Germination Response of Canola (Brassica napus L.) to Pre-Soaking Duration

The objective of the present study was to describe the trend of germination characteristics for a variety of canola ‘Okapi’ at different pre-soaking durations. For this purpose, seeds were placed in 250 ml of distilled water for 0 to 12h with intervals of 2h at room temperature. Each sample of seed was placed in Petri-dishes and germinated at the temperature of 25°C. Fitting logistic function on cumulative data at different pre-soaking durations indicated that maximum germination percentage (Gmax) did not differ significantly. Germination slope (GS) was estimated 0.07 seed h -1 for 0 and 12h and it had significant difference compared with other treatments (0.10-0.14 seed h -1 ). The results showed that the time taken to 50% of maximum germination percentage (T50) varied between 25.9 and 50.4h at different pre-soaking durations. The trend of T50 decreased with prolonging pre-soaking duration up to 10h but it increased for pre-soaking of 12h. In addition, tri-segmented function was used to describe the relationship between germination rates (GR) and pre-soaking durations. Results showed that the value of GR was minimal and it increased with slope of 0.0027 up to 6h. The value of GR was constant between 6-10h and decreased above 12h with slope of 0.0054. In generally, it concluded that pre-soaking seed during 6h was a proper treatment for increasing germination uniformity and rapid closure canopy.