[Objective] This study aims to set up a near infrared spectrum(NIR) calibration model for the protein content and oil content in fuzz cottonseed. [Method] In this study, the SPXY (sample set partitioning based on joint X-Y distance sampling) method was used to divide the 426 samples into 320 as calibration set and 106 as prediction set according to the ratio of 3∶1, and the model was optimized by combining spectral pretreatment methods such as multiplicative scatter correction and first derivative. Three methods, linear partial least square method (PLS), support vector machine (SVM), and random forest (RF) were used to build the NIR rapid determination models of cotton seeds protein content and oil content. The coefficient of determination (R²), root mean square error (RMSE), and residual prediction deviation (RPD) were used as the evaluation indexes of the models. [Result] The results showed that the SVM model and PLS model performed better in the calibration set with R² more than 0.8, but with R² less than 0.8 in the prediction set, indicating that the models were overfitting. While the RF model was very well trained on both the calibration set and prediction sets with R² more than 0.9. The R², predicted RMSE, and RPD of RF model were 0.945 9, 0.935 2, and 4.539 1 for protein content, and 0.909 7, 0.770 4, and 3.489 1 for oil content, respectively. [Conclusion] The prediction model based on RF method can be well applied to the NIR spectroscopy determination of protein content and oil content of fuzz cottonseed, which could replace the chemical method. The results of the study not only lay a foundation for the rapid and nondestructive evaluation of the nutritional quality of cotton seed for seed quality breeding, processing production and marketing, but also provide technical references for the nondestructive analysis of seeds of other crops.

[Objective] This study aims to detect the metabolites and candidate genes which affect the polymorphsim of cotton flower color. [Method] Before and after petal color was changed, the flower buds of yellow flower cotton variety CCRI 24 and pink flower cotton line Zhongyihong were extracted to perform anthocyanin content detection and RNA-seq analysis. [Result] Before flowering, the color of CCRI 24 buds and Zhongyihong buds was different, and the difference was gradually increased with the development of buds. Among them, pelargonidin-3-O-glucoside, cyanidin-3-O-galactoside, cyanidin-3-O-glucoside (Kuromanin) and cyanidin-3-O-(6''-O-malonyl)-glucoside were specifically accumulated in Zhongyihong buds. A total of 8 790 up-regulated and 8 521 down-regulated genes were obtained by differentially expressed gene (DEG) analysis between CCRI 24 and Zhongyihong, which were enriched in pathways such as proton-transporting V-type ATPase complex and flavonoid biosynthesis. Further analysis showed that there was no significant difference in the expression of genes related to anthocyanin synthesis between the two materials, while Gh_A07G083500, bHLH gene Gh_D11G130400, GST gene Gh_A07G079800， and V-type ATPase genes Gh_A09G123000, Gh_A08G012100, and Gh_D09G115200 involved in regulating anthocyanin synthesis, transporting and vacuolar acid-base balance were highly expressed in CCRI 24. [Conclusion] This study demonstrated the gene expression pathway of pink flower formation, and identified several candidate genes related to the flower color of cotton, which provide genetic resources for cotton breeding.

[Objective] In order to establish a theoretical basis for sustainable development of dry-sowing and wet-emergence, and determine the critical content of salinity in soil for cotton seedling development under this planting mode, this study analyzed the effects of dry-sowing and wet-emergence technique on emergence rates and the development of cotton seedling under different levels of salt stress. [Method] The pot experiment was conducted to study the agronomic traits, dry weight and K⁺/Na⁺ ratio of cotton with dry-sowing and wet-emergence technique under salt stress. A control treatment (CK, soil salt content: 0.30 g·kg^-1) and ten treatments with different soil salt content (T1: 1.13 g·kg^-1, T2: 2.47 g·kg^-1, T3: 4.03 g·kg^-1, T4: 5.43 g·kg^-1, T5: 6.75 g·kg^-1, T6: 7.96 g·kg^-1, T7: 9.31 g·kg^-1, T8: 10.66 g·kg^-1, T9: 12.10 g·kg^-1, T10: 13.48 g·kg^-1) were applied. Additionally, the experiment of sowing under suitable moisture was applied to compare the effect of dry-sowing and wet-emergence mode on the seedling emergence rates. [Result] Soil salinity significantly inhibited the germination and emergence of cotton seeds. By using the dry-sowing and wet-emergence technique, the germination rate of cotton significantly improved under salt stress. Compared with sowing under suitable moisture, treatments of T4-T10 using dry-sowing and wet-emergence technique resulted in an increase in the emergence rate to 69.1%-93.3%. Salt stress had significant effects on agronomic traits and dry matter accumulation in cotton by dry-sowing and wet-emergence technique. Plant height, stem diameter, leaf number, square number, and dry matter accumulation of cotton were significantly decreased with the increase of soil salt content. And above-mentioned indexes of CK, T1, and T2 are significantly higher than that of T4-T10. The K⁺/Na⁺ value of cotton plant was also decreased significantly with the increase of soil salt content, in which treatments of T4-T10 were significantly lower than CK, T1, and T2. The result of the principal component analysis based on cotton growth indexes indicated that soil salt stress had a more significant effect on cotton growth and development in T4-T10 compared with CK, T1-T3. [Conclusion] The findings showed that when the soil salt content surpassed that of the T3 treatment (4.03 g·kg^-1), the salt stress significantly inhibited the seedling growth and dry matter accumulation of cotton, while the K⁺/Na⁺ value in cotton plant were significantly decreased. Despite the dry-sowing and wet-emergence technique significantly increased the emergence rate, it mitigated the negative impact of salt stress on the growth and development of cotton. Based on the result of this study, the critical value of soil salt content for the development of cotton seedling under dry-sowing and wet-emergence mode was 4.03 g·kg^-1.

[Objective] This study aims to explore factors affecting the fertility of cotton transgenic regenerated plants produced by Agrobacterium-mediated transformation system via somatic cell embryogenesis. [Method] In this study, several factors, including vector size, transgene insertion size, and different duration of culturing period were analyzed for evaluating their effects on the fertility of regenerated transgenic plants (T₀ generation). [Result] There were significant differences in sterility rate among transgenic plants of 6 different transgene and expression vector size. But there was no obvious correlation between sterility rate and vector/insertion size. Further analysis showed that the sterility of regenerated transgenic cotton plant had significantly positive correlation with the duration of embryogenic callus differentiation to plantlet regeneration. The sterility rate of regenerated plants from the duration of embryogenic callus differentiation to plantlet regeneration of <110 d, 110-130 d, 130-150 d, 150-170 d, and >170 d were 19.6%, 45.5%, 63.8%, 72.3%, and 94.5%, respectively. However, transgenic cotton plant sterility was not correlated with the duration of callus induction to callus embryogenesis. [Conclusion] Through Agrobacterium-mediated cotton genetic transformation, the sterility of cotton regenerated plants was mainly affected by the duration of embryogenic callus differentiation to plantlet regeneration, and accelerating the procedure of embryogenic callus differentiation could increase the fertility of regenerated transgenic plants.

[Objective] Deficit irrigation is an effective irrigation method used in water-saving agriculture. This study aims to quantitatively analyze the influence on cotton yield and irrigation water productivity under deficit irrigation in China, and to provide the reference for further application of deficit irrigation in China. [Method] A meta-analysis was used to quantitatively evaluate the influence of different factors on cotton yield and irrigation water productivity under deficit irrigation in China by integrating 53 literatures published from 2010 to 2022. [Result] The result showed that compared with full irrigation, the average yield of seed cotton under deficit irrigation was decreased by 16.2%, while the irrigation water productivity was increased by 32.2% on average. The subgroup analysis showed that the highest increase of irrigation water productivity was observed in Northwest China under deficit irrigation, particularly in Xinjiang which had the best effect with less yield reduction. Field plantation and areas with relatively low precipitation had increased efficiency of water productivity under irrigation deficit condition. In areas with the annual average temperature ≥ 10 ℃, adopting the planting method of dry sowing and wet emergence, and moderately increasing irrigation frequency can effectively reduce the risk of yield reduction under deficit irrigation condition. Under the condition of soil bulk density <1.5 kg·cm^-3, the risk of seed cotton yield reduction was lower than that of the high soil bulk density under deficit irrigation condition. The application of 80%-100% of full irrigation, and application rate of 200-300 kg·hm^-2 nitrogen, 100-150 kg·hm^-2 potassium and 150-200 kg·hm^-2 phosphorus can effectively promote water utilization rate and reduce the risk of yield reduction under deficit irrigation condition. [Conclusion] It is suggested that the planting method of dry sowing and wet emergence is suitable to conserve water and stabilize yield under mild deficit irrigation condition in the Northwest China arid region with relatively high temperature. And appropriate increase of irrigation frequency and moderate fertilizer application rate can reduce the influence of deficit irrigation on cotton production.

[Objective] This study aims to investigate the effects of different short-season cotton cultivars and sowing dates on the spatial distribution of cotton yield and fiber quality, and to provide a reference for the selection of suitable sowing date and cultivar for the application of mechanized wheat-cotton intercropping system in the Yellow River basin cotton production region. [Method] A two years' field experiment was conducted using split zone design in 2019-2020, two short-season cotton cultivars (JX 707 and LM 2387) were taken as the main plot, and the four sowing dates were set as the sub-plot, including May 10th (SD1), May 20th (SD2), May 30th (SD3), June 10th (SD4). The cotton biomass, plant architecture, lint yield and yield components were investigated, and the main fiber quality index and comprehensive index of fiber quality Q score were measured. [Result] Late sowing date (SD4 treatment) showed prolonged flowering and boll development period of cotton, while leaf area index, number of fruit branches and number of fruit nodes decreased with the delayed sowing date. The sowing dates significantly affected the lint yield and boll distribution. There were no significant differences among lint yield of SD1, SD2, and SD3 in both experimental years. However, when the sowing dates was postponed to June 10th (SD4), the average lint yield of two cultivars in two years was reduced by 38.7%, 37.2%, 32.7% compared with SD1, SD2, and SD3, respectively. In addition, when the sowing dates was delayed, the proportion of bolls from the first to third fruit branches increased significantly and the proportion of bolls formed above the sixth fruit branch decreased significantly. Comparing the comprehensive index of fiber quality, Q score, the quality of the fibers from middle and upper branches of SD1, SD2, and SD3 were better than that of the late sowing treatment (SD4). There were significant differences between two cultivars in terms of yield and fiber quality. Specifically, the cotton lint yield was higher in LM 2387, and the fiber quality was better in JX 707 in both years. [Conclusion] In summary, for both cotton varieties, the sowing date in May (SD1, SD2, and SD3) showed no significant effect on lint yield, and with relatively better fiber quality. In order to avoid a significant reduction in yield, the cotton sowing date of the intercropping system of wheat and short-season cotton in the Yellow River basin cotton production region should not be later than May 30th.

[Objective] The objective of this study is to evaluate the control effect of spent Lentinus edodes substrate (SMS) on cotton Verticillium wilt and to clarify the effect of SMS on microbial community of cotton rhizosphere. [Method] The control effect of SMS on cotton Verticillium wilt was evaluated by pot and plot experiments under greenhouse and field condition. The population of Verticillium dahliae WX-1 in cotton rhizosphere was quantified by real time fluorescent quantitative polymerase chain reaction. The microbiome and functional genes composition in cotton rhizosphere were analyzed by metagenomic sequencing and bioinformatics method. [Result] Soil amended with 2% (mass fraction) SMS could successfully suppress cotton Verticillium wilt, and the greenhouse control effect of SMS on cotton Verticillium wilt was 76.8%. The population of V. dahliae WX-1 in cotton rhizosphere amended with SMS decreased by 81.02% compared with the blank control. The abundances of beneficial microorganisms such as Microbacterium spp., Mesorhizobium spp., Serendipita spp., Chaetomium spp. were significantly increased. Meanwhile, the co-occurrence pattern of bacteria and fungi was also changed in the SMS treatment, and the interspecific association of bacteria was increased while the interspecific association of fungi was decreased. Kyoto Encyclopedia of Genes and Genomes (KEGG) functional annotation showed that the relative abundance of ABC transporter (ko02010), two-component regulatory system (ko02020), and quorum sensing (ko02024) genes involved in bacterial signal recognition and colonization of cotton rhizosphere microorganisms were significantly increased after SMS treatment. In Hebei and Xinjiang, the highest field control effect of SMS on cotton Verticillium wilt was 36.84% and 43.98%, respectively. [Conclusion] SMS can effectively control cotton Verticillium wilt and decrease the population of V. dahliae in the cotton rhizosphere, and change the microbiome and functional gene composition.

[Objective] Frego bract can greatly reduce the attachment of bract to boll and help to reduce the percentage of trash of machine-harvested cotton. In this study, we aimed to fine mapping the frego bract fg gene in cotton, so as to provide reference for its cloning and breeding utilization. [Method] Two F₂ segregating populations were constructed by crossing Gossypium hirsutum T582 (as the female parent) with G. hirsutum TM-1 and G. barbadense 3-79, respectively. Population 1 (T582 × TM-1) included 370 individual plants, and population 2(T582 × 3-79) contained 2 667 individual plants. The developed Indel (insertion-deletion) markers based on the reference genomic data of TM-1 and 3-79 were used to fine mapping fg. Functional annotation and expression pattern analysis of genes within the mapped sequence were performed using cotton functional genomics and multi-omics data. [Result] Genetic analysis showed that frego bract is controlled by a single recessive gene. Based on the previous mapping result of fg gene, cotton fg gene was further mapped between molecular markers M3 and M4 on chromosome A03, with an interval size of 188 kb in this study. A total of fourteen annotated functional genes were predicted in the mapping region. Among them, Gh_A03G021700, Gh_A03G021900, Gh_A03G022600 and Gh_A03G022700 were highly expressed in sepal and epicalyx. [Conclusion] Frego bract fg gene was finely mapped on chromosome A03, with an interval size of 188 kb, and 14 candidate genes in the mapping interval were preliminarily analyzed, which lays the foundation for map-based cloning of this gene.

[Objective] Cadmium (Cd) is one of the serious environmental pollutants, and Cd stress affects seed germination. Melatonin (MT), as an antioxidant, and can promotes seed germination. In this study, the effects of MT on cotton seed germination, antioxidant activity, and osmotic adjustment content under Cd stress were analyzed to clarify the regulatory effect of MT on cotton seed germination under Cd stress. [Method] Seeds of the transgenic insect-resistant cotton variety Nongdamian 601 were used as material, Cd concentration and MT concentration were screened. And four treatments, CK (control, water), MT (melatonin treatment, 50 μmol·L^-1), Cd (cadmium stress 100 μmol·L^-1 treatment), CM (cadmium + melatonin treatment) were set. The germination potential, germination rate, seedling biomass, antioxidant enzyme activity, and osmotic adjustment content of cotton seed under different treatments were studied. [Result] Cd stress of 100 μmol·L^-1 significantly decreased the germination potential, the germination rate, the length of radicle and plumule, the fresh and dry mass of radicle, but had no significant effect on the fresh or dry mass of plumule. Under the stress of Cd, the activity of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and soluble protein content of cotton seed were decreased. The content of proline, soluble sugar and malondialdehyde (MDA) were increased. Application of MT (50 μmol·L^-1) increased the germination potential and germination rate of cotton seed under Cd stress, the activity of SOD, POD and CAT, the content of soluble protein, soluble sugar and proline, while decreased the content of MDA, significantly increased the length of radicle and plumule, and significantly increased radicle biomass. [Conclusion] Exogenous MT (50 μmol·L^-1) could effectively alleviate the inhibitory effeet of Cd stress (100 μmol·L^-1) on cotton seed germination.

[Objective] This study aims to establish a rapid and non-destructive near-infrared spectroscopy (NIRS) detection method for measuring the cottonseed oil content, then to facilitate the genetic improvement of high-oil cotton varieties and the utilization of cottonseed. [Method] The Soxhlet extraction method was used to determine the cottonseed oil content of kernel, delinted seed, and linted seed samples. And the spectral information of 3 morphological types of cottonseed were collected separately. By preprocessing the original spectral data with different mathematical parameters and scattering processing methods, we established the calibration model by modified partial least squares (MPLS) method and used verification sample for model validation. [Result] The best calibration model of NIRS for oil content in kernel, delinted seed, and linted seed were established. The validation of 3 NIRS models had the coefficient of determination of 0.95, 0.94, 0.93, and the residual prediction deviation (RPD) were 4.09, 3.47, 3.15. These results indicated that the 3 NIRS models for cottonseed oil content detection had excellent accuracy and stability. [Conclusion] In this study, 3 NIRS rapid non-destructive detection models for cottonseed oil content in kernel, delinted seed, and linted seed were constructed. The 3 models meet the need of cottonseed detection of different morphological types, and can replace traditional detection methods to avoid the complicated operation procedure and the problem of damaging seeds during the detection of cottonseed oil content. This study provides technical support for improving the comprehensive utilization value of cotton and the genetic improvement of cottonseed oil content.

[Objective] This research aims to investigate the function of S-adenosylmethionine synthetase (SAMS) gene in the resistant response to Helicoverpa armigera in Gossypium hirsutum. [Method] Real-time quantitative polymerase chain reaction (qRT-PCR) was used to analyze the expression pattern of GhSAMS gene under the H. armigera attack. Virus-induced gene silencing (VIGS) technology was adopted to suppress the expression of GhSAMS gene. The insect-resistant function of GhSAMS gene was preliminally investigated by analyzing the growth and development(changes in body weight and body length) as well as feeding preference of H. armigera, and the damage profile of cotton leaves. [Result] qRT-PCR results showed that the expression level of GhSAMS gene was increased during H. armigera feeding process. Compared with those fed with wild-type (WT) cotton leaves, H. armigera fed with pTRV2::GhSAMS leaves grew and developed faster. And H. armigera exhibited stronger feeding preferences towards pTRV2::GhSAMS leaves. 3,3'-diaminobenzidine (DAB) staining showed that pTRV2::GhSAMS cotton leaves accumulated more H₂O₂ compared with WT cotton. [Conclusion] Inhibiting the expression of GhSAMS gene reduces the resistance of G. hirsutum to H. armigera, and GhSAMS can be used as a candidate gene to improve the cotton resistance to H. armigera.

[Objective] Polyploidization is an important way for plant evolution and new species formation. Using the gene dosage effect caused by chromosome doubling and polyploid advantage, it aims to cultivate new autotetraploid germplasm of Gossypium herbaceum with multiple excellent characters, so as to broaden the cotton germplasm resources effectively. [Method] The autopolyploid S₁ and progeny S₂ of G. herbaceum were used as materials, and the ploidy was identified by flow cytometry. The morphological, cytological, physiological, and biochemical indexes of autotetraploid were determined. [Result] Ploidy identification showed that there were 1 triploid plant and 4 tetraploid plants in 5 S₁ plants, and 1 aneuploid plant and 6 tetraploid plants in 7 S₂ plants. S₂ plants were more stable than S₁ plants in terms of plant morphology, leaf characters, flower phenotype, and stomata characters. The cytological identification results showed that the proportion of normal tetrads (85.17%) and normal pollen grains (87.33%) in S₂ was higher than that in S₁, which indicated the meiosis in autotetraploid tending to be normal. The activity of superoxide dismutase, peroxidase, and catalase, the content of malondialdehyde, soluble protein, soluble sugar, proline, and chlorophyll in S₂ plants were all higher than those in S₁ plants and their diploid parents. In terms of seed setting rate, seed size, and fiber length, S₂ was better than S₁. [Conclusion] The new autotetraploid germplasm of G. herbaceum is successfully synthesized through chromosome doubling, and the restoration of fertility tends to be stable in S₂ generation with higher polyploid advantage.

[Objective] The effects of adjuvants on the physicochemical properties, evaporation resistance, deposition and distribution of droplet, and control effect of nanopesticide against cotton aphid were studied through spray tests carried out by plant protection unmanned aerial vehicle (UAV) in cotton field. [Method] The dynamic light scatterometer, automatic interfacial tensiometer, BP100 tensiometer, contact angle meter and super depth of field photography system were used to evaluate influences of adding adjuvants (0.1% volume fraction of Youruopai, 0.1% volume fraction of Jiexiaofeng, 0.6% volume fraction of Aero-Mate 320) on the physicochemical properties and anti-evaporation of solutions with 20% reduced nanopesticide 8% (mass fraction, the same as below) dinieramine dinotefuran compared to the recommended dosage of 1 200 g·hm^-2, in the laboratory. The effect of droplets with adjuvant on the deposition and distribution in the canopy of cotton and its effect on the cotton aphid were explored. [Result] The physicochemical properties of the solutions were improved by adding Youruopai, Jiexiaofeng and Aero-Mate 320 adjuvants into the nanopesticide solutions with 20% reduced dosage. The static surface tension of solutions decreased from 36.43 mN·m^-1 to 31.82-34.99 mN·m^-1. The contact angles decreased to 12.25°-14.85°, which were decreased by about 22.97%-36.46%. The wetting areas increased by 18.34%-33.57% and the inhibition rates of spray evaporation reached 27.72%-73.40%. The results of field test showed that, the median diameters of the droplets in the upper and lower canopy of cotton were significantly increased from 122.4 μm and 106.7 μm to 154.3 μm and 148.5 μm, respectively. After 7 days of application, the control efficacy of treatment with 20% reduction of nanopesticide against aphids was 47.6%. However, the efficacies increased to 63.2%, 65.0% and 73.3%, respectively, after three adjuvants were added in the above treatments. The efficiencies were comparable to that of conventional dosage sprayed by UAV (71.8%) and traditional pesticide sprayed by artificial knapsack sprayer (74.9%). [Conclusion] The results indicated that adding adjuvant could improve physicochemical properties, enhance wetting area, reduce evaporation and drift of droplets, and increase the efficiency of nanopesticide against A. gossypii.

[Objective] This study was aimed to clarify the physiological mechanism of a new plant growth regulator iron chlorine e6 (ICE6) in improving cotton drought tolerance under soil drought stress at the early flowering stage. [Method] In 2021-2022, the short-season cotton variety CCRI 425 were planted in pools with rainproof shelter, and ICE6 was sprayed on leaf at initial flowering stage to evaluate the effects on the photosynthesis, antioxidation, biomass, and yield under drought stress (without watering in 14 d), taking well water conditions as control (CK). [Result] Compared with the well water conditions, the net photosynthetic rate P_n, stomatal conductance, intercellular CO₂ concentration, and transpiration rate of cotton leaves under drought stress decreased by 41.5%, 37.2%, 11.1%, 23.1% in 2021 and 17.2%, 21.7%, 9.4%, 22.7% in 2022, respectively, while decreased by 31.3%, 18.6%, 4.4 %, 15.4% in 2021 and 6.6%, 3.7%, 4.2%, 11.0% in 2022 with spraying ICE6 under drought stress. This indicated that exogenous ICE6 can alleviate the reduction of the photosynthesis caused by drought. ICE6 also alleviated the reduction of the P_n at light saturation point and increased the reduction of the P_n at light compensation point, and significantly decreased the dark respiration rate under drought stress. ICE6 alleviated the reduction of the P_n at CO₂ saturation point under drought. ICE6 increased the activities of superoxide dismutase, peroxidase, and hydrogen peroxide under drought, and decreasad the content of malondialdehyde. ICE6 alleviated the reduction of biomass and seed cotton yield under drought. However, ICE6 had less effect on the photosynthesis and antioxidation of cotton leaves, and the yield under well water conditions. [Conclusion] Under drought stress, ICE6 can significantly increase the photosynthesis of cotton leaves, improving the utilization of low light, and alleviating photoinhibition and dark respiration, and improve the antioxidation, which were the basis of alleviating the reduction of biomass and yield under drought stress.

[Objective] This research aims to characterize the grouping and evolution of cotton Fusarium oxysporium f. sp. vasinfectum (FOV) strains in Xinjiang on the basis of genetic diversity analysis. [Method] A total of twenty-two FOV strains from different cotton planting areas in Xinjiang were isolated in 2022, and EF-1α and β-tubulin gene were amplified and sequenced. Sequences of other thirty-six cotton FOV strains were downloaded from National Center for Biotechnology Information (NCBI). Phylogenetic analysis and haplotype analysis were carried out based on the above-mentioned sequences. [Result] Phylogenetic tree analysis based on fifty-seven EF-1α gene sequences indicated that FOV strains can be divided into three groups. The first group included 31 FOV strains from Xinjiang, Hebei province and Australia. This group can be further divided into four subgroups. The second group, including 25 FOV strains and relatively complex composition, can be divided into three subgroups. The last group only included LA140 from America. Phylogenetic tree analysis based on twenty-eight β-tubulin gene sequences showed that FOV strains from Xinjiang are different from the race 7 and race 8. All strains were divided into nineteen haplotypes by haplotype network analysis based on EF-1α sequences. Twenty-one FOV strains isolated from Xinjiang belongs to five haplotypes, which share a common origin. [Conclusion] The strains isolated from Xinjiang in this research are different from the reported race 1 to race 8, but share a relatively close relationship with FOV in Hebei province. Haplotype analysis of EF-1α indicates all FOV strains in this research are evolved from race 1.

[Objective] The study aims to examine the rhizosphere soil enzyme activity and bacterial community response to foliar application of 1,1-dimethyl-piperidinium chloride (DPC) and sodium nitroprusside (SNP) at the cotton seedling stage, and to screen rhizoshpere events potentially involved in cotton seedling growth. [Method] An upland cotton line A201 was grown in nursery trays under a controlled environment. The treatment with DPC of 50 mg·L^-1 and SNP of 500 μmol·L^-1, respectively, was foliar-applied at the one-leaf-one-heart stage, and the treatment with deionized water application was selected as the control. The rhizosphere soil was sampled to quantify the activities of sucrase, urease, catalase, and alkaline phosphate at the three-leaf-one-heart stage. The rhizosphere bacteria composition examined by 16S rRNA sequence analysis. [Result] The root growth, stem diameter, and dry mass of whole cotton plant were significantly increased by the DPC and SNP treatments. The activities of urease and sucrase were significantly improved by the DPC treatment. SNP application significantly enhanced sucrase activity but significantly decreased urease activity, while DPC treatment and SNP treatment had no significant effect on the activities of catalase and alkaline phosphatase. DPC application increased the relative abundance of Patescibacteria and Simpson's diversity index of soil bacterial community, but reduced the relative abundances of Chloroflexi and Acidobacteriota and Shannon Wiener’s diversity index of soil bacterial community. The results of redundancy analysis on family and genus level showed that the abundances of Saccharimonadaceae and TM7a were higher in the DPC treatment; the abundance of Cellvibrionaceae was greater in the SNP treatment; the abundance of Rhizobiaceae was greater in the DPC and SNP treatments. The control exhibited greater Nitrospiraceae and Nitrospira abundances compared with the DPC and SNP treatments. Urease activity was positively correlated with Saccharimonadaceae and TM7a relative abundances. [Conclusion] DPC and SNP could promote the growth of cotton roots and aerial parts, and influence the soil enzyme activity and bacterial community composition in the rhizosphere.

Cotton is an important cash crop and main raw materials for textile industry, which plays a critical role in economic development of China. Since the founding of the People’s Republic of China, traditional breeding technology has made a great contribution to improve cotton production. With the advancement of sequencing technology, multi-omics research, and gene editing techniques, precise and efficient molecular design breeding has become an inevitable direction for cotton breeding. This review summarizes the present status of cotton production, the history of breeding development, and the achievements of molecular design breeding in genomic research, fiber development, disease resistance and mining of the molecular module of important traits, and proposes directions and path for the future cotton breeding.

[Objective] This study aims to explore the effects of exogenous methyl jasmonate (MeJA) on cotton tolerance to the heat stress. [Method] The self-bred line ZS08 was used as the test material. Distilled water (CK) and MeJA with different concentrations (200 μmol·L^-1, 400 μmol·L^-1 and 600 μmol·L^-1) were used on plants at the flowering and boll-setting stage. And after the artificial heat stress of 38.0 ℃/30.0 ℃ (day/night) for three days or under natural heat stress of 35.2-37.5 ℃/26.4-27.2 ℃ (day/night) for ten days, the pollen viability, photosynthetic characteristics, antioxidant enzyme activity, malondialdehyde (MDA) content, yield and fiber quality of each treatment were measured. [Result] The pollen viability was reduced under the artificial heat stress. The MeJA treatment of three concentrations all had alleviated the inhibition of heat stress on pollen viability compared with the water control. The net photosynthetic rate (P_n), transpiration rate (T_r) and stomatal conductance (G_s) of the fourth leaf from top of the main stem in the 400 μmol·L^-1 and 600 μmol·L^-1 MeJA treated plants were increased in various degree than those of the control under 2-3 days heat stress by 1.6%-3.7%, 7.2%-15.7%, and 44.4%-53.4%, respectively. The activity of superoxide dismutase (SOD) and peroxidase (POD) of the second leaf from top on the main stem in 400 μmol·L^-1 and 600 μmol·L^-1 MeJA treatment were increased by 3.1%-7.2% and 5.7%-20.0% than those of the control under 2-3 days heat stress. While the content of MDA was reduced by 10.9%-17.9%. Under the natural heat stress, plants which were treated by different concentrations of MeJA had improved boll-setting rate and boll weight in varying degree, and had significantly improved lint yield by 9.0%-18.3% compared with the control. [Conclusion] When encountering heat stress during the flowering and boll-setting stage, the application of MeJA can increase P_n and the activities of SOD and POD, reduce the degree of leaf damage, and improve pollen viability, thereby enhance the heat tolerance of cotton, and reduce the impact of heat stress on boll-setting rate, boll weight, and yield loss.

[Objective] Based on the integrated technology of water and fertilizer, the effects of different phosphorus (P) application methods were studied, so as to provide a basis for the rational application of P fertilizer in cotton field with drip-irrigation under plastic-film. [Method] The experiment was carried out in Xinjiang cotton field in 2021. Xinluzao 63 was used as the object, and four treatments were set up, CK: no P application; MAP-B: basal application of monoammonium phosphate (MAP), total amount of P₂O₅ was 100 kg·hm^-2 (same as below); MAP-D: basal application of 50% MAP + drip application of 25% MAP at bud stage and 25% at early flowering and boll development stage; MAP-DS: MAP-D + drip application of polyglutamic acid of 50% at bud stage and 50% at early flowering and boll development stage. Soil P content, inorganic P content in different forms, soil P adsorption-desorption characteristics, P use efficiency, and seed cotton yield of different treatments were compared and analyzed. [Result] P application could increase the available P content and total P content in 0-40 cm soil layer at the seedling stage and flowering and boll development stage, and the content of available soil P under MAP-D and MAP-DS treatment was significantly higher than that of other treatments at flowering and boll development stage. Compared with basal application of P (MAP-B), drip application significantly increased the content proportion of dicalcium phosphate (Ca₂-P), octa-calcium phosphate (Ca₈-P) and aluminum bounded phosphate (Al-P), and reduced the proportion of apatite(Ca₁₀-P) at the flowering and boll development stage. The isothermal adsorption and desorption curves of P in 0-40 cm soil layers under different treatments at the seedling stage and flowering and boll development stage showed similar trend, that is, with the increase of P concentration in equilibrium solution, the soil P adsorption increased rapidly at first and then slowly, and with the increase of P concentration in standard solution, the P desorption rate decreased rapidly at first and then tended to be stable. Compared with CK, the seed cotton yield of P application treatments increased. The P use efficiency and seed cotton yield under drip application of P were higher than that of basal application of P (MAP-B). MAP-DS treatment showed the highest P use efficiency and the highest seed cotton yield(6 829.75 kg·hm^-2). [Conclusion] Drip application of P fertilizer combined with polyglutamic acid under the integration of water and fertilizer in Xinjiang cotton planting region is more conducive to the absorption and utilization of soil P for Xinluzao 63, and further improves the P use efficiency and seed cotton yield.

[Objective] This research aims to investigate the role of calcium B-like protein (CBL) gene GhCBL3-A01 in resistance to Verticillium wilt in cotton, so as to provide genetic resource for cotton disease resistance breeding. [Methods] The homologous sequences of GhCBL3-A01 gene were obtained from cotton genomic database for bioinformatic analysis. The relative expression levels of GhCBL3-A01 under Verticillium dahliae, methyl jasminate (MeJA) and H₂O₂ treatments were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The function of GhCBL3-A01 in cotton resistance to Verticillium wilt was analysed by virus-induced gene silencing (VIGS) technique. The functional mechanisms of GhCBL3-A01 were analyzed by detecting the accumulation of reactive oxygen species (ROS) and the expression levels of related genes. [Results] GhCBL3-A01 and its three homologous proteins in upland cotton all contain three typical EF-hand domains of the CBL family. The expression level of GhCBL3-A01 was significantly increased under the treatment of Verticillium dahliae, MeJA, and H₂O₂. Silencing GhCBL3-A01 by VIGS resulted in a significant decrease in rate of diseased plants and disease index, a reduction in the browning degree of vascular bundles, and a decline in the number of hyphae in stem segments, which enhanced the resistance of cotton plants to Verticillium wilt. The expression levels of disease resistance-related genes (PR1, NPR1, PR4, and PDF1.2) and jasmonic acid (JA) signaling pathway genes (AOS1, OPR3, MYC2, and LOX2) were increased, and ROS accumulation was enriched in GhCBL3-A01 silenced cotton plants. [Conclusion] GhCBL3-A01 negatively regulates the resistance of cotton to Verticillium wilt by regulating the expression levels of defense-related genes and JA signaling pathway genes as well as the accumulation of ROS, which is a candidate gene for improving the resistance of cotton to Verticillium wilt.