The main purpose of the paper included research on the variability of stearic acid content in the seed oil of the accessions of the V.S. Pustovoit All-Russian Research Institute of Oil Crops (VNIIMK) sunflower genetic collection and to determine the mode of inheritance of the trait in F 1 generation for choosing a hybrid breeding strategy. Gas-liquid chromatography of methyl esters and infra-red spectrometry were used for the estimation of fatty acid profiles. The inbred lines of I 5 seeds LG31 LG32 LG33 LG34 and LG35 have been developed with high stearic acid content from 11.6 to 22.6%. Lines LG31 and LG32 showed relatively high values of oleic acid in the range of 56.7–70.5%. Lines LG33 and LG34 belonged to a group with a content of oleic acid in the range of 11.4–19.9%. An inbred line LG35 possessed increased content of stearic acid up to 11.6% on the low oleic background. The recessive type of inheritance of the mutations with high content of stearic acid in sunflower seed oil was verified. Both complete and incomplete dominance degree of standard content of stearic acid was found. Intermediate inheritance in F 1 of this character was firstly distinguished in the cross of standard with high stearic acid line LG35.

General and specific combining abilities of three cytoplasmic male sterile and four restorer lines of sunflower were studied in a randomized complete block design with three replications under normal irrigation and drought stress conditions in Eslamabad-e-Gharb Iran during two growing season (2019 and 2020). Drought stress reduced seed yield oil yield thousand seeds weight and head diameter by 21.9% 18.1% 14.3% and 11.5% respectively. Line × tester analysis indicated that the effect of lines was significant for the number of days to flowering plant height grain yield and seed oil percentage under both normal and drought stress conditions. The effect of lines was significant for number of days to maturity and number of seeds per head under normal condition and for thousand seeds weight under drought stress condition. Contribution of lines × testers were higher than the variances of lines or testers for of most of all the studied traits indicating the major role of non-additive effects on expression of theses traits. R131 was differentiated with the highest positive general combining ability for grain and oil yield in both normal and drought stress conditions. Among the testers AGK32 and AF81-222 had the highest general combining ability for grain yield under normal and stressed conditions respectively. R131×AGK38 with grain yields of 4414 and 3457 kg ha -1 under normal and drought stress conditions respectively had the highest specific combining ability for grain and oil yield under both conditions. The results of this study showed that the genetic materials and environmental conditions can affect the nature of gene effect and combining ability of sunflower parent lines and crosses.

In recent years Septoria leaf spot has taken a strong place in the list of economically important diseases of sunflower. It may be a favorable factor for the development of other diseases on sunflower plants too. The aim of the research was to evaluate the frequency and degree of infection of sunflower plants with Septoria helianthi as well as possibility of simultaneous infection with this pathogen and other fungi which cause foliar spots such as downy mildew Alternaria leaf spot and Phoma black stem under conditions of stationary infectious nursery. The year 2021 turned out to be extremely favorable for the development of fungal leaf spots on sunflower. Assessment of fungal diseases of sunflower plants was performed in F 2 families obtained after crossing ZL22A ZL58A ZL70A ZL78A and ZL169A lines of Zaporozhye breeding (Ukraine) with HAR7 line (originating from the USA). Each F 2 family (sample) was obtained from self-pollination of one F 1 plant with varying severity of Septoria disease. It was found that in the conditions of 2021 sunflower was quite affected by Septoria disease. The percentage of injured plants in F 2 samples ranged from 41.0 to 100.0%. The severity of disease was different. Less resistant genotypes included plants with lesions on sunflower leaves of lower middle and upper tiers in approximately equal numbers while more resistant genotypes had almost no plants with injured leaves of upper tiers. It was established that the development of Phoma disease occurred both on plants with Septoria leaf spot and on healthy plants. On average among the plants infected with Phoma macdonaldii the proportion of plants jointly affected by Phoma and Septoria diseases was 2/3. However the frequency of simultaneous infection of plants with S. helianthi and P. macdonaldii in genotypes with different resistance to Septoria leaf spot differed significantly and ranged from 80% in less resistant to 40% in more resistant accessions. Most plants (about 90%) infected with Plasmopara halstedii were simultaneously infected with S. helianthi . That is both of these pathogens can simultaneously develop on the same plant and lead to a decline in its basic physiological functions. The rate of simultaneous damage of sunflower by Alternaria and Septoria was quite low compared to plant damage by Alternaria alone and was less than 30%. This may mean that the pathogen of Alternaria leaf spot avoids plants with existing S. helianthi fungus.

The article is devoted to the analysis of production volumes and efficiency of sunflower cultivation in Ukraine. It is shown that sunflower occupies more than 70% of the total acreage under oil crops. Attention is focused on the fact that the dominance of sunflowers in the structure of the production of oil crops provides this crop with a special role in the agricultural market of Ukraine. The dynamics of sown areas gross harvests and the level of productivity of sunflowers in Ukraine for the period 2018–2020 were analyzed. The effectiveness of sunflower production was studied in terms of forms of management of agrarian formations and by the amount of land in use. It has been established that the most effective cultivation of sunflowers is carried out by agricultural enterprises with a land area of more than 2 thousand hectares. Cost calculations and their structure for growing 1 ha of marketable sunflower in 2021 are presented. The volumes and structure of the directions of consumption of marketable sunflower seeds in Ukraine are shown. Practical recommendations for improving the process of sunflower production are proposed taking into account the balance of supply and demand for marketable products.

The article provides a comparative analysis of sunflower seed production in Ukraine the EU and globally for the period from 2000 to 2021. The Ukraine’s share in the world sunflower production was found and analyzed. The analysis of the gross collection of sunflower seeds in the regions of Ukraine for two conditional periods (2000–2010 and 2011–2021) was carried out. Thus during the researched period the average yield increased from 1.04 t/ha in 2000 to 2.57 in 2021 i.e. by 2.5 times. It became possible due to the improvement and adaptation of cultivation technology and careful selection of sunflower hybrids that are better adapted to climatic changes. It was determined that the change in climatic conditions has affected the zones of comfortable sunflower cultivation in Ukraine. According to the yield index during the first conditional period the central regions of Ukraine were in the lead (1.57 t/ha) and during the second period the northwest regions of the country stepped up (2.83 t/ha). The above data suggest that the gradual change in sunflower cultivation technology and the search for new drought-resistant crop hybrids give hope that Ukraine will maintain its position in the world as a leader in the export of sunflower oil.