An experiment was laid out to study the dynamics of plant spacing and topping height with the objective to hasten maturity and enhance seed cotton yield and yield components. The experiment was conducted at Agronomic Research Area, University of Agriculture Faisalabad. Experiment was laid out in Randomized Complete Block Design (RCBD). Treatments’ structures were factorial and replicated three times. Treatments were comprised of three plant spacing’s viz. S₁ (22 cm), S₂ (30 cm) and S₃ (38 cm) and four topping heights viz. T₀ (Control/No topping), T₁ (Topping at 90 cm height), T₂ (Topping at 120 cm height) and T₃ (Topping at 150 cm height). Plant spacing of 38 cm took significantly lesser number of days from sowing to first floral bud initiation and appearance to first flower and boll opening. Topping effect remained non-significant for first two parameters. Whereas, no topping took significantly highest number of days to first boll opening and minimum duration was observed with topping at 90 cm height. Highest number of sympodial branches per plant were recorded with 38 cm plant spacing and with topping at 120 cm height. Significantly more earliness index was exhibited by plant spacing of 30 cm and topping at 120 cm height. Topping at 120 cm height depicted higher number of monopodial branches, opened bolls, boll weight, seed cotton yield per plant and per hectare at each plant spacing treatment. Minimum boll weight was observed for no topping at each plant spacing. Minimum seed cotton yield per plant and per hectare was manifested by topping at 90 cm height at each plant spacing treatment. As concluding remarks, topping at 120 cm height depicted highest seed cotton yield and other yield attributes at each plant spacing treatment. However, highest earliness index was recorded for 30 cm plant spacing and topping at 120 cm height.

Keywords: Canopy; Maturity; Plant height; Boll weight; Sympodial; Monopodial; Cotton