Background As the most widely cultivated fiber crop, cotton production depends on hybridization to unlock the yield potential of current varieties. A deep understanding of genetic dissection is crucial for the cultivation of enhanced hybrid plants with desired traits, such as high yield and fine fiber quality. In this study, the general combining ability (GCA) and specific combining ability (SCA) of yield and fiber quality of nine cotton parents (six lines and three testers) and eighteen F₁ crosses produced using a line × tester mating design were analyzed.
Results The results revealed significant effects of genotypes, parents, crosses, and interactions between parents and crosses for most of the studied traits. Moreover, the effects of both additive and non-additive gene actions played a notably significant role in the inheritance of most of the yield and fiber quality attributes. The F₁ hybrids of (Giza 90 × Aust) × Giza 86, Uzbekistan 1 × Giza 97, and Giza 96 × Giza 97 demonstrated superior performance due to their favorable integration of high yield attributes and premium fiber quality characteristics. Path analysis revealed that lint yield has the highest positive direct effect on seed cotton yield, while lint percentage showed the highest negative direct effect on seed cotton yield. Principal component analysis identified specific parents and hybrids associated with higher cotton yield, fiber quality, and other agronomic traits.
Conclusion This study provides insights into identifying potential single- and three-way cross hybrids with superior cotton yield and fiber quality characteristics, laying a foundation for future research on improving fiber quality in cotton.

Background Cotton (Gossypium hirsutum L.) is one of the most significant fibre and cash crops and plays an important role in Indian industrial and agricultural economies. However, over the years quantity and quality have been hampered by the pest leafhopper. Leafhopper alone has been shown to cause yield losses of up to 40%. In this study, screening and evaluation were performed to identify and categorize 100 cotton genotypes along with 5 checks as resistant, moderately resistant, sensitive and highly sensitive to leafhoppers.
Results A total of hundred genotypes were evaluated along with five checks for leafhopper resistance. Based on the screening results, a total of 19 genotypes were resistant to leafhoppers, which was on par with the findings of the check KC 3. The contents of total soluble sugar, total soluble protein, and total free amino acids were significantly positively correlated with the mean grade, whereas total phenols content and trichome density were significantly negatively correlated with the susceptibility grade. However, based on screening and biochemical analysis, the genotypes KC 2, JR-23, Samaru-26-T, D 4, TCH 1728, RS 253, and B-61-1862 exhibited high resistance to leafhopper.
Conclusion According to the findings of this study, choosing genotypes with high total phenolics content together with high trichome density and low contents of total soluble sugar, total soluble protein, and free amino acids may aid in the development of resistant genotypes.

Background Cotton is an economically important crop. It is crucial to find an effective method to improve cotton yield, and one approach is to decrease the abscission of cotton bolls and buds. However, the lack of knowledge of the genetic and molecular mechanisms underlying cotton boll abscission traits has hindered genetic improvements.
Results Pearson’s correlation analysis revealed a significant positive correlation between boll abscission rates 1 (AR1) and boll abscission rates 2 (AR2). A genome-wide association study was conducted on 145 loci that exhibited high polymorphism and were uniformly distributed across 26 chromosomes (pair). The study revealed 18, 46, and 62 markers that were significantly associated with boll abscission, fiber quality, and yield traits (P < 0.05), explaining 1.75%-7.13%, 1.16%-9.58%, and 1.40%-5.44% of the phenotypic variation, respectively. Notably, the marker MON_SHIN-1584b was associated with the cotton boll abscission trait, whereas MON_CGR5732a was associated with cotton boll abscission and fiber quality traits. Thirteen of the marker loci identified in this study had been previously reported. Based on phenotypic effects, six typical cultivars with elite alleles related to cotton boll abscission, fiber quality, and yield traits were identified. These cultivars hold great promise for widespread utilization in breeding programs.
Conclusions These results lay the foundation for understanding the molecular regulatory mechanism of cotton boll abscission and provide data for the future improvement of cotton breeding.

Background Globally, the cultivation of cotton is constrained by its tendency for extended periods of growth. Early maturity plays a potential role in rainfed-based multiple cropping system especially in the current era of climate change. In the current study, a set of 20 diverse Gossypium hirsutum genotypes were evaluated in two crop seasons with three planting densities and assessed for 11 morphological traits related to early maturity. The study aimed to identify genotype(s) that mature rapidly and accomplish well under diverse environmental conditions based on the two robust multivariate techniques called multi-trait stability index (MTSI) and multi-trait genotype-ideotype distance index (MGIDI).
Results MTSI analysis revealed that out of the 20 genotypes, three genotypes, viz., NNDC-30, A-2, and S-32 accomplished well in terms of early maturity traits in two seasons. Furthermore, three genotypes were selected using MGIDI method for each planting densities with a selection intensity of 15%. The strengths and weaknesses of the genotypes selected based on MGIDI method highlighted that the breeders could focus on developing early-maturing genotypes with specific traits such as days to first flower and boll opening. The selected genotypes exhibited positive genetic gains for traits related to earliness and a successful harvest during the first and second pickings. However, there were negative gains for traits related to flowering and boll opening.
Conclusion The study identified three genotypes exhibiting early maturity and accomplished well under different planting densities. The multivariate methods (MTSI and MGIDI) serve as novel approaches for selecting desired genotypes in plant breeding programs, especially across various growing environments. These methods offer exclusive benefits and can easily construe and minimize multicollinearity issues.

Background Understanding the mechanism of male sterility is crucial for producing hybrid seeds and developing sterile germplasm resources. However, only a few cytoplasmic male sterility (CMS) lines of cotton have been produced due to several challenges, like inadequate variation of agronomic traits, incomplete sterility, weak resilience of restorer lines, and difficulty in combining strong dominance. Therefore, the morphological and cytological identification of CMS in cotton will facilitate hybrid breeding.
Results Two F₂ segregating populations of cotton were constructed from cytoplasmic male sterile lines (HaA and 01A, maternal) and restorer lines (HaR and 26R, paternal). Genetic analysis of these populations revealed a segregation ratio of 3:1 for fertile to sterile plants. Phenotypic analysis indicated no significant differences in traits of flower bud development between sterile and fertile plants. However, sterile plants exhibited smaller floral organs, shortened filament lengths, and anther atrophy on the flowering day in comparison with the fertile plants. When performed scanning electron microscopy (SEM), the two F₂ populations revealed morphological variations in the anther epidermis. Cellular analysis showed no significant differences in pollen development before pollen maturation. Interestingly, between the pollen maturation and flowering stages, the tapetum layer of sterile plants degenerated prematurely, resulting in abnormal pollen grains and gradual pollen degradation.
Conclusion The results of this study suggest that fertility-restoring genes are controlled by a single dominant gene. Sterile plants exhibit distinctive floral morphology, which is characterized by stamen atrophy and abnormal anthers. Pollen abortion occurs between pollen maturity and flowering, indicating that premature tapetum degradation may be the primary cause of pollen abortion. Overall, our study provides a theoretical basis for utilizing CMS in hybrid breeding and in-depth investigation of the dominant configuration of cotton hybrid combinations, mechanisms of sterility, and the role of sterile and restorer genes.

Cotton, an important industrial crop cultivated in more than 70 countries, plays a major role in the livelihood of millions of farmers and industrialists. Cotton is mainly grown for its fiber, an economic component that can be differentiated from its epidermal cells in the outer integument of a developing seed. Fiber length, fiber strength, and fiber fineness are three main attributes that contribute to the quality of cotton fibers. Recent advancements in genomics have identified key genes, which are the most important factors that govern these three traits, can be introduced into cultivars of interest via gene editing, marker-assisted selection, and transgenics, thus the narrow genetic background of cotton can be addressed and its fiber quality traits can be enhanced. Over the past two decades, quantitative trait loci (QTLs) have been mapped for different fiber traits, approximately 1 850 QTLs have been mapped for fiber length, fiber strength, and fineness among which a few genes have been edited for quality improvement in cotton. In this background, the current review covers the development and the factors that influence these traits, along with the reported genes, QTLs, and the edited genomes for trait improvement.

Background Studies on genetic variation and combining ability are essential tools to employ the suitable breeding programme, particularly for hybrid production, to exploit the heterosis in cross-pollinated crops like cotton. Thus, combining ability studies in desi cotton (Gossypium arboreum L.) was carried out using 13 diverse parents through diallel mating design, evaluating 78 F₁ hybrids along with their parents, without reciprocals using Griffing’s and Hayman’s approaches.
Results Genotypes H 509, AC 3265, AKH 496, and PBN 565 exhibited superior per se performance, indicating their potential use as parents in future breeding programs to develop superior hybrids. The general combining ability (GCA) effect of the genotypes revealed that AC 3097 and AKA 13-SP1 were good general combiners for most traits in this study. Genotypes PBS 1127-SP1, AKH 496, H 509, N11-54-31-32, and AKA 13-SP1 exhibited strong combining ability, contributing to a significant specific combining ability (SCA) effect in seven selected crosses (AC 3265 × PBS 1127-SP1, AKH 496 × H 509, AKH 496 × AC 3097, PBS 1127-SP1 × N11-54-31-32, AC 3216 × AKA 13-SP1, H 503 × N11-54-31-32, and H 509 × AKA 13-SP1) for yield improvement. These crosses showed positive heterosis in a positive direction.
Conclusion From the present study, five genotypes (AC 3097, AKA 13-SP1, N11-54-31-32, AC 3265, and H 509) were identified as good general combiners for producing hybrids, and seven combinations showed a promising hybrid for future breeding programs.

Background Cotton is an important cash crop in China and a key component of the global textile market. Verticillium wilt is a major factor affecting cotton yield. Single nucleotide polymorphism (SNP) markers and phenotypic data can be used to identify genetic markers and loci associated with cotton resistance to Verticillium wilt. We used eight upland cotton parent materials in this study to construct a multiparent advanced generation inter-cross (MAGIC) population comprising 320 lines. The Verticillium wilt resistance of the MAGIC population was identified in the greenhouse in 2019, and the average relative disease index (ARDI) was calculated. A genome-wide association study (GWAS) was performed to discover SNP markers/genes associated with Verticillium wilt resistance.
Results ARDI of the MAGIC population showed wide variation, ranging from 16.7 to 79.4 across three replicates. This variation reflected a diverse range of resistance to Verticillium wilt within the population. Analysis of distribution patterns across the environments revealed consistent trends, with coefficients of variation between 12.25% and 21.96%. Families with higher ARDI values, indicating stronger resistance, were more common, likely due to genetic diversity and environmental factors. Population structure analysis divided the MAGIC population into three subgroups, with Group I showing higher genetic variation and Groups II and III displaying more uniform resistance performance. Principal component analysis (PCA) confirmed these divisions, highlighting the genetic diversity underlying Verticillium wilt resistance. Through GWAS, we identified 19 SNPs significantly associated with Verticillium wilt resistance, distributed across three chromosomes. The screening of candidate genes was performed on the transcriptome derived from resistant and susceptible cultivars, combined with gene annotation and tissue expression patterns, and two key candidate genes, Ghir_A01G006660 and Ghir_A02G008980, were found to be potentially associated with Verticillium wilt resistance. This suggests that these two candidate genes may play an important role in responding to Verticillium wilt.
Conclusion This study aims to dissect the genetic basis of Verticillium wilt resistance in cotton by using a MAGIC population and GWAS. The study seeks to provide valuable genetic resources for marker-assisted breeding and enhance the understanding of resistance mechanisms to improve cotton resilience against Verticillium wilt.

Background Cotton is a significant crop for fiber production; however, seed shape-related traits have been less investigated in comparison to fiber quality. Comprehending the genetic foundation of traits associated with seed shape is crucial for improving the seed and fiber quality in cotton.
Results A total of 238 cotton accessions were evaluated in four different environments over a period of two years. Traits including thousand grain weight (TGW), aspect ratio (AR), seed length, seed width, diameter, and roundness demonstrated high heritability and significant genetic variation, as indicated by phenotypic analysis. The association analysis involved 145 simple sequence repeats (SSR) markers and identified 50 loci significantly associated with six traits related to seed shape. The markers MON_DPL0504aa and BNL2535ba were identified as influencing multiple traits, including aspect ratio and thousand grain weight. Notably, markers such as HAU2588a and MUSS422aa had considerable influence on seed diameter and roundness. The identified markers represented an average phenotypic variance between 3.92% for seed length and 16.54% for TGW.
Conclusions The research finds key loci for seed shape-related traits in cotton, providing significant potential for marker-assisted breeding. These findings establish a framework for breeding initiatives focused on enhancing seed quality, hence advancing the cotton production.

Background Hybrid cotton enjoys overwhelming patronage among cotton farmers because of its superior yield capacity and fiber quality. However, various environmental factors affect its yield and fiber quality. This study aimed to assess 30 cotton hybrids for the stability of four traits (single-plant seed cotton yield, fiber upper half mean length (UHML), fiber strength, and micronaire) across three environments. Recent techniques, including genotype and genotype × environment (GGE) biplot, which provides a visual representation of performance and adaptability; weighted average absolute scores of the best linear unbiased predictions (WAASB), which balances the performance of the trait with stability; and multi-trait stability index (MTSI), which integrates multi-trait performance and stability, were used to analyze the stability of the four traits.
Results Analysis of variance revealed significant genotype and environment interactions for all the traits studied, highlighting the need for comprehensive stability analysis. The environment E2 was the most suitable for the evaluation of seed cotton yield, whereas E3 was suitable for the evaluation of UHML and fiber strength. A stable hybrid, H05 (TVH002 × MCU5), with superior performance for seed cotton yield and UHML, was identified based on the overall results from GGE and WAASB. The which-won-where bioplot showed that H25 (SVPR3 × MCU5) performed the best for seed cotton yield in E3, and H27 (Suraj × Sunantha) in E2 and E1. The hybrid H04 (TVH002 × CO14) in E1 and H30 (Suraj × MCU5) in E2 and E3 performed well for UHML. Similarly, H28 (Suraj × Suraksha) for E2 and E3 and H26 (Suraj × Subiksha) for E1 were the best performing in the case of fiber strength. Based on the MTSI, four promising hybrids, namely, H24 (SVPR3 × CO14), H09 (TVH2010 × CO14), H18 (MCU7 × Suraksha), and H29 (Suraj × CO14), were identified as stable with average performance for all four traits.
Conclusions The study identified a stable hybrid, H05 (TVH002 × MCU5), with superior performance for yield and UHML. The identified hybrids in this study hold significant potential for cultivation across Tamil Nadu, with a scope for further evaluation in diverse environments.

Aiming to study the effects of defoliation and ripening agent on yield and fiber quality of cotton cultivars in the light and simplified regional trials, so as to clarify the reasonable methods for spraying defoliation and ripening agent in Shandong. The paper analyzed the effects of defoliation and ripening agent on yield traits and fiber quality of different cotton varieties from the light and simplified regional trials of 2023 and 2024. 600 g thidiazuron (50% wettable powder) and 3000 mL ethephon (40% aqueous solution) per hectare were used at 60 days after topping, with spraying the equivalent volume of running water as the control. Results showed that defoliation and ripening agent exhibited no significant impact on seed cotton yield, fiber length, fiber strength, and uniformity index in the light and simplified regional trials. However, the extent of influence varied among the tested varieties, with approximately 50% of the varieties demonstrating either a decrease or no change compared to the control group across the two years. Defoliation and ripening agent significantly affected boll weight and seed index in cotton varieties under light and simplified cultivation. Specifically, boll weight decreased by an average of 4.23% to 6.0%, while seed index declined by an average of 5.51% to 8.31%, compared to the control group. Additionally, these agents considerably influenced lint percentage and micronaire, with the degree of influence differing among various cotton varieties across different years. Variance analysis indicated that the interaction between the defoliation and ripening agent and variety types had a highly significant effect on seed index but did not significantly affect seed cotton yield, lint percentage, fiber length, fiber strength, or micronaire. The interaction effect on boll weight was significantly influenced by both variety type and climatic conditions. In a word, reasonable application of defoliation and ripening agent has no significant impact on the yield and fiber quality of cultivars in the light and simplified regional trials. It is initially recommended that the application of defoliation and ripening agent in the light and simplified regional trials of cotton in Shandong should be 60 days after topping. The recommended application rate is 600 g thidiazuron (50% wettable powder) and 3000 mL ethephon (40% aqueous solution) per hectare. However, specific applications need to be adjusted based on the characteristics of the variety and the climatic conditions of the year.

The efficient genome editing tool (the CRISPR/Cas12a system) has been used in research on plant functionional genomics and improvement of agronomic traits.  In this study, CRISPR/Cas12a system was optimized by using the endogenous pGhαGloA promoter in cotton.  Using this system, crRNAs was driven by the Pol II pGhaGloA promoter to construct the pGhRBE3-pGhαGloA-GhPGF vector and carry out genetic transformation.  The vector could work efficiently in all positive transgenic plants and the editing efficiency at the crRNA1 target site was up to 93.37%, and the editing efficiency of the crRNA2 target was up to 88.24%, which is significantly higher in editing efficiency of the pGhRBE3 system with Pol III promoter-Ubi 6.7 promoter, this result indicates that the Pol II promoter is more suitable for expressing multiple sgRNA or crRNA than the pol III promoter in cotton.  The vector mainly generated the editing type of fragment deletion and the deletion size was in the range of 3-12 bp with the editing sites spanning at the 14th to 29th bases downstream of the protospacer adjacent motif (PAM).  All the targeted mutation loci were stably inherited from T₀ to T₂ generation and three transgene-free lines with target site mutations of GhPGF gene were obtained and these glandless and gossypol-free/(low contents) cotton germplasm will play key role for healthy cottonseeds oil/cake production.  Therefore, the CRISPR/Cas12a system driven by the pGhαGloA promoter can efficiently edit target genes in cotton, which provides a powerful tool for cotton functionional genomics and genetic improvement.

To investigate the effects of DPC on agronomic traits, dry matter accumulation, yield, and fiber quality of direct-seeded cotton following garlic in southwest Shandong, and to determine the appropriate growth regulator timing and dosage, a field experiment with single factor randomized block design was conducted in 2024 using the short-season cotton variety ‘Lumian 551’. Three treatments were designed and DPC was applied at the squaring, initial flowering, full flowering, and 7 days after topping stages, respectively. The spraying dosages were T1: 0, 0, 75.0, 105.0 g/hm²; T2: 0, 45.0, 60.0, 75.0 g/hm²; T3: 15.0, 30.0, 60.0, 75.0 g/hm², with water serving as the control (CK). Results showed that, under an equal total DPC dosage across the growth period, earlier and more frequent DPC applications significantly reduced plant height, increased boll number per plant and single boll weight, and ultimately improved lint yield. The lint yield followed the order T3>T2> T1 > CK, with T3 increasing yield by 3.8%, 12.5%, and 30.8% compared with T2, T1, and CK, respectively. DPC application also enhanced dry matter accumulation in roots and fruiting branches, while reducing that in vegetative branches. However, no significant differences were observed in fiber quality among treatments. Overall, the T3 treatment (15.0 g/hm² at squaring, 30.0 g/hm² at initial flowering, 60.0 g/hm² at full flowering, and 75.0 g/hm² 7 days after topping) exhibited the best yield and agronomic performance, suggesting it as the optimal DPC application strategy for direct-seeded cotton after garlic in southwest Shandong.

Recent publications have highlighted the development of an alternate cotton-peanut intercropping as a novel strategy to enhance agricultural productivity. In this article, we provide an overview of the progress made in the alternate cotton-peanut intercropping, specifically focusing on its yield benefits, environmental impacts, and the underlying mechanisms. In addition, we advocate for future investigations into the selection or development of appropriate crop varieties and agricultural equipment, pest management options, and the mechanisms of root-canopy interactions. This review is intended to provide a valuable reference for understanding and adopting an alternate intercropping system for sustainable cotton production.

Background Light is a critical factor in plant growth and development, particularly in controlled environments. Light-emitting diodes (LEDs) have become a reliable alternative to conventional high pressure sodium (HSP) lamps because they are more efficient and versatile in light sources. In contrast to well-known specialized LED light spectra for vegetables, the appropriate LED lights for crops such as cotton remain unknown.
Results In this growth chamber study, we selected and compared four LED lights with varying percentages (26.44%-68.68%) of red light (R, 600-700 nm), combined with other lights, for their effects on growth, leaf anatomy, and photosynthesis of cotton seedlings, using HSP lamp as a control. The total photosynthetic photon flux density (PPFD) was (215 ± 2) μmol·m^-2·s^-1 for all LEDs and HSP lamp. The results showed significant differences in all tested parameters among lights, and the percentage of far red (FR, 701-780 nm) within the range of 3.03%-11.86% was positively correlated with plant growth (characterized by leaf number and area, plant height, stem diameter, and total biomass), palisade layer thickness, photosynthesis rate (P_n), and stomatal conductance (G_s). The ratio of R/FR (4.445-11.497) negatively influenced the growth of cotton seedlings, and blue light (B) suppressed stem elongation but increased palisade cell length, chlorophyll content, and P_n.
Conclusion The LED 2 was superior to other LED lights and HSP lamp. It had the highest ratio of FR within the total PPFD (11.86%) and the lowest ratio of R/FR (4.445). LED 2 may therefore be used to replace HPS lamp under controlled environments for the study of cotton at the seedling stage.

Background Water deficit is an important problem in agricultural production in arid regions. With the advent of wholly mechanized technology for cotton planting in Xinjiang, it is important to determine which planting mode could achieve high yield, fiber quality and water use efficiency (WUE). This study aimed to explore if chemical topping affected cotton yield, quality and water use in relation to row configuration and plant densities.
Results Experiments were carried out in Xinjiang China, in 2020 and 2021 with two topping method, manual topping and chemical topping, two plant densities, low and high, and two row configurations, i.e., 76 cm equal rows and 10+66 cm narrow-wide rows, which were commonly applied in matching harvest machine. Chemical topping increased seed cotton yield, but did not affect cotton fiber quality comparing to traditional manual topping. Under equal row spacing, the WUE in higher density was 62.4% higher than in the lower one. However, under narrow-wide row spacing, the WUE in lower density was 53.3% higher than in higher one (farmers’ practice). For machine-harvest cotton in Xinjiang, the optimal row configuration and plant density for chemical topping was narrow-wide rows with 15 plants m^-2 or equal rows with 18 plants m^-2.
Conclusion： The plant density recommended in narrow-wide rows was less than farmers’ practice and the density in equal rows was moderate with local practice. Our results provide new knowledge on optimizing agronomic managements of machine-harvested cotton for both high yield and water efficient.

Background Natural 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.
Results The 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.
Conclusion The 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.

Background Cotton (Gossypium hirsutum L.), adapted to tropical and subtropical regions of the world, is highly sensitive to low temperatures throughout its life cycle. The objective of this study was to evaluate the mitigating effects of different doses of animal-derived (0.25%, 0.50%, and 1.00% Isabion® ), seaweed-based (0.165%, 0.330%, and 0.660% Proton®) biostimulants, as well as a copper (Cu)-containing fungicide application, on cotton cultivar Lazer seedlings at the four true leaves (V4) stage. The plants were exposed to a low temperature of 5 °C for 48 h, and the changes in morphological (seedling fresh and dry weight, plant height, and stem diameter) and physiological parameters (leaf temperature, chlorophyll content, relative water content, electrolyte leakage, and relative injury) were examined.
Results The results revealed that chilling stress reduced plant growth, while biostimulants helped protect the plants and overcome the adverse effects of chilling. Under chilling stress, there was a considerable reduction in seedling fresh weight (SFW), seedling dry weight (SDW), plant height (PH), stem diameter (SD), leaf temperature (LT), and relative water content (RWC). Cotton seedlings treated with the animal-derived biostimulants showed significantly enhanced SFW, SDW, PH, SD, LT, chlorophyll content (Chl), electrolyte leakage (EL), and relative injury (RI), although there were no positive changes in RWC. No significant differences in the morphological traits were observed among the doses of seaweed biostimulants. For SDW, PH, EL, and RI, the best results were obtained with the application of a fungicide containing copper.
Conclusion These results show the efficiency of the biostimulant and fungicide treatments in mitigating low-temperature stress in cotton seedlings. Applying a copper-containing fungicide to cotton seedlings helped to counteract the negative effects of low-temperature stress and to protect the plants from damage by maintaining electrolyte balance. Among the biostimulant applications, all levels of animal-derived biostimulant applications, as well as the 0.660% level of the seaweed-derived biostimulant, led to increased tolerance of cotton plants to chilling stress.

Lessons learned from past experiences push for an alternate way of crop production. In India, adopting high density planting system (HDPS) to boost cotton yield is becoming a growing trend. HDPS has recently been considered a replacement for the current Indian production system. It is also suitable for mechanical harvesting, which reducing labour costs, increasing input use efficiency, timely harvesting timely, maintaining cotton quality, and offering the potential to increase productivity and profitability. This technology has become widespread in globally cotton growing regions. Water management is critical for the success of high density cotton planting. Due to the problem of freshwater availability, more crops should be produced per drop of water. In the high-density planting system, optimum water application is essential to control excessive vegetative growth and improve the translocation of photoassimilates to reproductive organs. Deficit irrigation is a tool to save water without compromising yield. At the same time, it consumes less water than the normal evapotranspiration of crops. This review comprehensively documents the importance of growing cotton under a high-density planting system with deficit irrigation. Based on the current research and combined with cotton production reality, this review discusses the application and future development of deficit irrigation, which may provide theoretical guidance for the sustainable advancement of cotton planting systems.

Machine picking in cotton is an emerging practice in India, to solve the problems of labour shortages and production costs increasing. Cotton production has been declining in recent years; however, the high density planting system (HDPS) offers a viable method to enhance productivity by increasing plant populations per unit area, optimizing resource utilization, and facilitating machine picking. Cotton is an indeterminate plant that produce excessive vegetative growth in favorable soil fertility and moisture conditions, which posing challenges for efficient machine picking. To address this issue, the application of plant growth retardants (PGRs) is essential for controlling canopy architecture. PGRs reduce internode elongation, promote regulated branching, and increase plant compactness, making cotton plants better suited for machine picking. PGRs application also optimizes photosynthates distribution between vegetative and reproductive growth, resulting in higher yields and improved fibre quality. The integration of HDPS and PGRs applications results in an optimal plant architecture for improving machine picking efficiency. However, the success of this integration is determined by some factors, including cotton variety, environmental conditions, and geographical variations. These approaches not only address yield stagnation and labour shortages but also help to establish more effective and sustainable cotton farming practices, resulting in higher cotton productivity.

Cotton, a crucial commercial fibre crop, depends heavily on seed-associated characteristics like germination rate, vigour, and resistance to post-harvest deterioration for both production and lint quality. Serious cellular damage during post-harvest processes such as delinting, prolonged seedling emergence periods, decreased viability, increased susceptibility to infections, and lipid peroxidation during storage pose serious problems to seed quality. The performance of seeds and total crop productivity are adversely affected by these problems. Traditional methods of seed improvement, like physical scarification and seed priming, have demonstrated promise in raising cotton seed vigour and germination rates. Furthermore, modern approaches including plasma therapies, magnetic water treatments, and nanotechnology-based treatments have shown promise in improving seed quality and reducing environmental stresses. By offering sustainable substitutes for conventional approaches, these cutting-edge procedures lessen the need for fungicides and other agrochemicals that pollute the environment. This review explores various conventional and emerging strategies to address the detrimental factors impacting cotton seed quality. It emphasizes the importance of integrating classical and advanced approaches to enhance germination, ensure robust crop establishment, and achieve higher yields. In addition to promoting sustainable cotton production, this kind of integration helps preserve the ecosystem and create resilient farming methods.

Premature senescence in Bacillus thuringiensis (Bt) cotton has emerged as a significant challenge to the formation and realization of fiber yield and quality since its commercialization in 1997. Initially, premature senescence was thought to be an inherent trait associated with the Bt gene. However, subsequent research and practice have demonstrated that it is not directly linked to the Bt gene but rather results from a physiological imbalance between the sink and source, as well as between the root and shoot in Bt cotton. This short review provides an overview of the causes, mechanisms, and control measures for premature senescence in Bt cotton. It offers valuable insights for future research and the sustainable application of transgenic crops.

Background Zinc (Zn), being the most deficient micronutrient, can largely limit plant growth and development on alkaline calcareous soil. Crop species and varieties within species differently require Zn for optimum productivity. The current study aimed to optimize Zn level and mode of application for better growth, yield, and fiber quality of cotton (Gossypium hirsutum L.). The experimental plan comprised a control group with no Zn application, three Zn levels through soil application, i.e. 5 mg·kg^-1 (SZn5), 10 mg·kg^-1 (SZn10), and 15 mg·kg^-1 (SZn15), two levels of foliar application including 0.5% (FZn0.5) and 1% (FZn1) Zn solution, and various combinations of soil plus foliar application. Two cotton cultivars, CIM-663 (Bt) and Cyto-124 (non-Bt) were used, and each treatment was replicated thrice.
Results Zinc nutrition caused a significant (P ≤ 0.05) improvement in growth, yield, physiological, and fiber quality characteristics of both cotton cultivars. All levels and modes of Zn application were found effective in improving cotton productivity on alkaline calcareous soil. However, integrated soil application and foliar spray showed superiority over sole soil or foliar application. Among different treatments, SZn15 + FZn1 caused the highest improvement in most of the observed growth and yield traits. The said treatment maximally increased the leaf Zn concentration by 270.5% and 218.4% with a subsequent increase in plant height 23.2% and 28.0%, monopodial branches 40.7% and 42.1%, sympodial branches 37.2% and 35.2%, seed cotton yield 32.5% and 36.6%, and lint yield 30.0% and 34.6% in CIM-663 and Cyto-124, respectively, compared with the control. SZn15 + FZn1 also caused the highest increase in relative water contents 32.6% and 22.4%, chlorophyll contents 92.0% and 67.1%, and stomatal conductance 112.8% and 100.8% in CIM-663 and Cyto-124, respectively, compared with the control. Among the fiber quality characteristics, fiber fineness was maximally improved by 19.7% and 15.9% in CIM-663 and Cyto-124, respectively, with SZn15 + FZn1 compared with the control. Leaf Zn concentration was positively correlated with fiber length (R² = 0.717 3), fiber strength (R² = 0.548 3), and fiber fineness (R² = 0.637 9) of both cotton cultivars grown with different levels and application modes of Zn. The benefit-cost ratio was remarkably improved with Zn nutrition, and the highest value of 1.64 was found in CIM-663 at SZn10 + FZn1 and SZn15 + FZn1.
Conclusion The plant growth, physiological, yield, and fiber quality characteristics of cotton cultivars were significantly improved with Zn supply at different levels and modes of application. SZn15 + FZN1 could be recommended to get optimum seed cotton yield and fiber quality of cotton on alkaline calcareous soil.

Background The mulch-free subsurface drip irrigation system demonstrated water-saving potential as an alternative to traditional mulch-based drip irrigation while also eliminating residual film pollution at source. However, delayed sowing is unavoidable in mulch-free cultivation in ecological regions with a short frost-free period. Intercropping with cumin, which has a shorter growth period, served as an effective strategy to improve land use efficiency during the early growth stages of cotton. Therefore, a two-year field experiment was conducted to study the effects of intercropping cumin at the seeding rate of 2.5 (ID1), 3.85 (ID2), and 5.2 (ID3) kg·hm^-2 on cotton growth, interspecies competition, fiber quality, and water use efficiency (WUE), as well as system economic benefits under subsurface drip irrigation. Monocropping cotton was used as the control (CK) treatment.
Results At the initial flowering (IF) stage (the end of the co-growth period of cotton and cumin), cotton plant height in ID2 and ID3 treatments decreased by 5.93%-16.53% and 10.87%-31.11%, respectively, cotton stem diameter by 11.41%-14.25% and 3.37%-26.49%, respectively, and vegetative biomass by 14.46%-30.65% and 22.59%-49.91%, respectively, compared with CK treatment. With the increase in cumin density, the crop growth rate (CGR) and compensation effect in cotton tended to significantly decrease at the IF stage regardless of organs considered. For the non-co-growth period (after harvesting cumin), cotton reproductive organ biomass in ID2 and ID3 treatments increased by 4.09%‒14.61% at the boll opening stage, crop growth rate in reproductive organs by 20.74% and 74.26% from peak boll to boll opening stages compared with CK treatment, due to an enhancement of 19.09% and 49.30% in the compensation effect. Compared with ID1, the aggressivity treated by ID2 and ID3 decreased by 12.82%-46.34% and 17.95%-31.71%, respectively. However, owing to a greater number of green bolls in the upper canopy at the harvest stages in the ID3 treatment, the system production value (closely related to yield) treated by ID2 was 11.69%-16.89%, 6.56%-20.02%, and 16.48%-59.83% greater than that of the ID1, ID3, and CK treatments, respectively. This also led to the highest WUE and net profit under the ID2 treatment.
Conclusion Intercropping cumin with medium density improved the cotton biomass accumulation characteristics and increased resources such as land and water utilization efficiency and economic benefits through a stronger compensation effect after harvesting cumin under subsurface drip irrigation without mulch. This study not only provides alternatives to residual film pollution in arid cotton fields but also establishes a sustainable agro-ecological-economic planting paradigm by reducing plastic use and enhancing water and fertilizer use efficiency, holding significant implications for advancing resource-efficient agricultural systems.

Background Agroecological cropping systems are recognised as an alternative way to ensure the sustainability of cotton (Gossypium hirsutum L.) production in the context of climate change and degradation of soil fertility. A study was conducted in Benin from 2020 to 2023 to compare six different cotton cultivars in three agroecological cropping systems in two cotton-growing zones. Plough-based tillage plus incorporation of cover crop biomass (PTI), conservation agriculture with strip tillage (CA_ST), and conservation agriculture with no tillage (CA_NT) were compared with the reference plough-based tillage (PT). The objective was to identify morpho-physiological traits of cotton that increase yield in agroecological cropping systems. Our approach combined a field experiment and crop simulation model (CSM) of CROPGRO-Cotton to evaluate the effects of genotype (G) × environment (E) × management (M) interactions on seed cotton yield (SCY).
Results Cultivars Tamcot_camde and Okp768 and simulated ideotypes performed best in CA systems. Increased seed mass, large and thick leaves, and later maturity were identified as beneficial for yield enhancement in CA systems. Cultivars and ideotypes that combine these traits also resulted in better nitrogen and water use efficiencies in CA systems. Under different climate scenarios up to 2050, ideotypes designed could increase SCY in Benin.
Conclusion A set of morpho-physiological traits associated with vegetative vigour is required to ensure a good SCY in agroecological cropping systems. These results provide scientific evidence and useful knowledge for breeders and research programmes on cropping systems focused on the adaptation of cotton to climate change.

Background Irrigation has been a strategy used to reduce losses due to drought, which combined with a good supply of nitrogen (N), can improve the protective system of cotton plants. The objective of this study was to investigate the effects of irrigated and rainfed cotton cultivation using different rates and sources of N. Cotton cultivation was carried out in Selvíria-MS field in the 2017/2018 harvest. The experiment was conducted in randomized blocks, which were designed in a 4 × 2 × 2 factorial scheme. The factors were composed of 0, 40, 80, and 150 kg·hm^-2 level of N, using two sources of N under rainfed and irrigated systems.
Results The provision of irrigation provided an increase in the levels of chlorophylls (Chl) a, Chl b, total Chl, carotenoids, pheophytin, leaf chlorophyll index (LCI), N content, nitrate (NO₃^-), sucrose (SUC), the number of vegetative and reproductive branches, boll mass, and seed cotton productivity. There was no effect of N sources on any of the characteristics evaluated. Application of 150 kg·hm^-2 level of N increased in 11%, 59%, 22%, 15%, 15% and 17% in LCI, NO₃^-, N, total amino acids (TA), SUC, and proline concentration in leaves, compared with 0 kg·hm^-2 of N, respectively. Application of 150 kg·hm^-2 level of N improved the leaf catalase activity (CAT) under the irrigation system; however, in a rainfed system, the highest CAT was observed at rates of 0 and 150 kg·hm^-2 level of N. Irrigation increased in 55%, 117%, 68%, 46%, 8%, 36%, 24%, 118%, 48%, 10%, 11% and 72% in Chl a, Chl b, total Chl, CAR, LCI, pheophytins (Pheo), SUC, NO₃^-, the number of vegetative branches, the number of reproductive branches, mass of 20 bolls and seed cotton yield compared with rainfed system, respectively, however, the antioxidant system and the ammonium content of plants was stimulated by rainfed cultivation.
Conclusions Antioxidant responses increased during droughts in cotton farming, which may be connected to oxidative stress-related losses. Better N metabolism, photosynthetic pigments, and manufacturing components were all made possible by irrigated cultivation. The delivery of 150 kg·hm^-2 of N in topdressing in cotton agriculture promoted the N metabolism, sucrose, total amino acids, and the plant’s defense mechanism against oxidative stress.

In response to the need to improve the efficiency of cotton disease and pest detection, this paper proposed an enhanced detection model named YOLOv5sMBT, based on YOLOv5s, for identifying cotton diseases and pests in leaf images. The model incorporates 3 key improvements over the original YOLOv5s framework: a multi-scale feature extraction network (Multi-scale) was constructed to enhance feature extraction capabilities; and a Transformer attention mechanism was integrated between the feature extraction network and the neck network, combined with the C3 module to form C3TR, thereby improving the model’s attention to target features; a BiFPN (Bidirectional feature pyramid network) structure was introduced to efficiently fuse shallow and deep features. A dataset of 2 179 leaf images covering 4 common cotton diseases and pests (Nesidiocoris tenuis, spider mite, wilting, aphid) was used for validation. The dataset was split into training, validation, and test sets in a 3∶1∶1 ratio. Experimental results showed that the YOLOv5sMBT model achieved a mean average precision (mAP) of 0.838, outperforming the original model (mAP of 0.799). This study provides a reference for the intelligent detection of cotton diseases and pests.

Global cotton production faces mounting pressure to reconcile rising fiber demand with urgent sustainability imperatives, including water scarcity mitigation, greenhouse gas reduction, and agrochemical pollution control. Traditional practices, constrained by fragmented objectives and inherent trade-offs among yield, fiber quality, labor efficiency, and ecological impact, struggle to address these systemic challenges. Building upon previous concept of collaborative cultivation, this review for the first time introduces and comprehensively elaborates Multi-objective Integrated Cotton Cultivation (MOICC) —also referred to as Integrated Cotton Cultivation (ICC)—a transformative paradigm centered on three pillars: dynamic trade-off management (e.g., region-specific priority adjustment), systematic technology integration (precision seeding, dense planting, chemical regulation, water-nutrient synergy, targeted defoliation), and resource circularity (spatiotemporal optimization, waste recycling). MOICC leverages key physiological mechanisms—ethylene signaling enhancing stress-resilient seedling establishment; jasmonate-mediated pathways improving water/nutrient efficiency; canopy light competition coupled with hormonal regulation eliminating manual pruning; and growth regulators concentrating boll maturation—to overcome sustainability bottlenecks. Case studies from diverse Chinese agro-ecosystems (e.g., Xinjiang, Yangtze/Yellow River basins) and intercropping systems demonstrate significant synergies: yield gains (8–22%), resource efficiency improvements (water use efficiency increased by ≥20%, nitrogen productivity up to 35 kg kg^-1), and enhanced environmental performance (labor reduction 30–40%, carbon footprint reduction 24–37%, agrochemical savings: nitrogen reduction of 15–20%, pesticides reduction of 25%). Crucially, MOICC resolves core conflicts through integrated optimization: yield versus quality (via≥70% inner-position bolls), labor-saving versus eco-safety (precision defoliant timing), and productivity versus emissions (root-zone nitrogen monitoring). Future research priorities include deciphering multi-scale stress adaptation, developing intelligent decision-support systems (e.g., AHP-NSGA-II integration), advancing carbon-neutral value chains, addressing socio-economic adoption barriers, and fostering policy synergy. MOICC establishes a conceptually globally scalable pathway toward high-yield, superior-quality, resource-efficient, and ecologically sustainable cotton production, providing a viable framework for sector-wide sustainability transition and demonstrating adaptability to other major cropping systems.

In order to investigate regulatory effects of cotton chemical capping agents in the Liaohe River Basin, a comparative experiment was conducted from 2019 to 2020 at the Liaoning Institute of Industrial Crops (Liaoyang, Liaoning). The study used chemical capping agent from China Agricultural University, composed of 25% Mepiquat chloride (1,1-dimethyl-piperidinium chloride, DPC) and auxiliary naphthenate, with two application timings (July 13^th and July 18^th) and three concentration levels (750, 1125 and 1500 mL/hm²). A total of six treatments were set up, using no-topping as control (CK). Hormone contents including indole-3-acetic acid (IAA), abscisic acid (ABA), gibberellin (GA₃), and zeatin (ZR) were continuously measured in the main stem apex (0-5 cm) and sub-apex (5-10 cm). Plant growth parameters, including plant height (PH), number of fruit branches (NFB), average length of upper fruit branches (LFB), and average length of upper internodes (LUI) on the main stem, were also systematically observed and recorded. The variations in IAA and ABA contents were directly proportional to the concentration of the chemical agent, whereas changes in ZR content exhibited an inverse relationship. The fluctuation in GA₃ content was most pronounced at medium concentration. The variations in IAA, ABA and ZR contents of different dosages were more evident when treatment was applied on July 13^th, while no obvious differences were observed in GA₃ content between the two application timings. IAA content showed marked variation at the main stem apex, whereas ZR content varied more noticeably at the sub-apex; in contrast, ABA and GA₃ levels exhibited only slight differences between the two sampling sites. Chemical capping effectively inhibited plant growth. The inhibitory effects on NFB and LFB intensified with treatment concentration increasing. For the July 13^th application, the degree of inhibition on PH was positively correlated with treatment concentration, whereas for the July 18^th application, the suppression of both PH and LUI was more pronounced at medium treatment concentration. Following treatment with a chemical capping agent, the levels of IAA and GA₃ at the apical region of the main stem decreased significantly, whereas ABA content increased markedly, and ZR content remained relatively unchanged. Furthermore, the reductions in IAA and ABA levels were directly proportional to the concentration of the capping agent, with earlier application resulting in more pronounced effects. Notably, IAA content at the apex of the main stem and ZR content in the subapical exhibited significant changes. Plant development was inhibited after capping treatment, and this growth suppression was consistent with the observed hormonal fluctuations. In the future, combined with the yield and fiber quality indicators, the application parameters of chemical capping agent can be optimized, and a simplified cultivation technology system suitable for the cotton area of Liaohe River Basin can be established.

In response to the salt stress caused by NaCl and Na₂SO₄ in saline soil that restricts cotton production, and the problem that single salt stress identification is not comprehensive, in order to screen stable salt-tolerant varieties and comprehensively evaluate the salt tolerance of different materials, this study used 75 land cotton varieties as the experimental materials and simulated salt stress with 150 mmol/L NaCl and Na₂SO₄. The five traits such as germination potential, germination rate, hypocotyl length, root length and fresh weight were measured. Principal component analysis, membership function method and cluster analysis were used to comprehensively evaluate the salt tolerance. The results revealed as follows. (1) Compared with the control group, both salt stresses had different degrees of inhibitory effects on various germination indicators, and the inhibitory effect of Na₂SO₄ was stronger than that of NaCl. (2) Cluster analysis showed that under the Euclidean distance of 5, both salt stresses could divide the tested materials into 5 salt tolerance grades. Under NaCl salt stress, there were 6 high-tolerance varieties (accounting for 8.00%), 13 salt-tolerant varieties (accounting for 17.33%), 22 medium-tolerant varieties (accounting for 29.33%), 25 sensitive varieties (accounting for 33.33%), and 9 highly-sensitive varieties (accounting for 12.00%); under Na₂SO₄ salt stress, there was only 1 high-tolerance variety (accounting for 1.33%), 6 salt-tolerant varieties (accounting for 8.00%), 16 medium-tolerant varieties (accounting for 21.33%), 37 sensitive varieties (accounting for 49.33%), and 15 highly-sensitive varieties (accounting for 20.00%). (3) Under both salt stress conditions, materials with consistent salt tolerance performance were 22 in total, including 1 high-tolerance variety and 1 salt-tolerant variety. The salt tolerance of different land cotton varieties at the germination stage showed significant differences. 'Zhongmiansuo 96B' and 'Xinluzhong 73' were stable salt-tolerant varieties under both salt stress conditions. In the future, combined with the identification of salt tolerance at the seedling stage and molecular marker analysis, the research on the salt tolerance mechanism can be deepened, providing more comprehensive support for cotton salt-tolerance breeding.

Legume-based intercropping enhances asymbiotic biological nitrogen fixation (BNF); however, the underlying mechanisms remain unclear, including the roles of soil keystone diazotroph taxa with varying niche breadths. A field experiment was conducted to evaluate soil BNF variations between rhizosphere and bulk soils in peanut/cotton intercropping systems and monocultures. BNF activities were measured by nitrogen fixation rates, nitrogenase activity, and nifH gene abundance. Phylogenetic null models, co-occurrence networks, and niche breadth analysis were applied to investigate the roles of diazotrophic keystone taxa and their ecological niches. Rhizosphere soils exhibited 7.8–125.5% higher BNF potentials than bulk soils, whereas intercropping systems showed 11.6–323.0% increases over monocultures for nitrogen fixation rate, nitrogenase activity, and nifH gene abundance (all P<0.05). Diazotrophic community composition and diversity differed significantly, with Proteobacteria (excluding Alphaproteobacteria) enriched in intercropping and rhizosphere soils, while Cyanobacteria and Firmicutes were less abundant. Deterministic processes, particularly heterogeneous selection, dominated community assembly in the rhizosphere (91.9%) and intercropping soils (86.3%). The co-occurrence networks consistently revealed more complex and interconnected communities in intercropping and rhizosphere soils that were dominated by opportunistic diazotrophs (78.8–85.9%), followed by specialists (10.2–18.5%) and generalists (1.38–3.80%). Keystone taxa, including opportunists such as Azoarcus, Azohydromonas, and Steroidobacter, and generalists like Pseudomonas and Azotobacter, correlated positively with microbial biomass carbon and nitrate nitrogen, contributing to enhanced BNF. Peanut/cotton intercropping enhances BNF by selectively enriching the keystone diazotrophic taxa with varying ecological roles, particularly opportunists and generalists. Such targeted intercropping strategies can optimize BNF, improve soil fertility, and promote sustainable agricultural production.

Hydraulic theory predicts a positive coupling between leaf hydraulic conductance (K_leaf) and stomatal conductance (g_s); however, this theory has not been fully supported by observations, and the underlying mechanisms remain unclear.  Currently, subdividing K_leaf into leaf hydraulic conductance inside xylem (K_x) and outside xylem (K_ox) offers a new perspective for elucidating the regulatory mechanism of K_leaf on g_s.  Optimal planting density can enhance water use efficiency (WUE) by optimizing g_s; however, the changes in leaf hydraulic properties during this process and its regulation of g_s and WUE remain unclear.  We examined the relationships between K_x and K_ox with g_s, photosynthetic rate (A_N), and WUE, and investigated the structural basis determining K_ox in cotton under eight planting densities of 12, 18, 24, 36, 48, 60, 72, and 84 plant m^-⊃2;.  The results showed that as the increase of planting density, K_leaf and A_N remained consistent while K_ox and g_s decreased significantly.  K_ox was significantly influenced by leaf thickness and the volume fraction of inter-cellular air space.  K_leaf and K_x showed no correlation with A_N or g_s, but K_ox exhibited a significant positive correlation with g_s.  Furthermore, K_ox is significantly negatively correlated with WUE.  These findings suggest that K_ox modulates g_s to reduce water loss while maintaining A_N, thereby enhancing WUE in cotton under various planting densities.

【Objective】In light of the shortage of water resources and the lower fertility and poor quality of soils in Xinjiang, this study explored the effects of varying irrigation volumes and ratios of organic to inorganic fertilizer application under aerated drip irrigation on the soil quality, cotton growth, yield, and water use efficiency of cotton fields. The objective was to provide a theoretical basis for determining an irrigation and fertilization model for cotton in Xinjiang that was water-saving, highly efficient, and sustainable. 【Method】Field experiments were conducted in the 146th Regiment area of the Xinjiang Production and Construction Corps in 2023 and 2024. Under aerated drip irrigation, two irrigation volumes (W1: 80%ET_C and W2: 100%ET_C, where ET_C represents the crop evapotranspiration) and five ratios of organic to inorganic fertilizer application (OF1: 100% chemical fertilizer, OF2: 75% chemical fertilizer + 25% organic fertilizer, OF3: 50% chemical fertilizer + 50% organic fertilizer, OF4: 25% chemical fertilizer + 75% organic fertilizer, OF5: 100% organic fertilizer) were set up to study their impacts on the physical and chemical properties of soil quality, cotton growth including leaf area index (LAI), dry matter accumulation, yield, and water use efficiency (WUE). 【Result】The Soil Quality Index (SQI) increased with the rising proportion of organic fertilizer, showing an average increase of 9.9%-28.8% in the combined application of organic and inorganic fertilizers over the two years compared with the application of chemical fertilizer alone. Under deficit irrigation, soil moisture content, LAI, dry matter accumulation, and yield significantly decreased, while Water Use Efficiency (WUE) significantly increased. Under the two irrigation levels (W1 and W2), soil moisture content, cotton LAI, and dry matter accumulation first increased and then decreased as the proportion of organic fertilizer increased. Under W1, these indicators reached their maxima with the W1OF3 treatment, whereas under W2, their maxima were observed with the W2OF2 treatment. Compared with chemical fertilizer alone (OF1), the combined application of organic and inorganic fertilizers increased soil moisture content, LAI, and dry matter accumulation by 0.4%-5.2%, 4.1%-19.8%, and 3.7%-18.8% over two years, respectively. Over two years, the maximum seed cotton yield was observed under W2OF2 treatment, with an average yield of 6 739.99 kg·hm^-2, but the highest WUE was achieved under the W1OF3 treatment, with an average value of 1.42 kg·m^-3. The SQI, seed cotton yield, and WUE under different treatments were evaluated using the membership function method, TOPSIS method, and grey relational analysis, respectively. A comprehensive evaluation was carried out using an integrated differential combination evaluation model, determining the optimum treatment as W1OF3. 【Conclusion】Considering the priority of water-saving, while ensuring yield, and aiming to improve Water Use Efficiency (WUE) and soil quality, it was recommended that under aerated drip irrigation, applying 80% ET_C for irrigation water volume and a combined application of 50% organic fertilizer and 50% chemical fertilizer, for serving as the optimal management measure for water-saving and efficient production in cotton fields in Xinjiang.

This study investigated the effects of irrigation quotas under mulch drip irrigation on cotton growth, water consumption characteristics and yield, aiming to provide a theoretical basis for water saving, yield increase, and efficiency improvement in cotton production in northern Xinjiang. A field experiment was conducted from 2022 to 2024, with four irrigation quotas: 30.0 mm (I20), 37.5 mm (I25), 45.0 mm (I30), and 52.5 mm (I35). The effects of different irrigation quotas on cotton growth, water consumption patterns, and yield were analyzed. The results showed that plant height increased with higher irrigation quotas, reaching the maximum under I30 and I35 treatments. Leaf area index (LAI) and relative chlorophyll content (SPAD) showed a trend of first increasing and then decreasing, reaching the peak during I30 treatment. The water consumption at each growth stage increased with higher irrigation quotas, and the crop coefficient gradually rose. The seed cotton yield and lint yield showed a trend of first increasing and then decreasing with the increase of irrigation quota, among them, the yield under I30 treatment was the highest, with average values of 5535.35 kg/hm² and 2348.42 kg/hm² respectively. A fitting analysis between water consumption and yield indicated that the optimal water consumption range was 491.93-571.61 mm. A comprehensive evaluation showed that the I30 treatment achieved the highest scores across all three growing seasons. In conclusion, the I30 treatment can achieve optimal cotton yield under drip irrigation in northern Xinjiang. This study provides a theoretical basis for water-saving and high-yield cotton cultivation in the region.

Background Mepiquat chloride (MC) is a widely used plant growth regulator in cotton (Gossypium hirsutum L.). It regulates endogenous hormone content and crosstalk to control plant height and promote lateral root (LR) development. However, the roles of cytokinins (CTKs) in the MC-induced increase in LR number in cotton seedlings remain unclear. Therefore, in this study, whole-genome transcriptome analysis was performed to elucidate the molecular mechanisms, CTK transformation, and CTK signaling pathway response to MC in cotton roots.
Results In the present study, MC reduced the contents of the active CTK trans-zeatin (tZ) and N⁶-isopentenyladenine (iP) but increased the levels of the nucleoside CTK trans-zeatin riboside (tZR) and N⁶-isopentenyladenine riboside (iPR). RNA-seq data showed that the CTK biosynthesis genes GhIPTs and active CTK catabolism genes GhCKXs were obviously upregulated after MC treatment. The CTK-activating enzyme gene GhLOGs was repressed compared with the control. Furthermore, MC inhibited the expression of GhAHK4 and GhARR2/12, which are involved in the CTK signaling pathway, and activated the IAA-IAA14-ARF7/19 signaling module. Meanwhile, MC increased the expression levels of genes involved in sucrose synthesis, the cell cycle, cell division, and cell wall biosynthesis pathways. Silencing the GhCKX family separately decreased the LR number and active indole-3-acetic acid (IAA) level. The expression levels of GhPIN1, GhARF7, GhARF19, GhLBD16, GhLBD18, GhLBD29, and GhLBD33 were downregulated, but GhARR2/12 and GhIAA14 were upregulated. The total content of active CTKs was noticeably increased. The results of silencing the GhLOGs family were opposite to those of silencing GhCKXs. Silencing GhARR12 could upregulate GhPIN1 expression and increase LR number. In addition, the silenced GhCKXs, GhLOGs, and GhARR12 were less responsive to MC-induced LR growth than the control.
Conclusion These results suggested that MC treatment could upregulate CTK-nucleoside biosynthesis and CTK metabolism genes to decrease active CTK levels, promoting crosstalk between CTKs and auxin signaling pathways to enhance LR initiation.

Background Achieving a synergistic enhancement in both the yield and insect resistance of Bt cotton holds substantial importance for boosting farmers' income and ecological advantages. This study investigated the impact of amino acid foliar fertilizer (AAF) on the yield and Cry1Ac protein (CP) content, providing valuable insights for enhancing its productivity and insect-resistance capabilities. In 2021, Sikang 1 and Sikang 3 were treated with AAF once (A1) and water (CK) during the peak flowering stage. In 2022, AAF was sprayed one (A1), two (A2), and three (A3) times, respectively, with CK serving as the control.
Results Compared with the control, the A3 treatment increased seed cotton yield (SCY) by 16.0% and CP by 40.98% at 30 days after flowering. AAF application enhanced soluble protein content (SP) and glutamate pyruvate transaminase (GPT) activity, while suppressing protease and peptidase activities. Concurrently, AAF improved sucrose metabolism through elevated sucrose content and increased activities of sucrose synthase (SS) and sucrose conversion enzyme (SCE), which were also positively correlated with yield. A lower ratio of carbon-to-nitrogen (C/N) was linked to higher yields and CP content. Path analysis confirmed that SP, GPT, SS, and SCE demonstrated positive effects on CP content and SCY, respectively. Peptidase activity had negative effects on CP and SCY. The C/N ratio had negative effects on SCY and CP, respectively.
Conclusions Triple foliar application of AAF maintained lower C/N ratios with enhanced carbon metabolism and protein synthesis capacity, thereby simultaneously increasing both Cry1Ac protein content and yield in Bt cotton. These findings provide critical insights for improving both pest resistance and agronomic performance in Bt cotton cultivation.

Background Cotton lodging has become increasingly prevalent due to extreme environmental conditions and agronomic practices, severely compromising yield, fiber quality, and mechanical harvesting efficiency. However, research on cotton lodging remains limited, with most studies focusing on individual or isolated indices rather than a comprehensive system. This study systematically compared four lodging-resistant varieties (LR-1, LR-2, LR-3, LR-4) and four lodging varieties (L-1, L-2, L-3, L-4) across multiple indices: morphological traits, boll distribution, internode filling degree, stem density, mechanical strength, anatomical structure, and chemical composition.
Results The results showed that at the boll-opening stage, lodging-resistant varieties exhibited higher density in the first (increased by 11.6%) and third (increased by 23.5%) basal internodes compared with lodging varieties and significantly greater filling degree in the first (increased by 22.6%), second (increased by 23.1%), and third (increased by 26.1%) basal internodes; significantly higher stem puncture strength (increased by 41.2%) and stem bending resistance (increased by 38.2%); and a significantly lower stem lodging coefficient (19.0% lower in lodging-resistant varieties). Additionally, lodging-resistant varieties showed significantly enhanced anatomical structures, including greater cortex thickness, more mechanical tissue layers, and larger pith cavity, xylem, and phloem areas. Conversely, no significant differences were observed in morphological traits, boll distribution, or chemical composition between the lodging-resistant and lodging types.
Conclusion Lodging-resistant varieties exhibited thicker cortical tissue and mechanical tissue layers, along with larger xylem area and phloem area in basal internodes. These structural characteristics provide superior support for the filling degree and density of basal internodes, thereby enhancing stem puncture strength and bending resistance, and ultimately improving lodging resistance in cotton. These findings provide a theoretical basis for reducing the occurrence of cotton lodging.

Crop chemical regulation using plant growth regulators (PGRs) represents a key strategy for achieving high-efficiency cotton production in China. This review synthesizes four decades of research on mepiquat chloride (MC), an inhibitory PGR pivotal to optimizing cotton growth architecture, stress resilience, and yield-quality parameters. We detail MC's stage-specific roles—from root development and flowering acceleration to canopy optimization and assimilate partitioning—and its mechanistic interactions with hormones (e.g., gibberellin suppression, cytokinin enhancement) under biotic/abiotic stresses. Furthermore, we conceptualize MC deployment into three evolutionary tiers: (1) symptom-guided remedial application, (2) systemic growth-stage programming, and (3) integrated management with agronomic practices. These paradigms, supported by field validation across China's cotton belts, offer a roadmap for precision regulation. Future advancements in nano-formulations, digital agriculture, and PGR synergism are discussed to unlock next-generation yield frontiers.

Background Aquaporins (AQPs) are integral membrane proteins belonging to the major intrinsic protein (MIP) family, playing a crucial role in water transport, cell elongation, and stress responses. However, their evolutionary dynamics and functional roles in Gossypium species remain poorly characterized.
Results In the present study, a total of 55, 54, 54, 103, 106, 108, and 104 AQP genes were found in G. herbaceum, G. arboreum, G. raimondii, G. barbadense, G. tomentosum, G. mustelinum, and G. darwinii, respectively. Phylogenetic analysis classified them into five conserved subfamilies (PIP, TIP, NIP, SIP, and XIP), with 95 genes showing synteny across species and 17 displaying divergence, suggesting subgenome differentiation. Transcriptome analysis revealed that specific GbAQP genes are involved in early salt stress responses and fiber development. Physiological assays demonstrated stronger salt tolerance in tetraploid cottons, particularly G. darwinii, compared with diploids. Co-expression network analysis linked AQPs to abiotic stress and fiber traits, and virus-induced gene silencing (VIGS) confirmed four AQP genes as critical for salt tolerance.
Conclusion This study provides comprehensive insights into the evolution, expression, and functional roles of AQPs in cotton, identifying key candidate genes for improving salt tolerance and fiber quality in Gossypium species.

Background Thidiazuron (TDZ) is a widely used chemical defoliant in commercial cotton production and is often combined with the herbicide Diuron to form the commercial defoliant mixture known as TDZ·Diuron (T·D, 540 g·L^-1 suspension). However, due to increasing concerns about the environmental and biological risks posed by Diuron, there is an urgent need to develop safer and more effective alternatives. Jasmonic acid (JA) and its derivatives are key phytohormones in organ senescence and abscission.
Results Greenhouse experiments at the seedling stage revealed that Me-JA (0.8 mmol·L^-1) alone did not induce defoliation. However, its co-application with TDZ (0.45 mmol·L^-1) at concentrations of 0.6, 0.8, and 1.0 mmol·L^-1 significantly enhanced defoliation efficacy. The most effective combination—TDZ with 0.8 mmol·L^-1 Me-JA—achieved a 100% defoliation rate at 5 days after treatment (DAT), 23.7 percentage points higher than TDZ alone, and comparable to the commercial TDZ·Diuron formulation with equivalent TDZ content. Field trials conducted in Beijing (Shangzhuang), Hebei (Hejian), and Xinjiang (Shihezi) confirmed that the combination of 0.6 mmol·L^-1 Me-JA with 1.70 mmol·L^-1 TDZ provided optimal defoliation performance. At 21 DAT, the defoliation rate increased by 13.5-16.3 percentage points compared with TDZ alone. Furthermore, boll opening rates improved by 5.7-12.7 percentage points relative to TDZ-only treatments. Phytohormonal analyses from the Shangzhuang site showed that the combined treatment significantly altered hormone levels in both leaves and petioles. Compared with TDZ alone, the mixture reduced concentrations of auxin (IAA), cytokinins (Z + ZR, iP + iPA, DHZ + DHZR), and gibberellic acid (GA₃), while increasing levels of JA, abscisic acid (ABA), and brassinosteroids (BR). These hormonal shifts may underlie the enhanced defoliation observed with the combined treatment. Importantly, the TDZ-Me-JA combination did not adversely affect cotton yield, yield components, or fiber quality.
Conclusion The combination of Me-JA and TDZ has a good defoliation effect without affecting crop yield or fiber quality. And it provides a promising foundation for the development of novel, environmentally friendly cotton defoliants.