Seed Cotton Weight Research Articles

Impacts of wide row spacings on yield and yield components of upland cotton (Gossypium hirsutum L.)

AbstractThis study quantifies the effects of wide row spacing on lint yield, yield components, and fiber quality of upland cotton (Gossypium hirsutum L.). An experiment was conducted in Tifton, GA in 2021 and 2022, where cotton was planted in six replications of 91‐, 122‐, 152‐, and 183‐cm row spacings. Following defoliation, 1.8 m was hand harvested from each plot, and boll density plant−1 and density ha−1 were determined for sympodial and monopodial branches. Additional measurements included fruit and lint yield distribution assessments and intra‐boll yield components including seed cotton weight boll−1, seed index, seed boll−1, lint weight seed−1, seed surface area (SSA), fiber density, and single fiber weight. Lint yield was reduced 20% in the 183‐cm row spacing compared to the 91‐cm row spacing. The 91‐cm rows had the lowest number of sympodial bolls plant−1 with 152‐ and 183‐cm rows demonstrating a 24%–28% increase in sympodial bolls plant−1. Sympodial bolls ha−1 were reduced 22% in the 183‐cm row spacing compared to the 91‐cm row spacing. There were no differences in bolls ha−1 or lint yield ha−1 with respect to monopodial growth. There were no differences in seed cotton weight boll−1, seeds boll−1, fiber density, single fiber weight, or turnout. Seed index and SSA were increased in the 183‐cm row spacing. Lint weight seed−1 was reduced in the 91‐cm row spacing.

Enhanced Cotton Yield and Fiber Quality by Optimizing Irrigation Amount and Frequency in Arid Areas of Northwest China

Optimizing irrigation strategies is crucial for sustaining cotton production in the face of growing water scarcity. The three-year experimental study (2020–2022) focused on the impact of varying irrigation amounts (320, 370, and 420 mm) and frequencies (4-, 8-, and 12-day intervals) on cotton growth, yield, yield components, and fiber quality in southern Xinjiang. Employing a completely randomized design with three replications, the results indicated higher irrigation amounts resulted in numerically 2.5–7.5% higher lint yields compared to those under medium and low irrigation amounts, notably significant in 2021. Boll density emerged as the primary yield component influencing yield loss due to irrigation amount, followed by seed cotton weight boll−1. Increased boll density was associated with a greater total number of fruiting sites. Additionally, the increased seed cotton weight boll−1 could be linked to an increased seed number boll−1 and a decreased boll fraction at the lower fruiting branches with lower seed cotton weight boll−1. Higher irrigation frequency improved lint yield by increasing boll density, though a significant effect was observed only in 2020. Increased irrigation amounts generally led to longer fiber lengths but lower micronaire values, while increased irrigation frequency resulted in longer, stronger fibers and reduced micronaire values. Furthermore, the highest yield stability was observed under the condition of high irrigation amount and high frequency. This study holds certain guiding significance for water resource management in cotton production in arid regions.

Impact of intra‐boll yield components on lint production per boll and fiber quality in advanced cotton breeding lines

AbstractCotton (Gossypium hirsutum L.) lint yield and fiber quality are associated with various yield components. Research efforts addressing intra‐boll yield component contributors to lint production boll−1 are limited. Thus, a study was conducted in Tifton, Georgia with the objectives to quantify the contributions of intra‐boll yield components to lint production boll−1 and to identify yield components most strongly associated with lint production boll−1 in advanced breeding lines of upland cotton. Data collected included intra‐boll yield components and fiber quality parameters. A strong association was observed between lint production boll−1 and seedcotton weight boll−1 (r = 0.896) compared to lint production boll−1 and lint percent (LP, r = 0.574). For breeding lines with maximum lint weight boll−1, the contribution of seedcotton weight and LP ranged from 0.17 to 0.36 g boll−1 and 0.22 to 0.24 g boll−1, respectively, suggesting a relatively greater influence of seedcotton weight boll−1 on lint weight boll−1. Lint production boll−1 can be expressed as the product of seeds per boll, seed surface area, fiber density (FD), and individual fiber weight (IFW). IFW was the greatest contributor to lint production boll−1 for seven breeding lines and FD for nine breeding lines. A strong positive association was observed between lint production boll−1 and IFW (r = 0.656, p < 0.001); however, no significant association between lint weight boll−1 and FD suggesting a relatively greater influence of IFW on lint weight boll−1. Our work provides future direction aimed at improving lint yields through the selection of various yield components.

Effect of Organic Manure and Foliar Application of Boron on Morphological and Economic Parameters of Sindh-1 and CKC-3 Cultivars of Cotton Under Semi-arid Climate

Cotton (Gossypium hirsutum L.) has a central position in agriculture, similarly it adds to Pakistan’s economy as trade profit. Most of the cotton growing areas of Pakistan are deficient in organic matter due to continuous mono-cropping. Concerning these issues, a one-year field research was conducted during Kharif season in 2021 to evaluate the effect of organic manure and foliar application of boron on morphological and economic characters of CKC-3 and Sindh-1 cultivars under semi-arid climate. Treatments included soil applied farmyard manure (FYM) and foliar application of boron (B): T1 = Control (0 FYM + 0 B), T2 = FYM @10 tons/ha1, T3 = 1% B, T4 = 2% B, T5 = FYM @10 tons/ha1 + 1% B, T6 = FYM@10 tons/ha1 + 2% B. Our results suggested that the treatment of soil applied FYM and foliar applied B @ FYM 10 tons/ha1 + 2% B significantly (P≤0.05) influence the morphological characters including, sympodial branches per plant, opened bolls per plant, seed cotton weight per plant (g), seed cotton yield (kg ha-1), lint yield per plant (g), and GOT (%) of both Sindh-1 and CKC-3 cultivars of cotton. However, CKC-3 performed better than Sindh-1 cultivar in most of the growth and yield related parameters under different treatment regimes. Hence, the optimum FYM and B foliar application levels for economical cotton production was considered to be FYM @10 tons/ha1 + 2% boron along with recommended dose of NPK fertilizers under semi-arid climate.

Farklı sulama seviyelerinin ve sulama aralıklarının pamuk yetiştiriciliği üzerindeki etkileri: Verim, verim bileşenleri ve lif kalitesi parametreleri üzerine bir çalışma

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.

Production and Fiber Characteristics of Colored Cotton Cultivares under Salt Stress and H2O2.

Salt stress reduces the yield and quality of colored fiber cotton production, but this problem can be mitigated by the foliar application of hydrogen peroxide in adequate concentrations. In this context, the objective of the present study was to evaluate the production and characteristics of fibers of naturally colored cotton cultivares under irrigation with low- and high-salinity water and leaf application of hydrogen peroxide. The experiment was carried out in a greenhouse under a randomized block design, arranged in 4 × 3 × 2 factorial scheme, corresponding to four concentrations of hydrogen peroxide (0, 25, 50, and 75 μM), three cultivares of colored fiber cotton ('BRS Rubi', 'BRS Topázio', and 'BRS Verde'), and two electrical conductivities of water (0.8 and 5.3 dS m-1), with three replicates and one plant per plot. Irrigation with water of 0.8 dS m-1 associated with a foliar application of 75 μM of hydrogen peroxide favored the lint and seed weight, strength, micronaire index, and maturity of 'BRS Topázio'. The 'BRS Rubi' cotton cultivar showed higher tolerance to salinity, followed by the 'BRS Topázio' and 'BRS Verde' cultivares regarding the yield of seed cotton weight, with reduction below 20% under water of 5.3 dS m-1.

Effect of Reproductive Stage-Waterlogging on the Growth and Yield of Upland Cotton (Gossypium hirsutum)

The reproductive stage of cotton (Gossypium sp.) is highly sensitive to waterlogging. The identification of potential elite upland cotton (Gossypium hirsutum) cultivar(s) having higher waterlogging tolerance is crucial to expanding cotton cultivation in the low-lying areas. The present study was designed to investigate the effect of waterlogging on the reproductive development of four elite upland cotton cultivars, namely, Rupali-1, CB-12, CB-13, and DM-3, against four waterlogging durations (e.g., 0, 3, 6, and 9-day). Waterlogging stress significantly impacted morpho-physiological, biochemical, and yield attributes of cotton. Two cotton cultivars, e.g., CB-12 and Rupali-1, showed the lowest reduction in plant height (6 and 9%, respectively) and boll weight (8 and 5%, respectively) at the highest waterlogging duration of 9 days. Physiological and biochemical data revealed that higher leaf chlorophyll, proline, and relative water contents, and lower malondialdehyde contents, particularly in CB-12 and Rupali-1, were positively correlated with yield. Notably, CB-12 and Rupali-1 had higher seed cotton weight (90.34 and 83.10 g, respectively), lint weight (40.12 and 39.32 g, respectively), and seed weight (49.47 and 43.78 g, respectively) per plant than CB-13 and DM-3 in response to the highest duration of waterlogging of 9 days. Moreover, extensive multivariate analyses like Spearman correlation and the principle component analysis revealed that CB-12 and Rupali-1 had greater coefficients in yield and physiological attributes at 9-day waterlogging, whereas CB-13 and DM-3 were sensitive cultivars in response to the same levels of waterlogging. Thus, CB-12 and Rupali-1 might be well adapted to the low-lying waterlogging-prone areas for high and sustained yield.

The Effect of Application of Different Doses of Acid Mixture Seed Coating Method on Cotton (Gossypium hirsutum L.) Yield and Fiber Technological Characteristics

This study was carried out to determine the effects of different rates of seed coating of an organic acid mixture (citric acid, glutamate, and proline) on the yield and technological characteristics of cotton (Gossypium hirsutum L.). Before seeding, cotton seeds were coated with an organic acid mixture product [0.75% citric acid, 0.25% glutamate, 0.25% proline, and 98.75 inert ingredients (water)], in six different doses (500, 1000, 1500, 2000, and 2500 cc) to compare with control (uncoated). Seed cotton yield, fiber yield, plant height, number of monopodial branches, number of sympodial branches, number of nodes of the first fruiting branch, number of bolls per plant, boll weight, boll seed cotton weight, first picking percentage, 100 seeds weight, fiber fineness, fiber length, fiber strength, fiber elongation, fiber uniformity ratio, short fiber index, fiber yellowness (+ b), fiber reflectance (Rd) and spinning consistency index (SCI) values were examined. The results of statistical analysis indicated that there were significant differences between treatments in terms of seed cotton yield, fiber yield, boll weight, boll seed cotton weight, first picking percentage, and the number of nodes of the first fruiting branch, while there was a non-significant association in terms of other examined observations and fiber technological characteristics. The highest seed cotton yield was obtained from 1500 cc application doses as 5073.80 kg ha-1 which was 19,78% (838.00 kg ha-1) higher than that of the control (4235.80 kg ha-1). In conclusion in light of the information obtained from this study, a remarkable increase in yield was obtained as a result of coating the cotton seeds with the product containing organic acid mixtures (citric acid, glutamate, and proline) at different doses. For this reason, it was concluded that it may be recommended to cover the seeds with the aforementioned mixtures before sowing.

INHERITANCE OF YIELD AND SOME FIBER PROPERTIES OF LINE X TESTER HYBRIDS IN COTTON (Gossypium hirsutum L.)

The aim of this study was to determine the general combining ability (GCA) of the parents and the specific combining ability of their hybrid combinations and to evaluate the hybrid vigor of F1 by investigating the genetic structure of the lines and testers. The study was carried out in randomized complete blocks design with three replications in the trial site of Nazilli Cotton Research Institute in 2015 and 2016 years. 28 F1 hybrids (4 lines and 7 testers) were used as material which developed from line x tester method. Investigated properties except fiber length in the created populations were influenced by non-additive gene effect. The values of heterosis for the seed cotton weight per boll, earliness ratio, ginning percentage, fiber length and micronaire were found positive while seed cotton yield was negative. In the established populations, the investigated traits except fiber length were affected by the non-additive gene effect. Seed cotton weight per boll earliness ratio, ginning percentage, fiber length and micronaire were positive while seed cotton yield was found negative. For seed cotton yield Gloria, TMN 199 and ZN 1018; for earliness ratio TMN 199, GW 2357 and TMN 170; for seed cotton weight per boll GW 2357 and Gloria; for seed index İpek 607; for ginning percentage TMN 199, TMD 139 ZN 1018; for fiber length Gloria, Flash, İpek 607 and UA 48; for fiber fineness İpek 607 and TMD 139; for fiber strength Gloria and UA 48 were found the best parents and also performed the best overall combining abilities for these traits. TMN 199 x İpek 607, TMN 199 x UA 48, Flash x GW 2357, Gloria x İpek 607, Gloria x UA 48 and ST 468 x ADN 712 for seed cotton yield; TMN 199 x TMN 170 for earliness ratio; Flash x GW 2357 and Gloria x İpek 607 for seed cotton weight per boll; TMN 199 x GW 2357 and Gloria x ADN 712 for seed index; Gloria x TMD 139, TMN 199 x TMN 170, Flash x ZN 1018 and ST-468 x TMN 139 for ginning percentage; Flash x ADN 712 and ST-468 x İpek 607 for fiber length; ST-468 x İpek 607 for fiber micronaire; TMN 199 x UA 48, Flash x İpek 607, ST-468 x GW 2357 and ST-468 x UA 48 for fiber strength were indicated the most promising hybrids and had the best overall combining abilities.

Straw retention coupled with mineral phosphorus fertilizer for reducing phosphorus fertilizer input and improving cotton yield in coastal saline soils

Straw return can improve soil nutrient availability, but its interaction with phosphorus (P) fertilizer on cotton (Gossypium hirsutum L.) production and soil P availability has rarely been studied. Therefore, we carried out a four-year field trial to evaluate the effects of straw management (retention or removal) with P fertilizer (0, 22, 44, 66, 88 kg P ha–1) additions on seed cotton yield, cotton P uptake, soil fertility, and P apparent recovery efficiency (PRE) in a continuous barley–cotton rotation system in a coastal saline soil field from 2016-2019. Our results showed that the year and the interaction of P fertilization and straw management had significant effects on seed cotton yield and boll numbers, but there was no significant effects of straw management and the interaction of P fertilization and straw management on seed cotton weight per boll. An increase in P activation coefficient (14-28%) was observed due to the higher soil available P content following straw retention compared to the straw removal. Compared with straw removal, straw retention reduced mineral P fertilization by about 27-38% without affecting seed cotton yield, while increasing PRE by 14‒27% over the four years. In the 0-20 cm soil layer, straw retention reduced the Langmuir P sorption maximum (Qmax) and maximum buffer capacity (BCmax), and also increased the degree of P saturation (DPS), but it did no effect on the soil adsorption equilibrium constant (k). Straw retention significantly decreased the soil Qmax compared to straw removal under 0, 22, and 44 kg P ha–1, while no significant straw effects were found on Qmax under 66 and 88 kg P ha–1. Cotton P uptake and seed cotton yield were negatively correlated with the Qmax (P<0.01). Our results suggest that straw return may be a promising management practice to reduce mineral P fertilization without significant loss of seed cotton yield on coastal saline lands.

Phytomass and production components of colored cotton under salt stress in different phenological stages

ABSTRACT Scarcity of good quality water is a limiting factor for irrigated agriculture, especially in semi-arid regions, which induces the use of waters with high salt concentration in crop irrigation. In view of the above, the objective of this study was to evaluate the phytomass accumulation and production components of colored cotton genotypes during the different development stages, under conditions of high salinity, with plants grown in lysimeters under greenhouse conditions, at the Center for Technology and Natural Resources of the Federal University of Campina Grande, Paraíba, Brazil. Three cotton genotypes (‘BRS Rubi’, ‘BRS Topázio’ and ‘BRS Safira’) irrigated with salinized water (9 dS m-1) during the three stages of crop development (vegetative, flowering and fruiting) were evaluated. The experiment was conducted in a randomized block design with three repetitions and three plants per plot, in drainage lysimeters filled with 24.5 kg of an Oxisol, with sandy loam texture. Irrigation with salinized water during the vegetative stage promoted greater phytomass accumulation in the genotypes of naturally colored cotton. In the initial stages of the cotton development, irrigation with saline water can be used with the lowest losses in production components, which are negatively affected when saline water is applied in the fruiting stage. Among the genotypes, ‘BRS Topázio’ is the most tolerant to irrigation water salinity in terms of seed cotton weight and lint cotton weight, regardless of the development stage.

Improving boll capsule wall, subtending leaves anatomy and photosynthetic capacity can increase seed cotton yield under limited drip irrigation systems

Drought stress is considered to be the main source of yield reduction around the world. Improving plant performance under stressful environments by understanding growth and physio-biochemical responses are important. However, the detail mechanism of how boll capsule wall and subtending leaves anatomy, physio-biochemical characteristics and key enzymes i.e. Ribulose-1,5-bisphosphate carboxylase (RUBPC) and phosphoenolpyruvate carboxylase (PEPC) affect cotton (Gossypium hirsutum L.) yield have not yet been reported. To cover this knowledge gap, a two-year field experiment evaluated three drip irrigation rates [W1 (4800 m³ ha−1), W2 (3840 m³ ha−1) and W3 (2880 m³ ha−1)] effects on cotton main stem leaves, boll subtending leaves, capsule wall anatomy, biomass accumulation, RUBPC and PEPC activity. Compared with W1, W2 had 10.4–15.7 %, 8.3–24.6 %, 4.4–22.7 % and 5.0–15.3 % higher boll subtending leaf net photosynthetic rate, chlorophyll content, RUBP and PEPC activity at 21–42 days after anthesis. The palisade tissue thickness at 35 DAA (days after anthesis) and the ratio of palisade tissue to sponge tissue (p/s) of boll subtending leaf during 21–49 DAA were 7.7 % and 3.6–10.2 % higher for W2 over W1. Under W2treatment,improvements in these attributes significantly prolonged biomass accumulation rate (T, 6.9 d and 22.1 d) of main stem leaves and boll subtending leaf resulted in the maximum growth rate of seed cotton weight (Vx, 0.195 g d-1). Conclusively, higher photosynthetic capacity of the boll subtending leaves during 21–42 DAA and thicker capsule wall are the main drivers for achieving higher seed cotton weight under limited drip irrigation systems in arid region.

Toprak düzenleyicileri ve azot uygulamalarının pamukta (Gossypium hirsutum L.) verim ve lif teknolojik özelliklere etkisi

Çalışmada kimyasal gübre kullanımını azaltmak ve doğal kaynaklı toprak düzenleyiciler ile yeterli verim ve kaliteye ulaşmak amaçlanmıştır. 2019 yılında Amik Ovası koşullarında tesadüf bloklarında bölünmüş parseller deneme desenine göre yürütülen bu çalışmada pamukta (Gossypium hirsutum L.) bazı verim ve kalite öğeleri incelenmiştir. Denemede ana parsellere toprak düzenleyiciler (leonardit ve zeolit, 1000 ve 2000 kg ha-1), alt parsellere farklı azot dozları (0, 5, 10, 15, 20 kg ha-1) yerleştirilmiştir. İncelenen özellikler içerisinde bitki boyu, odun dalı sayısı, meyve dalı sayısı, koza sayısı, koza kütlü ağırlığı, lif inceliği, mukavemet ve 100 tohum ağırlığı her iki faktörden de etkilenmemiş, ortalamalar arasındaki fark istatistiki olarak önemsiz bulunmuştur. Farklı azot dozları yalnızca çırçır randımanı üzerinde istatistiki öneme sahipken, verim ve lif uzunluğunda her iki faktörün interaksiyonu gözlemlenmiştir. Doğal kaynaklı toprak düzenleyicilerin sürdürülebilir tarım hususunda potansiyeli ortaya konmuştur.

A Native Bee, Melissodes tepaneca (Hymenoptera: Apidae), Benefits Cotton Production.

The cotton agroecosystem is one of the most intensely managed, economically and culturally important cropping systems worldwide. Native pollinators are essential in providing pollination services to a diverse array of crops, including those which have the ability to self-pollinate. Cotton, which is autogamous, can potentially benefit from insect-mediated pollination services provided by native bees within the agroecosystem. Examined through two replicated experiments over two years, we hypothesized that native bees facilitated cross-pollination, which resulted in increased lint of harvested bolls produced by flowers exposed to bees and overall lint weight yield of the plant. Cotton bolls from flowers that were caged and exposed to bees, flowers that were hand-crossed, and bolls from flowers on uncaged plants exposed to pollinators had higher pre-gin weights and post-gin weights than bolls from flowers of caged plants excluded from pollinators. When cotton plants were caged with the local native bee Melissodes tepaneca, seed cotton weight was 0.8 g higher on average in 2018 and 1.18 g higher on average in 2019 than when cotton plants were excluded from bees. Cotton production gains from flowers exposed to M. tepaneca were similar when measuring lint and seed separately. Cotton flowers exposed over two weeks around the middle of the blooming period resulted in an overall yield gain of 12% to 15% on a whole plant basis and up to 24% from bolls produced from flowers exposed directly to M. tepaneca. This information complements cotton-mediated conservation benefits provided to native pollinators by substantiating native bee-mediated pollination services provided to the cotton agroecosystem.

The effect of defoliant application on yield and yield components of some cotton (Gossypium hirsutum L.) cultivars at timely and late sowing

This study was aimed to assess the effect of defoliant application on yield and yield components of some cotton cultivars at timely and late sowing under Harran Plain conditions in 2017 and 2018 growing seasons. Field trials were arranged employing randomized blocks split-split plots design with 3 replications. In the study, sowing times (i.e.10th of May and 10th of June) consisted the main plots, cultivars (i.e. Candia and Lima) placed in the sub-plots and defoliant applications (i.e. Control and Dropp Ultra (600 ml ha-1)) were in the sub-subplots. Each plot was sown with a length of 12 m and 6 rows, with a 70 cm inter-row and 15 cm intra-row spacing. In the trials, the defoliant chemical called Dropp Ultra (i.e.120 g Thidiazuron + 60 g Diuron) was used. The application was practiced when the 60 % of boll opened. It was found that Candia and Lima cotton cultivars sown timely gave seed cotton yields of 5296.7 and 5073.3 kg ha-1 respectively, whereas at late sowing gave the seed cotton yields of 4672.5 kg ha-1 and 4545.8 kg ha-1in 2017 and 2018; Candia gave the higher seed cotton yield (i.e. 5179.2 in 2017 and 5013.3 kg ha-1 in 2018) than Lima cultivar (i.e. 4790.0 in 2017 and 4605.8 kg ha-1 in 2018) in both years. Results indicated that that the defoliant application increased the seed cotton yield comparing control plots. Defoliant application positively influenced the seed cotton yield (kg ha-1), plant height (cm), number of opened bolls (per plant-1), boll weight (g) and boll seed cotton weight (g). However, there were no significant effects on the number of bolls (per plant-1) and 100 seed weight (g). It was concluded that defoliant application and timely sowing can be recommended for farmers in the region.

Ultraviolet B radiation affects growth, physiology and fiber quality of cotton

The effects of artificial biologically effective UV-B radiation on a range of growth and physiological parameters in two cotton (Gossypium hirsutum L.) cultivars (Romanos and Allegria) were recorded. Three levels of biologically effective UV-B were used: (1) zero (2) ambient and (3) elevated (determined as that associated with a notional 15% depletion of stratospheric ozone). Plants were grown under artificial light in growth chambers and subjected to the biologically effective UV-B radiation treatments. Compared to the zero level, the ambient and elevated biologically effective UV-B radiation significantly reduced plant height, leaf chlorophyll content, net photosynthetic rate, stomatal conductance, bract length, petal length, anthers number, pollen germination, seed cotton weight, fibre strength, fibre elongation, fibre micronaire, fibre maturity index, fibre spinning consistency index, mean fibre length, fibre yellowness and fibre uniformity index. Both the ambient and the elevated UV-B radiation also significantly increased stomatal density, short fibre index and fibre reflectance. Key words: UV-B radiation, cotton, photosynthesis, stomatal density, flower characteristics, pollen germination, seed cotton weight, fibre quality.

EFFECT OF DIFFERENT BORON APPLICATION ON COTTON YIELD COMPONENTS AND FIBER QUALITY PROPERTIES

This study was carried out to determine the effect of different boron application methods on cotton yield, plant growth and fiber technological properties. The study was conducted at Siirt University Faculty of Agriculture Department of Field Crops experimental area as randomized complete block design with four replications in 2018. Stoneville 468 cotton variety and boron liquid foliar fertilizer were used as material. Seven different boron applications were performed as (Control, 1000 cc ha-1 at pre-flowering stage, 2000 cc ha-1 at pre-flowering stage, 1000 cc ha-1 at flowering stage, 2000 cc ha-1 at flowering stage and 1000 cc ha-1 at boll formation stage, 2000 cc ha-1 at boll formation stage). The results of statistical analysis showed that there were significant differences between applications methods in terms of plant height and number of monopodial branches. But there were non-significant differences in terms of number of sympodial branches, number of first node of sympodial branch, number of nodes, height/node ratio, number of bolls, boll weight, seed cotton weight of per boll, number of seeds per boll, first picking percentage, 100 seeds weight, ginning percentage, seed cotton yield and fiber technological characteristics. In conclusion different application methods of boron increased plant height and number of monopodial branches of cotton when applied as 1000 and 2000 cc ha-1 at pre-flowering stages.

Agronomic traits at the seedling stage, yield, and fiber quality in two cotton (Gossypium hirsutum L.) cultivars in response to phosphorus deficiency

ABSTRACT Cotton is critical for phosphorus demands and very sensitive for its deficiency. However, identifying the effect of low-phosphorus tolerance on cotton growth, yield, and fiber quality by reducing phosphorus consumption. This may help to develop phosphorus-tolerant high-yielding cotton cultivars. In a two-year repeated (2015 and 2016) hydroponic experiment (using 0.01 and 1 mM KH2PO4), two cotton cultivars with phosphorus sensitivity (Lu 54; a low-phosphorus sensitive and Yuzaomian 9110; a low-phosphorus tolerant) were screened on the base of agronomic traits and physiological indices through correlation analysis, cluster analysis and principal component analysis from 16 cotton cultivars. Low phosphorus nutrition reduced the plant height, leaf number, leaf area, phosphorus accumulation and biomass in various organs of seedlings. The deficiency negatively affected the morphogenesis of seedlings, as well as yield and fiber quality. Further, these screened cultivars were tested in a pot experiment with 0, 50, 100, 150, 200 kg P2O5 ha−1 during 2016 and 2017. It was found to have a significant (P< 0.05) difference in boll number, lint yield, fiber strength, and micronaire at the harvest. Furthermore, after collectively analyzed the characteristics of Lu 54 and Yuzaomian 9110, there were six key indices that could improve the low phosphorus tolerance of cotton cultivars. These were root phosphorus accumulation, stem phosphorus accumulation percentage, leaf and total biomass of seedlings, seed cotton weight per boll and fiber length.

Agronomic performance of colored cotton influenced by irrigation with treated domestic sewage and potassium fertilization in semi-arid region of Brazil

This study evaluated the contribution of potassium (K) nutrition and application of wastewater depths to the agronomic performance of colored cotton. Treatments consisted of five irrigation depths (50, 75, 100, 125 and 150% of crop evapotranspiration -ETC) and five K doses (0, 50, 100, 150 and 200% of the recommendation for the crop) and an absolute control irrigated with 100% ETCwater depth and fertilized with 100% N-P-K recommendation. Each treatment and the control had four replicates. Plant height, stem diameter, leaf area and shoot dry matter accumulation of cotton were evaluated at 130 days after emergence (DAE), whereas seed cotton weight was evaluated at 135 DAE. Our findings indicate that the use of treated domestic sewage for 100% ETCreplacement promotes greater gains of weight and growth in colored cotton without the need for K fertilization, evidencing the potential of wastewater for colored cotton for sustainable agriculture.

Cotton Yield and Defoliation Efficiency in Response to Nitrogen and Harvest Aids

Core Ideas Defoliants enhanced seed cotton yield by increasing opening boll number. N application promoted cotton yield by increasing seed cotton weight per boll. 150 kg N ha−1 and thidiazuron+ethephon of 900+3000 g ai ha−1 was suggested. Appropriate nitrogen levels combined with safe rates of harvest aids can provide timely and efficient harvesting of cotton in the wheat–cotton double cropping system in the Yangtze River Valley Cotton Belt. Three rates of harvest aids (0+0, 450+1500, and 900+3000 g ai ha−1 of thidiazuron+ethephon) under four nitrogen levels (0, 75, 150, and 225 kg N ha−1) were established to study the interactive effects of N levels and harvest‐aid rates on defoliation, boll opening, and seed cotton yield in 2015 and 2016. Results showed that defoliation and boll opening percentages were significantly enhanced by 45 to 57% and by 35 to 41% after the application of harvest aids, especially for the elevated rate, under 150 and 225 kg N ha−1. Although a significant negative effect was observed on seed cotton weight per boll, total seed cotton yield was significantly increased by 28 to 42%, due to the favorable opening boll number after harvest‐aid application. Nitrogen application significantly increased seed cotton yield by 10 to 22%, owing to the enhanced seed cotton weight per boll, and the maximum total seed cotton yield was recorded under 150 kg N ha−1 when applied with harvest‐aid chemicals of 900+3000 g ai ha−1. Thus, the application of 150 kg N ha−1 combined with 900+3000 g ai ha−1 of harvest aids (thidiazuron+ethephon) was suggested for mechanized harvest in cotton to achieve a satisfactory defoliation and seed cotton yield in the Yangtze River Valley Cotton Belt.