Canola seed colour change indicates peak yield and oil content, making it the key determinant for timing windrowing or desiccation. While most growers and agronomists are aware of this key indicator, there are some misconceptions about what constitutes seed colour change and how it should be assessed.
South Australian consultant Trent Potter, Yeruga Crop Research, said that growers must stay in control of the timing for windrowing and desiccation, and need to know how to assess the maturity of the seed themselves.
“Adverse weather events such as a very dry finish or frost, such as is occurring in NSW this year, can result in low yields, low oil content and increased levels of green seed as the seeds are killed before they are fully mature. Unfortunately, there is nothing growers can do about that,” he said. “However, under favourable conditions the correct timing of windrowing or desiccation will mean growers maximise the yield and the oil content and also avoid any penalty for green seed.”
Mr Potter said it is imperative that growers open the pods and check the seed colour themselves. “A visual estimation based on pod colour is not sufficient and will result in lost profits if not quality downgrades,” he said.
The timing of windrowing has been the subject of significant research effort co-funded by the GRDC, NSW Department of Primary Industries, CSIRO and partner organisations under the Optimised Canola Profitability project (CSP00187). Researchers have re-confirmed studies from the 1970s and 80s that showed physiological maturity in canola is reached when 40–60% of seeds on the main (primary) stem change colour from green to red, brown or black. However, their research has also shown the importance of assessing seed colour change on the canola plant branches as around 70 per cent of the crop yield is held on the plant branches rather than the main stem.
Rick Graham, NSW DPI, Tamworth said windrow timing studies in 2015 and 2016 at Tamworth and Trangie, and Edgerio in 2016, clearly demonstrated the importance of correct timing.
“There was less than a week between too early and optimal timing,” he said. “In five days the seed colo...
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