Abstract

                                Field experiments were conducted at Tamil Nadu Agricultural University, Coimbatore, during Winter irrigated seasons of 2017-18 and 2018-19 to study the effect of weed growth by growth retardants on machine-sown cotton under high-density planting system. The experiment was laid out in a split-plot design, and the treatments were replicated thrice. Main plot treatments comprised of three crop geometries viz., 75 cm x 10 cm (M1), 75 cm x 20 cm (M2) and 75 cm x 30 cm (M3) and seven sub plots of foliar application of growth retardants along with one control viz., Cycocel 400 ppm (S1), Cycocel 500 ppm (S2), Mepiquat Chloride 100 ppm (S3), Mepiquat Chloride 200 ppm (S4), Maleic Hydrazide 400 ppm (S5), Maleic Hydrazide 500 ppm (S6) and Control (No Spray) (S7). Cotton genotype TCH 1819, developed for synchronized maturity exclusively to fit into high density planting system, was used as the test crop. The cotton crop was raised under raised bed and the major cultivation practices were carried out with machines namely; inclined plate planter for sowing, power weeder for weeding and drip system for irrigation and fertigation. However, harvesting was done manually. Weed infestation in cotton increased with 75 cm x 10 cm spacing compared to wider spacing. With respect to foliar application of growth retardants, there were no significant differences observed among the treatments tested during both the years of the study.

Key words : Cotton: High density planting system: growth Growth retardants: Weed growth