Winter rape cultivation has environmental justification not only in Europe, North America and other countries, but also in Ukraine.  This is due to the use of crop diversity. Its connected to production of vegetable oil, meal, green weight. This requires a sufficient number of the crop seeds, what can be achieved not only via expansion of crop area, but also via realization of higher  genetic potential of existing hybrids taking place in Ukraine, Europe and worldwide. Solving this problem is possible not only due to breeding, but to agricultural practices as well. Such is winter rape sowing optimizing. This is one of the central and complex directions of realization ofcrop genetic potential. This is evidenced by the data of seeding rate, which can vary from 3-5 kg to 10-12 kg. Our experimental results confirm the idea presented above. We carried out the research under  the Central Forest-Steppe of Ukraine, in the experimental fields of Bila Tserkva National Agrarian University in 2012-2014.
We have studied the Monsanto hybrids: Exotic, Exagone and Extarro by seeding them with a seeding rate of 300, 500 and
700 thous/ha viable seeds. Our results showed that seeding rates can influence the processes of structure elements formation
of winter rapeseed yield and this magnitude depends on plants density, their survival in the spring-summer period, the amount of branches of the first order, pods, seeds per plant.

The research of hybrid seed germination in 2012-2014 showed that germination of coated seeds in laboratory was ranged 98.0-98.5 % which indicates high seeds quality. Field germination of winter rape hybrid seeds which were researched in accordance to their seeding rates on average over three year was: Exotic – 91,6 %, Exagone – 90,6 %, Extarro – 89,4 %. Thus, hybrids and Extarro – 89,4 % are conceding to Exotic (control) for this indicator, accordingly 1.0 and 2.2 %. As for the controlling the formation of field germination with sowing norms, the following trend has been found out: increasing norms of coated rapeseed sowing from 300-700 thous. pcs./ha conditioned the decline: Exotic hybrid by 1.5 %; Exagone – 1.2 %, Extarro – 0.5 %. Increasing the seeding rate (average for 3 years) from 300 to 500 thous. pcs./ha and from 500 to 700 thous. pcs./ha reduced their field germination accordingly: Exotic hybrid 1.5-1.9 %; Exagone – 1.2-0.8 %; Extarro – 0.9-0.5 %. Therefore, genetic reaction of hybrids was found on increasing seeding rate from 300 to 500 and from 500 to 700 thous. pcs./ha. Field germination of seeds has a direct effect on the density of plants; this figure was the highest before wintering and threshing. It accounted: hybrid Exotic 438 and 411 thous. pcs./ha, Exagone – 435 and 405 thous. pcs./ha; Extarro – 429 and 396 thous. pcs./ha.

Hybrids and seeding rate affect the number of pods per plant. Our research showed that increasing seeding rate from 300 to 700 thous. pcs./ha causes a decrease in the number of pods per plant. Variations of plant density and the number of pods per plant identified difference in yield of our hybrids. The average yield of each hybrid can be positioned in the following order: Exotic – 2.63 t/ha; Extarro – 2.66 t/ha; Exagone – 2.83 t/ha. Therefore, we have found out that seeding rate is more important factor of regulation yield structure elements than field germination, plant density, the number of pods. 

Thus, it has been found out that seeding rate is more efficient factor in density plant regulation as compared with genotype. Difference of plant quantity per 1 ha between hybrids (average for 3 years) amounted in the variants with seeding rate: 300 thous. pcs./ha – 8-9 thous.; 500 thous. pcs./ha – 2-21 thous.; 700 thous. pcs./ha – 0-17 thous.;  between seeding rated of each hybrid, according to the lowest seeding rate: Exotic – 171 and 326 thous. pcs./ha, Exagone – 178 and 335 thous. pcs./ha, Extaro – 158 and 317 thous. pcs./ha.

The highest yield for 3 years of the research had Exagone hybrid.  The average yield amounted, according to the seeding rate: 300 thous. pcs./ha – 2.17 t/ha; 500 thous. pcs./ha – 3.1 t/ha; 700 thous. pcs./ha – 3.44 t/ha.

Key words: winter rape, field seed germination, plant density, seeding rate, survival plants, seed weight, seed yield.