<p style="text-align: justify;"><strong>Aim</strong>: Assessment of the genetic diversity and relationships in a group of 31 Bulgarian grape accessions through microsatellite markers.</p><p style="text-align: justify;"><strong>Methods and results</strong>: Thirty-one accessions, including 20 old rare local and 11 newly bred varieties were characterized through 13 nuclear and 5 chloroplast microsatellite loci. The genetic diversity (0.81±0.01) obtained for the investigated group of cultivars was comparable to those reported for other grapevine germplasms. The low PI value (1.0x10^-16) allowed proper genetic identification and determination of synonyms. Microsatellite analysis of the 31 accessions resulted in 26 unique genotypes and 2 groups of synonyms. Four cases of supposed synonymy with local Bulgarian and foreign cultivars were rejected. Three chlorotypes, B, C and D, were defined among the studied cultivars, with a prevalence of chlorotype C (62%).</p><p style="text-align: justify;"><strong>Conclusion</strong>: The high genetic diversity found in the set of old rare grapevines demonstrated their importance as a rich source of alleles for breeding. The pattern of chlorotype distribution observed among local varieties confirmed the previous results and supports the hypothesis of an Eastern origin of local Bulgarian cultivars.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: The obtained results provide an important support for the preservation of grape biodiversity in Bulgaria as well as for the clarification of genetic relationships between local and foreign cultivars.</p>

Eighteen Bulgarian newly bred grapevine varieties obtained by interspecific crossing were analysed through microsatellite markers in order to determine their genetic identity as well as the presence of resistance-related alleles linked to Rpv3, Rpv10 and Rpv12 loci. The levels of resistance of the investigated cultivars to downy mildew were assessed by leaf disk assay and were scored according to OIV descriptor 452. Seven isolates of Plasmopara viticola collected in different regions of Bulgaria were characterized and discriminated with seven microsatellite markers and were used in the assays. Analysis of variance showed significant differences in resistance to downy mildew among the analysed varieties. A clear correlation between the presence of particular Rpvs and the level of resistance was determined. Five cultivars, 'Droujba', 'Garant' and 'Plevenska rosa' harbouring Rpv3 and Rpv12, 'Kajlashki rubin' harbouring Rpv12 and 'Slava', Rpv10 and Rpv3, showed high level of resistance with mean OIV452 values ranging from 6.5 to 8.25 over all seven P. viticola isolates. The level of resistance of the remaining 14 cultivars, which carry only Rpv3 inherited from cultivar Villard Blanc, was found to vary significantly among the isolates with mean OIV452 values between 1.75 and 4.8 over all used P. viticola isolates. The results obtained in this study favoured five genotypes remarkable for their high resistance to downy mildew and very good quality of grape and wine. These varieties represent a valuable material for pyramiding of resistance through marker-assisted selection.

A survey of the macrozoobenthos communities in the Maritsa River (South Bulgaria) was carried out in the summer of 2021. Benthic samples were collected and physicochemical parameters (water temperature, pH, conductivity, dissolved oxygen and nutrients) were measured at 15 sites located on the main river and its tributary system. The studied sites belonged to different river types and characterised the diversity of the ecological conditions—from unaffected to anthropogenically influenced river stretches. In addition, data from a study conducted in the summer of 2020 were used to analyse species–factor interactions in the river ecosystems and to assess the bio-indicative potential of the aquatic invertebrates. The dynamics of the taxonomic composition and abundance of the macrozoobenthos were analysed in relation to environmental factors. The physicochemical conditions of the water environment changed during the period of high water, which led to a reduction in the composition of the macrozoobenthos. Plecoptera and Trichoptera decreased in richness and abundance downstream and under human impacts. Ephemeroptera and Chironomidae were permanently present along the whole river. Oligochaeta increased in the lower river reaches and at sites with a greater amount of organic matter. The ecological status determined by the macrozoobenthos varied from high (site 1) to good, moderate and bad (site 13) at the studied sites.

At Tell Yunatsite, a prehistoric settlement mound located in the Upper Thracian plain of Bulgaria, stratigraphic relationships between archaeological deposits are incredibly complex. Such complexity then prompted our exploration into developing a new methodology for the documentation of complex stratigraphic relationships. Here, we present the results of a new photogrammetry-assisted methodology that was developed to compensate for the shortcomings of currently utilized stratigraphic documentation methods, such as the Wheeler-Kenyon box grid and the Harris Matrix. First, using a UAV drone, we produce a high-resolution photogrammetric model of the entire site. Second, with structure from motion photogrammetry, we produce 2.5D models of excavation units in stratigraphic succession. Finally, utilizing GIS and Blender (a 3D computer graphics software application), we digitize the horizontal extents of each archaeological deposit and “fill” the space between their successive surfaces (from top to bottom) until a faithful 3D model of each deposit is generated. These deposit models are then combined and rendered simultaneously to form 3D block models of the excavation units that may, in turn, be cross-sectioned in any direction to view stratigraphic relationships in virtual profile.

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