A field experiment was conducted at Cotton Research Station, Nanded - Dhanegaon farm during
Kharif 2024 season to evaluate the effect of plant density and number of PGR spray on crop growth and yield of
Bt cotton straight variety. The experiment was laid out in a split plot design comprising twelve treatments and three replications. Four plant densities
i.e., D
1: 55,555 plants ha
-1, D
2: 83,333 plants ha
-1, D
3: 1,11,111 plant ha
-1, D
4: 1,66,666 plants ha
-1 were evaluated in main plot
with spacing 60 cm x 30 cm, 60 cm x 20 cm, 60 cm x 15 cm and 60 cm x 10 cm, respectively. Three treatments on number of PGR spray
i.e., P
1: one spray of PGR, P
2: two sprays of PGR, P
0: Control (Water spray) were tested in sub plot treatments. Plant growth retardant (PGR) Mepiquat chloride @ 25 g
a.i, per ha per spray was applied to restrict plant growth. First spray of PGR was given at square formation and second at 15 days after first spray as per treatment schedule.
The results showed that lowest height to node ratio (HNR) was recorded in plant density of 1.11 lakh plants ha-1 (spacing 60 cm x 15 cm). The height: node ratio was increase in closer spacing. However, highest density of 1.66 lakh plants ha-1 (60 cm x 10 cm) resulted in seed cotton yield (2109 kg ha-1), lint yield (813 kg ha-1), GMR (Rs.144825 per ha), NMR (Rs. 63037 per ha) and B:C ratio (1.77) whereas lower plant density exhibited greater number of picked bolls plant-1, yield plant-1, boll weight (g).
HNR was reduced due to two sprays of PGR over control. Two sprays of Mepiquat chloride @ 25 g a.i. ha-¹ at square formation and followed by 15 days has increased number of bolls plant-1, boll weight, yield plant-1, seed cotton yield (2116 kg ha-1), lint yield (802 kg ha-1), net monetary returns (Rs. 63,367/- ha-1) and B:C ratio of Bt hirsutum cotton variety over control.
