Vol 20, No 3 (2025): Varietal breeding — selection and retention of agronomic traits

Apple tree ( Malus × domestica Borkh.) is a leading agricultural pome crop, one of the main perennial fruit plants in the world, commercially in demand and widespread in the horticultural industry of Russia, including the North Caucasus region. In solving the problem of creating high-quality domestic apple varieties with a long-term type of resistance to the scab (pathogen - Venturia inaequalis (Cooke) G. Winter), the role of prebreeding, including research aimed at accelerated selection using the DNA method, is significant tagging valuable carriers of several Rvi scab resistance genes. The purpose of the study was to study the allelic polymorphism of 15 apple tree scab resistance genes ( Venturia inaequalis (Cooke) G. Winter) in 33 varietal and breeding samples of apple trees to identify sources of long-term resistance to increase efficiency of breeding process. The research was carried out in accordance with programs and methods for the study of apple varieties; Research and Selection Collection of Genetic Resources of Horticultural Crops and the Instrumentation and Analytical Center were used. DNA analysis methods were used in this work. For DNA extraction, a modification of the CTAB method was used, developed at North Caucasian Federal Scientific Center of Horticulture, Viticulture, Winemaking, allowing for better purification of DNA samples from polyphenolic compounds. The work used 22 markers to identify 15 apple scab resistance genes: Rvi1; Rvi2; Rvi3; Rvi4; Rvi5; Rvi6; Rvi8; Rvi9; Rvi11; Rvi12; Rvi13; Rvi14; Rvi15; Rvi16; Rvi17 . Marker selection of new varietal and breeding material made it possible to identify carriers of several genes for apple tree resistance to scab, having in the genome from 2 to 6 different Rvi genes in different combinations. Carriers of 6 resistance genes were identified as the most promising for selection for long-term resistance to scab: Rvi1, Rvi2, Rvi3, Rvi4, Rvi6, Rvi15-1 2/1-21-24; 5 genes: Rvi1, Rvi2, Rvi3, Rvi6, Rvi13 - Karmen; Rvi1, Rvi2, Rvi4, Rvi6, Rvi15 - Mikhsan; 4 genes: Rvi1, Rvi2, Rvi3, Rvi6 - Nadezhnoye; Rvi1, Rvi4, Rvi6, Rvi15 - Gaito Gazdanov; Rvi1, Rvi3, Rvi6, Rvi8-1 2/1-20-56, etc. Identified apple genotypes of domestic breeding, including those created in creative collaboration with colleagues from the Russian Research Institute for Breeding Fruit Crops and Stavropol Experimental Horticulture Station, promising for further breeding and accelerated creation of new high-quality, adaptive varieties with long-term high potential for resistance to the main fungal pathogen of the crop.

The research was conducted in 2020-2021 at Leningrad Research Institute ‘Belogorka’ - a branch of Russian Potato Research Centre, located in the village of Belogorka, Gatchina district, Leningrad region. The research was carried out to identify sources of economically valuable traits from the collection of Vavilov AllRussian Institute of Plant Genetic Resources on the main elements of crop structure to create valuable breeding material for spring barley. In accordance with the Methodological Guidelines for the Study and Preservation of the World Collection of Barley and Oats (2012) and the International comecon list of descriptors for genus Hordeum L. (1983), 17 new spring barley cultivars of different ecological and geographical origins were studied over two years. Two cultivars were used as standards - Suzdalets (by yield) selected by several organizations and Leningradsky (by early ripening) selected by Leningrad Research Agricultural Institute ‘Belogorka’. The standard cv. Leningradsky surpassed cv. Magutny (Belarus) by early ripening in both years. 7 cultivars were identified (Dhow, Dokuchaevsky 15, Lun, Magutny, Mustang, J.B. Maltasia, and Kazak), for which maturation occurred 5-14 days earlier compared to standard cv. Suzdalets (growing season averaged 81 days over two years). According to productive tillers, 3 cultivars were identified that exceeded the standard cv. Suzdalets (3.0 plants): Magutny - by 0.3, Dhow - by 0.5 and J.B. Maltasia - by 0.6 plants. By weight of 1000 grains (more than 45.9 g), 6 varieties were identified: Rubiola, Shlyakhtsich, Beatrice, Magutny, Kazak and Lun. A cultivar resistant to powdery mildew in both years of study was distinguished - J.B. Maltasia. The selected cultivars will be used in the breeding process as genetic sources of agronomic traits in the conditions of the Leningrad region.

For landscaping of northern cities, requirement for ornamental plants resistant to urban conditions is increasing, so there is a need to find a solution for multiplication at commercial scale. A technology of green cuttings of woody plants ( Syringa josikaea and Spiraea media ) has been developed as one of the promising methods of vegetative propagation of deciduous ornamental species in the Arctic region. The terms of cuttings (at the beginning of shoot lignification) have been established: for Spiraea media - July 1-10; for Syringa josikaea - July 10-25. A positive effect of the growth stimulator IBA 1000 ppm on the development of the root system and the above-ground part of the cuttings was determined with 6-hour and 12-hour treatment. It was shown that a longer treatment period (12 hours) was more effective. The length of the roots of Syringa josikaea exceeded the control with a 6-hour treatment by 52%; at 12 hours by 89%; in Spiraea media - by 27 and 42%, respectively. In both species the number of roots increased by 32-34% with a longer exposure. The treatment of cuttings for 12-hour significantly increased the formation of leaves on the cuttings of Syringa josikaea ( r = 0.87 p < 0.001) and Spiraea media ( r = 0.89 p < 0.001). The results revealed that the cuttings treated with IBA 1000 ppm (12h) registered maximum survival percentage of rooted cuttings of Syringa josikaea (95.1%) and Spiraea media (75.2%).

Under changing climate conditions, modern livestock production systems are becoming increasingly vulnerable, and highly productive animals are quite demanding in terms of housing and management conditions. An analysis of scientific studies dedicated to the problem of global warming and its impact on the dairy and beef cattle industries has been conducted. The research materials presented address the effects of heat stress on animals, noting the limited number of studies and the inconsistency of information available in the literature. Developments offering specific tools to mitigate the consequences of global warming for livestock enterprises are either absent or ineffective under the natural and climatic conditions of the Kabardino-Balkarian Republic.

In modern dairy farming, the study of genetic factors affecting the productive longevity and milk productivity of cattle is relevant. The leptin gene, involved in the regulation of energy metabolism, is a promising marker for selection. However, the influence of its polymorphism complex genotypes (A80V, R25C, Y7F) on the productivity and longevity of animals has not been sufficiently studied, which determines the importance of this research. The aim of the study was to investigate the influence of the leptin gene complex genotypes at sites A80V, R25C, Y7F on the milk productivity indicators and the duration of economic use of Kholmogory cattle. The study was conducted on 207 Kholmogory breed cows, divided into groups with different complex genotypes. For statistical analysis, the number of animals in the compared groups was equalized: 13 heads per group for the study of lifetime milk productivity and 19 heads per group for the assessment of the duration of use. Genotyping was performed by PCR-RFLP, and statistical processing was carried out using non-parametric methods (Mann - Whitney U test). Lifetime daily milk yield, milk fat and protein content, age at culling, and lifetime milking days (LMD) were analyzed. It was revealed that the AVRCYY genotype is associated with the maximum daily milk yield (22.04 kg) and the highest number of LMD (2032 days), indicating its positive influence on productive longevity. The lowest indicators were noted for the AVCCYY genotype (194 LMD). Significant differences in milk fat content were found between groups AACCYY, AARCYY, AARRYY, and AVCCYY. The AACCYY genotype showed the highest protein content (3.23%), but the lowest milk yield. Differences in the structure of culling reasons were also identified: gynecological diseases prevailed in animals with the AVCCYY genotype combination, while limb diseases prevailed in animals with the AVRCYY complex genotype. The results of the study demonstrate the significance of a comprehensive analysis of leptin gene genotypes for dairy cattle selection. The AVRCYY genotype can be recommended as a marker for increased productive longevity.

For the first time in the history of Russian veterinary medicine, a retrospective analysis of the clinical features of brain tumors (BT) in dogs was carried out. The study was conducted in the Moscow region in 2018-2024 on the basis of the Biocontrol veterinary clinic. The aim of the study is to determine the frequency, localization and clinical manifestations of BT. The data of 54,142 dogs were analyzed, of which 150 had BT (1.2% of oncological cases, 0.28% of the total number of patients). The average age was 9.4 years. Most often, BT was recorded in cross-breed, French bulldogs, Cane Corso and German shepherds. Brachycephalic breeds showed a predisposition to intra-axial lesions, mesocephalic to extra-axial. There was no gender predisposition. The main clinical manifestations included convulsions, ataxia, paresis and changes in consciousness depending on the location of the tumor. The median tumor volume was 6 cm³ for extra-axial and 9.4 cm³ for intra-axial lesions. Histological verification was performed in 23 patients. Diagnosis was carried out using MRI (1.5 Tesla), histology and immunohistochemistry. The study showed the need for histological analysis of BT for accurate typing of lesions and emphasized the importance of developing methods of imaging and invasive diagnosis in veterinary medicine. The data obtained partially differ from foreign ones, which is due to the difference in the breed sampling of the dog population. Unique results can serve as a basis for the development of standardized protocols for the diagnosis and treatment of canine BT.