Asian Journal of Research in Crop Science

A field experiment was conducted in the field of Noakhali Science & Technology University, Noakhali-3814, Bangladesh during the period from 5th December, 2017 to 27th April 2018 to study the effect of line sowing on growth dynamics and yield performance of onion. The experimental field was laid out in Randomized Complete Block Design (RCBD) with three replications. The treatments were T₁ = 2 m, T₂ = 3 m, T₃= 3.5 m. Key parameters including plant height, number of leaves per plant, leaf length, leaf breadth, and bulb weight were recorded at 40 and 55 days after sowing (DAS). Analysis of variance revealed significant differences among treatments for all measured traits. Plant height was consistently highest in T₂ at both 40 DAS (25.77 cm) and 55 DAS (33.50 cm), indicating enhanced vegetative growth, while T₁ produced the shortest plants. Leaf number showed slight variations, with T₃ producing the maximum leaves at 55 DAS (6.33) and T2 recording the lowest (5.33). Leaf length was highest in T₂ (23.83 cm at 40 DAS; 29.57 cm at 55 DAS), whereas T₃ produced the widest leaves at 55 DAS (0.93 cm). Bulb weight differed across treatments, with T₂ producing the heaviest bulbs at 40 DAS (13.50 g) and T₁ achieving the highest weight at 55 DAS (14.20 g). The results indicate that T₂ favored early vegetative growth and initial bulb development, while T₁ contributed to superior final bulb weight. These findings suggest that stage-specific management practices, particularly optimized plant spacing (3.0 m and 3.5 m), can enhance onion growth dynamics and maximize final bulb yield at harvest under similar agro-climatic conditions.