Research has confirmed there are no harmful yield or quality effects from sowing multiple generations of retained seed of open pollinated triazine tolerant (OP TT) canola, the AusCanola 2018 conference in Perth was told today.
More than 70 per cent of canola plantings in WA are sown to popular OP TT varieties, particularly ATR Bonito, which perform well in low to medium rainfall environments.
However, with few replacement varieties on the horizon, canola growers have become concerned about the use of seed that has been retained for many years or whether it would be more prudent to switch to more expensive hybrid TT seed.
Department of Primary Industries and Regional Development research officer Mark Seymour said the research evaluated the performance of multiple generations of OP TT seed.
The research was undertaken with co-investment from the Grains Research and Development Corporation.
Mr Seymour said field trials at Wittenoom Hills and two sites at Grass Patch sown in 2016 and 2017 to retained OP TT seed, showed very little difference in seed yields or quality performance.
“The result showed that generation 2-4 ATR Bonito seed yielded the same as a commercially purchased new, or generation one, seed,” he said.
“There was also no compromise in plant establishment, flowering time, date of maturity or oil content.”
Mr Seymour said the results showed there was little financial loss from sowing retained OP TT canola varieties.
“The gross margins of the Generation 4 seed at Grass Patch in 2017 and the generation 3 seed at Wittenoom Hills in 2016 were actually higher than new commercial seeds,” he said.
“The generation 3 seed sown at Wittenoom Hills in 2016 produced the highest gross margin of $612 per hectare, significantly larger than the other generations, which achieved margins of $511-522/ha.”
Further research compared generations of hybrid TT canola with each other and commercial seed lots of OP TT canola.
Mr Seymour said field trials of three generations of hybrid TT at Grass Patch, Ballidu, Merredin, Dalwallinu and Wittenoom Hills suggested that while there were some production risks, there was little difference in yield and quality results.
“We observed earlier flowering and flowers with male sterility in generation 2 and 3 hybrid TT plants, but there was little variation in mean site yields of 1.3t/ha,” he said.
“While the second and third generations of hybrid TT canola did not perform as well, the average yield loss was three per cent – much lower than previously thought.”
“As a consequence of the relatively small differences in yield and oil content, the research found no financial incentive to sow hybrid generation 1 seed instead of retained hybrid seed, with generation 2 averaging $10/ha higher returns than generation 1.”
At lower rainfall sites, where yield levels were below 1.5t/ha, the research showed OP TT canola produced equal or higher seed yields and gross margins than all the first generation hybrid seed treatments.
This resulted in an average gross margin of $515/ha for the OP TT canola, compared with $419/ha for first generation hybrid TT seed.
Mr Seymour said growers could be confident to continue to sow OP TT varieties, whether it was newly purchased seed or retained OP TT seed.
“In the majority of experiments, growing an OP variety and sowing at a target of 40 plants per square metre, produced higher yields and returns than any of the hybrid treatments,” he said.
“Growers are reminded to check the seed germination every year to ensure its performance.”
There are more details on this research in the department’s newly released ‘Canola agronomy research in Western Australia’ Bulletin, available at agric.wa.gov.au