When the 2025 season got underway across the South Australian Mallee, growers were once again faced with difficult establishment conditions.

A dry start, limited stored soil moisture, a late seasonal break and ongoing wind erosion created challenging conditions for crop establishment. In these seasons, every sowing decision matters – from variety selection and sowing depth through to herbicide choice.

To help investigate new options for managing establishment risk, Mallee Sustainable Farming (MSF), through a GRDC National Grower Network (NGN) investment, established long coleoptile wheat trials at Waikerie and Bowhill.

WHY LONG COLEOPTILE WHEAT?

The coleoptile is the protective sheath that emerges first from a germinating cereal seed.

Current wheat varieties have a relatively short coleoptile, which can limit the depth the seed can be safely sown. Long coleoptile varieties have been bred to emerge successfully from greater sowing depths, potentially allowing growers to place seed deeper into stored moisture and maintain good establishment.

A TOUGH SEASON PROVIDES A REAL-WORLD TEST

Trial sites at Waikerie and Bowhill were dry sown in early May and experienced a very late seasonal break in 2025.

At Waikerie, less than 10 mm of rainfall was recorded across April and May. The site then experienced significant wind erosion, resulting in furrow infill, sand movement and plant losses.

Bowhill also experienced a dry start, although seasonal conditions were less extreme than Waikerie. The site’s non-wetting sandy soils provided a unique opportunity to investigate how long coleoptile genetics respond to varying sowing depths and herbicide programs.

WAIKERIE: SEASONAL CONDITIONS DOMINATED

Plant establishment was well below target across all treatments, highlighting the impact of drought and wind erosion.

Shallow sowing consistently outperformed deeper sowing and no herbicide damage was observed.

BOWHILL: PROMISING SIGNS UNDER HERBICIDE PRESSURE

Long coleoptile varieties showed improved establishment when combining pre-emergent herbicides that have a greater crop safety risk with deeper sowing, particularly on lighter textured dune soils.

However, these establishment advantages did not translate into significant grain yield increases during the 2025 season.

WHAT DOES THIS MEAN FOR GROWERS?

• Seasonal conditions remain the biggest driver of crop establishment success.

• Shallow sowing was better suited to the dry sowing and late season break conditions experienced in 2025.
  • Care should be taken when using pre-emergent herbicides with greater crop safety risk on lighter textured soils.
  • Improved establishment does not necessarily result in higher grain yields.
  • Long coleoptile performance need to be evaluated across multiple and contrasting seasons before firm recommendations can be made.

LOOKING AHEAD

Research into long coleoptile cereal genetics will continue in 2026, helping build confidence around where these genetics may fit within Mallee farming systems.

📃 Download the factsheet here