Abstract
Brassica napus L., is very important oil plant grown in Czech and Slovak Republic, it is also allergology important plant.CHMI and SHMI observe winter rape at phenological network with subsequent phenophases: sowing, emergence, first leaves, stem elongation, beginning of flowering, full flowering, end of flowering, yellow ripeness and harvest. The beginning and end of flowering of winter rape and their interphase interval were evaluated in the period from 1996 to 2008.
The mean date of onset of beginning of flowering is from April 26th to May 8th in Czechia and from April 23rd to May 5th in Slovakia. From the trend analysis of the mean beginning and end of flowering resulted declining trend-it means the shift of phenological onsets towards to earlier date.