The aim of this study was to determine the lower base temperature (Tb) of two canola hybrids during the subperiods emergency-beginning of flowering (EM-IF), early-flowering-late flowering (FI-FF) and late-flowering physiological maturity (FF-MF), and the number of days in each subperiod. The experiment was carried out with nine seeding times with the hybrids Hyola 61 and Hyola 433 in Santa Maria, being utilized two methods to estimate: least deviation and relative development. There was a negative linear relationship between air temperature and cycle length in days. The Tb values of canola genotypes ranged from -0.6 to 9.1°C for relative development method, and -1 to 11°C for the least deviation method. The average duration for the subperiods EM-IF, IF-FF and FF-MF were respectively 65, 47 and 24 days for hybrid Hyola 61 and, 68, 48 and 23 days for hybrid Hyola 433. The cycle duration of two hybrids decreased with delayed sowing, which reduced from 162 to 100 days in Hyola 433 and 162 to 104 days in Hyola 61.
Brassica napus L.; air temperature; phenology
