Winter Wheat Seeding Decisions for Improved Grain Yield and Yield Components

The continual re-evaluation of agronomic practices is necessary to improve crop performance and sustainability of the production of winter wheat (Triticum aestivum L.), particularly as genetics and climate conditions change. Recommendations made about winter wheat planting dates, spacing, variety, and seed rates under normal climatic conditions may not be suitable in current times with more climate variability. Our experiment investigated the effect of planting date (early, historic-optimum, and late), row spacing (19 and 25 cm), variety (Goodstreak, Robidoux, and Wesley), and seed rate (1.8, 2.1, 2.3, 2.4, 2.6, 2.8, 3.1, and 3.4 M seeds ha⁻¹) on winter wheat grain yield and yield components. The seeding rate was nested within row spacing in nested-factorial design. A nested-factorial treatment design was used with testing at several locations in Nebraska across two years. Variety had a substantial effect on winter wheat grain yield (p < 0.05). Variety also had a substantial interaction effect with planting date and row spacing 50% of the time (p ≤ 0.01). At Hemingford, for example, Wesley planted at 19 cm had 5.9% more yield when compared to Robidoux planted at 19 cm (5.5 Mg ha⁻¹). Similarly, biomass was influenced by variety across sites (p < 0.01), but a substantial interaction effect also occurred between planting date and variety at two of the three sites. Narrow row spacing (19 cm) led to significantly more tillers (6.9 M ha⁻¹) when planted with Goodstreak at two of the sites. While planting date by itself did not affect any of the responses evaluated, this research highlights the importance of comprehensive and holistic approaches to wheat production in the High Plains.