Fiber Quality Research Articles

Experimental investigation on strengthening of Zea mays root fibres for biodegradable composite materials using potassium permanganate treatment

Humans are the only species who generate waste materials that cannot be broken down by natural processes. The ideal solution to this waste problem would be to employ only compostable materials. Biodegradable materials play a key role in creating a safer and greener world. Biodegradability is the gift that keeps on giving, in the sense of creating an Earth worth living. The future is thus best served by green energy, sustainability, and renewable resources. To realize such goals, waste should be considered as a valuable resource. In this context, Zea mays (Zm) root fibres, which are normally considered as agricultural waste, can be used as reinforcing substances in polymer matrices to produce structural composite materials. Before being used in composites, such fibres must be analysed for their physical properties. Chemical treatments can be employed to improve the structural quality of fibres, and the changes due to such modification can be analysed. Therefore, the current work examines the effect of permanganate treatment on the surface properties of Zm fibres. The raw and potassium permanganate-treated samples were assayed for various properties. Physical analysis of the fibre samples yielded details concerning the physical aspects of the fibres. The thermal conductivity and moisture absorption behaviour of the samples were analysed. Chemical analysis was employed to characterize the composition of both treated and untreated samples. p-XRD was employed to examine the crystalline nature of the Zm fibres. Numerous functional groups present in each sample were analysed by FTIR. Thermogravimetric analysis was used to determine the thermal stability of Zm fibres. Elemental analysis (CHNS and EDS) was used to determine the elemental concentrations of both raw and treated samples. The surface alterations of Zm fibres brought on by treatment were described using SEM analysis. The characteristics of Zm roots and the changes in quality due to treatment were reviewed, and there were noticeable effects due to the treatment. Both samples would have applications in various fields, and each could be used as a potential reinforcing material in the production of efficient bio-composites.

Genetic and Molecular Regulation of Cotton Fiber Initiation and Elongation

Cotton fiber, a crucial and sustainable resource for global textile production, undergoes a complex five-stage developmental process, encompassing initiation, elongation, transition, secondary cell wall biosynthesis, and maturation. These elongated single-cell fibers originate from the outer ovule epidermis. The development of cotton fibers involves intricate changes in gene expression and physiological processes, resulting in a nearly pure cellulose product that is vital for the global cotton industry. Decoding the genes associated with fiber development enhances our understanding of cotton fiber mechanisms and facilitates the cultivation of varieties with enhanced quality. In recent decades, advanced omics approaches, including genomics, transcriptomics, and proteomics, have played a pivotal role in identifying the genes and gene products linked to cotton fiber development, including the MYB transcription factor family, which coordinates cotton fiber development. Molecular studies have revealed the transcription factors, like MYB, WRKY, Homeodomain Leucine Zipper (HD-ZIP), and basic helix–loop–helix (bHLH), influencing fiber initiation and elongation. The intricate interplay of phytohormones, like auxin, gibberellic acid (GA), brassinosteroids (BRs), jasmonic acid (JA), ethylene, abscisic acid (ABA), and cytokinin, is explored, providing a comprehensive perspective on the shaping of cotton fibers. Numerous candidate genes and cellular processes affecting various aspects of fiber development hold promise for genetic engineering or marker-assisted breeding to improve fiber quality. This review presents a comprehensive overview of key achievements in cotton molecular biology, with a specific emphasis on recent advancements in understanding the transcription factors and phytohormones involved in cotton fiber initiation and elongation.

Conversion of Waste Agricultural Biomass from Straw into Useful Bioproducts—Wheat Fibers and Biofuels

Straw, the primary agricultural waste, constitutes approximately 20% of the total biomass in the EU. Only a small fraction of the material is applied in various products, e.g., animal bedding, mulch, building, and composite materials, while a significantly larger portion is often burned in the field. This practice, while prohibited for several reasons, including the increased risk of fire and the release of carbon dioxide contributing to global warming, is still prevalent. Given the increasingly evident effects of climate change, EU legislation aims to reduce greenhouse gas emissions as much as possible. One of the strategies includes applying the cascade principle in the circular economy. This principle aims to use the entire raw material, in this case, cereal crops, such that the products with the highest added value, like cellulose fibers from cereal straw, are extracted first. The vast potential for utilizing lignocellulosic agro-waste sustainably arises from its status as the most abundant organic compound on Earth. Its significant presence, renewability, and biodegradability make it a desirable source for producing materials in numerous industries. This study examines the potential of wheat fibers, isolated from the straw of two distinct cultivars (Srpanjka represents an old variety, and Kraljica represents the new variety) primarily for application in technical textiles. The following testing methods were applied: determination of wheat fibers and residues yield, fibers tensile properties, length, moisture content/regain, density, morphology, and Fourier transform infrared (FTIR) spectroscopy. The yield of isolated fibers relies on the wheat variety and the climatic conditions affecting plant growth, resulting in fiber yields from 10.91% to 15.34%. Fourier transform infrared (FTIR) analysis indicates reduced peak intensity, which is related to hemicellulose and lignin content, suggesting their improved deposition following the process of chemical maceration. Wheat fiber quality was found to be comparable to cotton fibers regarding its density. However, they showed a significant difference in higher moisture regain (9.72–11.40%). The vast majority of the scientific papers related to wheat fibers did not indicate the length of the individual fibers obtained by chemical maceration nor their strength. Therefore, this paper indicated that both varieties demonstrated sufficient fiber tenacity (greater than 10 cN/tex) and fiber length (2–3 cm), stressing the spinning potential of these fibers into yarns and extending their use to the apparel industry. Moreover, our research underscores the feasibility of adhering to the zero-waste principle. A high percentage of solid waste remaining after fiber extraction (25.3–39.5%) was successfully used for biofuel production, thus closing the loop in the circular economy.

Behavior of hybrid R.C. columns under the effect of fire furnace (experimental and numerical study)

ABSTRACT When fire exposes the hybrid reinforced concrete R.C. columns, it seriously damages the mechanical qualities of steel bars, concrete, and glass fiber reinforced polymer G.F.R.P. bars. This study focused on hybrid reinforced concrete R.C. columns’ behaviour and failure modes that were eccentrically and concentrically loaded during the fire until a failure. The behaviour of these R.C. columns will be quantified by demonstrating and going over the load-displacement relationships, failure mechanisms, crack patterns, strain distribution at failure, ductility, and stiffness. The number and width of cracks in the columns heated to 300 ºC, 500 ºC, and 700 ºC were significantly more than in the unheated columns. When the specimen is exposed to high temperatures, less force is needed to cause a first crack, and the ultimate strength decreases as the applied load and eccentricity ratio values increase. Hence, all specimens’ axial and lateral displacement values increase. This can be explained by two factors: the depth of the practical section because of the thermal expansion effect and the cracking expansion of concrete when subjected to high temperatures, and heating causes a loss in stiffness of column because the elasticity of concrete’s modulus of elasticity drops.

Review: Natural Fibres for Textile Application

Abstract Textile industries have a central role in human health, well-being, and the global economy. Sustainable development has become a necessity in this sector by utilizing natural, renewable, and biodegradable raw materials such as kenaf, ramie, pineapple fibres, wool, cotton, and other natural fibres. Science and technology expanding option for sustainable fibre-use in the textile industry due to source-scarcity of raw materials, environmental impact concerns, and market demands. This review discusses various aspects related to natural fibres, and their applications in addition to cotton, which is the most applied natural fibres for the textile industry. Key characteristics of natural fibres include physical, mechanical, and surface properties. These properties vary and are influenced by the chemical composition of the fibres and environmental conditions in growth and production. For plant-based fibres how the fibres are extracted from the plant, and from which vegetative or reproductive structures they are extracted, can affect the ultimate fibre quality and uses of the fibres. Similarly, there are a range of processing methods that affect the final quality and utility of the fibres and application in industry.

GhATL68b regulates cotton fiber cell development by ubiquitinating the enzyme required for β-oxidation of polyunsaturated fatty acids

E3 ligases are key enzymes required for protein degradation. Here, we identified a C3H2C3 RING domain-containing E3 ubiquitin ligase gene named GhATL68b. It is preferentially and highly expressed in developing cotton fiber cells and shows greater conservation in plants than in animals or archaea. The four orthologous copies of this gene in various diploid cottons and eight in the allotetraploid G. hirsutum were found to have originated from a single common ancestor that can be traced back to Chlamydomonas reinhardtii at about 992 million years ago. Structural variations in the GhATL68b promoter regions of G. hirsutum, G. herbaceum, G. arboreum, and G. raimondii are correlated with significantly different methylation patterns. Homozygous CRISPR-Cas9 knockout cotton lines exhibit significant reductions in fiber quality traits, including upper-half mean length, elongation at break, uniformity, and mature fiber weight. In vitro ubiquitination and cell-free protein degradation assays revealed that GhATL68b modulates the homeostasis of 2,4-dienoyl-CoA reductase, a rate-limiting enzyme for the β-oxidation of polyunsaturated fatty acids (PUFAs), via the ubiquitin proteasome pathway. Fiber cells harvested from these knockout mutants contain significantly lower levels of PUFAs important for production of glycerophospholipids and regulation of plasma membrane fluidity. The fiber growth defects of the mutant can be fully rescued by the addition of linolenic acid (C18:3), the most abundant type of PUFA, to the ovule culture medium. This experimentally characterized C3H2C3 type E3 ubiquitin ligase involved in regulating fiber cell elongation may provide us with a new genetic target for improved cotton lint production.

Assessment of Segal method for identifying crystallinity evolution in developing cotton fibers

AbstractThe crystallinity index (CI) is an important parameter in evaluating cotton fiber quality. Due to its ease and speed in measuring CIs from X‐ray diffraction (XRD) patterns, the Segal method is popularly used. In this study, we assessed the Segal method for monitoring the crystallinity evolution in developing cotton (Gossypium L.) fibers between 20 and 60 days post anthesis (DPAs) by comparing Segal CIs with those obtained from a Fourier transform infrared spectroscopy‐based method and other XRD‐based methods. The Segal method estimated higher CIs than other methods, especially for shorter DPAs. The Segal method suggested a rapid evolution of crystallinity in the early developmental stage, whereas other methods suggested a gradual increase in crystallinity. The calculation of diffraction patterns for cellulose Iβ crystallites with different sizes showed very little effect of the crystallite size on the Segal CIs for developing cotton fibers studied.

Pyramiding effects of favorable haplotypes of loci on major fiber yield and quality traits in Upland Cotton (Gossypium hirsutum L.)

Enhancing both fiber yield and quality is crucial in cotton breeding programs. Typically, a negative correlation exists between fiber yield and quality, and the strategy to decouple this relationship remains obscure. In this study, we generated three multi-parent intercross populations, encompassing 2,852 F2:3 lines, which represent fiber yield potential (FY), fiber quality potential (FQ), and a combination of both potentials (FYQ), derived from sixteen diverse Upland cotton cultivars. We utilized twenty-four kompetitive allele specific PCR (KASP) molecular markers, based on previously identified loci associated with fiber quality (FL5/FS1, FL3/FS2, and FL2) and fiber yield (BW1, BW2, and LP1), for genotyping purposes. The pyramiding of favorable haplotypes from three fiber quality-associated loci resulted in an increase exceeding 10% in fiber length (FL5+FL3+FL2+LP1) and in an increase exceeding 17% in fiber strength (FL5+FL3+FL2). Notably, our findings suggest that the combination of FL3+FL2+BW1+LP1 alleles has the potential to disrupt the negative correlation between fiber yield and quality. Lines harboring these alleles simultaneously exhibited an elevated lint percentage (LP), as well as enhanced fiber length and quality. This study offers robust molecular markers for the efficient selection of superior progeny with desired phenotypes in the early stages of cotton breeding. Furthermore, the allelic combination that concurrently improves fiber quality and yield sheds light on for further exploration the molecular basis of breaking unfavorable linkages in crop breeding.

Genome resources for three modern cotton lines guide future breeding efforts

Cotton (Gossypium hirsutum L.) is the key renewable fibre crop worldwide, yet its yield and fibre quality show high variability due to genotype-specific traits and complex interactions among cultivars, management practices and environmental factors. Modern breeding practices may limit future yield gains due to a narrow founding gene pool. Precision breeding and biotechnological approaches offer potential solutions, contingent on accurate cultivar-specific data. Here we address this need by generating high-quality reference genomes for three modern cotton cultivars (‘UGA230’, ‘UA48’ and ‘CSX8308’) and updating the ‘TM-1’ cotton genetic standard reference. Despite hypothesized genetic uniformity, considerable sequence and structural variation was observed among the four genomes, which overlap with ancient and ongoing genomic introgressions from ‘Pima’ cotton, gene regulatory mechanisms and phenotypic trait divergence. Differentially expressed genes across fibre development correlate with fibre production, potentially contributing to the distinctive fibre quality traits observed in modern cotton cultivars. These genomes and comparative analyses provide a valuable foundation for future genetic endeavours to enhance global cotton yield and sustainability.

СТАНДАРТИЗАЦІЯ ЛЛЯНОЇ СИРОВИНИ: ПОРІВНЯЛЬНИЙ АНАЛІЗ ДОСВІДУ США ТА УКРАЇНИ

The main problem in the primary processing of bast fiber raw materials is Ukraine's significant lag in the field of standardization compared to the USA, which negatively affects production efficiency, product quality, and competitiveness in the global market. The article aims to provide a comprehensive comparative analysis of flax raw material quality assessment systems in Ukraine and the USA, identify the key reasons for Ukraine's lag, and develop practical solutions to address these issues. The research found that while Ukraine still relies on outdated standards for flax fiber quality evaluation, which are primarily based on organoleptic methods and do not take into account modern requirements, the USA is actively developing and implementing innovative standards that regulate a wide range of quality indicators, such as fiber fineness, strength, color, shive content, and other important parameters. The main reasons for Ukraine's lag in the field of flax standardization include persistent economic difficulties, obsolete infrastructure and equipment, insufficient funding for scientific research, and weak integration with international standardization organizations. The authors propose a set of solutions to overcome these challenges, which involve increasing state support for the flax industry, intensifying research efforts aimed at developing new methods for assessing the quality of flax raw materials, harmonizing national standards with international ones, deepening international cooperation, and fostering the development of industry associations and clusters. The article emphasizes the necessity of introducing modern instrumental methods for assessing the quality of flax raw materials, such as spectrophotometry for color measurement, computer vision systems for analyzing fiber structure, and automated methods for determining fineness and shive content. The importance of developing standards for new and innovative flax products to expand the range, improve the competitiveness of domestic products, and enter promising markets is underlined.

GhFAD3-4 Promotes Fiber Cell Elongation and Cell Wall Thickness by Increasing PI and IP3 Accumulation in Cotton.

The omega-3 fatty acid desaturase enzyme gene FAD3 is responsible for converting linoleic acid to linolenic acid in plant fatty acid synthesis. Despite limited knowledge of its role in cotton growth, our study focused on GhFAD3-4, a gene within the FAD3 family, which was found to promote fiber elongation and cell wall thickness in cotton. GhFAD3-4 was predominantly expressed in elongating fibers, and its suppression led to shorter fibers with reduced cell wall thickness and phosphoinositide (PI) and inositol triphosphate (IP3) levels. Transcriptome analysis of GhFAD3-4 knock-out mutants revealed significant impacts on genes involved in the phosphoinositol signaling pathway. Experimental evidence demonstrated that GhFAD3-4 positively regulated the expression of the GhBoGH3B and GhPIS genes, influencing cotton fiber development through the inositol signaling pathway. The application of PI and IP6 externally increased fiber length in GhFAD3-4 knock-out plants, while inhibiting PI led to a reduced fiber length in GhFAD3-4 overexpressing plants. These findings suggest that GhFAD3-4 plays a crucial role in enhancing fiber development by promoting PI and IP3 biosynthesis, offering the potential for breeding cotton varieties with superior fiber quality.

Transcriptome analysis of Gossypium hirsutum cultivar Zhongzhimian No.2 uncovers the gene regulatory networks involved in defense against Verticillium dahliae

BackgroundCotton is globally important crop. Verticillium wilt (VW), caused by Verticillium dahliae, is the most destructive disease in cotton, reducing yield and fiber quality by over 50% of cotton acreage. Breeding resistant cotton cultivars has proven to be an efficient strategy for improving the resistance of cotton to V. dahliae. However, the lack of understanding of the genetic basis of VW resistance may hinder the progress in deploying elite cultivars with proven resistance.ResultsWe planted the VW-resistant Gossypium hirsutum cultivar Zhongzhimian No.2 (ZZM2) in an artificial greenhouse and disease nursery. ZZM2 cotton was subsequently subjected to transcriptome sequencing after Vd991 inoculation (6, 12, 24, 48, and 72 h post-inoculation). Several differentially expressed genes (DEGs) were identified in response to V. dahliae infection, mainly involved in resistance processes, such as flavonoid and terpenoid quinone biosynthesis, plant hormone signaling, MAPK signaling, phenylpropanoid biosynthesis, and pyruvate metabolism. Compared to the susceptible cultivar Junmian No.1 (J1), oxidoreductase activity and reactive oxygen species (ROS) production were significantly increased in ZZM2. Furthermore, gene silencing of cytochrome c oxidase subunit 1 (COX1), which is involved in the oxidation-reduction process in ZZM2, compromised its resistance to V. dahliae, suggesting that COX1 contributes to VW resistance in ZZM2.ConclusionsOur data demonstrate that the G. hirsutum cultivar ZZM2 responds to V. dahliae inoculation through resistance-related processes, especially the oxidation-reduction process. This enhances our understanding of the mechanisms regulating the ZZM2 defense against VW.

Can cotton seed size mitigate preemergence herbicides injury?

AbstractPreemergence herbicides (PRE) have become integral for weed control in cotton (Gossypium hirsutum L.), especially with the prevalence of glyphosate‐resistant Palmer amaranth (Amaranthus palmeri S. Wats.). However, PRE herbicides have the potential to injure cotton seedlings. Previous research has shown that a larger seed size can compensate for early season stresses which could mitigate potential PRE herbicide injury. In this study, we evaluated growth and yield of two cotton varieties with different seed sizes (large and small) in response to three PRE herbicides alone and in combination. Percent visual injury, biomass, plant heights, stand counts, lint yield, and fiber quality were obtained to make comparisons between seed sizes and PRE treatments. In both years, the large‐seeded variety had a higher biomass at 3‐leaf stage. However, both varieties had “grown out” of the herbicide injury at 42 days after planting and the early season vigor of the larger seed did not result in higher lint yield. The small‐seeded variety had greater yield in both years of the study. This may be due to the genetics or yield potential of the small‐seeded variety, or bolls containing smaller seeds typically have a greater number of seeds with more opportunity for lint production. Cotton treated with diuron had the most visual injury and decreased biomass. The results from this study will allow growers to make more informed decisions with regards to seed size, vigor, and PRE herbicide choices. If crop injury is likely, a larger seeded cotton variety may mitigate potential early season injury; however, seed size did not have an impact on final lint yield.

Utilization of Areca leaf residues for sustainable production of greyboard

This study primarily focused on the production of greyboard using waste materials from small scale industries, and specifically using Areca leaf waste fibers as a sustainable and environmentally friendly resource. Areca leaf waste fibers were employed as the primary raw material for greyboard manufacturing. The resulting greyboard exhibited commendable properties, including a tear index of 7.53 mN·m2/g, tensile index of 18.34·N·m/g (i.e., breaking length of 1870 m), burst factor of 9.24 (gf/cm2)/(g/m2) and stiffness factor of 33.1. This greyboard was created through a series of steps, including hydrothermal treatment of the material at 155°C and mechanical pulping refinement. The produced greyboard met the specifications outlined in the Indian Standard 2617 (1967) for greyboard. The key objective of this work was to leverage agricultural waste resources to develop a chemical-free greyboard, resulting in reduced waste disposal in open fields and a decrease in chemical usage within the greyboard manufacturing industry. Various characterization techniques, including field emission scanning electron microscopy (FE-SEM), attenuated total reflection•Fourier transform infrared (ATR-FTIR) analysis, and X-ray diffraction (XRD), were used to assess the fiber quality, including aspects such as functional groups, morphology, and crystallinity for the materials used in the manufacturing process.

Retting with efficient microbial consortium helps in improving jute fibre quality and profitability: a study in Eastern India

Aim: To determine the effect of application of microbial consortium for faster retting of jute (Corchorus spp.) over conventional retting without microbial consortium on jute fibre recovery and fibre quality improvement. Methodology: Large scale retting trials of jute were conducted in five important jute growing districts of West Bengal, India for four consecutive years with and without microbial consortium. After completion of jute retting, fibre was extracted manually, processed and dry fibre weight was recorded. Jute fibre samples were collected and analysed for fibre quality parameters. The fibre strength was estimated using electronic fibre bundle strength tester, fibre fineness by air flow method and root content is measured as the length of fibre up to which root is present out of the total length of the fibre and is expressed as percent length. Results: Application of microbial consortium reduced the retting duration and root content in jute fibre in all the locations irrespective of years. The jute fibre recovery increased by 9.64 to 10.97% and 9.73 to 10.63% with microbial consortium over without microbial consortium respectively in different locations and different years under study. The maximum jute fibre yield with (33.17 q ha-1) and without microbial consortium (29.89 q ha-1) was recorded in Murshidabad district. Nadia district recorded significantly higher fibre strength of 24.92 g tex-1 and lowest retting duration of 11.92 days with microbial consortium among all the locations. Interpretation: The application of microbial consortium improved the fibre recovery and fibre quality leading to the increase in net income by ₹15624 to ₹18017 ha-1 of jute farmers. Hence, the application of microbial consortium for jute retting can be used extensively by the jute farming community in jute growing states of India for faster retting of jute along with quality fibre production, higher net income and doubling farmers’ income. Key words: Corchorus spp., Fibre quality, Jute retting, Microbial consortiu

Insights into genetic diversity and functional significance of the bHLH genes in cotton fiber development

This study investigated the identification and distribution of single nucleotide polymorphisms (SNPs) within basic Helix-Loop-Helix (bHLH) transcription factors (TFs) across diverse cotton (Gossypium hirsutum) accessions, including wild, landrace, and improved varieties. Comprehensive genomic analyses revealed substantial SNP diversity in wild cotton, distinct from that observed in landraces and improved accessions. Comparative analysis showed notable variations in SNP abundance and impact levels across different accessions, with missense SNPs being prevalent. Nucleotide substitution patterns highlighted the dominance of G>A and A>G substitutions. Population genetic analyses unveiled significant genetic diversity within wild accessions and distinct clustering between wild and improved accessions. Temporal expression profiling of bHLH genes during cotton fiber development demonstrated dynamic expression patterns, emphasizing their roles in fiber initiation, elongation, and cellulose biosynthesis. Moreover, association analysis identified SNPs significantly associated within bHLH genes, particularly GhbHLH149, with fiber quality traits, indicating their potential functional significance. Population genetic analyses further revealed evidence of positive selection on GhbHLH149 during cotton improvement. This study provides a comprehensive understanding of SNP diversity, gene expression dynamics, and genetic selection in bHLH genes, offering valuable insights for future cotton breeding efforts aimed at improving fiber quality traits in cotton.

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.

Investigation of salt tolerance in cotton germplasm by analyzing agro-physiological traits and ERF genes expression

The development of genotypes that can tolerate high levels of salt is crucial for the efficient use of salt-affected land and for enhancing crop productivity worldwide. Therefore, incorporating salinity tolerance is a critical trait that crops must possess. Salt resistance is a complex character, controlled by multiple genes both physiologically and genetically. To examine the genetic foundation of salt tolerance, we assessed 16 F1 hybrids and their eight parental lines under normal and salt stress (15 dS/m) conditions. Under salt stress conditions significant reduction was observed for plant height (PH), bolls/plant (NBP), boll weight (BW), seed cotton yield (SCY), lint% (LP), fiber length (FL), fiber strength (FS), potassium to sodium ratio (K+/Na+), potassium contents (K+), total soluble proteins (TSP), carotenoids (Car) and chlorophyll contents. Furthermore, the mean values for hydrogen peroxide (H2O2), sodium contents (Na+), catalase (CAT), superoxide dismutase (SOD), peroxidase (POD), and fiber fineness (FF) were increased under salt stress. Moderate to high heritability and genetic advancement was observed for NBP, BW, LP, SCY, K+/Na+, SOD, CAT, POD, Car, TSP, FL, and FS. Mean performance and multivariate analysis of 24 cotton genotypes based on various agro-physiological and biochemical parameters suggested that the genotypes FBS-Falcon, Barani-333, JSQ-White Hold, Ghauri, along with crosses FBS-FALCON × JSQ-White Hold, FBG-222 × FBG-333, FBG-222 × Barani-222, and Barani-333 × FBG-333 achieved the maximum values for K+/Na+, K+, TSP, POD, Chlb, CAT, Car, LP, FS, FL, PH, NBP, BW, and SCY under salt stress and declared as salt resistant genotypes. The above-mentioned genotypes also showed relatively higher expression levels of Ghi-ERF-2D.6 and Ghi-ERF-7A.6 at 15 dS/m and proved the role of these ERF genes in salt tolerance in cotton. These findings suggest that these genotypes have the potential for the development of salt-tolerant cotton varieties with desirable fiber quality traits.

Exploitation of heterotic effects in F1 hybrids for promoting earliness, yield components, and fiber quality of upland cotton (Gossypium hirsutum L.) genotypes

Exploitation of heterotic effects in F1 hybrids for promoting earliness, yield components, and fiber quality of upland cotton (Gossypium hirsutum L.) genotypes

Genomic insights into local adaptation of upland cotton in China and Pakistan.

Different kinship and resistance to cotton leaf curl disease (CLCuD) and heat were found between upland cotton cultivars from China and Pakistan. 175 SNPs and 82 InDels loci related to yield, fiber quality, CLCuD, and heat resistance were identified. Elite alleles found in Pakistani accessions aided local adaptation to climatic condition of two countries. Adaptation of upland cotton (Gossypium hirsutum) beyond its center of origin is expected to be driven by tailoring of the genome and genes to enhance yield and quality in new ecological niches. Here, resequencing of 456 upland cotton accessions revealed two distinct kinships according to the associated country. Fiber quality and lint percentage were consistent across kinships, but resistance to cotton leaf curl disease (CLCuD) and heat was distinctly exhibited by accessions from Pakistan, illustrating highly local adaption. A total of 175 SNP and 82 InDel loci related to yield, fiber quality, CLCuD and heat resistance were identified; among them, only two overlapped between Pakistani and Chinese accessions underscoring the divergent domestication and improvement targets in each country. Loci associated with resistance alleles to leaf curl disease and high temperature were largely found in Pakistani accessions to counter these stresses prevalent in Pakistan. These results revealed that breeding activities led to the accumulation of unique alleles and helped upland cotton become adapted to the respective climatic conditions, which will contribute to elucidating the genetic mechanisms that underlie resilience traits and help develop climate-resilient cotton cultivars for use worldwide.