Australia
July 24, 2014
Southern region grain growers have just seen the finish of their traditional window of canola sowing, but research suggests larger canola seeds could give them an advantage and allow timelier plantings for given environments.
Researchers from New South Wales Department of Primary Industries (DPI) have observed canola varieties with large seeds can better endure sowing in early to mid-April, taking advantage of earlier rain events.
Results from trials funded by the Grains Research and Development Corporation (GRDC) at Coonamble, Nyngan and Trangie in the Central West region showed that seeds greater than five grams per 1000 seeds, (often hybrid varieties) stood a better chance of establishing from greater sowing depths.
DPI researcher Rohan Brill said planting at greater depths could allow growers to take advantage of rain events from February by utilising moisture stored further below the surface.
“Historically, canola has been sown between two and three centimetres deep, but we’ve had an increase of hybrid varieties on the market in recent years, which generally have bigger seeds,” he said.
“Generally we’re looking at five to six grams per 1000 seeds for hybrid varieties, compared to around three grams per 1000 seeds for open-pollinated lines. The range in canola seed size is much greater than we see for most other crop types.
“We wanted to see if that size offers an opportunity to plant it a little bit deeper when a rain might have occurred six or seven weeks ago, where there’s still a bit of moisture deeper down, but the surface is dry.
“The main benefit we hope will come out of this research is the improved ability for producers to get canola established on time.
Over two seasons, the trials involved both open pollinated and hybrid varieties being planted at 2.5cm, 5cm and 7.5cm depths.
Planting at 7.5cm and 5cm resulted in establishment reductions and sometimes in yield penalties; however, large seeded varieties fared significantly better at the greater depths.
Generally the larger seeded varieties were hybrids in these trials.
“This was consistent across the trials that the larger the seed, the less reduction there was in establishment with deeper sowing. While it was consistent that we always saw at least some establishment reduction at deeper sowing, we didn’t always see a yield loss,” Mr Brill said.
“The establishment advantage of the larger seeded lines also carried through to improved early vigour.”
“We did look at whether the varieties that performed well did so because they were hybrids or because of their inherent larger seed. The majority of the benefit for crop establishment actually seemed to be from large seed, although a proportion of the advantage was from ‘hybrid vigour’.”
While the vigour of hybrid canola varieties aids with canola establishment with deeper, earlier sowing, growers retaining seed with open-pollinated varieties can look to gain the advantage offered by large seed.
Cleaning seed with a 2mm screen should give growers seed large enough for improved establishment from early sowing at depth and Mr Brill says the importance of screen size in this instance should not be underestimated.
“If growers screen to at least 2mm, they’ll get that larger seed. Being a spherical seed, a small increase in screen size makes a large difference to the resultant seed size - for example a 10 per cent increase in screen size will result in about 33 per cent larger seed”.
To view a video interview with Rohan Brill on sowing depth for canola, go to
https://www.youtube.com/watch?v=R00qjlkCHK0&feature=youtu.be.
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