The effectiveness of Architect, SE growth regulator (mepiquat chloride, 150 g/l + pyraclostrobin, 100 g/l + prohexadione-calcium, 25 g/l) in winter rapeseed var. Vitovt and Mazari and Mercedes hybrids is shown. The application of the preparation in the phase of 4–5 leaves at the application rate of 1,5 l/ha reduces the height of the growing point by 47,7–55,2 %, increases the diameter of the root crown on the average by 13,5–22,8 %, increases crop overwinter survival by 3,7–12,3 % and the oilseed yield by 5,8–10,2 dt/ha depending on the variety.