Melnyk A. Agrobiological grounds of sunflower and spring rape yield formation under conditions of Left Bank Forest-Steppe of Ukraine.

Agrobiological peculiarities of sunflower and spring rape yield formation depending on the weather conditions of Left Bank Forest-Steppe of Ukraine are found in the dissertation thesis. It is grounded the fundamentals of yield formation, its stability and plasticity depending on agrobiological features of new varieties and hybrids of sunflower and spring rape. Peculiarities of cultivation technology elements (variety, terms and technique of sowing, sowing rates, seed placement depth, biological preparations and growth regulators application, terms of seed harvesting) influence on yield of sunflower and spring rape were determined. The influence of researched elements of cultivation technology on peculiarities of commercial and sowing qualities of sunflower and spring rape seeds was established. Interrelations between morpho-biological peculiarities (matrical heterogeneity and missed grains), weather conditions, technological factors and formation of sunflower and spring rape fruits were detected. Comparative analyzes of varieties and hybrids of ornamental sunflower and spring rape fruits and their properties were determined on suitability for cultivation under conditions of Left Bank Forest-Steppe of Ukraine and formation of main features of ornamentality by their bio-morphological peculiarities allows to determine the three groups of them depending on the way of their use. Theoretical and agrotechnical grounds of flowerbed and pot cultures of ornamental sunflower were developed. Efficiency of oilseed crops cultivation technologies for northern part of Left Bank Forest-Steppe of Ukraine was economically and energetically substantiated.