Productivity of sunflower hybrides depending on long terms

The results of the observations on the influence of sowing dates of the studied hybrids on sunflower grain yield capacity are highlighted. The largest number of plants was formed by the studied sunflower hybrids at sowing in the optimal time in the crops of the hybrid NK Delphi - 57 thousand pieces/ha, the hybrid NK Rocky - 67 thousand pieces/ha. Under the influence of different sowing dates, the height of plants increased and fluctuated in the hybrid NK Delphi from 164 to 186 cm, in the hybrid NK Rocky - from 123 to 145 cm. NK Delphi was significantly inferior in the level of yield of the hybrid NK Rocky, the difference was 0,56 t/ha - in 2013 and 0,64 t/ha - in 2014. Sowing in the optimal time significantly exceeded the yield of sunflower for all studied hybrids compared to sowing in the early and late period, the difference was 0,27 and 0,45 t/ha - in 2013 and 0,27 t/ha - in 2014. Key words: sunflower, hybrid, sowing dates, yield, grain quality.