Mepiquat Chloride and Irrigation versus Cotton Growth and Development

Abstract

Cotton (Gossypium hirsutum L.) produces excessive vegetative growth when grown under optimum water and nutrient conditions. The plant growth regulator Mepiquat Chloride (MC); 1,l‐dimethyl piperidinium chloride reduces vegetative growth and can promote early maturity. Its effect on yield has been inconsistent, with some researchers showing an increase while others have indicated a decrease. This variation in yield has often been attributed to environmental factors and variations in water and fertilizer inputs. This study examined the effect of MC on cotton growth, under varying irrigation treatments, to determine if soil moisture interacts with MC. The experiment was conducted in 1987 with two cotton cultivars, Stoneville 825 (‘ST825’) and Deltapine 20 (‘DP20’), grown in pots, with five irrigation treatments [1.2,1.0,0.8,0.6, and 0.4 times previous day's pan evaporation (PE)] each with and without MC applied. Mepiquat Chloride reduced plant height, number of main stem nodes, and internodal length. The effect on boll numbers was mixed between cultivars. In some instances under the same irrigation treatment (1.2 PE), the number of bolls was higher in ST825 with MC applied than with control while in DP20 the control treatment had the higher number of bolls. Mepiquat chloride's effectiveness on vegetative growth tended to decrease as the number of days after application increased. Differences in response within irrigation treatments was attributable to MC. Differences in response between irrigation treatments with MC applied was attributable to irrigation and cultivar differences and not to interaction between soil moisture and MC.

Growth regulator losses from cotton plants due to rainfall

“…They have similar modes of action and effects, which is to inhibit gibberellic acid biosynthesis and thus reduce cellular elongation, resulting in lower growth rate (Lamas, 2001). The technique also increases 100-seed weight and cotton boll size, enhancing early fruit opening, harvest efficiency and production of high quality fibers (Cruz et al, 1982;Reddy et al, 1992).…”

Effects of Mepiquat Chloride and Trinexapac-Ethyl on Oil Composition, Seed Yield and Endogenous Gibberellins in Flax

“…MC regulating plant growth has been extensively researched and well documented (York, 1983a;1983b). It was reported that MC tends to be shorter and more compact than untreated plants (Jung et al, 1975;Willard et al, 1976;Stuart et al, 1984;Kerby, 1985;Hodges et al, 1991;Reddy et al, 1992). Number of branch per plant in the MC and TE was increased by high concentration, which is attributed to the significant increase in seed yield.…”

“…In addition, the good population type and canopy structure for dwarf plants, smaller leaves and bigger bolls could be achieved by mepiquat chloride application. Mepiquat chloride and trinexapac-ethyl tend to be shorter and more compact than untreated plants (Jung et al, 1975;Willard et al, 1976;Stuart et al, 1984, Kerby 1985Hodges et al, 1991;Reddy et al, 1992). Hence, we proposed these studies with the objective to demonstrate the effect of MC and TE on oil composition, seed yield, endogenous gibberellins content in flax plant.…”

Plant growth regulation: a method for fine-tuning mepiquat chloride rates in cotton1

“…Mepiquat chloride, a gibberellic acid synthesis inhibitor, is one of the most widely used growth regulators in cotton. The impact of mepiquat chloride on stem elongation and plant height are temperature dependent (Reddy et al 1992) and, at high temperatures, higher PGR rates are needed to control plant growth (Rosolem et al 2013). The PGR 1.…”