, +40, +50, 60λεπτά). Οι ληφθείσες ψηφιακά επεξεργασμένες εικόνες μικροδομής συσχετίστηκαν (μέσω εκτεταμένου προγράμματος γραμμικών παλινδρομήσεων) με τις τελικές μηχανικές αντοχές των παραχθέντων σκυροδεμάτων και συμπεραίνεται η εντονότερη βαρύτητα/σχέση των μορφολογικών παραμέτρων του “κεντροειδούς” και του “αριθμού Euler” (καθόλες τις χρονικές στιγμές), σε μεγέθυνση 25x και όριο κατωφλίωσης/threshold 110. Πέραν αυτών, η αποτίμηση της μικροδομής από τα ληφθέντα image pattern ενσωματώνεται επιτυχώς σε εξειδικευμένη γνωσιολογική βάση δεδομένων και η Γνώση αυτή μετατρέπεται (μέσω τεχνητής νοημοσύνης και εφαρμογής γενετικών αλγορίθμων σε περιβάλλον MatLab®) σε έμπειρο σύστημα (“expert system”) υποβοήθησης/υποστήριξης αποφάσεων (“decision support system”) Αειφορίας στην Κατασκευή

Comparative molecular and cytogenetic methods can clarify meiotic incongruities in Avena allopolyploid hybrids

Avena longiglumis is a diploid species that has been proposed as the A-genome donor of allopolyploid oats. In order to clarify its participation in the evolution of oats, a triploid A. magna × A. longiglumis hybrid was synthesized and studied, via a concurrent combination of cytogenetic and molecular techniques. The analysis of pollen mother cells revealed that synapsis percentage and chromosome chiasmata per cell were low; still they were the highest recorded among the diploid species used as pollinators of AC-genome tetraploids. In addition, genomic in situ hybridization revealed extensive chromosomal translocations among the allopolyploids that may have contributed to the low chromosomal affinity. Furthermore, amplified fragment length polymorphisms revealed the extensive genomic modifications that followed the interspecific hybridization, depicted mainly as the loss of parental bands (51.29%) and the creation of novel bands in the progeny (15.73%). As a result, the combination of cytogenetic and molecular techniques can elucidate meiotic incongruities that can make the unraveling of oat evolution challenging

Screening A. ventricosa populations for 2n gametes

Sexual polyploidization via the formation of 2n gametes has been acknowledged as the most significant evolutionary mode of polyploidization among plant species. The present study was conducted in order to determine whether 2n gametes are present in the C-genome diploid Avena ventricosa Bal. ex Coss., a species that contributed to the evolution of the cultivated hexaploid species (Avena sativa L). Individual plants belonging to four different Cypriot populations, were screened for pollen grain size variation with the aim to distinguish 2n gametes. Avena ventricosa ARI00-845 was identified to produce large pollen grains at a low percentage (1.21%). Subsequent analysis using flow cytometry confirmed the presence of 2n gametes in the pollen. Cytogenetic analyses of pollen mother cells revealed cells with twice the typical chromosome number at metaphase I (i.e., 28 chromosomes). We postulate that irregularities in cell wall formation preceding meiosis could have contributed to the mode of chromosome doubling

Structural patterns and genetic diversity among oat (Avena) landraces assessed by microsatellite markers and morphological analysis

As a counterweight to genetic erosion, landraces could become important germplasm resources for breeding. In the present study the genetic diversity of 62 Greek and Eastern European oat accessions (seven cultivars and 55 common and red oat landraces collected from 1904 to 1960) was studied using simple sequence repeats and 31 morphological descriptors. High levels of polymorphism were detected and 209 distinctive alleles were identified; on average 14.65 alleles per primer. Both, the principal component analysis derived from the morphological data, and the unweighted pair group method with arithmetic mean from the molecular analysis clustered the oat genotypes according to their type (common and red oats). In addition, the analysis of molecular variation showed that there were noteworthy differences within designated geographic regions. Moreover, a more discrete subpopulation structure was identified based on allele frequency using a Bayesian clustering approach. A clear distinction was evident among the red and common oats suggesting that they should be considered as separate species

Genetic variability in landraces populations and the risk to lose genetic variation. The example of landrace 'Kyperounda' and its implications for ex situ conservation

Genetic characterization enhances the development of rational conservation strategies and the utilization of germplasm to plant breeding programs. In the present study, 19 microsatellite markers were employed to evaluate the genetic diversity and the genetic affiliations across 20 Cypriot durum wheat (Triticum turgidum L. subsp. durum) landraces, 13 landraces from the broader Mediterranean basin and 22 modern varieties. Cluster analysis depicted a clear separation among modern varieties and landraces, regardless of their origin. Landraces presented the highest genetic variation (average discriminating power of 0.89) and a high number of private alleles (131) was detected; underlying the unique genetic mark-up of this genepool. AMOVA revealed that the highest variability was detected within the landraces originating from Cyprus and landraces from the broader Mediterranean basin. The Cypriot landrace 'Kyperounda' was selected for further evaluation of its' intra-genetic variation and it was determined that genetic diversity was higher in accessions conserved as sublines (He 0.643-0.731) than bulks (He 0.384-0.469). Bayesian analysis revealed substantial admixture within 'Kyperounda' accessions, depicted also by Principal Coordinate Analysis. The findings of the current manuscript emphasize that high intra-genetic diversity is retained when landraces are conserved as sublines in ex situ collections, while landraces that are conserved as bulks have a higher risk of bottleneck. Hence, a more exhausting diversity evaluation is needed in order to fully utilize landraces in breeding schemes and to prevent the loss of genetic variation

Evolutionary insights inferred by molecular analysis of the ITS1-5.8S-ITS2 and IGS Avena sp. sequences

In an attempt to clarify phylogenetic and genome relationships among 35 diploid (A and C genomes), 13 tetraploid (AB and AC genomes) and 6 hexaploid (ACD genome) Avena taxa, 71 clones of the ITS1-5.8S-ITS2 fragment were sequenced, aligned and a network was constructed. In addition, the intergenic spacer (IGS) fragment was fingerprinted by means of a RFLP analysis using three different restriction enzymes. Both approaches led to comparable results. Clustering among the 54 Avena sp. entries was according to karyotype. Major genic divergence between the A and C genomes was revealed, while distinction among the A and B/D genomes was not possible. High affinity among the AB genome tetraploids and the A(s) genome diploid A. lusitanica was found, while AC genome tetraploids and ACD hexaploids were highly affiliated with the A(l) genome diploid A. longiglumis. The possible role of A. longiglumis in Avena sp. evolution is discussed

Genetic structure and population diversity of eleven edible herbs of Eastern Crete

Background: The present work aimed to investigate the genetic structure of 11 edible herbs grown in the wild of eastern Crete that are becoming vulnerable due to habitat destruction and unregulated harvesting. Thirty three populations (268 individuals) of Reichardia picroides, Scolymus hispanicus, Scandix pecten-veneris, Leontodon tuberosus, Cichorium spinosum, Sonchus asper ssp. glaucescens, Urospermum picroides, Prasium majus, Hypochoeris radicata, Centaurea raphanina ssp. raphanina and Anagallis arvensis were collected and identified from nine regions with distinct microclimate (Lassithi prefecture), and their genetic composition was studied by means of RAPD markers. Results: A total of ten primers per population were used to detect genetic diversity and bootstrap analysis was conducted for clustering the samples. High levels of heterogeneity were revealed while the Analysis of Molecular Variance documented that variance was allocated mainly within populations and at a lesser extent among populations. Fst values among regions were moderate to high, suggesting partial population fragmentation. Bayesian structure analysis revealed fine genetic composition and substantial admixture between species present in different regions, although clustering was mainly geographically related. Conclusions: High altitude regions, with little residential and agricultural development (Kefala, Agrilos, Ziros and Tziritis), were the areas where high biodiversity was detected. On the other hand, coastal regions had lower biodiversity, probably due to degradation of their habitat