Despite the high nutritional value of cowpea and its potential for sustainable farming, its cultivation is limited by the lack of vegetable varieties adapted to different soil and climatic conditions, which complicates the fight against food insecurity in many countries. Therefore, this study aims to conduct a comprehensive evaluation of cowpea (Vigna unguiculata (L.) Walp. subsp. sesquipedalis (L.) Verdc.) varieties with the aim of identifying genotypes with high productivity potential and resistance to the main adverse environmental factors of the Right-Bank Forest-Steppe of Ukraine. The experimental study was carried out in a three-year period (2014–2016). Depending on the variant of the experiment, cowpea germination was observed from 25 May to 30 May. The shortest sowing–shoot period (10 days) was observed in the variety ‘U-Tya-Kontou’ (China), with the longest (13 days) in the varieties ‘Kafedralna’ (Ukraine) and ‘American Improved’ (USA). In the control variant, shoots were obtained on 28 May. Flowering started from 9 July to 16 July; technical maturity (unripe (green) beans) started from 27 July to 2 July; and biological maturity of the seeds started from 30 August to 5 September. For the variety ‘American Improved’, the shortest period of seedling–technical maturity (unripe (green) beans) (58 days) and seedling–biological maturity (92 days) was recorded. By cultivar, the maximum plant height was achieved with varieties ‘Groik’ (Israel) at 100.5 cm and ‘Gasson’ (Vietnam) at 61.8 cm, which are 52 cm and 13.3 cm more than the control height. They differ by the quick growth of the main and side shoots, which allows them to be grown on supports. The highest yield of green beans was recorded in the cowpea variety ‘Gasson’ at 14.4 t∙ha⁻¹, which is 38.5% higher than the control. In the variety ‘Groik’, the yield of green beans (11.4 t∙ha⁻¹) did not differ significantly from the control (‘Kafedralna’—10.4 t∙ha⁻¹). The varieties ‘U-Tya-Kontou’ and ‘American Improved’ were characterized by the lowest yield of green beans, which reached 5.8 and 4.2 t∙ha⁻¹, respectively, which is 44.2 and 59.6% less than the control. As a result of statistical analysis of cowpea yields, the limits of its fluctuation were established as follows: fluctuations in the sum of effective temperatures by 10 °C (>10 °C) contributed to a deviation in green bean yields from 20.0 to 24.7 kg (ha)⁻¹, and fluctuations in precipitation by 10 mm contributed to a deviation in green bean yields in the range from 34.3 to 208.2 kg (ha)⁻¹. The results of the study presented in this article have practical application for the development of effective methods of growing local varieties of long-stemmed cowpea, which will increase yields and meet the needs of both farmers and consumers in regions with similar climatic conditions.

Due to the intensification of production of parsnip, the question arises to clarify the elements of cultivation technology that should ensure its high productivity. The use of varietal plant resources is one of the most important parts of agriculture - the basis of economic and social development of the state. The most efficient and cost-effective is the widespread introduction of new varieties and hybrids with a genetically determined level of adaptation to the conditions of soil and climatic zones of their cultivation. The indicator of the dynamics of the formation of photosynthetic productivity is the basis of the yield of each crop. The purpose of the research was to study the dynamics of leaf surface formation in varieties of parsnip in the conditions of the Right-Bank Forest-Steppe of Ukraine. The studied cultivars of parsnip sowing formed a high area of active assimilation surface, the dynamics of which depends on the stage of organogenesis, soil and climatic conditions of the year and varietal characteristics. With the highest average for the growing season leaf area (49.0-49.6 thousand m2 on ha), photosynthetic potential (1.79-1.83 million m2 per day on ha) and net productivity of photosynthesis - 5.56 g on m2 per day) were characterized by varieties Stymul and Pulse in terms of other varieties. It is established that in order to obtain stably high yield (44.4-45.4 t on ha) and marketability of root crops (85-93%) in the conditions of the Right-Bank Forest-Steppe of Ukraine it is necessary to sow highly productive varieties of parsnip sowing Stymul and Pulse.

The commodity output of parsnip was formed in the conditions of the Right‑Bank Forest-steppe of Ukraine within the limits of the sum of active temperatures 1356‑1495 °С, the amount of precipitation 171‑318 mm and relative humidity 57‑64 %. The crop yield had an invert dependence on the sum of temperature and the direct dependence on the amount of precipitation, relative humidity of air and hydrothermal coefficient. The highest yield in the conditions of the Right-bank Forest-steppe of Ukraine provided the Stymul and Pulse varieties with a total yield of 46,2 and 44,8 tons/hectare, and the commodity output of roots of 89 and 88 %, accordingly. It was calculated that the varieties Pulse and Stymul had the highest selective value of the genotype (SCGi = 46,2 and 44,8 accordingly) for yield, high ecological stability (Sgi = 3,43 and 1,96 accordingly) and plasticity (bi = 1,47 and 0,89 % accordingly). The highest indicator of the total adaptive capacity for plant productivity was noted in the Stymul (ZAZ = 3,12) and Pulse (ZAZ = 1,76) varieties. According to the indicator of specific adaptive ability, the Stymul variety (SAZ = 2,52) and Pulse (ZAZ = 0,78) was distinguished. According to the biochemical composition of roots, the investigated varieties did not exceed the control. However, in Boris variety the content of dry matter (25,1 %), dry soluble substance (15,8 %) and sugar (6,4 %) was at the control level. All varieties showed high levels of vitamin C – 8,9‑10,1 mg/100 g. The varieties were not susceptible to accumulation of nitrates and their content varied from 67 to 80 mg/kg and was below the maximum acceptable level (MDR 250 mg/kg). The highest tasting score of 5,6 points got the Pulse. To obtain a consistently high root crop yield at the level 44,8‑46,2 tons/hectare and marketability of roots at the level of 88‑89 % with a high content of major biochemical components in the conditions of the Right‑Bank Forest-steppe of Ukraine on medium-podzolic, roughly dusty, easy loamy soil with the usage of high-yielding of the varieties parsnips Pulse and Stymul.

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.

The main drivers influencing plant growth, yield increase and its quality characteristics are biotic and abiotic factors. Combinations of abiotic stresses, such as drought and heat, have a much greater impact on yields and product quality. Plants' response to these stresses can vary depending on the species and different stages of development. Understanding the mechanisms and how they protect plants from stress has become vital for improving the yield and quality of parsnip products in changing climates. The purpose of the study was to determine the influence of abiotic factors (temperature and precipitation) on the yield, duration of phenological phases of growth and development of plants, the dynamics of leaf and root mass growth of parsnip in the conditions of the Right-Bank Forest-Steppe of Ukraine. The research was carried out in the field experiment of the Department of Vegetable Growing and Closed Ground in the National Research Institute “Fruit and Vegetable Garden” of NUBiP of Ukraine within the conditions of the Right-Bank Forest-Steppe of Ukraine during 2015-2017. The area of the registered plot was 11.3 m2, and the repetition rate of the experiment is four times. The placement of variants is systematic. The research found that the shortest sowing-emergence period lasted 16 days in the variants sown in the 3rd ten-day period of May and the 1st ten-day period of June. A significant delay of 21 days in this period was noted for sowings from 1st to 3rd ten-day periods of April. The duration of the period from the beginning of root crop formation to bunch ripeness was the shortest when sown in the 1st ten-day period of April – 28 days, and the longest when sown in the 1st ten-day period of June – 51 days. The growing season ranged from 110 to 165 days and was characterised by GDD (> 10 °C) of 1102.4-1439.0 °C and precipitation of 128.1-225.2 mm. After sowing in April, intensive growth of root crops from 2.9 to 3.5 g / day was observed in the second half of August. After sowing in May, the greatest increase in root crops from 2.1 to 2.7 g/day was noted in the first half of September. Thus, for sowings in the 1st ten-day period of June, this figure was the highest in the second half of September (1.9 g/day). The variant sown in the 1st ten-day period of April provided a high yield of root crops of 50.3 t/ha, which is 5.3 t/ha or 11.8% significantly more than the control variant. When sowing in the following terms, a significant decrease in yields was observed compared to the control, namely: for 3rd ten-day period of April – by 3.5 t/ha, or 7.7%, for 1st ten-day period of May – by 8.8 t/ha, or 19.6%, for 2nd ten-day periods of May – by 17.4 t/ha, or 38.6%, for 3rd ten-day periods of May – by 23.0 t/ha, or 51.1%, for 1st ten-day period of June – by 31.7 t/ha, 70.6% compared to the control. A strong direct correlation (r = 0.74-0.99) was found between the growing season and yield, root mass, marketability, and biochemical parameters, namely: dry matter, dry soluble matter, sugars, vitamin C. An inverse correlation (r = -0.98) was observed between the duration of the growing season and nitrates. Increasing the growing season by 10 days increases the yield up to 6.9 t/ha, marketability up to 2.7%, root weight up to 31 g, dry matter content up to 0.7%, dry soluble matter up to 0.3%, sugars up to 0.5%, vitamin C up to 0.8 mg/100 g and reduces the nitrate content to 8.4 mg/kg. Leaf area, photosynthetic potential, and net photosynthetic productivity are strongly directly related (r = 0.92-0.98) to yield. For increasing the leaf surface area to 1.0 thousand m2 the yield is also growing up to 0.7 t/ha. Increasing the photosynthetic potential to 0.05 million m2 days/ha increases the yield to 0.2-1.2 t/ha. Also, the yield increases to 0.3-0.7 t/ha with an increase in net photosynthetic productivity to 0.05 g/m2 per day. The molecular knowledge on plant responses to abiotic stress is promising for further study and is likely to advance crop resilience to climate change and increase the economic efficiency of production

The main factors that have a great influence on plant growth, as well as on increasing the yield and its quality characteristics, are biotic and abiotic. Combinations of abiotic stresses, such as drought and heat, have a much greater impact on yields and product quality. The response of plants to these stresses can vary depending on the species, as well as at different stages of development. Understanding the mechanisms and how they protect plants from stress has become vital to improving the yield and quality of parsnip products in changing climatic conditions. The research aimed to study the influence of abiotic factors (temperature and precipitation) on yield, duration of phenological phases of plant growth and development, dynamics of growth of leaves and roots of parsnip in the Right Bank Forest-Steppe of Ukraine. The research was conducted in the field experiment of the Department of Vegetable Growing and Closed Soil in NL "Fruit and Vegetable Garden" NUBIP of Ukraine in the Right Bank Forest-Steppe of Ukraine during 2015-2017. The area of the accounting plot was 11.3 m2, the repetition of the experiment was 4 times. The arrangement of the research plots was systematic. As a result of research, it is established that the shortest period of sowing-seedlings lasted 16 days in the options for sowing in the 3rd decade of May and the 1st decade of June. Significant delay for 21 days of this period was observed for sowing from the 1st to the 3rd decade of April. The duration of the period from the beginning of root formation to beam ripeness was the smallest for sowing in the 1st decade of April – 28 days, and the largest for sowing in the 1st decade of June – 51 days. The vegetation period ranged from 110 to 165 days and passed for the sum of temperatures (> 10 °С) 1102.4-1439.0 °C and the sum of precipitation 128.1-225.2 mm. During sowing in April, an intensive increase in root crops from 2.9 to 3.5 g/day was observed in the second half of August. During sowing in May, the largest increase in root crops from 2.1 to 2.7 g/day was observed in the first half of September. Thus, for sowing in the 1st decade of June, this figure was highest in the second half of September (1.9 g/day). The option for sowing in the 1st decade of April provided a high yield of root crops of 50.3 t/ha, which is 5.3 t/ha or 11.8% significantly more than the control. When sowing in the following periods, a significant decrease in yield was observed compared to the control, namely: for the 3rd decade of April – by 3.5 t/ha, or 7.7%, for the 1st decade of May – by 8.8 t/ha, or 19.6%, for the 2nd decade of May – by 17.4 t/ha, or 38.6%, for the 3rd decade of May – by 23.0 t/ha, or 51.1%, for the 1st decade of June – by 31.7 t/ha, 70.6% compared to the control. There was a direct strong relationship (r = 0.74-0.99) between the growing season and yield, root weight, marketability, and biochemical parameters, namely: dry matter, dry soluble matter, sugars, vitamin C. The inverse of the strong (r = -0.98) was observed between the duration of the growing season and nitrates. Increasing the growing season by 10 days increases the yield to 6.9 t/ha, marketability up to 2.7%, root weight up to 31 g, dry matter content up to 0.7%, dry soluble matter up to 0.3%, sugars up to 0,5%, vitamin C to 0.8 mg/100 g and reduces the nitrate content to 8.4 mg/kg. Leaf area, photosynthetic potential, net photosynthesis productivity are in strong direct connection (r = 0.92-0.98) with yield. As the leaf surface area increases to 1.0 thousand m2/ha, the yield increases to 0.7 t/ha. Increasing the photosynthetic potential to 0.05 million m2 per day/ha increases the yield to 0.2-1.2 t/ha. Also, the yield increases to 0.3-0.7 t/ha by increasing the net productivity of photosynthesis to 0.05 g/m2 per day. Promising for further study is molecular knowledge of plant responses to abiotic stress, likely to pave the way for making crops resistant to climate change and increase the economic efficiency of production.