The start of the season was a test for canola with dry conditions and small rain events resulting in late and in some cases, poor establishment. A sowing depth trial at Watchupga funded by GRDC showed it was the year to ensure seed placement was not too deep. A distinct difference was also observed comparing an open pollinated variety to a hybrid with advantageous early vigour (figure 1). Seed size of the hybrid was also greater than that of the open pollinated variety also contributing to it establishing better from depth.
Figure 1. Emergence rate of canola in sowing depth trial at Watchupga. Establishment (% of target density) as plants were emerging with rainfall events (mm). ATR stingray (OP) and Hyola350TT (hybrid) sown 19 April at 3 depths which averaged to 2cm (shallow), 2.3cm (normal) and 3.5cm (deep) from seedling depth assessment.
The late start to the season has resulted in later than optimal germination of canola. As a flow on effect, the majority of canola crops have begun to flower outside the optimal start of flowering window (table 1). Optimal start of flowering is when 50% of plants have at least one fully open flower.
| Location | Start of optimal flowering window | End of optimal start of flowering window |
|---|---|---|
| Birchip | 10 July | 11 August |
| Horsham | 18 July | 24 August |
Flowering late places canola at a lower risk of frost damage however yield potential is not maximised due to the grater risk of moisture and heat stress towards the end of the season. In canola the critical period of sensitivity to heat stress (temperatures above 27°C) is from 50% flowering to mid podding (Uppal et al. 2019).