Cane varieties with lower fibre content could be a winner for growers come processing time, according to research from the Queensland University of Technology.
But sugar researcher Geoff Kent from QUT's Centre for Tropical Crops and Biocommodities has warned that not all varieties are created equal.
While speaking at the Australian Society of Sugar Cane Technologists conference in Toowoomba, Mr Kent said the variety Q240 was the standout performer at the Racecourse mill at Mackay and at the Isis Central mill near Childers, while Q208 was at the forefront of results at the Harwood mill in northern NSW.
"The economic model that we've got does provide a consistent approach to assess the overall benefits of a variety," he told the conference. "It does take into account the processing costs of varieties in addition to some of the more easily modified parameters such as cane yield and CCS."
He emphasised that the study, undertaken in collaboration with Sugar Research Australia, was limited by the amount of rakes available for testing in some areas and that not all lower fibre content varieties performed better, saying there was a lower limit where processing costs started to affect the benefit.
Mr Kent began his presentation by explaining that the SRA breeding program made use of the relative economic genetic value parameter, which worked well as a measure for cane yield, CCS, fibre content, appearance grade and disease resistance, but not for fibre quality.
"Fibre quality is another parameter that's incredibly important in terms of millability," he said.
To address that limitation, researchers had to find an approach that produced an economic value that made assessing cane varieties comparable.
Once they'd factored in a number of income and cost criteria - sugar production, molasses production and electricity production, as well as harvest and transport costs and issues around season length - they tested the model with data from the three factories in different sugar-producing locations.
Attention was focused on the six varieties that constitute the largest percentage of cane supply, benchmarking against Q208, the major variety in each of the data sets looked at.
At the Racecourse mill, Q240, Q242 and Q183 did better than Q208 in terms of fibre properties - sheer strength, impact resistance and short fibre content.
Q240 was on the softer side of normal for short fibre content and lower fibre content, and Q242, a harder cane, was still in the lower fibre quadrant.
At the Isis mill, Mr Kent said Q238 was second-best to Q240 over three seasons in that they were both softer, lower fibre canes.
"We then move onto Harwood with a somewhat different set of varieties and you see Q208 sitting right at the forefront of results in that case," he said. "The second-best appeared to be the Q183."
For all of the major varieties, Mr Kent said one could look at the sugar income parameter and get a pretty good assessment of where they would sit on the net economic value scale.
"When we start talking about softer canes, and I would hazard a guess, harder canes, we're talking about varieties where processing costs become important other parameters," he said.
As far as the 2016-released soft cane SRA1 was concerned, its sugar benefit was much better than the other varieties but the impact of the number of stops was high at Isis in 2016.
Mr Kent said that at this stage, they didn't have enough information on SRA1 to confidently use the latest economic modelling with it.
"The biggest weakness in the model that I see at the moment is that ability to be able to predict the number of stops that we're going to face with this new variety.
"I'd like to think that we can get a much more robust relationship if we processed a lot more data, from a lot more factories."
While he was confident that if they looked at varieties that were on either the very high, hard or very soft ends, they would see a higher number of stops than what has been shown so far, there is still more research to be done this year to confirm that.