Long coleoptile wheat a game changer for Australian growers

The Grains Research and Development Corporation (GRDC) recently announced the AUS $ 12.7 million (US $ 8.45m) research project. Chair John Woods says long coleoptile wheat will extend options for early sowing to meet the challenges of increasing enterprise sizes and changing climates.

The coleoptile is the protective sheath which encloses the emerging shoot and first leaves. The longer the coleoptile is, the greater the emergence potential when deep sowing. Long coleoptile wheats can be sown at depths of more than 10 centimetres, making better use of stored soil moisture.

If you don’t have the right equipment, and the soil is too hard, sowing could be challenging

Lead researcher and CSIRO plant geneticist Dr Greg Rebetzke expects the high value long coleoptile wheat to be available within two to three years from breeding companies. The long coleoptile wheat will be on the market in Australia, and could also be exported to various other markets.

Farmers might need to modify their sowing equipment, when using long coleoptile wheat. “The depth will be determined by different factors, and better understood in this new project”, Dr Rebetzke points out. “If you don’t have the right equipment, and the soil is too hard, sowing could be challenging.”

“This is part of the project, that is aimed at increasing the adoption around factors that increase the uptake of the long coleoptile trait. It is around nutrition, herbicides, ensuring there is moisture at depth, and the right equipment is used. So, when the wheat is available, the uptake will be maximised because the risk is reduced.”

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New genes from across the world

Mr Woods explains that the project builds on decades of research by CSIRO and previous GRDC investment of approximately AUS $ 11.5 million (US $ 7.66m) to introduce new climate-adaptive traits into commercial wheat varieties.

“The significant work to date by Dr Greg Rebetzke and his team at CSIRO has focused on identifying and sourcing new genes from across the world, and then assessing them in Australia under both laboratory and field conditions.”

Climatic modelling work using on-farm field and usage trials suggests a 20% increase in yields from long coleoptile varieties

The project addresses identified knowledge gaps around how these genetics perform across contrasting production environments, soils and farming systems, and should equip growers with the tools to better respond to changing climates and seasonal variability in their farming systems.

Common industry standard

National trials will explore a range of genetic, environmental and management factors relating to long coleoptile wheat implementation. The project will also include the development of a common industry standard for measuring and defining the categories for wheat coleoptile length.

Dr Greg Rebetzke says the project was working to mitigate sowing risks for growers and provide greater flexibility around time of sowing. “Climatic modelling work using on-farm field and usage trials suggests a 20% increase in yields from long coleoptile varieties.”

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The right fit for a farming system

Dr Rebetzke says that sowing varieties that have the right fit for a farming system ensures crop growth coincides with climatic conditions to which the crop is best suited. “For example, ensuring germination and seedling growth occurs at planting so that varieties flower at the optimal time for which they are bred and avoid those very hot, very dry conditions at the end of the season.”

He emphasises that with increasing climate variability, particularly rainfall variability, taking advantage of summer rainfall with early sowing would better optimise water productivity. “With today’s changing climates, ensuring you have adequate moisture for germination in those top five centimetres of soil is increasingly risky for growers. Long coleoptile varieties should make this less of an issue into the future.”

New long coleoptile wheat varieties are being developed and are close to commercial release

“The goal here is more ‘crop for drop’ in sowing, and getting the crop away at the right time of year, rather than risking delayed germination and delayed emergence. New long coleoptile wheat varieties are being developed and are close to commercial release. This project will create the supporting agronomic packages so growers can optimise their performance.”

Grower interest in long coleoptile or moisture-seeking wheat is strong, particularly in WA, where growers have been involved in trials over the past three years to inform future agronomic and farming systems guidelines.

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An increase of water productivity by 25%

Southern Cross grower Callum Wesley instigated a long coleoptile wheat trial on his farm in 2020, in collaboration with Dr Rebetzke, after receiving 150 millimetres of rain in February but no follow-up rain until late May.

Mr Wesley faced persistent changes in rainfall patterns that drenched his paddocks over summer but left the topsoil dry by sowing time. This new rainfall pattern had made it difficult to get a decent sowing opportunity for the previous three seasons.

To fully exploit the genetic potential of long coleoptile wheat we need to understand the relationship between genetic, environmental and management factors and optimise that

Dr Rebetzke says that seeding early, using these long coleoptile varieties, increased Mr Wesley’s water productivity by around 25%. “Which is remarkable in what was a decile one rainfall year. It was one of the driest years on record and yet Callum yielded 1.3 tons per hectare, whereas the standard wheat varieties germinating later were producing significantly less yield. And it’s largely because Callum sowed early, and the early emerging crop could make use of that deep moisture and mature ahead of the hot November-December months.”

GRDC’s manager West, Rowan Maddern, says the project with CSIRO and its partners would build on the previous work undertaken at national and regional levels to deliver a complete agronomic package to growers. “To fully exploit the genetic potential of long coleoptile wheat we need to understand the relationship between genetic, environmental and management factors and optimise that.”