The development of widespread herbicide resistance in ryegrass and other weed species has led to a sharper focus on integrated weed management and increased research into the weed competitive abilities of crops.

The Grains Research and Development Corporation (GRDC), on behalf of growers and the Australian Government, is supporting pre-breeding efforts to increase the weed competitive ability of wheat, in particular.

Gurjeet Gill and Michael Zerner from the University of Adelaide’s School of Agriculture, Food and Wine, are undertaking research involving selecting for weed competitive ability from a population of 6000 wheat lines developed at the CSIRO.

Dr Gill says wheat is widely accepted as the weak link in weed management in Australian cropping systems.

“Research undertaken in a previous GRDC-funded project showed that the increase in ryegrass seed bank after wheat was significantly greater than after other cereals such as barley or oaten hay,” Dr Gill said.

“Farmers face an ongoing need to use selective herbicides year after year, partly due to the poor capacity of wheat to compete and suppress surviving weeds thereby reducing their seed production.”

Dr Gill said if the competitive ability of wheat could be enhanced to a level close to barley (50 per cent greater than current wheat varieties), it was expected to have a major influence on weed populations on Australian farms.

He said current pre-breeding research had achieved significant progress in enhancing the competitive ability of wheat against weeds.

“The challenge now is to select lines which not only possess high weed competitive ability but also possess high yield, good disease tolerance and grain quality.”