Nitrogen and mepiquat chloride can affect fiber quality and cotton yield

Abstract

The use of mepiquat chloride (MC) in cotton (Gossypium hirsutum L.) cultivation has increased significantly in recent years. The use of MC, a growth regulator, results in higher precocity and lower height and consequently increases yield and reduces crop costs. The objective of this study was to evaluate the effects of nitrogen (N) and MC doses on fiber quality and cotton yield. This study was conducted during the 2012/13 and 2013/14 harvests in the experimental area of the Fundação de Apoio à Pesquisa Agropecuária de Chapadão, located in the municipality of Chapadão do Sul, MS, Brazil, at 18° 48’ 45.9” S, 52° 36’ 3” W, having an altitude of 820 m. The experimental design was a randomized blocks in a 5 × 4 factorial scheme comprised of five N doses (0, 40, 80, 120, 160 kg ha-1) and four MC doses (0, 50, 100, 150 mL ha-1) with four repetitions. Analyses of fiber quality included: length, uniformity, elongation, strength, micronaire index, reflectance, yellowing degrees and short fiber content. Regarding cotton yield, green color index (GCI), plant height at harvest time, and cotton seed yield were determined. The best results for fiber quality and productivity occurr with the application of 76.8 mL ha-1 of MC to the cotton crops when the N dose is greater than 80 kg ha-1. Increasing N doses causes an increase in cotton yield and micronaire index, but there is a decrease in fiber uniformity.

The effects of mepiquat chloride (DPC) on the soluble protein content and the activities of protective enzymes in cotton in response to aphid feeding and on the activities of detoxifying enzymes in aphids

“…Therefore, in the cultivation and planting of cotton, the grower should not only focus on the management of water and fertilizer in the field [ 4 , 5 ], but should also consider the use of exogenous plant hormones for chemical regulation [ 6 ] for reasonable control of cotton growth and development. This will determine the shape of the ideal plant type [ 7 ] by reducing plant height [ 8 ], shorten the main stem and fruiting branch internodes [ 9 , 10 ], improve light transmittance, reduce boll shedding [ 11 ], and promote boll opening [ 12 ] to improve economic yield [ 13 , 14 ].…”

Cotton root growth response to mepiquat chloride application in early reproductive stages are cultivar dependent

“…Most Brazilian cotton crops are sown in wide row spacings (0.75–0.90 m) with populations ranging from 50,000 to 130,000 plants ha −1 . Under these conditions, management of growth regulators is mostly performed via foliar spraying (Echer & Rosolem, 2017; Leal et al., 2020). However, there is no consensus regarding appropriate application rates, especially for early sprays (Pinhead square stage).…”

“…Low MC rates can lead to uncontrolled growth, especially for cultivars in the late reproductive stage in highly fertile soil (Echer & Rosolem, 2017; Leal et al., 2020). High rates can result in temporary growth disruptions.…”

Changes in the Activities of Protective Enzymes Induced by Mepiquat Chloride (DPC) in Cotton to Defend Against Aphids

“…Therefore, in the cultivation and planting of cotton, the grower should not only focus on the management of water and fertilizer in the eld (Zhao and Oosterhuis, 2000;Schaefer et al, 2017), but should also consider the use of exogenous plant hormones for chemical regulation (Kaur et al, 2021) for reasonable control of cotton growth and development. This will determine the shape of the ideal plant type (Hussain et al, 2020) by reducing plant height , shorten the main stem and fruiting branch internodes (Wang et al, 2014;, improve light transmittance, reduce boll shedding (Gao et al, 2019), and promote boll opening (Liao et al, 2021) to improve economic yield (Tung et al, 2019;Leal et al, 2020).…”