Effects of mepiquat chloride and foliar nutrition on growth, yield, and fiber quality in High-Density Planting System (HDPS)

Mepiquat chloride (MC) is a plant growth regulator used to manage the rampant vegetative growth of cotton. A two-year field experiment was conducted at the Postgraduate Agricultural Research Station, University of Agriculture, Faisalabad, Pakistan, during 2017 and 2018 to investigate the influence of MC applied at different times on phenology, morphology, lint yield and quality of cotton cultivated using different sowing techniques. MC was applied 50 days after sowing (DAS), 60 DAS and 70 DAS to cotton planted in flat fields (flat sowing), ridges (ridge sowing) and beds (bed sowing). The interactive effect of MC application time and sowing technique did not influence crop phenology, morphology, and lint yield and quality. It was revealed that the crop planted on beds took fewer days to flower (10%) as compared to that on the flat field, and the bed-sown crop produced a higher number of opened bolls (60%) and was characterized by a higher boll weight (32%) and seed cotton yield (50%) in comparison to the flat-sown crop. A late application of MC (at 70 DAS) caused a significant reduction in the time to flowering (8%), with a simultaneous increase in the number of opened bolls (60%), boll weight (32%), ginning out turn (8%) and lint yield (27%) as compared to MC application at 50 DAS. In terms of lint quality, cotton planted on beds had better fiber uniformity (8%) compared to that on the flat field, while MC applied at 70 DAS produced better fiber fineness by 27% in comparison to MC applied earlier. Overall, cotton planting on beds and MC application at 70 DAS may help improve cotton yield and fiber quality and may help in the mechanical picking of cotton.

Trials were conducted during three years from 2021-22 to 2023-24 at Main Cotton Research Station, Navsari Agricultural University, Surat, Gujarat to study the effect of nitrogen levels on yield of cotton and to find out the efficacy of growth retardants on plant canopy of cotton grown under high density planting system. Nine treatment combinations comprising of three nitrogen levels viz; 375 kg N/ha, 300 kg N/ha and 225 kg N/ha with three treatments of growth retardants viz; Cycocel spray @ 50 g a.i./ha in each spray at 60 and 75 days after sowing, Mepiquat chloride spray @ 37.5 g a.i./ha in each spray at 60 and 75 days after sowing and Control (water spray at 60 and 75 days after sowing) were laid out in factorial randomized block design. Nitrogen levels significantly influenced on growth parameters viz; plant height, number of sympodial branches/plant, sympodial length and days to 50 % flowering, yield attributes viz; number of bolls/plant and boll weight, seed cotton yield (kg/ha), lint yield (kg/ha) and stalk yield (kg/ha). Important growth and yield parameters viz; plant height, number of sympodial branches/plant, sympodial length, days to 50 % flowering, number of bolls/plant and boll weight, seed cotton yield (kg/ha), lint yield (kg/ha) and stalk yield (kg/ha) were significantly influenced by growth retardant treatments. Conclusion of the experiment was drawn that application of 300 kg nitrogen/ha in five equal splits at 30, 60, 75, 90 and 105 days after sowing along with 40 kg P2O5/ha as basal dose and spraying of mepiquat chloride 5 % AS @ 37.5 g a.i./ha at 60 and 75 days after sowing found optimum for obtaining higher seed cotton yield as well as net returns from Bt cotton hybrid grown with high density planting system maintaining 60 x 45 cm spacing under irrigated condition of south Gujarat.

Architecture of stem and branch affects yield formation in short season cotton

Elucidating the phenotypic basis of multi-environment stability for fiber yield and quality traits of cotton (Gossypium hirsutum L.) using 498 recombinant inbred lines

Field experiments were conducted during winter season of 2011-12 and 2012-13 at Tamil Nadu Agricultural University, Coimbatore to study the feasibility of using cotton genotypes under high density planting system and to assess its effect on seed cotton yield, oil content and fibre quality parameters. The experiments were laid out in a strip plot design, replicated thrice. The soil in the experimental site was sandy clay loam with low available nitrogen (182 kg/ha), medium available phosphorus (12.6 kg/ha) and high available potassium (340 kg/ha). The experiment consisted of seven cotton genotypes viz., Jai, Ranjeet, TCH 1608, SVPR 3, Anjali, Suraj and LH 900 with four spacings viz., 30 × 30, 45 × 30, 60 × 30 and 90 × 30 cm. Ranjeet planted at the spacing of 30 × 30 cm recorded significantly higher seed cotton yield. The percentage of oil content was significantly higher in Ranjeet genotype than other cotton genotypes. The fibre quality parameters viz., fibre length, fibre strength, micronaire, elongation percentage were significantly influenced by different cotton genotypes. The oil content and fibre quality was not significantly influenced by plant densities.

Mepiquat chloride effects on potassium acquisition and functional leaf physiology as well as lint yield in highly dense late-sown cotton

Breeding of brown cotton for spinnable yarn in intraspecific and interspecific hybrids (G. hirsutum L. and G. barbadense L.)

Due to the changing climate, frequent episodes of drought have threatened cotton lint yield by offsetting their physiological and biochemical functioning. An efficient use of irrigation water can help to produce more crops per drop in cotton production systems. We assume that an optimal drip irrigation with low mepiquat chloride application could increase water productivity (WP) and maintain lint yields by enhancing leaf functional characteristics. A 2-year field experiment determines the response of irrigation regimes (600 (W1), 540 (W2), 480 (W3), 420 (W4) 360 (W5) m3 ha−1) on cotton growth, photosynthesis, fiber quality, biomass accumulation and yield. Mepiquat chloride was sprayed in different concentration at various growth phases (see material section). Result showed that W1 increased leaf area index (LAI) by 5.3–36.0%, net photosynthetic rate (Pn) by 3.4–23.2%, chlorophyll content (Chl) by 1.3–12.0% than other treatments. Improvements in these attributes led to higher lint yield. However, no differences were observed between W1 and W2 in terms of lint and seed cotton yield, but W2 increased WP by 3.7% in both years. Compared with other counterparts, W2 had the largest LAI (4.3–32.1%) at the full boll stage and prolonged reproductive organ biomass (ROB) accumulation by 30–35 d during the fast accumulation period (FAP). LAI, the average (VT) and maximum (VM) biomass accumulation rates of ROB were positively correlated with lint yield. In conclusion, the drip irrigation level of 540–600 m3 ha−1 with reduced MC application is a good strategy to achieve higher WP and lint yield by improving leaf photosynthetic traits and more reproductive organ biomass accumulation.

A three year study with the objective of exploring the possible role of different sowing dates and cotton genotypes on seed cotton yield, fiber quality and virus attack was conducted at the Cotton Research Station (CRS), Multan, Pakistan during three consecutive years (2006, 2007 and 2008). Two cotton genotypes namely: MNH-6070 and CIM-496 were sown on five different sowing dates (15th April, 1st May, 15th May, 1st June and 15th June) during the three consecutive years (2006, 2007 and 2008). The analyzed data indicated that early sown cotton (15th April) resulted in low virus attack (21.06%) and enhanced seed cotton yield (1575%), together with yield components (number of bolls per plant and boll weight), and improved fiber quality (staple length and micronaire) during all the three years as compared with late sown crop (15th June). Likewise, MNH-6070 also resulted in low virus attack (45.79%) and higher seed cotton yield (117.19%), as well as yield components. Regarding fiber quality, MNH-6070 resulted in higher micronarie, while CIM-496 resulted in higher staple length. Early sowing and cotton genotype MNH-6070 also resulted in maximum ginning out turn (GOT). Nonetheless, seed cotton yield and fiber quality were both negatively affected due to late sowing (1st and 15th of June) in both cotton genotypes. In crux, early sowing enhanced seed cotton yield due to increased number of bolls per plant, boll weight and low virus attack. Similarly, cotton genotype MNH-6070 also resulted to higher seed cotton yield, GOT and more resistance against virus attack due to its better genetic makeup. In summary, cotton genotype MNH-6070 should be sown on 15th April in order to obtain maximum seed cotton yield under agro-climatic conditions of Multan, Pakistan.

BackgroundNatural and synthetic plant growth regulators are essential for plant health, likewise these regulators also play a role in increasing organic production productivity and improving quality and yield stability. In the present study, we have evaluated the effects of foliar applied plant growth regulators, i.e., moringa leaf extract (MLE) and mepiquat chloride (MC) alone and in combination MC and MLE on the conventional cotton cultivar (CIM 573) and transgenic one (CIM 598). The growth regulators were applied at the start of bloom, 45 and 90 days after blooming.ResultsThe application of MC and MLE at 90 days after blooming significantly improved the relative growth rate, net assimilation rate, the number of bolls per plant, and seed cotton yield. Likewise, the combined application of MLE and MC at 90 days after blooming significantly boosted the nitrogen uptake in locules, as well as the phosphorus and potassium uptake in the leaves of both cotton cultivars. The application of MLE alone has considerably improved the nitrogen uptake in leaves, and phosphorus and potassium contents in locules of Bt and conventional cotton cultivars. Similarly, Bt cotton treated with MLE at 90 days after blooming produced significantly higher ginning out turn and oil contents. Treatment in combination (MLE + MC) at 90 days after blooming produced considerably higher micronaire value, fiber strength, and staple length in conventional cultivar.ConclusionThe natural growth enhancer, MLE is a rich source of minerals and zeatin, improving the nutrient absorption and quality of cotton fiber in both conventional and Bt cotton cultivars.

Irrigation depth and nitrogen rate effects on seed cotton yield, fiber quality and water-nitrogen utilization efficiency in southern Xinjiang, China

<abstract><title><italic>Abstract. </italic></title> Cotton production practices have changed in the Southern High Plains of the United States over the last decade resulting in increased yields and improved fiber quality. Moreover, the majority of U.S. cotton now competes in a global fiber market that demands higher quality fiber for ring spun yarn than the former domestic open-end market. The brush-roll stripper harvester is the predominate machine used to harvest the Southern High Plains cotton crop, but interest in spindle pickers has increased recently in efforts to better preserve fiber quality, enhance profitability, and maintain the market share of U.S. cotton in the global fiber market. This work was conducted to compare yields, fiber quality, and agronomic parameters between picker and stripper-based harvest systems under commercial production and ginning conditions. Large-scale harvest system comparison tests were conducted at seven sub-surface drip irrigated sites across the Texas High Plains during the 2008-2010 crop years using brush-roll strippers with field cleaners and spindle pickers. Four cotton modules harvested from each site under each harvest method were ginned by a commercial gin. Compared to picker-harvested cotton, stripper-harvested cotton had 1096 kg ha^-1 higher seed cotton yield which increased ginning charges by $72.40 ha^-1. Seed and lint yields were 217 and 108 kg ha^-1 higher, respectively, for stripper-harvested cotton resulting in $88.78 ha^-1 higher total production revenue. Notwithstanding higher lint yield for the stripper system, custom harvesting was $51.38 ha^-1 more expensive for the picker system due to the custom harvesting rates used (picking: $0.22 per lint kg; stripping: $0.18 per lint kg). Except for strength and reflectance that showed no difference by harvest method, all High Volume Instrument (HVI) fiber quality parameters were improved for picker-harvested cotton. Due to improved HVI fiber quality and a substantial decrease in the number of bark contaminated bales, lint value was higher for picker-harvested cotton. However, increased lint value was offset by decreased yield such that net revenue was $66.76 ha^-1 higher for stripper-harvested cotton across all sites.

Foliar application of silicon and boron improves boll retention, lint yield and fiber quality traits of transgenic cotton

This study was conducted for investigating the impact of irrigation interval and deficit irrigation on seed cotton yield, fiber quality, and water productivity of cotton (Gossypium hirsutum L.) in the Şanlıurfa province of Türkiye during the years 2020 and 2021. The experiment was conducted using a randomized complete block design with split plots. The main plots included three irrigation intervals (D1: 4 day, D2: 8 day, and D3: 12 day), while the sub-plots consisted of three irrigation levels (I1: %150, I2: %120, and I3: %90) considered by Class A pan evaporation using the drip irrigation method. The study resulted in that the crop evapotranspiration varied from 693 to 1153 mm in 2020 and from 716 to 1126 mm in 2021, respectively. Irrigation interval and deficit irrigation had a statistically significant effect on seed cotton yield, seed cotton weight, and ginning outturn in both years of the study. The highest seed cotton yield, seed cotton weight, and lint yield were obtained from the treatment with a 4-day irrigation interval and irrigation water level at 150% (D1-I1), while the lowest values were obtained from the treatment with a 12-day irrigation interval and irrigation water level at 90% (D3-I3). However, irrigation interval and deficit irrigation did not have a statistically significant effect on 100-seed weight, fiber fineness, fiber length, and fiber strength in both years of the study. In the study, water use productivity (WP) ranged from 0.32 to 0.55 kg m-3, while irrigation water use productivity (IWP) ranged from 0.33 to 0.59 kg m-3, and similar results were obtained in both years of the research. According to the research findings, to achieve the highest cotton yield and quality, an irrigation interval of 4 days and a total seasonal irrigation water of 1062 mm are recommended.

Cultivar, irrigation management, and mepiquat chloride strategy: Effects on cotton growth, maturity, yield, and fiber quality