【Objective】Cotton bollworm (Helicoverpa armigera) and field weeds are major constraints to high-yield cotton production. Existing varieties with single traits (insect resistance or herbicide tolerance) fail to meet the demands of efficient cultivation. Developing transgenic cotton varieties with combined insect resistance and glyphosate tolerance will provide high-efficiency germplasm resources for stress-resistant cotton breeding.【Method】The insect-resistant fusion gene cry1Ac-vip3Da and glyphosate-tolerant gene g10-epsps were introduced into cotton R15 through Agrobacterium-mediated method, regenerated transgenic plants were screened via PCR, positive lines underwent multi-generation self-pollination to achieve homozygosity, and stable lines with superior resistance were selected. The expression of target genes in different tissues of transgenic lines was analyzed using qRT-PCR and ELISA. Bioactivity assays and glyphosate tolerance tests were conducted to evaluate the genetic stability of insect resistance and herbicide tolerance across generations (T₄-T₆). Agronomic traits of transgenic lines were comprehensively assessed. 【Result】Eight positive transgenic lines with dual resistance were identified through PCR screening, and CA-6, CA-7 and CA-17 lines exhibited higher resistance. qRT-PCR revealed high expression of cry1Ac-vip3Da and g10-epsps in all tissues of these lines, and expression levels varied significantly among tissues. ELISA analysis demonstrated significant differences in Cry1Ac-Vip3Da and G10-EPSPS protein content across tissues of the three transgenic lines, with the highest levels observed in leaves. Protein accumulation gradually decreased during the developmental stages (from the four-leaf stage to boll-opening stage), but remained stable across T₄-T₆ generations. Bioactivity assays and glyphosate tolerance tests demonstrated that three transgenic cotton lines (T₄-T₆ generations) exhibited corrected mortality rates of 65.12%-82.75%, tolerated glyphosate at over four times the recommended dosage, and showed no attenuation of resistance across generations. There were no significant differences in plant height, number of fruit branches, number of bells per plant, bell weight, lint percentage, seed cotton yield, and lint cotton yield between transgenic lines and R15.【Conclusion】The exogenous genes cry1Ac-vip3Da and g10-epsps were stably inherited across generations in transgenic lines CA-6, CA-7, and CA-17, conferring dual insect resistance and glyphosate tolerance without compromising agronomic performance.

【Objective】The current post-planting film-covering technology in the Yellow River Basin cotton-growing areas relies on manual seedling release and thinning, which hinders the development of full-scale mechanization. This study explored the adaptability of the dry sowing and wet emergence technology (used in northwestern inland cotton regions) to the Yellow River Basin. By comparing the effects of different sowing methods on seed germination environment, cotton emergence rate, and seedling growth, this study aimed to identify key environmental constraints and provide the theoretical support for optimizing mechanized planting techniques. 【Method】From 2023 to 2024, using the cotton cultivar Ji863 as the experimental material, four treatments were implemented: single-seed seeding without mulching (T1), single-seed post-planting film covering (T2), dry sowing and wet emergence with single-seed sowing (T3), and dry sowing and wet emergence with double-seed sowing (T4). The study was conducted in Quzhou County, Hebei Province, and the effects of these treatments on soil environment, cotton emergence, and growth of above-ground and root systems were evaluated. 【Result】Compared with T1, T2 and T3 significantly increased soil temperature at 5 cm, soil moisture content, emergence rate, plant height, above-ground dry matter weight, root length, root surface area, root volume, and root vigor, while significantly reduced soil compaction, emergence time, and root diameter. Compared with T2, in 2023 and 2024, T3 reduced the daily temperature range at 5 cm soil depth by 3.67 and 1.58 ℃ within 30 days after sowing, and reduced soil compaction by 9.36% and 27.06% within 10 days after sowing, respectively, which decreased emergence days in 2024 by 0.6 days, and increased root length, surface area, volume, and root activity in both years. Compared with T4, single-grain sowing in 2023 and 2024 significantly increased emergence time and decreased emergence rate but increased aboveground dry matter weight by 13.98% and 55.00%. The structural equation model showed that different sowing methods affected cotton seedling emergence rate by altering soil temperature at 5 cm depth, daily temperature range, soil moisture content, and soil compaction, while seedling dry matter weight was mainly affected by soil moisture content, plant height, and soil compaction. 【Conclusion】In the Yellow River Basin cotton areas, the dry-sowing and wet-emergence improved emergence speed and rate by reducing the diurnal temperature fluctuation at 5 cm and soil compaction, thereby promoting uniform and robust seedlings, and sowing one seed per hole was the optimal strategy.

The traditional sowing of cotton in southern Xinjiang needs spring irrigation or winter irrigation for salt suppression to ensure the seedling emergence, but the water consumption is large. The ‘dry sowing and wet emergence’ model has emerged as an innovative approach, enabling precise water management to reduce consumption while effectively regulating soil salt-alkali distribution and ensuring normal cotton growth. Current research on regional adaptability of this mode remains preliminary. This study systematically reviewed existing progress, discussed optimal irrigation volume and frequency under this model, and summarized its regulatory mechanisms on soil salt distribution dynamics, physical structure, moisture dynamics, and cotton growth. Production practices and literature analysis demonstrate that this model maintains soil salinity within suitable ranges for cotton development. Future research directions are proposed, including climate-adaptive planting patterns, the intelligent irrigation monitoring, combined application of soil amendments, and microbial regulation.

With the advancement of agricultural supply-side structural reforms and the growing demand for high-quality, safe, and eco-friendly agricultural products in China, cotton production now faces the challenge of coordinating multiple objectives, including yield enhancement, quality optimization, simplified and efficient management, and environmental sustainability. To address these challenges, this paper proposes the novel concept of multi-objective collaborative cultivation (hereafter termed “collaborative cultivation”). We systematically elaborate on the theoretical foundations underpinning this approach, including mechanisms of precision sowing for robust seedling establishment, synergistic water-fertilizer management under partial root-zone irrigation, population regulation through high-density planting with chemical regulation and pruning-free canopy shaping, physiological mechanisms of defoliation-ripening for synchronized boll maturation, and compensatory growth strategies ensuring yield stability under abiotic stress. Building on these theorical bases and international research insights, we identify four core technologies of collaborative cultivation: (i) precision sowing coupled with stress-resilient seedling establishment under adversity, (ii) high-density planting with chemical regulation for canopy shaping, (iii) variable-rate drip irrigation with water-fertilizer synergy management, and (iv) synchronized maturation control technology. Empirical evaluations demonstrate that the integrated application of these technologies optimizes resource utilization, enhances productivity, and ensures fiber quality consistency, while reducing labor inputs and chemical usage. Case studies from major cotton-producing regions validate that collaborative cultivation achieves synergistic outcomes in productivity, sustainability, and economic viability, aligning with green agricultural development goals. Future research priorities include optimizing multi-objective trade-offs, deciphering genotype-environment-management interactions, enhancing stress compensation mechanisms, and extending collaborative principles to multi-cropping systems. Through interdisciplinary innovation and technology integration, this framework offers a systemic solution for high-quality cotton industry development, demonstrating significant potential to drive the sector's green transformation and sustainable advancement.

Improving cotton fiber quality can increase the economic income of cotton farmers, however achieving high fiber quality without decreasing cotton fiber yield remains a major challenge in saline-alkaline cotton fields. A field experiment was conducted in 2020 and 2021 on saline-alkaline soil with cotton under drip irrigation to examine how amount and timing of leaching affected soils salinity, cotton fiber yield and quality. There were five leaching amounts (CK: 0 mm, W1: 75 mm, W2: 150 mm, W3: 225 mm and W4: 300 mm) and three leaching timings (T1: once at the seedling stage, T2: twice at the seedling and budding stages, and T3: thrice at the seedling, budding and pollen-setting stages). Soil salinity, soil nitrate nitrogen (NO₃-N), cotton nitrogen (N) uptake, irrigation water productivity (IWP), cotton fiber yield, fiber length, fiber uniformity, fiber strength, fiber elongation, micronaire and fiber quality index (FQI) were investigated. The results indicated that soil salinity and NO₃-N reduced with increasing leaching amount. The N uptake of cotton bolls was greater than in cotton leaves, stems and roots, and total N accumulation increased with increasing leaching amount. The optimal cotton fiber yield and IWP occurred in treatment W3T2, and were 3,199 and 2,771 kg ha⁻¹, and 0.5482 and 0.4912 kg m⁻³ in 2020 and 2021, respectively. Fiber length, strength, elongation, and uniformity increased with increasing leaching amount, while there was a negative relationship between fiber micronaire and leaching amount. Soil salinity,  NO₃-N and fiber micronaire were negatively correlated with fiber quality (i.e., length, strength, elongation and uniformity) and yield, nitrogen uptake of various organs (i.e., root, stems and leaves) and whole plant nitrogen uptake. Pearson correlation analysis revealed that fiber elongation was most sensitive to soil salinity. The method of Entropy–Order Preference by Similarity to Ideal Solution (EM–TOPSIS) indicated that leaching of 300 mm of water applied equally at the seedling and budding periods was the optimal treatment to maintain soil salinity and nutrient levels and achieve high cotton fiber yield and quality. In conclusion, the optimal level of leaching treatment decreased soil salinity and improved nitrogen uptake and was beneficial to achieve high fiber yield and quality. Our results will be significant for guiding drip irrigation practice of leaching on saline-alkaline soils for sustainable cotton fiber production.

【Background】 Cotton is one of the most important crops globally. The application of bioengineering technology has greatly improved the efficiency of molecular breeding. However, current cotton genetic transformation faces challenges such as genotype dependency, lengthy timelines, and limited transformation methods.【Objective】This study aims to establish an efficient Agrobacterium rhizogenes-mediated genetic transformation system for cotton to expand genetic breeding methodologies.【Method】Using the common cotton receptor varieties WC and R18 as primary materials and mRUBY as a reporter gene, the root inducing process mediated by A. rhizogenes was optimized through screening hormone combinations (types and concentrations), analyzing differences in explant types and genotype-specific rooting systems. A stable genetic transformation system was subsequently developed and applied to gene editing.【Result】The addition of naphthaleneacetic acid (NAA) and lovastatin to the root inducing medium (RIM) promoted more efficient root formation compared to NAA alone or combinations of NAA+indole-3-butyric acid (IBA) or NAA+Lovastatin+IBA. The optimal concentrations for inducing hairy roots were both 2 mg·L^-1 for NAA and lovastatin. Cotyledons were the most effective explants for root induction: WC cotyledons, cotyledon nodes, and hypocotyls exhibited rooting efficiencies of 398%, 72%, and 39%, respectively. Cotyledons required the shortest induction time (7 d), 3 d shorter than cotyledon nodes and 8 d shorter than hypocotyls. Cotyledons were also the optimal explants for R18, their rooting capacity differed. Genotype comparisons revealed that 20 days post-infection (dpi), the rooting efficiencies per cotyledon were 398% (WC), 116% (R18), 199% (NDM8), 103% (XLZ61), 57% (Gb-1), and 0 (Gb-2). Upland cotton varieties (WC, R18, NDM8, and XLZ61) exhibited rooting efficiencies above 100%, while sea island cotton varieties (Gb-1, Gb-2) were below 100%. Notably, Gb-2 began to root at 35 dpi. Receptor varieties of upland cotton generally showed slightly higher rooting efficiency than production varieties. There was a certain difference between the positive rate of genetic transformation and the rooting rate. The positive rates of NDM8, XLZ61, Gb-1 and Gb-2 at 20 dpi were 59.8%, 16.0%, 38.5% and 0, respectively. Using positive roots as explants, non-embryogenic and embryogenic callus induction yielded transgenic mRUBY-expressing plants, establishing a complete genetic transformation system. The intensity of plant coloration correlated positively with mRUBY expression levels. Additionally, cotton plants with edited GhGI genes were successfully obtained.【Conclusion】The study optimized the A. rhizogenes-mediated root induction process in cotton and established a robust genetic transformation system. This system was successfully applied to gene editing, generating transgenic cotton plants expressing mRUBY and edited GhGI genes.

【Objective】This study aimed to investigate the harm of low temperature in the cotton (Gossypium hirsutum L.) seedling stage on floral bud differentiation and the effect on seedcotton yield, to analyze the change characteristics of cotton floral bud differentiation phenotypes and terminal buds endogenous hormones under low temperature, so as to provide the theoretical basis for the high-quality and high-efficiency cultivation technology of cotton under low temperature.【Method】Using the early-maturing and high-quality cotton variety Zhong 425 as the material, a pot experiment was conducted in the smart greenhouse of the Pailou Experimental Station of Nanjing Agricultural University from 2022 to 2023 to simulate the daily average temperature environment during the cotton seedling stage in Aksu, southern Xinjiang. Two temperature treatments were set up: the control (CK, with a daily average temperature of 27 ℃, and daily maximum and minimum temperatures of 32 and 22 ℃, respectively) and the low-temperature treatment (LT, with a daily average temperature of 20 ℃, and daily maximum and minimum temperatures of 25 and 15 ℃, respectively). The number, size, and morphological anatomical structure of cotton flower bud differentiation were investigated, and the changes in endogenous hormones in shoot apices under low temperature during the seedling stage were analyzed. Additionally, the changes in cotton bolls and their component biomass, as well as relevant indicators of seed cotton yield, were examined after the removal of low temperature stress during the seedling stage.【Result】During the differentiation of cotton flower buds, the increase in Indole-3-acetic acid (IAA) content and the decrease in trans-Zeatin-riboside/Gibberellin A₃ (ZR/GA₃ ) ratio in the terminal buds of cotton under low temperature during the seedling stage inhibited flower bud differentiation. Meanwhile, the content of abscisic acid Abscisic Acid (ABA), GA₃, and ZR increased in response to the adverse effects of low temperature. Changes in endogenous hormones in the shoot tips caused by low temperature during the seedling stage slowed down the process of flower bud differentiation. When the flower buds of the first fruit node on the first fruit branch differentiate from the bract differentiation stage to the sepal differentiation stage, petal-stamen differentiation stage, pistil differentiation stage, and sexual organ formation stage, the leaf age increased by 16.6%-19.4%, 26.5%-31.3%, 17.6%-29.0%, 16.6%-23.3%, and 26.6%-30.0%, respectively; the number of flower buds at the 4-leaf-1-heart, 5-leaf-1-heart, and 6-leaf-1-heart stages of cotton seedlings decreases by 33.3%-55.2%, 24.0%-53.1%, and 26.8%-32.9%, respectively. Due to the slow growth and development of cotton seedlings under low temperature during the seedling stage, the number of flower buds in cotton seedlings exposed to the same number of days of temperature treatment decreased more significantly, with reductions of 66.7%-85.7%, 74.0%-87.8%, and 70.7%-81.7% compared with the control group at the 4-leaf-1-heart, 5-leaf-1-heart, and 6-leaf-1-heart stages, respectively; the sizes of flower buds at these stages also decreased by 33.3%-36.4%, 70.7%-71.6%, and 44.6%-48.3%, respectively. After the removal of low temperature stress during the seedling stage, the development of cotton bolls was still affected, with significant reductions in boll and its component biomass. Specifically, the biomasses of boll shell, fiber, and cottonseed decreased by 64.6%, 65.5%, and 66.7%, respectively. The number of cotton bolls decreased by 65.4%, ultimately leading to a 65.5% reduction in seed cotton yield.【Conclusion】Under low temperature conditions during the seedling stage, the increased IAA content and decreased ZR/GA₃ ratio in the apical buds of cotton inhibited the differentiation of pre-summer peach flower buds. Low temperature during the seedling stage retarded the reproductive development of cotton by delaying flower bud differentiation, which reduced the biomass of cotton bolls. Low temperature at this stage also decreased the number of flower buds, ultimately leading to a reduction in the number of cotton bolls and lower seed cotton yield.

In order to clarify the effects of chemical topping on agronomic, yield and quality traits of long-staple cotton, ‘YL39’ with vigorous growth and long internodes and ‘YL62’ with steady growth and short internodes were used as test materials, and a randomized block test was conducted with four spraying doses to analyze the response of different types of long-staple cotton to chemical topping. The results showed that: the increase of plant height, number of fruiting branches, plant height growth and bolls per plant after chemical topping showed a decreasing trend with the increase of spraying dose, and more than 60% of the bolls of the two materials were concentrated in 5-12 fruiting branches; chemical topping had no effect on the boll weight, lint, yield; there was a tendency to increase the micronaire value and maturity after chemical topping. ‘YL62’ had more newborn fruiting branches and effective bolls after chemical topping, which had good yield potential; ‘YL39’ was more sensitive to chemical topping, with limited newborn fruiting branches and less effective bolls at high doses, which affected the final yield. On the whole, the spraying of chemical topping agent 1125 mL/hm² + 150 g/hm² 98% mepiquat soluble powder can replace manual topping, which can control growth and ensure yield and quality.

In order to understand the salt tolerance of different genotypes of upland cotton germplasm resources, this study subjected 40 samples to salt stress using NaCl solutions with concentrations of 0, 50, 100, 150, 200, and 300 mmol/L, and measured relevant indicators during the seed germination period. Principal component analysis and membership function analysis were used to comprehensively evaluate the salt tolerance of seeds during germination. The results showed that (1) under the stress of high concentration NaCl solution, germination potential, germination rate, hypocotyl length, root length and fresh matter mass per plant all showed a downward trend. (2) Correlation analysis, principal component analysis and membership function comprehensive evaluation were performed on 30 materials with germination rate >50% at A4 concentration, four materials with strong salt tolerance were obtained, namely ‘Han 8266’, ‘Rihui Mian 6’, ‘Zhong R971708’ and ‘Kuaiyu 2’. (3) Through cluster analysis, at the Euclidean distance of 5, the 30 materials could be divided into 3 categories. There were 1 salt-tolerant material in Category I, 18 moderately salt-tolerant materials in Category II, and 11 salt-sensitive materials in Category III.

In order to understand the current situation of cotton stalks crushing and returning to the field for decomposition in Xinjiang, we took the returned cotton stalks and soil as the research objects to investigate the effect of cotton stalks returning to the field on the nutrient content of the soil in the soil layer of 0-30 cm. Soil samples were collected from 0-10, 10-20 and 20-30 cm in Tumushuke, Korla, Kuitun and Shihezi areas by field research method and five-point sampling method. The crushed length of cotton stalks in the field was 17%-18% at <10 cm, about 60% at 10-20 cm, and about 25% at >20 cm; the distribution of the length of cotton stalks in the depth of soil layer from 0 to 30 cm was 52% at <10 cm, 35% at 10-20 cm, and 13% at >20 cm; soil samples collected from 0-10, 10-20 and 20-30 cm of cotton fields were analyzed. The results showed that the soil moisture content of cotton fields in Tumushuke and Korla was 10%-18%, the organic matter was about 20 g/kg, and the quick-acting potassium was about 200 mg/kg; and that of cotton fields in Kuitun and Shihezi was 16%-20%, the organic matter was about 30 g/kg, and the quick-acting potassium was about 300 mg/kg. The highest quick-acting phosphorus was 181.44 mg/kg in Kuitun site and the lowest was 7.34 mg/kg in Korla, showing that the mean nutrient value in the southern border area was lower than that in the northern border. There are differences in the effects of returning cotton stalks to the field on soil properties in various regions, and these differences are not only affected by natural environmental factors, but also closely related to different grain sizes of cotton stalks, different burial depths and other factors. Cotton stalks crushed and returned to the field need to be adapted to local conditions, scientific return to the field.