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Background. Citrullus lanatus (Thunb.) Matsum. & Nakai is an important cucurbit crop. The efficiency of in vitro methods is limited by the genotype-specific response of explants to culture media composition, which necessitates protocol optimization for commercially important cultivars. Materials and methods. Nine watermelon cultivars bred at VIR were studied. The research used modified MS culture media for introducing explants into in vitro culture, as well as various combinations of phytohormones (BAP, NUK, IUK, 2,4-D, and TDZ) for rooting, callus formation, and regeneration. Statistical analysis was performed using Fisher’s exact test (p<0.05). Results. Hormone-free culture media ensured the introduction of up to 88% of viable explants into in vitro culture. On the NAA-supplemented media, rooting reached 70-88%. Optimal callus induction (up to 100%) was observed on the medium with 0.5 mg/L BAP and 0.1 mg/L 2,4-D, while regeneration was most effective on the medium with 1 mg/L BAP and 0.1 mg/L NAA. Conclusion. The stages of in vitro explant cultivation for various watermelon cultivars have been optimized, ensuring highly efficient introduction into culture, callus formation, and regeneration, thus creating a basis for subsequent biotechnological research.

Background: Pear (Pyrus L.) is one of the most important fruit crops, widespread in the world. While in Europe and historically associated countries (USA, Australia), cultivars of one domesticated species Pyrus communis L. are grown, in the Asian region (China, Korea, Japan, Far East), cultivars were created based on individual botanical species, primarily Pyrus pyrifolia (Burm.fil.) Nakai, P. bretschneideri Rehder., P. ussuriensis Maxim., and P. × sinkiangensis T.T. Yu. The Caucasus region is considered as one of the most important centers for the formation of European pear cultivars. The concentration of a large number of species with overlapping ranges in the Caucasus promoted intensive interspecific hybridization and the emergence of polyhybrid forms that could be used in folk breeding. Commercial pear cultivation faces a number of difficulties, not the least of which is the self-incompatibility of cultivars. Gametophytic self-incompatibility in pear is controlled by the S-locus, which includes the S-RNase gene and multiple SFBB genes. These genes are highly polymorphic, so the study of the S-locus applies not only to the selection of pollinators in commercial pear orchards, but also to molecular S-genotyping. The aim of this work was to characterize the pear collection maintained at the VIR Maikop Experiment Station, and primarily landraces of Caucasian and Crimean origin, using various systems of S-locus allele markers. Materials and methods: we studied a subset of 194 accessions, including 182 cultivars and four hybrid forms from the collection of the Maikop Experiment Station of VIR, as well as eight accessions collected as part of the VIR expedition to the North Caucasus in 2022. The main analyzed groups were cultivars bred in Europe (49), those created by breeding institutions in the Caucasus (63), local Caucasian cultivars (46) and a group of Crimean cultivars (13). In the work, we used consensus PycomC1/PycomC5 and allele-specific primers selected from the literature data. Results: using both molecular marker systems, we were able to identify 25 S-alleles in the subset. Seven alleles (S₁₀₁, S₁₀₂, S₁₀₃, S_104-1, S_104-2, S₁₀₈, and S₁₂₂) were present with a frequency of ≥10%, the differences between frequencies of some of them were statistically significant in groups of local Caucasian, European and Crimean cultivars. These groups also differed in the presence of rare and unique alleles and in the presence of a large number of triploid forms. Conclusion: molecular screening of a large subset of pear accessions has established the allelic diversity of the S-locus and the uniqueness of the folk cultivars from the Caucasus and Crimea. Local cultivars with the original S-allele profile can be valuable material for breeding.

Relevance. Common plum Prunus domestica L., cherry plum Prunus cerasifera Ehrh. and blackthorn Prunus spinosa L. belong to the section Prunus of the subgenus Prunophora (Neck. ex Spach) Focke of the genus Prunus L. It is believed that the species P. domestica originated from hybridization of cherry plum and blackthorn, however, due to the phenotypic heterogeneity of the European plum, the presence of a wide range of variations and transitional forms, as well as a complex hexaploid genome, the question of its origin is still a matter of debate. For in-depth study of phylogenetic relationships, the analysis of polymorphism of plastid genome sites using molecular marking and DNA barcoding technologies is currently widely used. In this study, we aimed to develop a set of CAPS markers for rapid analysis of plastid DNA polymorphism in representatives of the Prunus section. Materials and methods. Based on the analysis of the cpDNA sequence of Prunus cerasifera var. pissardii (Carrière) L.H. Bailey, 21 pairs of plastid-specific primers have been developed. The primers previously applied to cpDNA analysis in other species of the Rosaceae family, namely in representatives of the genus Rubus L., were also used. To test the primers and select restriction enzymes, a subset consisting of seven accessions of P. cerasifera, four cultivars of P. domestica, four accessions of blackthorn P. spinosa and one cultivar of the hybrid species Prunus×rossica Eremin was used. Results. We have developed 10 potential CAPS markers (primer/restriction enzyme combinations) that provide the most visual picture of plastid DNA polymorphism in accessions of European plum, cherry plum and blackthorn. To confirm the diagnostic value of the selected CAPS markers, an analysis was performed on an experimental subset of stone fruit crops from the VIR collection, which included 19 cultivars of P. domestica, 16 accessions of P. spinosa, seven cultivars of P. cerasifera and one hybrid involving Chinese plum Prunus salicina Lindl. The CAPS markers used in the work showed different levels of detectable polymorphism, most of the markers identified from three to five variants of restriction profiles, the most polymorphic was the petN/psbM region (RubPlast9/TaqI marker) with nine different spectra of restriction fragments. Combinations of different restriction profiles for each accession were assessed as a haplotype of cpDNA; in total, 20 haplotypes were identified in a relatively small subset of 43 accessions. Conclusion. The developed CAPS markers allow us to effectively analyze the polymorphism of stone fruit plastomes in the future. They will be used to study broader experimental sets of accessions of European plum, cherry plum, and blackthorn and to investigate the relationships between these species.

The Herbarium of cultivated plants of the world, their wild relatives and weeds (WIR) at the N.I. Vavilov All-Russian institute of plant genetic resources (VIR) houses Russia's largest collection of historical herbarium specimens of cultivated potato species. The plant samples were collected in 1925-1928 by S.V. Yuzepchuk and S.M. Bukasov, members of an expedition to Latin American countries organized by N.I. Vavilov. This material is of undoubted interest for molecular genetics research. However, there are methodological limitations due to varying degrees of DNA degradation in plants preserved long-term in herbarium collections. The original set of PCR markers specific to different loci of plastid DNA, developed by Japanese researchers K. Hosaka and R. Sanetomo (2012), is widely used for studying the genetic diversity and origin of cultivated potato species maintained in field and in vitro collections of various Genebanks. Applying this marker set in full for detecting different types of chloroplast DNA (cpDNA) in historical herbarium specimens is problematic, as some primers in this set generate amplicons larger than 1000 bp. In this study, new primers A494 were developed to detect A-type plastid DNA in ~100-year-old herbarium specimens of cultivated potato species. The efficiency of A494 primers, with the use of which amplicons of the expected size were obtained for 22 of 25 herbarium specimens, was significantly higher compared to the results obtained with primers A from the Hosaka and Sanetomo (2012) set, that is, amplicons for five out of 25 specimens. The expanded marker set for detecting various cpDNA types will be used in further studies of historical herbarium collection of cultivated potato preserved in the VIR Herbarium.

Background. Cryopreservation is a promising strategy for the long-term preservation of genetic diversity of rowan species and cultivars in controlled environments. It minimizes the risk of genetic changes in accessions stored in liquid nitrogen. However, only a few studies on the cryopreservation of single rowan accessions are known. The objective of our study was the cryopreservation of six rowan cultivars bred in Russia and their transfer to the VIR cryobank for long-term storage. Materials and methods. Accessions of six Russian rowan cultivars (‘Alaya krupnaya’, 'Burka', 'Granatnaya', ‘Krasnaya krupnaya’, 'Sorbinka' and 'Titan') from the VIR in vitro collection, including two cultivars bred by I.V. Michurin, were taken for cryopreservation. The droplet vitrification method modified at VIR was used for cryopreservation of microplant apices. Results and discussion. The level of post-cryogenic regeneration in the control variants varied from 53% ('Granatnaya') to 97% (‘Alaya krupnaya’). The duration of in vitro cultivation of the accessions which varied from two to 17 years did not significantly affect the level of their post-cryogenic regeneration. All six cultivars were transferred to the VIR cryobank for long-term storage in the amount of 90 apices per accession. Conclusion. The droplet vitrification method modified at VIR has demonstrated high efficiency for cryopreservation of rowan accessions. Six rowan cultivars were placed in the VIR cryobank with the post-cryogenic regeneration level of 53%-97%. Further increase of the cryocollection of rowan accessions is planned.

Alexander Vladimirovich Kilchevsky, Doctor of Biological Sciences, Professor, Honored Scientist of the Republic of Belarus, Chairman of the Belarusian Society of Geneticists and Breeders, laureate of the Prizes of the National Academy of Sciences of Belarus and the Union State Prize, Academician of the National Academy of Sciences (NAS) of Belarus, a talented scientist in the field of genetics and biotechnology, known in the country and abroad, the leader of the Belarusian scientific school in the field of genetics, genomics, biotechnology and plant breeding, Deputy Chairman of the Presidium of the NAS of Belarus, turned 70 on August 17, 2025. He was the first in the country to create the Department of Biotechnology and the Biotechnology Center at the Belarusian State Agricultural Academy; identified the main patterns of genotype-environment relationships that manifest themselves at different stages of breeding; developed principles and methods of ecological plant breeding using modern biotechnological approaches aimed at creating highly productive and environmentally sustainable plant varieties, and methods for marker-assisted selection of nightshade vegetable crops; co-authored creation of 79 plant varieties regionally adapted in Belarus, including 57 tomato and 18 pepper varieties. The results of his scientific activities have been published in more than 800 scientific papers, including 10 monographs, four books, and textbooks. Under the supervision of A.V. Kilchevsky, four doctoral and 22 candidate scientific papers were defended; also, the National Coordination Center for Biosafety, the Republican Center for Genomic Biotechnology, the Republican DNA Bank of Humans, Animals, Plants, and Microorganisms, and the Republican Center for Microbiome Research were established. His achievements are recognized both in the country and abroad. Academician A.V. Kilchevsky is a member of the Presidium of the Higher Attestation Commission of the Republic of Belarus, a member of the Board of the Foundation for Fundamental Research of the Republic of Belarus, an Honorary Doctor of the Belarusian State Agricultural Academy, an Honorary Professor of the University of Warmia and Mazury in Olsztyn, and an Honorary Member of the European Biotechnology Association. Alexander Vladimirovich has been awarded the Francysk Skaryna Medal, the Medal of the National Academy of Sciences of Belarus "For Achievements in Science," the I.V. Kurchatov Medal, 1st Class, and the N.I. Vavilov Medal, as well as certificates of honor from national and international agencies.