Cropping

Weeding out competition

By Country News

Growers are one step closer to accessing wheat varieties that can compete better against weeds, particularly herbicide-resistant annual rye-grass.

The first weed-competitive wheat lines were delivered to commercial breeders in April for preliminary yield and quality testing and, if successful, varieties may be available to growers within five years.

These have been developed as a part of Grains Research and Development Corporation investments to help growers protect wheat yields and reduce herbicide costs.

The cost to Australian agriculture from weeds is estimated at $4billion annually in crop yield losses and seed contamination alone.

CSIRO research geneticist Greg Rebetzke said new genetics and an improved ability to predict plant traits had enhanced the development of genetics that were used as parents in the development of the new lines.

‘‘Increasing herbicide resistance, together with no new modes of herbicide action, are contributing to a perfect storm in grain growers’ ongoing battle against weeds,’’ Dr Rebetzke said.

‘‘Wheat is particularly vulnerable, with the commonplace use of glyphosate as a chemical control of annual rye-grass.

‘‘It is poor control of rye-grass that makes wheat the weakest link in weed management in Australian cereal rotations.

‘‘The aim of this research is to assist the development of weed-competitive wheats that can be used as part of integrated weed management strategies, adding another option to the growers’ weed control toolbox.

‘‘Currently there are few new herbicide technologies that will assist in managing weeds in wheat and dealing with herbicide resistance issues.

‘‘However, along with the use of appropriate agronomic management practices, the adoption of harvest weed seed collection and destruction technologies — and the careful management of any future new chemistries to prolong their effective life — competitive wheats have the potential to help control weeds and reduce costs to growers.’’

Researchers engaged closely with commercial breeders throughout the process to ensure the project delivered varieties that were the most commercially relevant to growers.

■Dr Rebetzke’s paper is available by searching ‘competitive wheat’ at: www.grdc.com.au/updates