Results
Comparisons to retaining CB Telfer and sowing at 2kg/ha:
- Grading seed over a 1.85mm slotted sieve did not increase plant establishment, with the only reliable way to improve plant numbers being to increase seed rate.
- Compared to sticking with the grower retained CB Telfer seed and sowing it at 2kg/ha, only purchasing new CB Telfer seed and sowing it at either 2 or 4kg/ha and purchasing the new hybrid variety (cv. name not disclosed) and sowing it at 4kg/ha increased grain yield.
- However the extra expenses incurred resulted in no treatment producing higher returns than the farmer retained CB Telfer seed sown at 4kg/ha.
Comparisons to retaining hybrid TT seed and sowing at 4kg/ha:
- F1 hybrid seed is relatively expensive at $24/kg, therefore seeding rates are usually on the low end at approximately 2kg/ha.
- If growers were to retain hybrid TT seed and sow the F2 at 2kg/ha they would lose yield and be financially worse off than buying fresh F1 seed.
- However as F2 hybrid seed cost is reduced to approximately $2/kg growers are more likely to increase seeding rate to 4kg/ha, in which case yields and returns similar to F1 sown at 2kg/ha cold be achieved.
- The mix of 25% F1 and 75% F2 was not quite as productive as 100% F1 seed but indicated it might be more productive than 100% F2 seed.
Of note in this experiment was the observation that the F2 hybrid TT was the earliest flowering variety at the site – even earlier than CB Telfer.
Another observation was that in the good conditions experienced in 2013 at Grass Patch we did not observe any visual differences in vigour between F1 and F2 hybrids.
Despite improving the performance of hybrids by higher seeding rates etcetera – at Grass Patch in 2013 the open pollinated CB Telfer produced similar yields and higher gross margins.
Figure 1 Purchase of new seed compared to retained seed.
Figure 2 Retaining hybrid seed and sowing impact on gross margins