This study presents the results of scientific research analyzing the resistance to late blight in created potato hybrids of various maturity groups and the possibility of identifying early-maturing forms with increased resistance to both leaf and tuber late blight. The aim of the study is to evaluate potato breeding material for resistance to late blight, identify combinations for crossing with a high percentage of disease-resistant and early-maturing forms. The methods of field, laboratory, and statistical research were employed. The article presents the results of breeding work on evaluating potato varieties and hybrids to create breeding material resistant to late blight. Maternal and paternal forms were identified, along with crossing combinations yielding a large number of disease-resistant offspring. Hybrids and breeding material have been developed, combining resistance: 13 hybrids to late blight of leaves and tubers, and 14 hybrids combining resistance to late blight and early maturity. These hybrids will be further used in breeding practices to develop new potato varieties resistant to late blight. Based on the conducted research, the following main conclusions were formulated: parental forms and crossing combinations were identified, which provide the majority of late blight-resistant offspring and are valuable for breeding practices. Hybrids combining resistance to late blight of leaves and tubers, as well as resistance to late blight and early maturity, have been developed. The breeding material will be used as a basis for creating new potato varieties resistant to the pathogen. In 2022–2023, work on the breeding project was completed, resulting in the identification of combinations forming from 0.2 to 2.5% of forms resistant to late blight of leaves and tubers in combination with early maturity. As a result of the research, hybrids derived from the crosses Slavyanka/Povin, 04/21c31/Bellarosa, and Virinea/Strumok have been identified. These hybrids, named Solomia, Sofia, and Mirami, were submitted for trials in 2022–2023. The varieties Mirami and Solomia combine early maturity with resistance to late blight of leaves, while Sofia combines early maturity with resistance to late blight of tubers.

Climate variability necessitates the optimization of sowing dates for vegetable crops to stabilize yields and mitigate abiotic stress risks. This study aimed to evaluate the effect of sowing dates on the productivity of daikon radish (Raphanus sativus L. convar. acanthiformis Sazon.) cultivars Gulliver and Minowase under medium-podzolic, light loamy soil conditions with a pH (pHKCl) of 6.74 during the period 2022–2024. Field experiments were conducted across four sowing dates (ranging from July to early August), accounting for the hydrothermal conditions of the growing season. Effective air temperatures ranged from 428 to 950 °C, with precipitation levels between 36.9 and 252.3 mm. It was established that the sowing date significantly influenced daikon yield (p < 0.001). A significant positive correlation was identified between yield and precipitation (r = 0.76–0.84; p < 0.05), whereas the correlation between yield and the sum of effective temperatures was weak to moderate and predominantly negative (r = −0.62 to −0.10). The highest yields were achieved with sowing in the third ten-day period of July: 54.6 t ha⁻¹ for the Gulliver cultivar and 58.9 t ha⁻¹ for the Minowase cultivar. The Minowase cultivar consistently outperformed Gulliver in terms of yield and exhibited higher ecological plasticity under fluctuating hydrothermal conditions. These findings confirm the feasibility of optimizing sowing dates as an effective adaptive tool for enhancing the stability of daikon production amidst climate change.

The article is devoted to studying the effect of different sowing dates on the productivity and marketable quality of daikon varieties. Between 2022 and 2024, a field experiment was conducted on the territory of the Fruit and Vegetable Garden training laboratory of the National University of Life and Environmental Sciences of Ukraine. The experimental plots were located in the Right-Bank Forest-Steppe of Ukraine. The plot area of each repetition was 5 m², and the variants were randomly arranged with three repetitions.The study found that growing the Minovasi variety is significantly more profitable than the control variety, Gulliver. Overall, Minovasi showed a 4.3–10.6% increase in yield compared to Gulliver, with the largest increase (5.4 t/ha) recorded when sowing in the first ten days of August. The highest yield for the studied varieties was achieved when sowing in the third ten days of July, which confirms the relationship between sowing time and productivity. During this optimal sowing period, the yield was 58.9 t/ha for the Minovasi variety and 54.6 t/ha for the Gulliver variety, and the average root weight reached its highest values – 426 g and 414 g, respectively. Also, at other sowing dates, the average root weight of the Gulliver variety exceeded that of the Minovasi variety, with a deviation ranging from 3 to 17 g within the experiment. In addition, the Minovasi variety demonstrated higher marketability, as the percentage of non-marketable root crops was lower (37.8–42.6%) compared to the Gulliver variety (40.7–44.0%). Analysis of the structure of non-marketable root crops showed that the largest share (75.5–76.5%) was damage caused by cabbage flies. Here again, an important interdependence was revealed: sowing in the third decade of July and the first decade of August ensured the highest resistance of both varieties to this pest, reducing the level of damage to 28.7–32.1%. These same sowing dates were also optimal for reducing other indicators, ensuring the lowest percentage of disease damage (1.1–1.8%) and cracking (4.6–4.9%), as well as a low branching rate (3.0–3.5%) of root crops. Thus, the study confirmed that the optimal sowing date in the third decade of July and the first decade of August is a key factor that comprehensively affects yield, quality, resistance to pests and diseases, ensuring maximum economic efficiency. Стаття присвячена дослідженню впливу різних термінів сівби на продуктивність та товарну якість сортів дайкону. У період з 2022 до 2024 рік на території навчальної лабораторії «Плодоовочевий сад» Національного університету біоресурсів і природокористування України було проведено польовий експеримент. Дослідні ділянки були розташовані в Правобережному Лісостепу України. Облікова ділянка кожної повторності площею 5 м², варіанти розміщувались рендомізовано із триразовою повторністю.В результаті дослідження було встановлено, що вирощування сорту Міновасі є значно доцільнішим порівняно з контрольним сортом Гулівер. Загалом, Міновасі демонстрував підвищення врожайності на 4,3–10,6% порівняно з Гулівером, причому найбільший приріст (5,4 т/га) був зафіксований при сівбі в першій декаді серпня. Найвища ж врожайність для досліджуваних сортів була досягнута за сівби в ІІІ декаді липня, що підтверджує взаємозв'язок між терміном сівби та продуктивністю. За цього оптимального терміну сівби врожайність становила 58,9 т/га для сорту Міновасі та 54,6 т/га для сорту Гулівер, а середня маса коренеплоду досягала найвищих значень – 426 г та 414 г відповідно. Також за інших термінів сівби спостерігалося перевищення середньої маси коренеплоду в сорту Гулівер відносно сорту Міновасі, а відхилення становило в межах досліду від 3 до 17 г. Крім того, сорт Міновасі продемонстрував вищу товарну якість, оскільки відсоток нетоварних коренеплодів у нього був нижчим (37,8–42,6 %) порівняно з сортом Гулівером (40,7–44,0 %). Аналіз структури нетоварних коренеплодів показав, що найбільшу частку (75,5–76,5 %) становило пошкодження капустяною мухою. Тут знову проявилася важлива взаємозалежність: сівба у III декаді липня та I декаді серпня забезпечила найвищу стійкість обох сортів до цього шкідника, знизивши рівень ураження до 28,7–32,1 %. Ці ж терміни сівби були оптимальними й для зниження інших показників, забезпечивши найменший відсоток ураження хворобами (1,1–1,8 %) та розтріскування...

Lobo radish yield and quality depend heavily on summer sowing dates. A three-year field trial (2022–2024) in the Central Forest-Steppe of Ukraine evaluated four sowing dates–D1 (first decade of July), D2 (second decade of July), D3 (third decade of July), and D4 (first decade of August)–for cultivars Troiandova and Lebidka. Sowing in late July (D3) was optimal, securing maximum marketable yield (42.2 t·ha⁻¹ for Troiandova, 38.9 t·ha⁻¹ for Lebidka), peak marketability (70.5–72.0%), and minimal bolting (2.1–2.8%). Early sowing dates (D1–D2) increased bolting (up to 20.0%) and pest damage by cabbage root fly (Delia radicum L., 25.1–27.3%), reducing marketability to 45.4–52.0%. August sowing (D4) reduced root weight (204.6–224.3 g) but increased dry matter (8.6–9.8%) and soluble sugars (4.8–5.5%). AMMI and GGE biplots revealed higher yield stability for cultivar Lebidka (notably at D4), whereas Troiandova was highly responsive to optimal conditions (Troy-D3). Overall, sowing in the third decade of July (D3) is recommended for commercial production.