New breakthrough for long coleoptile wheat

Breakthroughs in long coleoptile wheat good for drought, heat tolerance


Researchers are pleased with work on new wheat varieties bred for long coleoptile wheat

CSIRO researcher Greg Rebetzke says work on new wheat lines with longer coleoptiles will help growers plant wheat deeper and access stored moisture.

CSIRO researcher Greg Rebetzke says work on new wheat lines with longer coleoptiles will help growers plant wheat deeper and access stored moisture.

AUSTRALIAN wheat researchers continue to make inroads towards helping developing varieties better suited to the country's increasing hot and dry climate.

Farmers across the country have nominated the development of cultivars better suited to growing with the lower growing season rainfall (GSR) seen over the past 25 years and more tolerant of the high temperatures often seen in the Australian spring as key priorities for the grains industry.

And the good news is progress is being made in a joint project between CSIRO and the Grains Research and Development Corporation (GRDC) primarily in the form of the development of genetic material with positive attributes.

These include reducing plant height while increasing yield, greater early vigour and increased weed competitiveness and critically long coleoptile lenght.

CSIRO wheat geneticist Greg Rebetzke outlined some of the key areas of the research, particularly focusing on the coleoptile work, which will allow farmers to be able to deep sow more safely.

By increasing farmers' ability to deep sow to up to a whopping 140mm, farmers will be able to make better use of stored soil moisture.

This would be particularly useful in situations where there was stored soil moisture following summer rain but a dry surface.

Traditionally this would be encountered more often in the northern cropping zone, but in recent years there has been more useful summer rain in southern and western regions as well.

Current Australian wheat cultivars contain dwarfing genes that reduce coleoptile length by an average 40 per cent, inhibiting crop emergence when sown at depths greater than 50mm.

To address this issue, scientists have identified a range of alternative dwarfing genes in overseas wheats that can maintain longer coleoptile length without compromising production potential.

Lines with the new genetic material are in trials in both Western Australia and New South Wales with promising results, showing increased emergence at sowing depths of up to 120mm without changing plant height.

Dr Rebetzke said Australian wheat breeders now had genes that could produce a wheat plant the same height as standard commercial varieties Mace or Yitpi with a longer coleoptile of up to 125mm in length.

"If there are no problems with the new dwarfing genes, we may see the first of these long coleoptile wheat varieties using these genes in National Variety Trial testing within four to five years," Dr Rebetzke said.

While the new genetics have been enthusiastically welcomed within the research community, Dr Rebetzke said the in-paddock benefits could be magnified when used with existing seeding technologies and optimal agronomic management.

"Matching new genetics with appropriate agronomy and technologies should ensure the successful emergence and establishment of deep-sown wheats, particularly when sown early to make use of residual soil moisture or to increase sowing opportunities in May and June," he said.

"There is the opportunity for a system change that will increase profitability and reduce risk in current and future climates with sowing deeper than previously.

"Longer coleoptiles could allow for use of knockdown herbicides ahead of crop emergence especially where herbicide resistance to pre-emergent herbicides is an issue," Dr Rebetzke said.


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