This study mainly based on the Xinjiang Statistical Yearbook, the annual global supply and demand information of extra-fine cotton published by the International Cotton Advisory Committee (ICAC), combined with the data provided by agricultural departments of Xinjiang prefectures (autonomous prefectures), Development and Reform Commission of Xinjiang Uygur Autonomous Region, and other relevant institutions. The development status and its influencing factors of sea island cotton production in Xinjiang from 1955 to 2024 were analysed, and relevant recommendations were offered, to provide references for the sustainable development of sea island cotton production in Xinjiang. From 1955 to 2024, the planting area, yield per unit area, and total production of Xinjiang sea island cotton showed inter-annual fluctuations. From 1955 to 1990, the fluctuating growth trend was obvious, while in the 21st century, the planting area and total production fluctuated obviously. Sea island cotton varieties in Xinjiang have fully achieved independent breeding, with 88 excellent varieties developed, of which 20 varieties have been widely promoted and planted, supported by the planting technology of "short, dense, early, film, drip irrigation". It was analysed that the key factors influencing the production of sea island cotton include varieties, technology, economic returns, trade wars, and natural disasters. Sea island cotton production currently faces a historical low point in the 21st century in Xinjiang. To overcome these challenges, both technological support and policy guidance are needed.

Transgenic crops, including insect-resistant cotton, have been widely cultivated globally, yielding significant economic and social benefits. Cotton is the foremost natural fiber source and one of the most important cash crops worldwide. The genetic transformation technology mediated by Agrobacterium tumefaciens, based on somatic embryogenesis or organogenesis, has become the primary method for obtaining transgenic plants. Particularly for cotton, a crop that typically regenerates through somatic embryogenesis, this process is not only crucial for the application of modern biotechnology in cotton, but also plays a vital role in genetic improvement and variety innovation in cotton. However, cotton somatic embryogenesis is a complex process; although its regulatory mechanisms have been extensively studied, genotype-dependence and low regeneration efficiency remain significant challenges in cotton genetic transformation. This article provides an overview of the research progress in cotton somatic embryogenesis, summarizing the status of the cotton somatic embryogenesis system, including key influencing factors and molecular mechanisms, and offers perspectives on future research in this area.

[Objective] The study aims at investigating the optimal transformation system to enhance genetic transformation efficiency of cotton shoot tips. [Methods] The shoot tips of Baimian 1 seeds were used as the explant. Different concentrations of ethylenediaminetetra-acetic acid(EDTA), various water bath treatment times, and different concentrations of bacterial suspension were set during the infection stage. During the co-culture stage, six exogenous additives (lanthanum chloride, EDTA, salicylic acid, thidiazuron, zeatin, and silver nitrate) at varying concentrations were introduced. During the screening stage, the concentrations of spectinomycin and ratios of various plant growth regulators (kinetin, naphthalene acetic acid, 6-benzylaminopurine, indole butyric acid, and 2,4-dichlorophenoxyacetic acid) were adjusted. The effects of these treatments on the transient transformation efficiency, germination rate, seedling survival rate, and positive rate of cotton shoot tips were analyzed. [Results] During the infection stage, adjusting the OD₆₀₀ of bacterial suspension to 0.7 and pre-treating shoot tips with 100 μmol·L^-1 EDTA in a water bath for 15 min can significantly improve the transient transformation efficiency (28.09%). During the co-culture phase, adding 1.5 mg·L^-1 thidiazuron obtained the highest transient transformation efficiency (41.47%) and a relatively high germination rate (32.79%). In the screening phase, adding 200 mg·L^-1 spectinomycin resulted in a higher seedling survival rate (32.44%) and the highest positive rate (19.97%); 1 mg·L^-1 6-benzylaminopurine + 0.1 mg·L^-1 naphthalene acetic acid treatment yielded a significantly higher germination rate (34.73%) than other plant growth regulator combinations. Under the optimized conditions described above, the transformation efficiency of cotton shoot tips reached 7.62%, with a positive rate of 18.52%. [Conclusion] The cotton genetic transformation system has been optimized, providing a reference for further improving the transformation efficiency of cotton shoot tips.

[Objective] The study aimed to examine the effects of nitrogen, phosphorus, and potassium fertilizers on soil nutrient contents, cotton growth, and yield-related traits in the arid and nutrient-deficient Heilonggang region. [Methods] The experiment was conducted from 2022 to 2024 at the Weixian Experimental Station of the Cotton Research Institute, Hebei Academy of Agriculture and Forestry Sciences. A randomized block design was adopted with five treatments: no fertilizer, conventional fertilization, nitrogen deficiency, phosphorus deficiency, and potassium deficiency. Soil total nitrogen, alkali-hydrolyzable nitrogen, available phosphorus, and available potassium contents were measured after cotton harvest. At the square stage, early flowering stage, peak boll stage, and boll opening stage, dry matter accumulation of aboveground parts and plant nutrient contents were determined, and fertilizer utilization efficiency was calculated. Boll number per plant were counted on July 15, August 15, and September 10. The boll weight and lint percentage were measured after harvest, and the seed cotton yield and lint yield were calculated. [Results] The effects of nitrogen deficiency on soil total nitrogen and alkali-hydrolyzable nitrogen content were not significant. In the three-year experiment, the phosphorus deficiency treatment significantly reduced soil available phosphorus content by 8.5%, 14.6%, and 19.9%, compared with conventional fertilization, while potassium deficiency treatment significantly reduced available potassium content by 10.3%, 18.9%, and 24.6%, respectively. Compared with conventional fertilization, nitrogen uptake of aboveground parts of cotton in the nitrogen deficiency treatment significantly decreased by 35.7%, 35.4%, and 47.1%, while phosphorus uptake of aboveground parts of cotton in the phosphorus deficiency treatment showed no significant difference, and potassium uptake of aboveground parts of cotton in the potassium deficiency treatment significantly decreased by 15.3%, 13.0%, and 21.1% in 2022, 2023, and 2024, respectively. For agronomic efficiency, fertilizer contribution rate, and apparent utilization rate, nitrogen was the most efficient, followed by potassium, with phosphorus showing near-zero efficiency. Seed cotton yield in the nitrogen deficiency treatment significantly decreased by 5.5%, 13.1%, and 25.7%, while phosphorus deficiency had no significant effect on yield, and potassium deficiency led to a reduction of 3.1% over three years. [Conclusion] In the arid and nutrient-deficient Heilonggang region, fertilizer strategy should follow the principle of "applying efficient nitrogen, moderating potassium use, and reducing phosphorus".

[Objective] This study aimed to comprehensively evaluate the drought resistance of major cotton cultivars in southern Xinjiang, screen drought resistance indicators, and identify superior drought-resistant cultivars (lines). [Methods] A sand culture experiment was conducted using 15% PEG6000 to simulate drought stress on 15 cotton cultivars from southern Xinjiang. Phenotypic and physiological traits were investigated, and drought resistance coefficients were calculated. Comprehensive evaluation of drought resistance was performed through correlation analysis, principal component analysis (PCA), entropy-weighted TOPSIS method, and cluster analysis. A multiple stepwise regression model was established to optimize the evaluation system for drought resistance. [Results] Compared with the control, drought stress reduced the germination energy (GE), germination index (GI), root number (RN), main root length (MRL), hypocotyl length (HL), fresh weight (FW), and dry weight (DW) by over 30%, with HL showing the most significant decline (50.55%) and hypocotyl diameter (HD) the least (24.66%). Conversely, superoxide dismutase (SOD) and peroxidase (POD) activities, along with malondialdehyde (MDA) content, increased by over 20%. PCA condensed the original 12 indicators into two independent comprehensive factors, explaining 82.80% of variance, and identified five key drought resistance indicators during germination: MDA, SOD, DW, HD, and GR. Using entropy-weighted TOPSIS, a comprehensive drought resistance index was determined, and cluster analysis classified the 15 cultivars into four drought resistance types, including three high drought-resistant cultivars (Tahe 2, Zhongmian 113, and Xinluzhong 40), four moderate drought-resistant cultivars (Zhongmian 88, CCRI 979, Xinluzhong 61, and Jiumian 20), four drought-tolerant resistant cultivars (Xinluzhong 88, Zhongmian 619, Zhongmian 96A, and Zhongshengmian 17), and four drought-susceptible cultivars (Xinluzao 50, Xinluzhong 67, JBK16, and Xinluzhong 37). A reliable regression model for drought resistance evaluation was established: I=0.74-0.51C_MDA+0.15C_SOD+0.20C_DW+0.24C_HD+0.45C_GE, with a coefficient of determination of 0.99. [Conclusion] High drought-resistant cultivars exhibited significantly lower stress impacts and higher antioxidant capacity compared to sensitive ones. The entropy-weighted TOPSIS method identified Tahe 2 as the most drought-resistant cultivar. This study established a precise and efficient drought resistance evaluation system, providing a theoretical and technical support for cotton breeding and cultivation under drought conditions.

[Objective] Cotton yield prediction is an important part of cotton production management in our country. The accuracy of boll detection during the boll-opening stage directly affects the precision of yield estimation. In order to solve the problem that the computational complexity of existing cotton boll detection models increases significantly due to the pursuit of detection accuracy, this study proposes a lightweight cotton boll detection model, Slim-YOLOv8n, based on improved YOLOv8n. [Methods] This model takes YOLOv8n as its main framework. On one hand, it integrates a lightweight cross-scale feature fusion network in the neck structure to effectively reduce the dimensionality of multi-scale feature fusion and lower computational complexity. On the other hand, it reconstructs the detection head through reparameterized convolution and the idea of sharing, designing a reparameterized head and a two-stage feature processing stream to maintain accuracy while achieving model lightweighting. [Results] Experimental results show that this model achieves a detection accuracy of up to 98.20%. Compared with the YOLOv8n model, it reduces the number of parameters by 44.84%, computational cost by 39.51%, and model size by 43.34%, verifying the superiority of the model improvement. [Conclusion] Slim-YOLOv8n fully meets the dual demands of high accuracy and lightweighting for boll detection tasks, providing strong technical support for the efficient and precise detection of bolls at the boll-opening stage in cotton yield prediction.

[Objective] This study aimed to investigate the effects of different defoliants on the seed vigor and storage substance content of machine-harvested cotton seeds with different maturities, providing references for the rational selection of defoliants in cotton production. [Methods] Field experiments were conducted in Shihezi City, Xinjiang, from 2020 to 2021. The main plot involved the application of two different defoliants: Ruituolong and Yeluokong. The subplots included two cotton materials: an early-maturing variety, Shidamian 268 (S268), and a late-maturing line, Shidamian 451 (S451). On September 27, cotton bolls that had developed for 30 d, 35 d, 40 d, 45 d, and 50 d on August 31 (the first application of defoliant) were harvested. Naturally-opened cotton bolls before defoliant application served as the control (CK). Seed coat color was observed, and seed index, seed specific weight, oil content, and protein content were measured. Seed germination percentage, germination potential, germination index, and vigor index were determined at 18 ℃ and 28 ℃. [Results] Compared with CK, the white seed rate (the proportion of immature seeds) of 30-day bolls and 35-day bolls of S268 significantly increased under Ruituolong and Yeluokong treatments; while the black-brown seed rate (the proportion of mature seeds), seed index, seed specific weight, protein content, oil content, germination percentage, germination index, and vigor index of cotton seeds all significantly decreased in 2020 and 2021. For S451, the white seed rate of bolls at 30 d, 35 d, and 40 d significantly increased; while the black-brown seed rate, seed index, seed specific weight, protein content, oil content, germination percentage (except for the 40-day bolls), germination potential (except for the 40-day bolls at 28 ℃), germination index, and vigor index of seeds all significantly decreased. After spraying Ruituolong and Yeluokong, there were no significant differences in the black-brown seed rate, germination percentage, and germination potential for 45-day and 50-day cotton bolls of S268 and S451 compared with CK; as well as the seed oil content and protein content of 50-day cotton bolls compared with CK. For S268 and S451, compared with Ruituolong, the black-brown seed rate of 30-day bolls, seed index of 50-day bolls, protein content of 35-day bolls, seed germination index of 35-day bolls at 28 ℃, and vigor index of 40-day bolls at 18 ℃ all significantly decreased. [Conclusion] Under the conditions of this experiment, the superior defoliant was Ruituolong. Spraying Ruituolong had a relatively minor impact on seed vigor and the content of storage substances of 45-50 days cotton bolls.

[Objective] This research aimed to study the effects of different amounts of carbon-containing organic fertilizer on cotton biomass, nutrient accumulation, yield, and soil nutrient content to provide a reference for local cotton production. [Methods] From 2022 to 2023, field experiments were conducted in Wusu City, Tacheng Prefecture, Xinjiang. Six treatments were set up: no fertilization (CK), no application of carbon-containing organic fertilizer (C0), and application of carbon-containing organic fertilizer at 400 kg·hm^-2, 800 kg·hm^-2, 1 200 kg·hm^-2, and 1 600 kg·hm^-2 throughout the cotton growth period (referred to as C400, C800, C1200, C1600, respectively). The effects of different amounts of carbon-containing organic fertilizer on the aboveground dry matter mass; accumulation and distribution of nitrogen, phosphorus, and potassium of cotton; yield; and soil nutrient content were analyzed. [Results] From 2022 to 2023, the dry matter mass, the accumulation of nitrogen, phosphorus, and potassium of cotton straw, fiber, cottonseed, and aboveground parts; and seed cotton yield all showed an overall upward trend with the increase of carbon-containing organic fertilizer application. The proportion of dry matter mass in fiber under C1600 treatment was higher than that in the other treatments. CK treatment exhibited the lowest proportion of nitrogen accumulation in straw and fiber but the highest proportion of nitrogen accumulation in cottonseed. Compared with C0 treatment, the application of carbon-containing organic fertilizer showed no obvious effect on the proportion of phosphorus and potassium accumulation in various aboveground parts of cotton. The seed cotton yield under C1600 treatment was highest, significantly increasing by 53.79%-83.34% and 8.95%-11.77%, respectively, compared with CK and C0 treatments. After harvesting cotton in 2023, the contents of organic carbon, nitrate nitrogen, ammonium nitrogen, available phosphorus, and available potassium in the 0-20 cm soil layer, as well as the content of available potassium in the 20-40 cm soil layer, all showed an upward trend with the increasing application rate of carbon-containing organic fertilizer. [Conclusion] Under the conditions of this experiment, the application of 1 600 kg·hm^-2 carbon-containing organic fertilizer is beneficial for increasing soil nutrient content, promoting cotton's uptake of nitrogen, phosphorus, and potassium; increasing cotton aboveground dry matter mass; and achieving the highest seed cotton yield.

[Objective] This study aimed to explore the application potential of cotton-soybean intercropping in addressing prominent issues such as the intense conflict between grain and cotton for land, as well as soil degradation, in the cotton-growing areas of the Yellow River Basin. [Methods] The experiments were conducted in Binzhou City, Shandong Province, from 2023 to 2024. Different treatments were set up, including cotton monocropping (CK1), soybean monocropping (CK2), and five row ratio configurations of cotton-soybean intercropping (2 rows of cotton intercropped with 2 rows of soybean, 2 rows of cotton intercropped with 3 rows of soybean, 2 rows of cotton intercropped with 4 rows of soybean, 4 rows of cotton intercropped with 4 rows of soybean, and 4 rows of cotton intercropped with 6 rows of soybean, denoted as 2||2, 2||3, 2||4, 4||4, and 4||6). The effects of these intercropping patterns on soil nutrient content, crop agronomic traits and yield, fiber quality, land equivalent ratio (LER), and comprehensive economic benefits were studied. [Results] Compared with monocropping, the intercropping system increased the contents of alkali-hydrolyzable nitrogen and available phosphorus in the 0-20 cm soil layer between cotton rows. The 4||6 intercropping pattern was beneficial for increasing the soil organic matter content and total humus content in the 0-20 cm and 20-40 cm soil layers between cotton rows and soybean rows. At the boll-opening stage, the number of mature bolls per plant under the five intercropping treatments was significantly lower than that under CK1. At the maturity stage, compared with monocropping, the number of nodes and effective branches per plant of intercropped soybeans decreased. Compared with CK1, the intercropping patterns led to a reduction in the number of bolls per plant and boll weight; however, the seed cotton yield increased due to the higher harvest density. In 2023, the 4||6 treatment achieved the highest seed cotton yield, which was significantly 19.34% higher than that of CK1. In 2024, the 2||3 treatment had the highest seed cotton yield, showing a significant increase of 15.20% compared with CK1. There were no significant differences in cotton fiber quality indicators among different treatments. Compared with CK2, the soybean yield under the 4||4 and 4||6 patterns increased by 1.58% and 12.00%, respectively in 2023. In 2024, the soybean yield under the 2||3, 4||6, and 4||4 treatments increased by 17.76%-26.18%. In 2023, the 4||6 treatment had the highest LER (1.15) and the highest net income. In 2024, the 2||3 treatment achieved the highest LER (1.19) and the highest net income. [Conclusion] Cotton-soybean intercropping was beneficial for increasing seed cotton yield, land use efficiency, and net income. Among the tested intercropping patterns, the 4||6 and 2||3 patterns showed greater promotion potential in the cotton-growing areas of the Yellow River Basin.

[Objective] The aim of this study was to analyze the genetic diversity of morphological traits, yield, and fiber quality characteristics in introduced upland cotton resources so as to provide references for the exploration and utilization of superior germplasm. [Methods] A total of 213 Gossypium hirsutum accessions introduced from Central Asia were planted in Aksu, Xinjiang, from 2023 to 2024. Twenty-six traits were measured. Through analysis of the coefficient of variation and genetic diversity index, correlation analysis, cluster analysis, principal component analysis, and comprehensive evaluation, superior germplasms were identified and screened. [Results] The genetic diversity indices of 13 traits (plant type, stem color, main stem hardness, stem hair number, leaf color, corolla color, anther color, style length, fruiting branch type, boll arrangement, boll type, ease of boll opening, and color of short fiber) ranged from 0.09 to 1.04. For the other 13 traits (growth period, plant height, first fruiting branches node, number of fruiting branches per plant, number of bolls per plant, boll weight, lint percentage, seed index, upper half mean length, uniformity index, breaking tenacity, breaking elongation, and micronaire), the coefficients of variation ranged from 1.37% to 19.20%, and the genetic diversity indices ranged from 1.85 to 2.11. Among them, the genetic diversity indices of 12 traits were greater than 2. Plant height showed highly significant or significant positive correlations with the number of fruiting branches per plant and lint percentage. Boll weight was significantly positively correlated with seed index, upper half mean length, and uniformity index. Cluster analysis classified the materials into six major groups at a Euclidean distance of 9.5. Groups Ⅱ and Ⅵ exhibited superior overall performance. From these two groups, 31 materials met the Type Ⅲ fiber quality standard, and one material met the Type Ⅱ standard. Group Ⅱ contained the highest number of resources with high boll weight (≥ 7 g). Principal component analysis extracted five principal components, with a cumulative contribution rate of 73.522%. The top ten materials based on comprehensive evaluation scores were 13TJ272 selected line, 13TJ186 selected line, Jimian 5, 13TJ111 selected line, 12TJ11 selected line, 17W1-17, 12TJ15 selected line 1, 13TJ229 selected line, 17W1-3, and 13TJ207. [Conclusion] The 213 introduced upland cotton resources exhibit relatively rich genetic diversity. Ten materials with high comprehensive scores were screened, which can serve as genetic improvement materials for breeding new upland cotton varieties.

[Objective] This study aimed to analyze the influencing factors of farmers' participation in the futures market, and provide reference for using the futures market to promote the development of the cotton industry. [Methods] A theoretical analysis framework was constructed along the lines of "risk aversion motivation→futures function cognition→futures market participation willingness→futures market participation behavior". The ordered Logit model and multinomial Logit model were comprehensively used to analyze the influencing factors of cotton farmers' futures market participation willingness, and the Logit model was further used to discuss the influence of social capital and intermediary organizations. [Results] The results showed that 70% of farmers have heard of the futures market, but only 5% of farmers participate in the futures market. Farmers' resource endowments, such as education level, planting scale, age, as well as market risk avoidance motivation, futures function cognition, social capital, and intermediary organization development, have important impacts on cotton farmers' participation in the futures market. [Conclusion] Currently, the proportion of farmers participating in the futures market is still very low. The main factors that inhibit cotton farmers from participating in the futures market are insufficient motivation to avoid market risks, unclear understanding of futures functions, lack of demonstration guidance and social capital, and immature development of intermediary organizations.

[Objective] This research aimed to investigate the effects of different pruning methods on the content of storage substances in upland cottonseed. [Methods] A field trial was conducted in Kashgar Prefecture, Xinjiang, in 2023, using a split-plot design. The main plots consisted of two cotton varieties (J8031 and Yuanmian 8), while the subplots involved different pruning treatments: retaining 3, 5, 7, or 9 bolls per plant from the flowering and boll-setting stage to harvest (T1, T2, T3, and T4 treatments); removing vegetative branches during the budding stage(T5); removing axillary buds during the flowering and boll-setting stage (T6); removing vegetative branches from the initial flowering stage to the flowering and boll-setting stage (T7); removing empty branches during the late flowering stage and early boll-opening stage (T8); and topping during the full flowering stage to boll opening stage (T9). No pruning was used as the control treatment (CK). The contents of total protein, 19 amino acids, total fat, 25 fatty acids, and gossypol in cottonseeds were measured under different treatments. [Results] Under T1 to T9 treatments, the total protein and total fat contents in cottonseed of J8031 and Yuanmian 8 showed no significant difference compared with CK. Compared with CK, T5 treatment significantly increased the contents of phenylalanine, arginine, tyrosine, proline, and glycine in J8031, as well as the contents of methionine, phenylalanine, arginine, tyrosine, proline, cysteine, and hydroxyproline in Yuanmian 8, significantly reduced the content of methionine in J8031. T6 treatment significantly increased arginine, tyrosine, and serine contents in J8031, as well as phenylalanine, tyrosine, and hydroxyproline contents in Yuanmian 8, significantly reduced methionine content in J8031. Compared with CK, the contents of stearic acid, heneicosanoic acid, and linoleic acid in J8031, and the contents of palmitic acid and eicosadienoic acid in Yuanmian 8 all significantly increased under T2 treatment. The contents of myristic acid, arachidic acid, eicosapentaenoic acid, and oleic acid in J8031 under T7 and T9 treatments significantly decreased. Under T1 treatment, the contents of palmitic acid, hexanoic acid, eicosapentaenoic acid, and eicosenoic acid significantly increased in Yuanmian 8; while the oleic acid content in J8031 and Yuanmian 8 significantly decreased. Under T7 and T8 treatments, the contents of heneicosanoic acid, linoleic acid, palmitoleic acid, oleic acid, and eicosenoic acid in Yuanmian 8 significantly decreased. Under T3, T5, T7, T8, and T9 treatments, both total (-)/(+)-gossypol and free (-)/(+)-gossypol contents in J8031 were significantly higher than that in CK. Compared with CK, total (-)/(+)-gossypol content in Yuanmian 8 significantly increased under T8 treatment, while free (-)/(+)-gossypol content significantly decreased under the nine treatments from T1 to T9. [Conclusion] Compared with CK, pruning treatment had no significant effect on the total protein and total fat contents in cottonseed of J8031 and Yuanmian 8, but significantly influenced the contents of certain amino acids, certain fatty acids, and gossypol.

[Objective] This study aimed to investigate the role of sucrose in cotton resistance against Verticillium wilt and verify the function of GhSWEET55, providing a theoretical basis for revealing the molecular mechanism of cotton resistance to Verticillium wilt. [Methods] Cotton were inoculated with Verticillium dahliae using the root-wounding method. Sucrose content in cotton roots was determined by spectrophotometry. Differentially expressed genes were obtained by transcriptome sequencing. The enrichment of differentially expressed genes was studied by KEGG pathway analysis. Differentially expressed genes and SWEET family expression patterns were analyzed by transcriptome sequencing, and validated by quantitative real-time polymerase chain reaction (qRT-PCR). Bioinformatics analysis was performed to characterize the protein sequence features and phylogenetic relationships of GhSWEET55, and its expression pattern was analyzed by qRT-PCR. The function of GhSWEET55 was verified by virus-induced gene silencing (VIGS). [Results] Sucrose content in cotton roots increased significantly at 12 h and 48 h after V. dahliae infection, and decreased significantly at 96 h after V. dahliae infection. Some differentially expressed genes were enriched in sucrose-related energy metabolism pathways and defense response pathways. Most members of the SWEET family were differentially expressed, and GhSWEET55 from Clade III was significantly up-regulated. GhSWEET55 was predominantly expressed in cotton leaves, and the encoded protein was localized to the plasma membrane. Silencing of GhSWEET55 enhanced cotton resistance to Verticillium wilt. [Conclusion] Sucrose is involved in cotton resistance against Verticillium wilt. The SWEET gene family responds to V. dahliae infection. GhSWEET55 negatively regulates cotton resistance to V. dahliae.

[Objective] Gossypium aridum exhibits excellent stress tolerance. Plant homeodomain (PHD) proteins play a crucial role in regulating plant responses to abiotic stress. This study aimed to mine PHD genes in the whole genome of G. aridum, and analyze their expression patterns under abiotic stress. [Methods] G. aridum genome was mined for PHD using bioinformatics methods. The physicochemical properties, conserved domains and motifs, phylogenetic relationships of PHD proteins, cis-acting elements and transcription factor binding sites in the promoter region were predicted and analyzed. The expression levels of GarPHD genes under salt, drought, and low-temperature stresses were analyzed using quantitative real-time polymerase chain reaction (qRT-PCR). [Results] A total of 38 GarPHD genes were identified in G. aridum. The PHD domain of GarPHD proteins contains the consistent sequence: X(0-1)-C-X(1-2)-C-X(8-13)-C-[DESANQ]-X(1-2)-C-X(4)-H-X(2)-C-X(9-16)-[WYF]-X-C-X(2)-C. PHD proteins of G. aridum, G. tomentosum, and G. barbadense were divided into 5 subgroups. The promoter regions of GarPHD contain cis-acting elements related to growth and development, plant hormones, and stress responses, as well as binding sites for 33 transcription factors. The qRT-PCR analysis revealed significant changes in the expression levels of certain GarPHD genes in response to salt, drought, and low-temperature stress. Specifically, GarPHD19 was found to respond to both low-temperature and drought stress, GarPHD31 responded to both salt and drought stress. [Conclusion] Thirty-eight PHD genes were identified in G. aridum. Some GarPHD responded to salt, drought, and low-temperature stress, which lays the foundation for further research on the function of GarPHD genes.

[Objective] This study aims to address the issues of impurity contamination in machine-picked seed cotton in Xinjiang and the low efficiency of manual sorting, we propose a highly efficient and precise method for detecting impurities in seed cotton to enhance cotton quality. [Methods] An improved CID-YOLO model is introduced based on YOLO v11. Firstly, a normalization-based attention mechanism module is introduced to enable the network to balance target channel features and pixel features while reducing parameter count and computational complexity, thereby improving detection accuracy. Secondly, according to the characteristics that the detected target is easy to appear at the edge, the lightweight adaptive convolution module is used to replace some convolution modules in the backbone network and neck network, which can better preserve the edge and structure information of the sampling phase, and effectively reduce the amount of parameters. Finally, an efficient layer aggregation network is used to replace the improved pyramid pooling module in the backbone network to enhance the ability of feature multi-scale extraction and information aggregation, so as to improve the perception performance of targets of different scale targets in complex background. [Results] Experimental results demonstrate that the CID-YOLO model achieves outstanding performance in seed cotton impurity detection, with a detection accuracy of 92.1%, recall of 89.5%, F₁ score of 90.8%, and mean average precision of 92.8%. Its overall recognition effectiveness significantly outperforms existing YOLO series models. [Conclusion] The proposed CID-YOLO method enables rapid and precise identification of drip irrigation tapes, colored impurities, cotton stalks, and plastic mulch in machine-picked seed cotton. It provides effective technical support for real-time seed cotton impurity detection and holds promising application prospects.

[Objective] A disease that damages cotton fiber has been found in the Xinjiang cotton fields in recent years. The infected cotton fiber turned into mouse-gray and failed to fluff as the boll opens, losing all commercial value. The purpose of this study was to identify the pathogen causing lint rot in Xinjiang cotton fields, and to explore the relationship between mite and disease transmission. [Methods] A total of 161 diseased boll samples were collected from 25 cotton-growing units across northern and southern Xinjiang in 2021 and 2023. The strains were isolated and purified using the tissue isolation method. The pathogen was identified based on morphological characteristics, molecular biological analysis, and pathogenicity test. Different tissues and organs of cotton plants were artificially inoculated in the field to determine the infection sites of the pathogen. The correlation between cotton boll rot and mite was investigated by examining the occurrence frequency of the mite in diseased bolls in cotton field, and combining with the experiment of artificially inoculating healthy detached cotton bolls with mites carrying conidia. [Results] The cotton Nigrospora lint rot is widespread in Xinjiang cotton fields, and the damage is gradually worsening. A total of 146 Nigrospora strains were isolated from diseased samples collected from cotton fields in Xinjiang. The morphological characteristics of the strains were consistent with N. gorlenkoana. The DNA sequences of the internal transcribed spacer in eukaryotic ribose rDNA-ITS, translation elongation factor TEF1-α, and β-tubulin TUB2 in 27 representative strains exhibited high homology with N. gorlenkoana. Field and laboratory pathogenicity tests of 5 representative strains showed that the lint displayed extensive black-gray rot. Therefore, the pathogen causing cotton Nigrospora lint rot in Xinjiang was identified as N. gorlenkoana. The pathogen exclusively infected cotton fiber and did not affect seed, leaf, stem, bud, and flower of cotton. Siteroptes reniformis was closely associated with cotton Nigrospora lint rot. Adult mites or their physogastric females were found in all the diseased bolls, and they can carry the conidia of N. gorlenkoana into the bolls to spread the disease. [Conclusion] The cotton lint rot caused by N. gorlenkoana in Xinjiang in recent years is a disease specifically targeting cotton fiber, with S. reniformis as the primary transmission vector.

[Objective] To address the issues of idle field in winter and spring, low utilization efficiency of cotton straw, and declining profitability in cotton production in the Yellow River Basin, a cotton-Stropharia rugosoannulata double cropping system was proposed, which utilize crushed cotton straw for S. rugosoannulata cultivation in the winter fallow field, followed by S. rugosoannulata residue returning to field. The objective was to investigate the comprehensive effects of this system on productivity, economic benefit, and soil fertility, aiming to provide technical support for the green and sustainable development in the local cotton-growing region. [Methods] Field experiments were conducted from 2022 to 2024 in Linqing City, Shandong Province. Using monocropped spring cotton (MFC) and monocropped short-season cotton (MSC) as controls, the annual yield, economic returns, and soil nutrient content dynamics of two double cropping patterns, intercropping of spring cotton with S. rugosoannulata (FC+SR), short-season cotton followed by S. rugosoannulata in succession planting (SC+SR), were systematically compared. [Results] Compared with MFC treatment, the seed cotton yields of FC+SR and SC+SR treatments significantly decreased by 7.7% and 14.2%, respectively. However, by harvesting S. rugosoannulata (fresh yield: 20.80-21.53 t·hm^-2), the system's net profit was significantly increased to 216 700-244 100 yuan·hm^-2, which was 43.3-48.8 times that of MFC treatment. The net profit of SC+SR pattern was 12.6% higher than that of the FC+SR pattern. Compared with monocropped cotton, the double cropping patterns combined with straw and S. rugosoannulata residue returning significantly increased the contents of alkali-hydrolyzable nitrogen, available phosphorus, and available potassium in the 0-20 cm, 20-40 cm, and 40-60 cm soil layers. And the improvement effect of the SC+SR pattern was generally superior to that of FC+SR. [Conclusion] The cotton-S. rugosoannulata double cropping system is feasible in the Yellow River Basin, with the short-season cotton followed by S. rugosoannulata in succession planting (SC+SR) being the preferred choice. This pattern achieved the recycling of field straw resources and synergistic enhancement of economic benefits and soil fertility, serving as an effective pathway for promoting high-quality agricultural development in the cotton-growing regions of the Yellow River Basin.

[Objective] Construct a yeast two-hybrid (Y2H) library of Gossypium barbadense, and screen for interacting proteins of GbbHLH130 using Y2H assays. [Methods] This study constructed a Y2H library of G. barbadense using the Gateway technique, and employed the Y2H system to screen for candidate proteins interacting with GbbHLH130. [Results] This study successfully constructed a G. barbadense Y2H library, with a second library capacity of 1.36 × 10⁷ CFU, and insert fragment length >1 000 bp, and a recombination rate of 100%. Using Y2H technology, 298 initial positive clones were screened, and the interaction between GbRAV1, GbHSFA1b, and GbbHLH130 was verified through Y2H assays. [Conclusion] This study successfully constructed a Y2H library of G. barbadense and preliminarily screened candidate interacting proteins for GbbHLH130. GbRAV1 and GbHSFA1b were verified to interact with GbbHLH130 through Y2H assays, suggesting that they may play a role in the biological process of response to drought stress mediated by GbbHLH130. However, their interaction mechanisms and specific roles in drought response need further research.

[Objective] Forkhead box protein G1 (FOXG1), as a transcription factor, plays a crucial role in cell proliferation and differentiation. At present, the FOXG1 gene family has not been systematically studied in cotton. This research aimed to identify and analyze FOXG1 gene family in cotton. [Methods] FOXG1 gene family members were identified in cotton using bioinformatic approaches. Analyses were performed on the physicochemical properties, conserved motifs, and phylogenetic relationships of the corresponding proteins. The expression patterns of FOXG1 genes in Gossypium hirsutum and G. barbadense were investigated using transcriptome data. Preliminary functional exploration of the FOXG1 genes was conducted through association analysis between haplotypes of G. hirsutum FOXG1 genes and fiber quality traits, as well as via transgenic overexpression of GhFOXG1-4 gene in Arabidopsis thaliana. [Results] A total of 6, 5, 3, 3, 6, 6, 6, and 3 FOXG1 genes were identified in G. hirsutum, G. barbadense, G. raimondii, G. arboreum, G. tomentosum, G. mustelinum, G. darwinii, and G. herbaceum, respectively. These 38 FOXG1 proteins and 3 FOXG1 proteins of A. thaliana could be divided into 4 clades. GhFOXG1-1 was highly expressed in anther and ovule. GhFOXG1-2, GbFOXG1-1 and GbFOXG1-2 were highly expressed in anther, ovule and fiber. GhFOXG1-4 was highly expressed in ovule. GhFOXG1-4 and GhFOXG1-5 had 2 and 3 haplotypes, respectively. Significant differences in upper half mean length, breaking strength, and micronaire were observed among these haplotypes. The stem cell width of A. thaliana overexpressing GhFOXG1-4 gene was significantly larger than that of wild type. [Conclusion] A total of 38 FOXG1 genes were identified in 8 cotton species. The excellent haplotypes of some GhFOXG1 genes have the potential to synergistically improve fiber quality. GhFOXG1-4 positively regulates the stem cell width in A. thaliana, which lays a foundation for further study the function of FOXG1 family genes.

[Objective] This research aimed to investigate the effects of reclaimed water irrigation and different mulching methods on cotton growth, yield, and fiber quality. [Methods] A field experiment was conducted in Hutubi County, Changji Hui Autonomous Prefecture, Xinjiang in 2024. Six treatments were established: well water irrigation throughout the whole growth stage + straw mulching (T₁); reclaimed water irrigation throughout the whole growth stage + straw mulching (T₂); reclaimed water irrigation at critical water-demand stages (squaring stage and flowering and boll-setting stage) + straw mulching (T₃); reclaimed water irrigation throughout the whole growth stage + plastic film mulching (T₄); reclaimed water irrigation at critical water-demand stages + plastic film mulching (T₅); and well water irrigation throughout the whole growth stage + plastic film mulching (CK). Cotton plant height, stem diameter, leaf area index (LAI), yield traits, irrigation water use efficiency (IWUE), and fiber quality were compared across different treatments. The entropy-weighted technique for order preference by similarity to ideal solution (TOPSIS) method was used for comprehensive evaluation to select the optimal treatment. Meanwhile, the heavy metal contents in the soil and different cotton organs were determined and analyzed. [Results] During the flowering and boll-setting stage, and boll-opening stage, reclaimed water irrigation significantly increased plant height, stem diameter, and LAI compared with well water irrigation. The plant height, stem diameter, and LAI under straw mulching were greater than those under plastic film mulching; the T₂ treatment exhibited the maximum plant height, stem diameter, and LAI. T₂ also achieved the highest seed cotton yield, lint yield, and IWUE, and upper half mean length, breaking tenacity, breaking elongation, and micronaire of fiber of T₂ were superior to those of other treatments. Comprehensive evaluation using entropy-weighted TOPSIS showed that the T₂ treatment performed best. Compared with well water irrigation, reclaimed water irrigation significantly increased the contents of chromium (Cr) and lead (Pb) in the 0-60 cm soil layer and Cr content in cotton roots, stems, and leaves, while significantly reducing the arsenic (As) content in the 0-60 cm soil layer and cotton roots. However, the contents of mercury (Hg), cadmium (Cd), Cr, Pb, and As in soil and cotton plants under different treatments were all below the risk screening values. [Conclusion] Under the conditions of this experiment, the combination of reclaimed water irrigation throughout the whole growth stage and straw mulching showed the best comprehensive performance.