Sandplain soils are important for wheat production but are often affected by numerous constraints including water repellence, subsoil acidity, compaction, and poor water and nutrient retention. Strategic deep tillage techniques such as deep ripping and rotary spading can address these issues, potentially boosting wheat yields by up to 35%.

However, achieving consistent seeding depth and preventing furrow infill after amelioration are crucial for successful crop establishment and maximising wheat productivity. Long coleoptile wheat carrying alternative Rht18 dwarfing gene and characterised by an elongated protective sheath for the developing shoot, could mitigate these limitations. This hypothesis was evaluated in field experiments across Ogilvie, Merredin, and Yuna regions of Western Australia in 2022-23. A CSIRO developed long coleoptile line, Mace-18 was compared with Scepter, Mace (short/medium coleoptile) and Calibre (mid-long coleoptile).

Genotypes were sown shallow (3-4cm) and deep (10-12cm) on no-till, ripped (except Ogilvie), and rotary spaded soils. Coleoptile length (except Ogilvie), plant density, crop weed competition and grain yield responses were assessed. At Ogilvie in 2022, deep sown Mace establishment was reduced by 55% compared to a 22% reduction for long-coleoptile Mace-18. The poorer establishment of Mace resulted in poorer crop competition resulting in more grass weeds compared to the long coleoptile Mace-18.

Wheat grain yield recovery from deep sowing was excellent for Mace-18, Scepter and Calibre, except for the short coleoptile Mace, exhibiting 13% grain yield reduction. Soil amelioration improved grain yield by 15-26% across all sowing depths and genotypes. In 2023, as characterised, Mace-18 on deep sowing had 15-30% longer coleoptiles over the other genotypes demonstrating potential for overcoming deeper placement. In Merredin, and Yuna experiments, regardless of soil treatment, Mace-18 maintained higher plant density at deep sowing compared to the other genotypes highlighting its establishment advantage.

Overall, shallow sowing increased grain yield by 8-10% compared to deep sowing. In Merredin, across both sowing depths, Mace-18 maintained the same yield, while the other genotypes at deep sowing showed a yield reduction of 8-17% compared to shallow sowing.

Ripped and spaded soil treatments improved yield by 16% and 19%, respectively, regardless of sowing depth in Merredin, although these responses were not repeated in Yuna, likely due to a warm-dry finish to the season in 2023.

While ongoing research is crucial for optimising agronomic practices and varietal selection, the preliminary evidence overwhelmingly indicates that long coleoptile wheat holds significant promise for farmers managing ameliorated soils and sustainable production of wheat.