Seed Rate and Row Spacing Effects on Yield and Quality of Sorghum Maturity Groups Under Central European Conditions

Efficient and climate-resilient Sorghum bicolor L. cultivation is increasingly important under Central European conditions. This study evaluated two hybrids across two locations in 2023–2024 with row spacings of 25, 45, and 75 cm and four sowing densities of 210,000–300,000 seed ha−1. Row spacing, year, and genotype exerted a strong and consistent effect on grain yield and quality, with multiple instances reaching high statistical significance (p < 0.001). In contrast, seed rate had no significant main effect, influencing results only via site- and season-specific interactions. At a 45 cm row spacing, sorghum exhibited the highest grain yield (8.59 t ha−1), the lowest seed moisture content (13.59%), and the greatest protein yield (1.094 t ha−1). The 25 cm spacing with higher density produced with 0.46 t ha−1 higher yields than 75 cm and the highest protein content (13.35%), but 0.48 t ha−1 lower yield than the 45 cm treatment. The 75 cm spacing generally gave 12.29% lower yield and 6.72% lower quality despite higher tillering. TKW was highest at 45 cm row spacing (31.12 g), 23.3% greater than at 75 cm (25.25 g). The 45 cm row spacing provided the most stable yield, superior quality, and balanced agronomic performance, representing the most practical configuration for sustainable sorghum production under Central European conditions.