Background. The method of agrobacterium mediated transformation is most often used for the transformation of higher plant cells. The choice of explant type, the composition of nutrient media for the selection and regeneration of transformants are important. Cowpea Vigna unguiculata (L.) Walp. is a legume crop. It is recalcitrant for transformation due to its low regeneration after agrobacterial inoculation. The search for genotypes with a high regeneration ability, as well as the creation of an effective protocol for optimal Agrobacterium tumefaciens-mediated transfection protocol are urgent tasks for the delivery of editing system components. The aim of this study is to develop an effective protocol for obtaining cowpea transformants carrying editing constructs. Material and methods. The development of the efficient protocol for obtaining cowpea transformants for the delivery of editing system components was carried out using accessions from the VIR collection. Cotyledonary node parts were used as explants formed by longitudinal incision of the cotyledon node in order to increase the wound surface area. The agrobacterium mediated transformation was performed using a vector on the base of pKSE401 with components of the CRISPR/Cas9 editing system. Organogenesis was induced on MS nutrient medium with phytohormones. The article describes a step-by-step protocol for the efficient production of fertile cowpea transformants. Results and discussion. We experimentally confirmed the organogenetic capacity of the cowpea cotyledonary node to produce shoots in vitro, as well as the possibility of using them as explants for agrobacterium mediated transformation. The frequency of fertile transformants was 6.2% for k-642 genotype. A comparison of the transformation efficiency with the data from previous studies on the cowpea agrobacterium mediated transformation indicates a better yield of transformants based on our proposed protocol. Since the protocol has been validated in the experiment with a vector carrying components of the CRISPR/Cas9 editing system, it can be recommended for use in studies on the production of edited cowpea plants. Conclusion. The obtained results of the agrobacterium mediated transformation of cowpea modified type explants indicate the possibility of successful use of the presented protocol for the genetic transformation of this crop. The k-642 genotype was efficient not only at the stages of regeneration and transformation, but also at the stages of rooting and subsequent plant adaptation to non-sterile conditions. This genotype can be recommended for further fundamental cowpea studies using reverse genetics methods.

Background. The creation of early maturing, photoperiod-insensitive cultivars is a perspective direction of durum wheat (Triticum durum Desf.) breeding. The collection of wheat genetic resources at VIR can serve as a source of the genes for valuable breeding traits. The potential of durum wheat collection for important adaptation characters has been poorly studied, and the allelic diversity at the development rate gene loci is unknown. Screening of the collection with the use of the allele-specific molecular markers of the genes for vernalization response (Vrn) and photoperiod sensitivity (Ppd) is relevant. Material and methods. A sample set for genotyping loci of high growth rate included 48 T. durum accessions previously characterized for physiological characters and productivity components. Eight common allele-specific PCR markers selected from literature sources were used for the molecular screening. The photoperiod sensitivity coefficient was determined in a vegetation experiment under natural illumination and short 12-hour day conditions. Results. With the use of diagnostic markers, the dominant Vrn alleles for spring growth habit were identified in 24 accessions: 23 accessions were found to carry Vrn-A1 allele determining the spring growth habit; the dominant Vrn-B1 allele was detected in 24 accessions, while the Vrn-B3a allele was found only in the Ambo 7 accession. The dominant Ppd-A1 and Ppd-B1 alleles determining photoperiod insensitivity were identified in 21 accessions. A vegetation experiment has confirmed a weak response to the day length in eight Mexican lines that harbor markers of the dominant Vrn and Ppd alleles. Conclusion. Based on the phenotypic analysis and molecular genotyping data, 24 sources of early maturity genes were identified in durum wheat.

Background: Pear (Pyrus sp.) is one of the economically important fruit crops grown in 50 countries worldwide. However, pear cultivars are affected by many pathogens, including scab caused by the ascomycete fungus belonging to the genus Venturia Sacc. The two pear-damaging species of this genus are Venturia nashicola S. Tanaka & S. Yamam. that affects Asian pears (P. pyrifolia (Burm.fil.) Nakai, P. bretschneideri Rehder, P. ussuriensis Maxim.), and Venturia pirina Aderh. that affects specifically the European pear P. communis L. The use of molecular markers for the selection of scab-resistant varieties will improve the efficiency of breeding programs. The aim of this work was to test the markers of the Rvn2 and Vnk (Rvn1) genes, which control scab resistance to Venturia nashicola, using the material from the collection maintained at the Maikop Experiment Station, and accessions from a collecting mission. Materials and methods: A sample of 255 accessions was studied, including 246 cultivars from the collection of the Maikop Experiment Station, and nine accessions from the VIR collecting mission to the North Caucasus in 2022. The basis of the sample were 152 cultivars of Caucasian origin, including local forms; the second large subsample (61) was made up of European cultivars. The research used the markers of the Rvn2 gene – PSC217/XhoI and PSC234/HaeIII, and of the Vnk (Rvn1) gene – STS-OPO9/SalI and STS-OPAW13, selected from the literature. Results: A wide distribution of both markers of the Rvn2 gene among the accessions was shown (89.4% for PSC217/XhoI and 30.9% for PSC234/HaeIII), while the frequency of their occurrence among the two main subsamples was approximately the same. When comparing the molecular screening results with the data on the accessions resistance to pear scab, a low diagnostic value of both markers was shown – the PSC217/XhoI marker had an efficiency of 47.2%, and that of the PSC234/HaeIII marker was 51.4%. On the contrary, the STS-OPAW13 and STS-OPO9/SalI markers of the Vnk (Rvn1) gene were present only in single cultivars (seven) bred in China and the Caucasus. However, according to their pedigrees, the latter ones were created without the use of original local material. Conclusion. The study of a large sample of pear accessions has shown a wide distribution of Rvn2 gene markers in the studied material, which, however, demonstrated low efficiency and are unsuitable for molecular screening. The Vnk (Rvn1) gene markers were detected only in few accessions. Of interest for breeding is the Chinese cultivar ‘Dan-Shansu-li’, which has both markers of the gene Vnk (Rvn1), and exhibits resistance to pear scab.

Background. Unique apple cultivars have been created at the Sverdlovsk Horticultural Breeding Station and adapted to growing in the harsh natural and climatic conditions of the Middle Urals. Sharp temperature changes and a significant amount of precipitation in summer contribute to the development of fungal and bacterial diseases. Therefore, the main direction in breeding is the creation of forms with a complex of genes for resistance to various types of diseases. To search for sources of valuable features, the use of the molecular marker method remains relevant, which shortens the analysis time and allows for selection directly on the basis of gene presence instead of the external manifestation of а trait. The aim of our work was to search for scab and fire blight resistance genes in apple cultivars bred by the Sverdlovsk Breeding Station of Horticulture using DNA markers. The study used the VfC marker of the Rvi6 scab resistance gene, AE10-375 and GE-8019 QTL FBF7 markers of resistance to fire blight of apple trees. The results of molecular identification of the scab resistance gene were compared with those of evaluating the field resistance in the cultivars studied during the epiphytotic years. 21 apple cultivars were analyzed. Results. In the course of the research, the Rvi6 gene was identified in three apple cultivars – ‘Pervouralskaya’ ‘Aksyonaʼ and ʻBlagaya Vestʼ. An assessment of field resistance to scab showed that a number of cultivars were not affected. It was established that all varieties with a fragment indicating the presence of the Rvi6 gene were not affected by scab during epiphytotic years. The cultivars ʻTavatuyʼ, ʻRozochkaʼ, ʻDanilaʼ, ʻVEM Rozovyjʼ, and ‘Rodnikovayaʼ also showed no signs of the disease. The pedigree analysis showed that scab resistance donors carrying the Rvi5 gene were used to create these cultivars.In the analyzed collection, markers AЕ10-375 and GE-8019 QTL FBF7 of resistance to bacterial fire blight of apple trees were noted in almost the same number of cultivars (AЕ10-375 was identified in 12 accessions, and GE-8019 in 10). However, the presence of resistance is evidenced by the presence of two markers in one genotype. The five identified accessions are ʻIset Belaya’, ‘Pervouralskaya’, ʻAksyonaʼ, ʻSerebryanoye Kopyttseʼ, and ʻBlagaya Vest’. Conclusions. The performed research made it possible to establish the sources of valuable characters in apple cultivars bred in the Urals. The identified genotypes are promising for further use in breeding and industrial horticulture.