ABSTRACT

Plant growth regulators (PGRs) are used in cotton production to optimize yield and quality and even suppressing excess growth whenever necessary. Experiments were conducted Plant growth regulators (PGRs) are used in cotton production to optimize yield and quality and even suppressing excess growth whenever necessary. Experiments were conducted in 2017 at Cotton Seed Multiplication, Training and Research Farm, Sreepur, Bangladesh to study the response of cotton yield and quality to 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. Seed index of cotton was maximum (12.96 g) at spacing 60 cm × 30 cm and the lowest seed index (11.93 g) was recorded from spacing 45 cm × 30 cm. The highest seed index (13.62 g) was from control and the lowest (11.26 g) with 1 ml MC L-1 water at 50 DAE treatments. SI observed highest (15.01 g) from water  sprayed with 60 cm × 30 cm spacing  and marked lowest (10.33 g) at 3 ml MC L-1 water  at 25 DAE with 60 cm × 30 cm spacing treatment combinations. 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, seed index, cotton.