FARMERS have been urged by the canola industry to ignore the temptation to cut the costs of planting the oilseed by cutting the sowing rates of expensive hybrid seed.
Hybrid canola seed is in hot demand this season, and some growers are looking to reduce seeding rates to cut the cost of growing the crop, as seed can be more than double the price of traditional open-pollinated seed at around $22 a kilogram.
But hybrid canola growers are being reminded that although sowing rates may be cut back a little, it is important not to go overboard as low plant densities can severely cut yields, especially in favourable seasons.
Pioneer Hi-Bred Australia sales manager Kevin Morthorpe says sowing equipment needs to be calibrated to match seed size of individual seed lots and seedbed conditions, rather than a “one sowing rate fits all approach”.
Mr Morthorpe believes the trend to reducing sowing rates over recent years is partly due to increased seed costs and partly due to good commercial practice, where leading growers can obtain excellent establishment of their crops, with up to 80 to 90 per cent of seeds becoming viable plants.
According to Better Oilseeds project coordinator, Felicity Pritchard, a number of factors need to be considered when calculating sowing rates for all crops.
These included seed size, anticipated establishment percentage, average rainfall and row spacing.
Ms Pritchard says hybrid canola seeds are generally much bigger than open pollinated varieties, so each kilogram contains less seeds.
Some hybrid seed is twice the size of some open pollinated varieties.
“With larger seed, a higher sowing rate is generally needed as you get a lot less seeds for each kilogram,” she said.
“However, a major positive with hybrids is that the percentage of plants establishing may be better due to the large seed and the hybrid vigour.”
In one Better Oilseeds trial held on South Australia’s Eyre Peninsula last year, only two-thirds of the seeds of the triazine tolerant, or TT, variety grew into plants, whereas nearly nine of every 10 hybrid seeds established as plants. The figure was eight in 10 for a conventional open pollinated variety.
The minimum percentage of commercial hybrid seeds germinating in laboratory tests is 85, although it may be higher and varies between seed companies.
However, good establishment of canola in a paddock may be compromised by a number of factors, in particular, dry conditions.
“Moisture plays a critical role in establishment of canola. In some of our trials in recent years, average canola establishment has been around 40 to 50 per cent due to poor seedbed moisture,” Ms Pritchard said.