Optimizing yield and quality suppressing excess growth using plant growth regulators (PGRs) in cotton production an experiment was set in 2017 at Cotton Seed Multiplication, Training and Research Farm, Sreepur, Bangladesh to evaluate the response of cotton yield and quality in respect of different plant spacings, concentration and time of application of mepiquat chloride (MC) growth regulator. Plant spacings like 45 cm × 30 cm, 60 cm × 30 cm and 75 cm × 30 cm; MC spray @ 1.0, 2.0, 3.0 and 4.0 ml  L-1  water at 25, 50 and  75 DAE for each concentration along with water spray as control, were the treatment variables. Maximum leaf canopy size 0.36 m2 was observed from 75 cm×30 cm spacing but lower leaf canopy size 0.33m2 was recorded at spacing of 45 cm × 30 cm. In case of MC application, the maximum leaf canopy size 0.37 m2 was obtained from control but minimum leaf canopy size 0.32 m2 was observed from 2 ml MC L-1 water at         25 DAE treatment. Combined influence of plant density and time of application as well as concentration of growth regulator revealed that the maximum leaf canopy size (0.46 m2) was observed with water sprayed at 75 cm × 30 cm spacing but lower canopy size 0.16 m2 was obtained from 2 ml MC L-1 water at 25 DAE with 60 cm × 30 cm spacing treatment combination. So, cotton cultivation in Sreepur, Gazipur areas may be accelerated with foliar application of mepiquat chloride @ 2 ml L-1 water at 25 DAE along with plant spacing of 60 cm x 30 cm for higher yield and quality.

Key words: Plant spacing, growth regulator, time of foliar, canopy, cotton