- In dry years open-pollinated (OP) canola can produce small seed in low rainfall areas. Sowing the small seed at a low seeding rate of 2 kilograms per hectare (kg/ha) reduced yield and farmers could benefit by increasing the seeding rate to 4kg/ha in the following year or purchasing fresh seed.
- Grading small seed hard was not as reliable as increasing the seeding rate to 4kg/ha.
- F2 hybrid seed produced lower yields than F1 seed unless seeding rates are increased to 4kg/ha or mixes are made with F1 seed. (Growers buy first generation hybrid seed (F1), F2 seed is the subsequent generation.)
- Hybrid Triazine Tolerant (TT) was less productive than OP TT canola .
In low rainfall areas grower retained seed of varieties like CB Telfer TT can be small. Growers and their agronomists approached the department to determine if the retained small seed which had been commercially cleaned was less vigorous and yielded less than newly purchased seed, or if it was worth grading the seedlot further to retain larger seed or should they simply increase seed rate?
We thought this experiment would also be a good place to see how much yield, if any, was lost if growers retained hybrid TT F2 seed – and to test if similar strategies such as grading, seeding rate and using mixes of F1 and F2 seed would compensate for genetic drift in the F2 seed.
To investigate if retained open-pollinated seed, which is smaller than commercially available seed, is less productive than new seed, and if grading or increasing seed rates can compensate.