Viral infections in stone fruit crops cause substantial economic losses across all sectors of production. Despite their significance, viruses affecting stone fruits remain under-investigated in Kazakhstan. Among these, plum pox virus (PPV, genus Potyvirus, family Potyviridae), commonly known as Sharka, is the most critical viral pathogen worldwide, severely threatening the sustainable cultivation of stone fruits and posing risks to food security. This study aimed to evaluate virus management strategies in stone fruit crops to facilitate the production of healthy planting material from valuable genotypes. Field surveys were conducted in plum and apricot orchards located in the Almaty region (Southeast Kazakhstan) and the Saryagash region (Southern Kazakhstan). Plant samples were tested for the presence of the following viruses: apple chlorotic leaf spot virus (ACLSV), apple mosaic virus (ApMV), PPV, prune dwarf virus (PDV), prunus necrotic ringspot virus (PNRSV), cherry green ring mottle virus (CGRMV), and myrobalan latent ringspot virus (MLRSV). Real-time RT-PCR diagnostics confirmed the presence of PPV in the ‘Stanley’ and ‘Ansar’ cultivars and Prunus armeniaca genotypes, while both PPV and ACLSV were detected in the ‘Ayana’ variety. Chemotherapy (Ribavirin), thermotherapy, cryotherapy, and shoot apical meristem (SAM) culture, both individually and in combination, were used to eliminate viruses and regenerate virus-free plants. Successful virus eradication was achieved for PPV and ACLSV. However, the ‘Stanley’ and ‘Ansar’ cultivars did not survive the treatment process, likely due to high thermo- or cryo-sensitivity. As a result of this research, an in vitro collection of virus-free plants was established, comprising eight rootstocks, six plum cultivars, and three apricot genotypes.

Pear rootstocks play an important role in intensive orchards by influencing tree vigor, productivity, stress tolerance, and environmental adaptation. However, the response of pear rootstocks used in Kazakhstan to different in vitro culture medium formulations remains insufficiently characterized. This study evaluated six modified Murashige and Skoog medium formulations as complete treatment combinations for shoot multiplication and growth of the introduced clonal rootstocks OH×F₂₃₀ and OH×F₆₉ and the local genotype Pyrus pyraster L. Experiments were conducted during 2024-2025 under controlled in vitro conditions. Aseptic establishment of field-derived Pyrus pyraster explants was evaluated separately. Treatment with 0.2% mercuric chloride for 3.5 and 4 min resulted in the highest regeneration rates, reaching 69.84 ± 8.40% and 64.29 ± 7.14%, respectively. Culture medium formulation significantly affected the multiplication coefficient. The highest mean multiplication coefficient, 3.69 ± 0.25, was obtained on M3, which contained 75% of the standard mineral nitrogen concentration, 0.8 mg L⁻¹ 6-benzylaminopurine, 0.5 mg L⁻¹ gibberellic acid, and 0.1 mg L⁻¹ indole-3-butyric acid. M3 also produced the numerically greatest mean shoot length of 5.13 cm, although shoot-length observations were evaluated descriptively. Genotype-specific responses were likewise interpreted descriptively because genotype and genotype × medium effects were not statistically tested. Because several medium components varied simultaneously, the performance of M3 cannot be attributed to an individual component. M3 was therefore identified as the best-performing complete formulation and a candidate for further factorial evaluation and pilot-scale propagation of the evaluated pear rootstocks.

Введение. Существенное сокращение площадей садов в последние десятилетия связано с воздействием неблагоприятных абиотических факторов и распространением бактериальных патогенов, что привело к обеднению сортимента груши. Быстрое внедрение устойчивых сортов и подвоев в промышленное садоводство ограничено дефицитом качественного посадочного материала. Методы. В работе исследованы особенности клонального микроразмножения семенного подвоя Pyrus pyraster и клоновых подвоев OHxF230 и OHxF69 . Подобран оптимальный режим стерилизации эксплантов и изучено влияние различных концентраций азотных солей (NH₄NO₃ и KNO₃) и регуляторов роста (6-БАП, ИМК, ГК) на эффективность пролиферации побегов. Результаты. Установлено, что при стерилизации эксплантов Pyrus pyraster максимальный процент регенерации (78,57%) достигался при обработке 0,2% раствором HgCl₂ в течение 4 мин, тогда как сокращение времени экспозиции увеличивало уровень контаминации. Оптимальные показатели микроразмножения получены на среде с 75% содержанием нитратного азота, дополненной 6-БАП (0,8 мг/л), ГК (0,5 мг/л) и ИМК (0,1 мг/л). Повышенная концентрация 6-БАП (1,8 мг/л) в сочетании с пониженным уровнем азота снижала эффективность размножения, особенно у Pyrus pyraster, тогда как у подвоя OHxF230 сохранялся относительно высокий коэффициент размножения (2,67 ± 1,15). Выводы. Полученные результаты демонстрируют возможность оптимизации условий культивирования для повышения эффективности микроразмножения подвоев груши и могут быть использованы при разработке биотехнологических протоколов получения посадочного материала в условиях in vitro.

At each stage of clonal micropropagation, problems such as unsuccessful disinfection, weak reproduction, and abnormal development of microplants appear. The consequences of such failures can lead to necrosis of plants, and sometimes death. Successful plants micropropagation depends on several internal and external factors, including in vitro conditions. It is important to create optimal conditions at each stage of clonal micropropagation to achieve a high rate of in vitro explants multiplication. The article presents the results of optimization of clonal micropropagation of Armeniaca vulgaris wild apricot and domestic and foreign cultivars Balkiya, Monitoba, Kolkhoznyi, Nikitskyi krasnoshchekyi, Alexander at different propagation stages. Research results showed that the most suitable nutrient medium for wild apricot and cultivated apricot cultivars was Quorin-Lepoivre (QL) containing 0.5 mg/L 6-benzylaminopurine (BAP), 0.5 mg/L gibberellic acid (GA), 0.1 mg/L indole butyric acid (IBA) and 10 mg/L Iron chelate, 1.5 mg/L vitamin C, 0.5 mg/ L B1; 0.5 mg/L B6, also Murashige and Skoog (MS) nutrient medium containing 1.2 mg/L BAP, 0.8 mg/L GA, 0.1 mg/L IBA. The optimal nutrient medium for clonal micropropagation was a mineral medium containing 0.8 mg/L BAP, 0.5 mg/L GA, 0.1 mg/L IBA on the MS base. In vitro conditions, 5 varieties of apricots were introduced and propagated.