Significant losses in both emergence rates and grain yield can be expected from using less than optimum seed quality and agronomic practices in canola crop establishment.
Researchers have shown that seed placement accuracy and avoiding proximity to fertilizer in the seedbed are important for canola establishment. Bigger seeds (>1.95mm screen) have also been shown to help optimise canola performance particularly when seed is sown at deeper depths (beyond 10-15mm optimum).
It is noteworthy that researchers found the following outcomes specifically for canola hybrids:-
- no significant difference in canola emergence, days to flowering and grain yield between hybrids having seed ranging from 3.96 to 5.7 grams per 1,000 seeds (equivalent to seed count of 252,000 to 175,000 seeds per kilogram);
- plants grown with larger seed showed greater biomass at the six-leaf stage and finished flowering more quickly. Both of which are positive benefits in terms of enhancing crop competitiveness against weeds and pests in addition to reducing risk of high temperatures and/or frosts during flowering;
- deeper sowing promoted significantly smaller grain size although studies consistently show no clear effect of seed size at sowing on harvested grain weight;
- only small differences (3-4% reduced emergence rate) were detected and no significant difference in grain yield shown between the control (commercial seed) and the graded, larger seed fraction. Grading bin-run seed may partially compensate poor seed boot setting and field operation, but use of the larger seed fraction only for commercial seed sales would not be practical in terms of adjusted value or price of the seed.
- studies highlight a threshold canola seed size that optimizes canola emergence and yield may exist and that larger seed do provide an advantage but only when compared to very small canola seed (less than 3.0 grams per 1,000 seeds or seed count greater than 330,000 seed per kilogram).
High seed quality helps ensure that the seed will perform up to its genetic potential. However even with the best genetics and highest seed quality, environmental factors including sowing practices are the major determinants of stand establishment.
The key practices that markedly reduce the risks of not achieving successful crop establishment and optimal grain yield in canola are:
- Sourcing Pioneer quality assured commercial seed produced and conditioned by seed professionals;
- Properly calibrate seed lots of different seed counts to achieve the right plant population for the targeted environment and genetics;
- Careful seed boot setting and speed of field operation to control soil throw and correct furrow ridging, which are common sources of seed depth bias across seed rows and influence the extent of securing shallow and uniform seeding depth;
- Viligant fallow management and low disturbance seedbed preparation that helps ensure adequate soil moisture at sowing to get canola seed out of the ground quickly.