EFFECT OF SEED DENSITY ON THE GROWTH AND BIOMASS PRODUCTION OF SORGHUM (SORGHUM BICOLOR L.)

ABSTRACT This research investigated the effect of seed density on the growth and biomass production of Sorghum bicolor (L.) under unfertilized conditions in Maiduguri, Borno State, Nigeria. Sorghum is an important cereal crop in semi-arid regions, valued for its nutritional content, resilience to drought, and contribution to food security. However, low productivity in the region is often linked to suboptimal agronomic practices, particularly inappropriate seed density. This study aimed to evaluate the effect of different seed densities on sorghum growth performance and identify the optimal seed density for maximizing biomass and yield potential. The experiment was conducted using a Randomized Complete Block Design (RCBD) with four seed density treatments—10, 20, 30, and 40 seeds per polythene bag—each replicated three times. Data on plant height, leaf area, and biomass (fresh and dry weight) were collected weekly from 1 to 8 weeks after planting (WAP). Statistical analysis was performed using ANOVA, and mean separation was done with Fisher’s LSD at a 5% significance level. The results revealed that seed density significantly influenced early growth stages (2–4 WAP). At 2 WAP, higher densities (40 seeds) recorded greater initial height, while by 4 WAP, lower densities (10 seeds) produced taller plants and larger leaf areas due to reduced competition for light and nutrients. Biomass production (both fresh and dry) was also higher at lower densities (10s and 20s), indicating better resource utilization efficiency. By 8 WAP, differences across treatments became statistically insignificant. The study concluded that lower seed densities enhance early vegetative growth and biomass accumulation of Sorghum bicolor. Therefore, moderate to low seed densities (10–20 seeds per planting unit) are recommended for optimal productivity under low-input, semi-arid conditions. Future studies should examine the interaction between seed density and soil fertility to further improve sorghum yield potential.