First commercial crops of XtendFlex planted in central Queensland

It's the start of commercial trials across 50,000 hectares in Queensland and New South Wales.

The Volck family of Emerald has just planted 64 hectares of one of the new XtendFlex varieties, CSX4133B3XF (yet to be formally named), selected based on growth habits best suited to their system.

The remaining fields were planted with existing varieties Sicot 606B3F, Sicot 746B3F, and Sicot 748B3F.

The Volck family runs an irrigated cotton operation, growing 500 hectares per year across three properties located near Retreat Creek. For the 2023-24 growing season, they have been allocated 52 per cent irrigation from Fairbairn Dam.

They join 15 other CQ growers between the Emerald Valley and the Dawson - Callide Valley, growing a XtendFlex limited supply allocation across 3000 hectares of this season.

The new varieties were bred by the CSIRO from new germplasm for the purpose of better yield, cotton quality, disease resistance, and a wider spectrum of weed control.

XtendFlex is the first of its kind to be tolerant to over-the-top applications of dicamba and glufosinate-ammonium herbicides, and would assist in killing weeds showing resistance to glyphosate.

Cotton Seed Distributors owns the new seed varieties, with technology trademarked by Bayer.

CSD Central Queensland and Burdekin E&D extension agronomist Stewart Brotherton said the new varieties meant growers had more flexibility to manage a wider-spectrum of difficult-to-control and resistant weeds in-crop, which was particularly important as herbicide resistance increased.

Graham Volck said he was keen to try the new varieties due to yield advantage but also because it meant dicamba and glufosinate, which would have previously killed his crop, could be used to get rid of hard-to-kill weeds on the property like wild sunflower and fleabane.

Mr Brotherton said other cotton farms in the CQ region were also dealing with increased resistance to glyphosate in feathertop Rhodes grass.

The Volck family was about to start their third growing season with the CSD Ambassador Network Program, having chosen the paddock growing the XtendFlex variety to be analysed this year.

Mr Brotherton said CSD would be collecting data and monitoring growth from planting to picking to build tools for growers as the shift to the new variety occurred across the industry.

Mr Volck said the benefit of the program was access to data collected by CSD, which he used to benchmark his practices with other growers nationally.

"It's worthwhile to see whether you're performing as well as you could be, not only bench marking yield, but are we being nitrogen-use and water-use efficient - all the things that get compared in the ambassador trail," Mr Volck said.

Agnvet Rural agronomist Ellie Amory, who has been working on the Volck family farm, said she expected wide-scale use of the new varieties across CQ in the coming years.

She said she would observe the new variety closely during its current growing season.

She thought the best way agronomists working with growers could get their heads around the new varieties was through talking to CSD agronomists, reading the data collected, and visually observing during plant mapping practices.

"The best way to get the knowledge of how it grows is to literally be in the trenches," she said.

"You can read and listen to what people say but it you've got to be out there to understand how the plant grows and see how it performs and look at the bigger picture of how the season went."

Ms Amory said if any adaptation were to be made on farm it would depend on the grower's preferences, personal situation, and their practices such as whether they rotated their cotton crop with a legume.