The article highlights the results of studying hybrid combinations of common onion to the Botrytis allii Munn pathogen. It is found out that as for the combinations being studied the resistance to pathogen was inherited as dominant, intermediate or recessive trait. Better resistance to neck rot was inherent in the hybrid combinations which parents comprised resistant and immune varieties, insofar as the determination of inheritance coefficient has indicated F1 hybrids have this characteristic expression dependant by 50 to 78% on the parental plant (h2 =0,50–0,78). Studying the determination of the impact of both parental components on inheritance of the resistance to B. allii pathogen showed that the regression coefficient subject to hybrid combination fell within R = 0,12–0,39, while the resistance coefficient within 0,24–0,78, respectively. Efficiency of selection is proved by the trait of resistance to neck rot based on the populations of Grandina х Mavka, Olina х Grandina, Grandina х Skvyrska і Skvyrska х Grandina, as their respective inheritance coefficient reached the level of 0,42 to 0,78.

The article features results of studying suitability to processing for various varieties of onion as grown in the conditions of Ukrainian Forest-Steppe. A complex assessment has been completed for fresh products of onion for 9 different varieties by the content of basic biochemical, biological, economic, organoleptic characteristics with the view of determining the most suitable for drying. Varieties are singled out , which bulbs accumulate the biggest dry matter, sugar, C vitamin content and display the highest yield of consumable products. Assessment of dry products against the set of organoleptic and technological indicators has been completed. This revealed loss of basic biochemical components of onions during drying and long-term storage of dried products, as well as established increasing of the content of dry matters and acids and decreasing of that of sugars and vitamin C while storing the dried onion. The set of examined parameters

Results of research on application of plant growth regulators in cultivation of Onion Napiform from seeds in non-irrigated grain-vegetable crop rotation of Northeast Forest-steppe of Ukraine. Efficiency of seeds presowing damping was established, in the solutions of preparations Baikal EM and Emistim С and in the solution of preparation Emistim С for double use - of seeds presowing damping and of plants spraying in 5-6 leaves phase.