Papers by Christos Dordas
Social Science Research Network, 2022
International Journal of Data Analysis Techniques and Strategies, 2020
Data from molecular markers used for constructing dendrograms, which are based on genetic distanc... more Data from molecular markers used for constructing dendrograms, which are based on genetic distances between different plant species, are encoded as binary data. For dendrograms' construction, the most commonly used linkage method is the UPGMA in combination with the squared Euclidean distance. It seems that in this scientific field, this is the 'golden standard' clustering method. In this study, a review is presented on clustering methods used with binary data. Furthermore, an evaluation of the linkage methods and the corresponding appropriate distances (comparison of 163 clustering methods) is attempted using binary data resulted from molecular markers applied to five populations of the wild mustard Sinapis arvensis species. The validation of the various cluster solutions was tested using external criteria. The results showed that the 'golden standard' is not a 'panacea' for dendrogram construction, based on binary data derived from molecular markers. Thirty seven other hierarchical clustering methods could be used.
Springer eBooks, 2001
Boron enters plant roots as undissociated boric acid (H3BO3). significant differences in B uptake... more Boron enters plant roots as undissociated boric acid (H3BO3). significant differences in B uptake are frequently observed even when plants are grown under identical conditions. It had been theorized that these differences reflect species differences in permeability coefficient of H3BO3 across plasma membrane. The data presented in this study suggest that B enters the plant cells in part by passive diffusion through the lipid bilayer of the plasma membrane and in part through proteinaceous channels. Also the lipid composition of the plasma membrane can affect total B uptake.
Frontiers of Agricultural Science and Engineering, 2021
HIGHLIGHTS • The 4C approach considers intercropping performances as the result of joint 4C effec... more HIGHLIGHTS • The 4C approach considers intercropping performances as the result of joint 4C effects. • Partial land equivalent ratios indicate which effect(s) are the major one(s). • A major effect of complementarity is related to a better capture of abiotic resources.
Weed Science, Aug 1, 2009
Variations in the acetolactate synthase (ALS) gene sequence were determined from 28 populations o... more Variations in the acetolactate synthase (ALS) gene sequence were determined from 28 populations of corn poppy resistant (R) to tribenuron and from 6 populations susceptible (S) to this herbicide. TheALSgene fragment (634 bp) sequence revealed in R populations five point mutations at the codon Pro197, and among them the substitution of Pro197by Ala was the most common. The sequencing chromatograms revealed that nine R individuals had only the mutantALSgene and were homozygous (RR), 18 R individuals had both the wild type and the mutantALSgene and were heterozygous (RS), whereas one R individual was heterozygous but with two different mutantALSalleles (R1R2). The use of restriction digestion profile analysis to verify the DNA sequence results by detecting the existence of point mutations at the codon 197 managed to distinguish the R and S alleles and confirmed the results obtained from the sequencing chromatograms analysis. The secondary protein structure prediction suggested the formation of novelβ-strands for each of the five mentioned amino acid substitutions that was not present in wild type ALS around the mutant site. These findings support the hypothesis that the substitution of Pro197by Ser, Thr, Ala, Arg, or Leu resulted in altered secondary structure, which stabilizes an ALS tertiary conformation that prevents tribenuron binding and thus confers resistance to this herbicide.
European Journal of Agronomy, Mar 1, 2023
Field Crops Research, Dec 1, 2017
Reducing interspecies competition and enhancing complementarity through cultivar selection in int... more Reducing interspecies competition and enhancing complementarity through cultivar selection in intercrops is important for achieving sustainable intensification. Under Mediterranean conditions, pea-oat intercrop has shown high land-use efficiency (LER). Field experiments were established under rainfed conditions in two locations in Greece for two growing seasons (2011-12 and 2012-13) to assess agronomic traits [date to flowering, plant height at stem elongation BBCH32, final plant height, and lodging], dry matter yield (DM), quality traits (protein, fat and ash concentrations, nitrogen free extracts), crop protein yield (CPY), and the competitive ability of three oat and three field pea cultivars in intercrops and sole crops. The intercrops produced on average 6.7% less DM than the oat sole crops, but had 27% higher CPY. However, interactions were found for the DM between the two locations, regarding species, cultivars and cropping systems, indicating that cultivars performed differently in sole crop and intercrops. Across locations, a pea-oat combination was the most consistent, showing the highest values of LER and monetary advantage index (MAI) that indicated its wide adaptation. Moreover, a second pea-oat combination showed specific adaptation to the warm and soil N-poor location. One testing environment favoured the high competitive ability of peas, whereas the other favoured the oat, possibly due to higher N-NO 3 availability. Intercropped oat flowered later, was shorted at the stem elongation stage, and lodged more than sole crops. On the other hand, peas flowered later and were taller at stem elongation stage, as well in final plant height in comparison to their peers in sole crop. Overall, the results highlighted the need of multienvironment trials to assess the effects of genotype × environment interactions in order to select compatible cultivars for maximizing the productivity and stability of the pea-oat intercrops.
GA – 70th Annual Meeting 2022
GA – 70th Annual Meeting 2022
GA – 70th Annual Meeting 2022
GA – 70th Annual Meeting 2022
The present study aimed to investigate whether<br> chlorophyll meter readings (SPAD) can be... more The present study aimed to investigate whether<br> chlorophyll meter readings (SPAD) can be used as criterion of singleplant<br> selection in maize breeding. Experimentation was performed at<br> the ultra-low density of 0.74 plants/m2 in order the potential yield per<br> plant to be fully expressed. R-31 honeycomb experiments were<br> conducted in three different areas in Greece (Thessaloniki, Giannitsa<br> and Florina) using 30 inbred lines at well-watered and water-stressed<br> conditions during the 2012 growing season. The chlorophyll meter<br> readings had higher rates at dry conditions, except location of<br> Giannitsa where differences were not significant. Genotypes of<br> highest chlorophyll meter readings were consistent across areas,<br> emphasizing on the character's stability. A positive correlation<br> between the chlorophyll meter readings and grain yield was<br> strengthening over time a...
Towards a better efficiency in N use, 2007, ISBN 978-84-9743-247-4, págs. 173-175, 2007
Plants
Basil (Ocimum basilicum L.) is a member of the Labiatae family and is one of the most widely cons... more Basil (Ocimum basilicum L.) is a member of the Labiatae family and is one of the most widely consumed aromatic and medicinal plants in many countries due to its numerous properties and uses. The objective of the study was to determine whether landraces are better adapted to water-limited environments compared to commercial cultivars. Irrigation levels and genotypes affected plant height and leaf area index, with 25% and 33% higher values observed under complete irrigation, respectively. Additionally, limited water availability resulted in a 20% reduction in dry matter yield and a 21% reduction in essential oil yield over the three years in all of the genotypes tested, specifically in the lower irrigation treatment (d40), compared to the control treatment (d100). The landraces that performed the best under limited water supply were Athos white spike (AWS) and Gigas white spike (GWS), indicating their suitability for environments with limited water resources. The results demonstrate t...
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Papers by Christos Dordas