With the development of cotton genomics and transcriptomics, cotton genetics and breeding would be enhanced by the identification of differentially expressed genes and the development of molecular makers based on candidate genes. The salt-tolerant cotton variety Miscott 7913-83 and salt-sensitive variety Su 12 were used as experimental materials in this study. RNA samples prepared from the roots and leaves of the two cultivars were pooled for transcriptome sequencing. Variations in gene expression were then examined after exposing the plants to 200 mmol·L^－1 NaCl for 12 and 72 h. A total of 3232 differentially expressed genes were then examined between Miscott 7913-83 and Su 12, and functional molecular markers such as EST-SSR and EST-InDel were designed by informatics tools according to differentially expressed gene sequences. Some SSR and InDel primers were randomly selected and further confirmed the accuracy. This research provides efficient methods for the rapid development of polymorphic markers in cotton. By focusing on functional molecular markers associated with salt tolerance, this should aid the improvement of salt tolerance by marker-assisted selection in upland cotton.

The expression changes of transcriptome of tender leaves of Z12/Z12YW were analyzed by RNA-Seq to reveal the molecular mechanism of gland formation. Z12/Z12YW are cotton near-isogenic lines with a common genetic background but contrasting a gland phenotype. A total of 306 differentially expressed genes were uncovered, of which 282 were down-regulated and 24 were up-regulated in the glandless material Z12YW. Gene Ontology functional annotation showed that the cell part, the extracellular matrix part and the cell killing played important roles in the process of gland development. Clustering of Orthologous groups and Kyoto Encyclopedia of Genes and Genomes enrichment analyses revealed that the upstream key genes of the mevalonate pathway had a great influence on the biosynthesis of gossypol and other terpene compounds. In addition, we screened 13 transcription factors with different expression levels, which might display key function in gland formation and gossypol biosynthesis.

The TCP gene family encodes a specific type of plant transcription factors that are involved extensively in plant growth, development, and the signal transduction pathways of many physiological and biochemical responses. However, limited information is available about cotton TCP genes. Thirty-seven TCP genes were identified from the diploid cotton Gossypium arboreum (A2) and G. raimondii (D5) genome databases. According to the conserved motifs defined in Arabidopsis thaliana L., the protein structure and conserved sequences of each TCP motif were analyzed. We also analyzed the phylogenetic relationship and subcellular localization of the identified gene sequences. Structural analysis revealed that most TCP genes had simple structures and did not contain introns. The putative proteins of these genes contained highly conserved TCP structural domains and shared similar motifs. These proteins could be classified into two subfamilies according to their structure and phylogenic relationships. These results provide a basis for the further study of cotton TCP transcription factors.

[Objective] The aim of this study was to clarify the role of host plant volatiles in the chemical communication of Lygus pratensis adults, and the effects of rapeseed (Brassica campestris L.) as a trap plant on the trapping and control in cotton fields, so as to provide basic informations for the development and ecological regulation of plant-derived attractors for the insect. [Method] Solid phase microextraction (SPME) and gas-mass spectrometry (GC-MS) were used to analyze and identify the volatiles of host plants. The electroantennography (EAG) and four-arm olfactory instrument were used to measure the EAG response and tendency behavior response of L. pratensis adult to selected volatiles. At the same time, cotton fields were planted with rapeseed attractor zone, and the populations of L. pratensis in the attractor zone and its adjacent cotton fields and control fields (without rapeseed cultivation) were investigated and analyzed. [Result] A total of 25 volatile compounds were identified in 5 species of host plants of L. pratensis, including 9 compounds were identified in Brassica napus, 9 in Chenopodium glaucum, 11 in Gossypium hirsutum L., 10 in Solanum nigrum and 6 in Portulaca oleracea. The EAG response of female L. pratensis to phenylacetaldehyde was the highest, and the attraction of phenylacetaldehyde and S-butyl isothiocyanate to female L. pratensis reached an extremely significant and significant level, respectively. The direct assay showed that rapeseed was more attractive to L. pratensis than other host plants. The rapeseed trapping zone in cotton field had a good trapping effect on L. pratensis, and the occurrence of L. pratensis in cotton field was significantly reduced. [Conclusion] The attraction of phenylacetaldehyde and S-butyl isothiocyanate to the female L. pratensis reached an extremely significant or significant level, which could be used as potential attractant candidates. The rapeseed trapping belt planted in cotton field has a good trapping effect on L. pratensis, which is an ideal trapping plant for L. pratensis.

Twenty-three Xincaimian cotton cultivars as authorized until 2012 were used as materials in the construction of DNA fingerprinting and analysis of genetic diversity with simple sequence repeat(SSR) markers. Fifty-two primer pairs with high polymorphism, good repeatability, and even distribution on the 26 chromosomes were screened out from 5000 pairs of SSR primers to genotype the 23 cultivars. A total of 47 SSR primer pairs were polymorphic and generated 162 polymorphic loci among the 23 cultivars; each marker detected 2-7 polymorphic loci with an average of 3.45; the polymorphism information content ranged from 0.4537 to 0.8686, with an average of 0.7096. The results showed that there 14 cultivars could be differentiated by specific or characteristic primer, the rest 9 cultivars could be identified by primer combinations. In the end, 18 specific or characteristic and primer combinations could completely differentiate the 23 Xincaimian cotton cultivars from each other. DNA fingerprinting of Xincaimian 1 to Xincaimian 23 were constructed with 18 pairs of SSR markers. NTSYSpc v2.10 software was used to analyze genetic diversity of the 23 cultivars; the results indicated that genetic similarity coefficient of the 23 cultivars ranged from 0.3781 to 0.9298 with an average of 0.5511, which showed that there was abundant genetic diversity in Xincaimian cotton varieties.

Cotton whole genome SNP (Single nucleotide polymorphism) markers were evaluated and screened across representative cotton materials, with the aim of obtaining an appropriate set of core SNP markers suitable for high-throughput identification of cotton hybrid purity based on KASP (Kompetitive allele specific PCR) technology. 5474 and 1850 single-copy SNP markers were screened out of a 63K SNP array with reference to two TM-1 genome versions (Institute of Cotton Research of the Chinese Academy of Agricultural Sciences version; Nanjing Agriculture University version), respectively. A set of 26 pairs of core SNP markers (one marker per chromosome) was achieved in view of polymorphism, genotyping quality, and homozygous and heterozygosis rates. The set of core SNP loci were then converted to KASP markers using Kraken^TM software. Genotyping assays of the KASP markers set were then performed on the SNPline platform. High-throughput genotyping assays of large numbers of samples were achieved, especially for the rapid purity tests.

The Zinc finger-homeodomain (ZF-HD) protein family of homeobox genes plays a vital role during the development processes of plants and animals. The number, subcellular localization, chromosome distribution, motif, evolutionary relationships and tissue-expression patterns of the ZF-HD protein family were studied in the genome of Gossypium hirsutum L. acc. 'TM-1' using bioinformatics methods. In total, 35 GhZHD genes were identified in the 'TM-1' genome, and a majority of the members are located in nucleus. The family members were distributed on 20 chromosomes and two scaffolds, and 11 pairs were orthologous genes. The family could be divided into six groups based on the phylogenetic analysis, and there were similar motif types and arrangements in each group. Most GhZHD genes were expressed in ovules and fibers, some were expressed in roots, stems, buds and flowers, and a fraction were expressed in leaves and calli.

[Objective] Na₂SO₄ stress is a major type of salt stress in Xinjiang and has seriously restricted the cotton production in Xinjiang. This study aims to explore the effect of Na₂SO₄ stress on cotton metabolism and to investigate the key metabolites and metabolic pathways in the stress response of cotton. [Method] The metabolic analysis was applied in cotton roots and leaves under two treatment settings, including control (CK) and sulfate stress (Na₂SO₄, SS), to explore the changes of metabolite content and metabolic pathways in cotton under Na₂SO₄ stress. [Result] Sulfate stress significantly inhibited the growth of cotton. Compared with CK, the dry mass of leaves, stems, and roots, and total mass of plant under SS treatment decreased by 46.9%, 50.9%, 43.0% and 47.9%, respectively. Under sulfate stress, there were 42 up-regulated and 10 down-regulated organic acids, 32 up-regulated and 16 down-regulated amino acids and amino acid derivatives, 23 up-regulated and 1 down-regulated carbohydrate in root. There were 37 up-regulated organic acids and 7 down-regulated organic acids, 16 up-regulated and 17 down-regulated amino acids and amino acids derivatives, 16 up-regulated and 4 down-regulated carbohydrate in leaves. A total of 30 differential metabolic pathways were selected in roots, including 9 pathways related to amino acid metabolism, 7 pathways related to organic acid metabolism, and 7 pathways related to carbohydrate metabolism. A total of 17 differential metabolic pathways were selected in leaves, including 7 pathways related to amino acid metabolism, 4 pathways related to organic acid metabolism, and 3 pathways related to carbohydrate metabolism. [Conclusion] Cotton responded to sulfate stress by accumulating organic acids, carbohydrate and alcohols in roots and leaves. The up-regulation of citric acid, succinic acid, pyruvic acid and linoleic acid in leaves suggested the enhanced tricarboxylic acid (TCA) cycle and β-enhanced oxidation. And up-regulation of citric acid, succinic acid and pyruvic acid in roots indicated the enhanced TCA cycle. This study explored the mechanism of Na₂SO₄ stress response in cotton and provided a theoretical basis for cotton cultivation in Xinjiang.

In this study, F₂ populations from two chromosome segment substitution lines MBI7455 and MBI7358, were quantified using SSR to evaluate the parents' genotype and detect QTL related to fiber quality plus yield traits of cotton. Results show that the recurrent parent (CCRI45) hosted 96.70% and 95.60% of chromosome segment substitution in MBI7455 with 12 chromosome segments and in MBI7358 with 16 chromosome substitution segments of Gossypium barbadense, respectively. In the F₂ population, the average rate of chromosome substitution of the recurrent parent (CCRI45) was 96.44%, and the average segments of chromosome substitution of Gossypium barbadense was 13.42, with an average segments of homozygous donor chromosome value of 3.90. Analysis showed 19 fiber quality-related QTL with a phenotypic variance of between 2.52%-13.11% and seven yield traits-related QTL with a range of 2.93%-11.40% phenotypic variance, resulting in a total of 26 QTL. The CSSLs could be used to detect QTL for fiber yield and quality traits, which offer an important foundation for the cotton molecular-assisted breeding.

A FT-like homolog was isolated from Gossypium hirsutum L. CV. Xinluzao 33 through RT-PCR and RACE, which was named GhFTL1 gene (accession number: HM631972). The 525-bp open reading frame encoded a putative protein of 174 amino acids with high similarity to FT proteins of different plants which contains two critical residues and conserved motif, both of which identified as diagnostic of true FT. GhFTL1 gene showed constitutive expression in root, stem, flower, leaf, fiber, and ovule. The levels of transcript in leaf and ovule were higher than that in other tissues. Phylogenetic analysis at the amino acid level confirmed that the isolated sequence is FT-like, and also showed that GhFTL1 had shorter genetic distance with MdFT1 compared with other 18 FT homologs confirmed to inducing early flowering from 13 different plants. Over-expression of GhFTL1 in Arabidopsis using the CaMV 35S promoter resulted in significant accelerated flowering compared with wild-type plants. Based on our results, we concluded that GhFTL1 was responsible for inducing flowering and may be one of important components for the flowering pathway in cotton.

[Objective] The glycosylphosphatidylinositol-anchored lipid transfer protein (LTPG) genes were identified from the whole genome of Gossypium hirsutum to provide support for subsequent research. [Method] Bioinformatics methods were used to screen and identify the LTPG gene family from the TM-1 genome, and the physicochemical properties of proteins, phylogenetic relationship, gene duplication, gene structure, and cis-acting elements in the promoter region were predicted and analyzed. Transcriptome data and real-time quantitative polymerase chain reaction (qRT-PCR) were used to analyze their expression pattern in different tissues and organs and under different abiotic stresses. The subcellular localization of the target proteins was identified by transient transformation in tobacco leaves. [Result] Ninety-five GhLTPG genes were identified in the G. hirsutum genome, which were clustered into 5 categories by phylogenetic tree analysis. Segment duplication is the main reason for the expansion of the GhLTPG gene family. K_a/K_s analysis indicated that GhLTPG underwent strong purification selection. Transcriptome data analysis showed that some GhLTPG responded to low temperature, high temperature, salt, or drought stress. The results of qRT-PCR analysis showed that GhLTPG11/14/52/62 responded to low temperature, high temperature, salt and drought stress, and GhLTPG24/56 responded to low temperature, salt, or drought stress. Subcellular localization experiments showed that both GhLTPG24 and GhLTPG62 were localized in the cell membrane. [Conclusion] Ninety-five GhLTPG genes were identified in the whole genome of G. hirsutum. Some GhLTPG genes responded to abiotic stresses such as low temperature, high temperature, salt and drought, which laid a foundation for in-depth analysis of the function of specific GhLTPG gene.

[Objective] The purpose of this investigation was to systematically study the standard techniques used to identify and evaluate Verticillium wilt resistance in cotton to solve the traditional methods or develop a new one. [Method] Fourteen nationally recommended cotton varieties in 2014 were used to systematically study the importance of inoculum concentration, sample number, disease level, and evaluation method. We also used the relative area under the disease progress curve and the related disease index at the disease peak to evaluate Verticillium wilt resistance in cotton in two consecutive years. [Results] The ideal concentrations for plot and column inoculations were 60 g·m^-2 and 10 g·m^-1 based on the real-time monitoring of the disease index of susceptible variety (Jimian 11) plants. To improve the reliability of the data, the minimum number of investigated plants was set as 50 according to the divergence rate analysis. The new disease grading standard related to cotton yield was based on the foliar disease rate and included the following levels: 0 level (0%), first level (1%-33%), second level (34%-66%), third level (67%-99%), and fourth level (100%). And disease resistance evaluation results in two consecutive years showed applying the relative area under the disease progress curve produced 100% consistent results between years. [Conclusion] The present study provides potentially useful data for improving the techniques used to evaluate cotton variety disease resistance, and may stimulate the breeding, authorization and promotion of new cotton varieties.

[Objective] The purpose of this study was to evaluate the selection and pyramiding effects of quantitative trait loci (QTL) related to fiber length and fiber strength through molecular marker-assisted selections using populations of chromosome segment substitution lines (CSSLs) from Gossypium hirsutum × G. barbadense. [Method] In this study, CSSL MBI7561 with excellent fiber quality selected from BC₄F_3:5 of CCRI 45 (G. hirsutum) × Hai 1 (G. barbadense) was used to construct the secondary segregating populations of two generations BC₅F₂ and BC₅F_2:3. Then two populations (BC₆F₂ and BC₆F_2:3) were obtained through backcrossing with the recurrent parents and selfing. Four simple sequence repeat markers, CGR6894a, PGML02608, NAU5408 and NAU3594, linked to three major QTL for fiber length (qFL-16-1, qFL-16-4, qFL-16-5) and three major QTL for fiber strength (qFS-16-1, qFS-16-4 and qFS-16-5) on chromosome 16, were used to screen individuals of BC₆F₂ and BC₆F_2:3. [Result] Four markers related to qFL-16-1, qFL-16-4, qFL-16-5, qFS-16-1, qFS-16-4 and qFS-16-5 indicated obvious and significant single marker selection effect and pairwise marker pyramiding effect for fiber length and fiber strength in the two populations of BC₆F₂ and BC₆F_2:3. Furthermore, the excellent individual which contain more than two QTL was screened. [Conclusion] The analyzed QTL related to fiber length and fiber strength on chromosome 16 had significant genetic effects in different generations of the CSSLs, and the fiber length and fiber strength of individuals were significantly increased by pyramiding two QTL. This study laid an important foundation for molecular marker to assist the pyramiding selection of fiber length and strength.

Salinity stress is one of the major abiotic factors affecting the growth and productivity of cotton(Gossypium hirsutum L.). To further understand the possible mechanism of salt tolerance, an experiment was conducted to investigate the effect of salt stress on growth and K⁺/Na⁺ homeostasis of cotton seedlings using three cultivars(CCRI 49, CCRI 35 and Zhong 51504). We found that 150 mmol·L^－1 NaCl treatment significantly decreased biomass accumulation, photosynthesis rate(P_n), photochemical quenching(qP), photochemical quantum yield of photosystem (Φ_PSII) and electron transport rate(ETR), but significantly increased non-photochemical quenching coefficients(qN) in PSII. The biomass accumulation of Zhong 51504 was less affected by salt stress than CCRI 49 or CCRI 35, and Zhong 51504 also retained higher P_n, ΦP_SII, ETR and qN but lower ETR/P_n under saline conditions. Compared with the control, the salinity treatment caused a significant rise in Na⁺ concentration and decreased K⁺ concentration. The limited negative impact in Zhong 51504 derived from the lower content of Na⁺ and higher K⁺ in the tissues under salt stress. As expected, Zhong 51504 also retained a higher Na⁺/K⁺ ratio than other cultivars under salt treatment. Experiments of salt shock and long exposure to salt tested by the non-invasive ion flux measuring technique also revealed that Zhong 51504 not only had higher Na⁺ exclusion but also showed better K⁺ retention. Our results indicated that maintaining the K^+/Na⁺ homeostasis can contribute to genotypic differences in salinity tolerance under conditions of high salinity.

Crop maturity is the comprehensive performance reflection of crop growth, development and maturation. It is usually expressed by the growth period or life cycle from seedling emergence to harvest. It is also a critical indicator of crop ecological adaptability. The selection of cotton varieties with appropriate maturity is an important prerequisite to ensure normal maturity, high yield, superior fiber quality, and timely harvest. Accurate evaluation of cotton crop maturity is an important basis for cotton cultivation management and genetic improvement. Due to the indeterminate growth characteristic of cotton, the evaluation of cotton crop maturity is complicated, and there are still controversies so far. This manuscript clarifies the concept of cotton crop maturity, and discusses its main influencing factors (genetic factors, environmental factors, and cultivation measures), and reviews predictors and methods used for cotton crop maturity evaluation based on growth characteristics (the first fruit branch node, fruit branch occurrence speed and flowering time interval, pre-frost seed cotton rate, etc.), growth process (growth period, physiological termination period, the number of fruit branches above cracked boll, early maturity index, etc.) and the comprehensive index. In the end, the following suggestions have been given: enhancing the innovation of evaluation predictors for cotton crop maturity, establishment of the evaluation system for cotton crop maturity, and creation of an innovative information collection system, which will provide theoretical and technical support for cotton simplified and mechanized production.

[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] The purpose of this study is to study the influence of cotton-wheat cropping modes on yield and cotton maturity in the Yellow River Basin, to provide technical support for the whole-process mechanization management under the machine-harvested cotton mode. [Method] The experiments were carried out in Anyang, Henan in 2017/2018 and 2018/2019 seasons including 6 treatments with 2 cotton varieties (ZM50, ZM79) and 3 cropping modes, W6C2 (6 rows wheat and 2 rows cotton), W3C1 (3 rows wheat and 1 row cotton) and W2C1 (2 rows wheat and 1 row cotton) under the machine-harvested cotton row space (76 cm) cultivation. Some key indexes such as the wheat yield and side effects, and cotton biomass accumulation, the time distribution of cotton bolls, percentage of seed-cotton yield before frost, and fiber quality were compared and analyzed. [Result] The wheat yield was significantly higher in the mode W3C1 than the mode W2C1 and W6C2 by 16.2%-43.3% and 28.4%-52.3% respectively; the number of effective panicles significantly increased by 29.2%-47.5% and 34.9%-53.6%, respectively; however, the indexes such as wheat yield(2019) and effective panicles per hectare(2018) of W3C1 were significantly lower than W6C2. No significant differences in fiber length, breaking tenacity, and micronaire were found among different cropping modes. There was no significant difference in the seed cotton yield and harvest index(HI) of ZM50 under different modes，while the seed cotton yield and HI of ZM79 in the mode W3C1 in 2018 was lower than that in W6C2 and W2C1. Under W3C1 mode, short season cotton ZM50, compared with ZM79, showed an earlier maturity performance, such as a lower node/branch ratio, and faster reproductive growth, higher ratio of the middle season bolls between July 16 and August 15, lower cotton boll shell ratio, and higher percentage of seed-cotton yield before frost by 38.7%-54.2%; moreover, land equivalent ratio (LER) of this mode is over 1.689-1.697, significantly higher than other modes. [Conclusion] It is suggested that under the machine-harvested cotton row space in the Yellow River Basin, adopting the short-season cotton ZM50 and mode W3C1 can obtain a higher LER and percentage of seed-cotton yield before frost, and is conducive to increasing crop uniformity and yield of wheat. So, taking this configuration for wheat-cotton cropping in the Yellow River Basin is helpful to improve the mechanized management level of the crops and the planting benefit.

To develop an expression system to study the function of the GhVP gene in cotton (Gossypium hirsutum), we successfully cloned GhVP and used it to construct a pBI121-GhVP∷GFP fluorescence expression vector. We transformed the vector into onion (Allium cepa) epidermal cells using gene gun technology and found that the GhVP protein was located on the cytomembrane. The pBI121-GhVP∷GFP vector was then transformed into cotton pollen. Detection of green fluorescence in the pollen indicated that the gene was successfully expressed from the pBI121-GhVP∷GFP vector. These results lay the foundation for the study of GhVP in cotton and the development of salt tolerance breeding.

[Objective] The study aimed to investigate the response of cotton phenophase to climate change in Hebei Province. [Method] Using 1981-2010 cotton phenophase and meteorological data from agricultural meteorological experimental stations and meteorological stations in Hebei Province, China, we analyzed trendsin climatic factors, cotton phenophase, and the timingof different cotton developmental stages. We also calculated Spearman coefficients between the days of different cotton developmental stages and meteorological factors at typical stations in Hebei Province. [Result] We observed the following results over the investigated timeframe: 1) In Hebei Province, T_mean and accumulated temperature ≥0℃ increased during each cotton developmental stage. 2) Sowing, emergence, squaring, flowering and boll-opening phenophases advanced, but harvesting was delayed. Consequently, developmental stages prior tothe flowering phenophase were shortened, whereas those after flowering were lengthened. The entire developmental period was therefore extended. 3) Prior to boll opening, T_mean and accumulated temperature ≥0℃ at each developmental stage were negatively correlated with the length of different developmental stages. After boll opening, however, T_mean andaccumulated temperature ≥0℃ at each developmental stage as well asover the entire period of development were positively correlated with developmental stage length. [Conclusion] This research, which helps explain the mechanisms underlying the impact of climate change on cotton growth and development, can aid the development of technologies and strategies for adaptation of cotton production to climate change.

[Objective] This study aims to investigate the regulatory effect of "fertigation adjusted water management" on the physiology and the growth of drip-irrigated cotton in alleviating drought stress, and to enhance cotton yield under limited water resource. [Methods] Using Zhongmian 619 as the test material, two types of irrigation quotas for deficient irrigation (W1: 45 mm) and full irrigation (W2: 54 mm) in combination of three nitrogen input doses, including low nitrogen (F1: 150 kg·hm^-2), medium nitrogen (F2: 225 kg·hm^-2), and high nitrogen (F3: 300 kg·hm^-2) were set. The effects of different irrigation quotas and nitrogen doses on cotton physiological growth indicators and seed cotton yield were analyzed. [Results] The results indicated that increased irrigation quotas promoted cotton growth, enhanced two-year average leaf area index (LAI), relative chlorophyll content (soil and plant analyzer development, SPAD value), and net photosynthetic rate (P_n), while redued the activities of cotton superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and malondialdehyde (MDA) content. With the increase of nitrogen application, LAI, SPAD, P_n, and antioxidant enzyme activity were increased, MDA content was decreased on average, and the influence of water deficiency on cotton development was alleviated. Under W1 treatment, increased nitrogen application improved cotton yield, while under W2 treatment, cotton yield showed the trend of increasing first and then decreasing with the increase of nitrogen application. Under water-nitrogen interaction, the highest two-year average seed cotton yield (6 821.86 kg·hm^-2) was recorded under W2F2 treatment followed by W1F3 treatment (6 717.72 kg·hm^-2). In the technique for order preference by similarity to ideal solution(TOPSIS) analysis, the comprehensive scores of W1F3 and W2F2 were 0.57 and 0.56, respectively, and the differences between the two-year yield of W1F3 and W2F2 treatments were not significant. [Conclusion] Increased nitrogen application under deficit irrigation effectively alleviates the adverse effects of drought on the physiological characteristics and yield in cotton. It is recommended to use 45 mm irrigation quota combined with 300 kg·hm^-2 nitrogen application as the fertigation strategy for the filmless drip-irrigated cotton in southern Xinjiang, to effectively ensure cotton yield under limited water resource.

【Objective] In this study, we examined the effect of row spacing and planting density on canopy structure and yield. [Method] Hybrid cotton Lumianyan 24 and conventional cotton Xinluzao 60 were used as materials for field experiments. Our experimental design consisted of three arrangements: a film of three lines with equal row spacing (76 cm+76 cm+76 cm) under low planting density, a film of six lines with wide-narrow row spacing (66 cm +10 cm) under high density, and a film of three lines with equal row spacing (76 cm+76 cm+76 cm) under high density. [Result] Cotton growth in a film of three lines with equal row spacing under low planting density was vigorous, with LAI and R_LI increasing rapidly and peaking at the early growth stage. Under this arrangement, the decrease intensity of LAI and R_LI were 10.4%-13.6% and 3.7%-4.2% lower than the other two treatments, respectively; this arrangement of hybrid cotton also exhibited the highest dry matter accumulation at the late growth stage and gave the highest yield at harvest. [Conclusion] Compared with the other two arrangements, hybrid cotton planted in equally spaced rows under low planting density conditions had the greatest dry matter accumulation in the late growth stage and gave the highest yields because LAI, R_LI and dry matter accumulation increased rapidly in the early growth stage, with photosynthetic efficiency accordingly increased by high LAI and R_LI.

[Objective] This study aimed to map the fuzzless mutant (i.e., naked seed) gene n₂ in XZ142w cotton plants. [Method] An F₂ population of upland cotton (Gossypium hirsutum L.) was generated from a cross between XZ142 and the lintless-fuzzless mutant XZ142w. First, 108 simple sequence repeat (SSR) markers were used for mapping. High resolution melting (HRM) technology was then applied to screen 50 single nucleotide polymorphism (SNP) primer pairs designed based on a comparative transcriptomic analysis of the two parents. The SNP markers were used for genotyping. [Results] The n₂ gene was first mapped to a 20.2-cM region on chromosome 26 based on 108 SSR markers. Nine pairs of SNP markers from the HRM screening were used to genotype the F₂ progeny. Using the linkage map based on SSR markers, the genetic interval of n₂ was finally narrowed to a 19.5-cM region. At a genetic distance of 5.5 cM, the closest marker was Cricaas20158 (an SNP marker). The linkage map was mostly consistent with an in silico physical map based on a sequenced upland cotton genome. [Conclusion] The application of HRM technology is useful for detecting cotton SNPs and mapping the n₂ gene.

Cotton has obvious heterosis, which is manifested in traits including yield, fiber quality, and resistance to diseases and insects. Hybrid seed production is a very important step in the utilization of cotton heterosis. Recently, as the cost of manual pollination in seed production increases year by year, the simplified, efficient, and low-cost seed production techniques have become an inevitable trend for future hybrid cotton development. The field practice shows that the use of cytoplasmic male sterile lines not only simplify the procedure of seed production but also save labor costs, so it has become a research hotspot in the utilization of crop heterosis. However, the sterile cytoplasm does have certain impacts on cotton morphogenesis, anther development, yield formation, fiber development, and have negative effects on cotton growth and development, thereby limiting the further promotion and utilization of “three-line (male sterile line, maintainer line, and restoring line)” hybrid cotton. In this paper, the effects of male sterile cytoplasm on the main traits of cotton and the molecular basis for its negative effects were systematically reviewed. And the potential ways to overcome the negative effects of male sterile cytoplasm in cotton were preliminarily discussed, which would provide new ideas for breeding and improvement of cotton cytoplasmic male sterile restorer lines and excellent “three-line” hybrids in the future.

Cotton Verticillium wilt caused by Verticillium dahliae Kleb. has become one of the main impediments to cotton sustainable production in China in recent years．This disease is a soil-borne and seed-borne vascular disease and difficult to control. The host range of V. dahliae is unusually wide as a plant pathogen．This paper summarized the latest research progresses of the pathogenicity differentiation, genome sequence, pathogenesis mechanism, microsclerotial development and germination mechanism of V. dahliae, molecular mechanism of disease resistance in cotton as well as the control methods of cotton Verticillium wilt．

Cotton is an important commercial crop around the world, however, its chromosomes are too small and similar to identify by karyotypic analysis and chromosome banding. The cytogenetics of cotton lag behind many other crop species, and the nomenclature for individual chromosome hasn't been widely accepted except for G. hirsutum. A set of 13 BAC clones specific to A-subgenome chromosomes of G.hirsutum are labeled and hybridized with the chromosomes in metaphase of A-subgenome of G. barbadense cv. pima 90-53, G. herbaceum cv. hongxing, and G. herbaceum raced africanum by BAC-FISH. There are distinctive signals on each chromosome, so these BAC clones are proved to be cytogenetic markers to identify each of them. Most of signals are located on the terminal of chromosomes. The signals on corresponding chromosomes have similar position among the three cotton varieties. Six BAC clones are consistent with their SSR markers by comparing the physical map of BAC clones with the genetic linkage map of SSR markers, and the individual chromosome can be linked with the linkage group. The chromosomes were numbered as A_b01- A_b13 (or A（_AD）■01- A（_AD）■13) in A-subgenome of G. barbadense, A₁01- A₁13 in G. herbaceum, and A_1a01- A_1a13 in G. herbaceum raced africanum. The results will help to analyze the origin and evolution of cotton, to orient new genetic markers on chromosomes, to construct physical map of chromosomes, and so on.

Salinity is the major environmental factor limiting cotton germination and growth during the seedling period. To evaluate the potential of the phytotoxin coronatine (COR) for alleviating salt stress on cotton germination and seedling growth, hydroponic culture experiments were carried out using transgenic insect-resistant cotton(Gossypium hirsutum L, cv. CCRI 45) treated with NaCl and COR. We found that cotton germination and seedling growth were limited under high level salt stress (150 mmol·L^-1 NaCl), which increased the root/shoot ratio. The reduction in cotton biomass was alleviated by the application of COR (0.01 μmol·L^-1). An in situ histochemistry assay indicated that COR at low concentrations decreased H₂O₂ accumulation under induced salt stress. COR appears to have potential as a positive regulator for improving the salt tolerance of cotton.

[Objective] Screening the drought- or salt-resistant lines and measurement of key physiological and biochemical indexes for a set of monosomic alien addition lines (MAALs) derived from Gossypium anomalum in G. hirsutum background would provide the theory and material basis for drought and salt resistance breeding in cotton. [Method] The genotypes of all the MAALs were confirmed by chromosome-specific simple sequence repeat (SSR) markers of G. anomalum. The MAALs with drought or salt resistance potential was screened based on the phenotypic observation and related indexes measurement, and physiological and biochemical indexes were determined, including the content of hydrogen peroxide(H₂O₂), malondialdehyde (MDA), proline(PRO) and chlorophyll(SPAD value) and the activity of peroxidase(POD), catalase(CAT) and superoxide dismutase(SOD). [Result] The transmission rate of MAALs ranged from 34.66% to 51.50%. MAAL_1B, MAAL_5B, MAAL_7B, MAAL_8B, MAAL_11B, and MAAL_12B had drought resistance potential, while MAAL_4B, MAAL_6B, MAAL_8B, MAAL_9B, and MAAL_10B showed salt resistance potential. Under drought or salt stress, the content of MDA, H₂O₂ and PRO of all the tested plants increased compared with the control conditions, and the content of MDA and H₂O₂ of the recurrent parent G. hirsutum Su8289 was higher than that of MAALs with drought or salt resistance potential. The CAT and SOD activity in MAAL_1B, the CAT, SOD activity and PRO content in MAAL_5B, the SOD activity in MAAL_7B, the POD, CAT, SOD activity and SPAD value in MAAL_8B, the POD and CAT activity in MAAL_11B, and the CAT activity and SPAD value in MAAL_12B were significantly or extremely significantly higher than that in Su8289 at 10 days after drought treatment. Three days after 350 mmol·L^-1 NaCl treatment, the POD, SOD activity and SPAD value in MAAL_6B, the CAT activity in MAAL_8B, the POD and SOD activity in MAAL_9B, and the SOD activity and SPAD value in MAAL_10B were significantly or extremely significantly higher than that in Su8289. [Conclusion] Some MAALs had drought or salt resistance potential, and may respond to drought or salt stress through different physiological and biochemical process.

[Objective] This study aims to clarify the regulatory effects of Glycyrrhiza uralensis strips on population abundances and biocontrol function of Hippodamia variegata, so as to provide references for the rational use of G. uralensis strips to biologically control aphids (Aphis spp.) in cotton fields. [Method] Population abundances of aphids and H. variegata in cotton fields with G. uralensis strips and cotton fields without G. uralensis strips and cotton fields away from G. uralensis strips at different distances(1m, 5m, 10m, 20m) were systematically investigated in Korla of Xinjiang, and the effects of G. uralensis strips on relative growth fold of aphids and biocontrol function of H. variegata were evaluated by using the caged-natural enemy exclusion method. [Result] The high density of Aphis atrata in the G. uralensis strips could conserve a large number of H. variegata in early to mid-June, which is an important source of H. variegata in adjacent cotton fields. A large number of H. variegata occurred in cotton fields from late-June to mid-July. And the ratios of H. variegata to aphids in cotton fields away from G. uralensis strips at 1 m, 5 m, 10 m and 20 m were to varying degrees higher than those of cotton fields without G. uralensis strips from mid-June to late-July. Among them, the ratio of H. variegata to aphids reached the highest (2.502 9) in cotton fields away from G. uralensis strips at 1 m on June 17. The relative population growth folds of aphids in the cages at 7 and 14 days post caging were significantly higher than those in the non-caged correspondingly. Biocontrol index of H. variegata to aphids in cotton fields with G. uralensis strips was significantly higher than that of cotton fields without G. uralensis strips at 14 days post caging. [Conclusion] The G. uralensis strips can effectively increase the population abundances of H. variegata and improve the ratio of H. variegata to aphids, which shows an important regulatory effect on biocontrol function of H. variegata to aphids in cotton fields.

对不同品种彩色棉纤维品质、纤维素含量、蜡质含量研究结果表明，纤维素含量越高、蜡质含量越少，纤维品质越好；同时电镜检测结果发现，棕色棉和绿色棉纤维中色素分布位置具有较明显差异，细胞中色素含量越少，纤维品质越好。从总体材料来看，绿色棉纤维品质总体最差，个别经过改良的棕色棉纤维品质已经达到甚至超过对照白棉；棕色棉纤维品质可能和其色泽深度有关系，颜色越浅纤维品质越好，这可能是因为与白色棉杂交改良的结果。

[Objective] Leaf area index (LAI) is one of the important indexes for crop growth diagnosis, biomass estimation and yield prediction in agriculture. Rapid inversion of LAI using unmanned aerial vehicle (UAV) multispectral remote sensing is important for cotton growth monitoring and field management. [Methods] Cotton at flowering and boll-setting stage in Aral reclamation area in Xinjiang was taken as the research object. The ground measured cotton LAI data and UAV multispectral images were used as data sources. After the image stitching was completed, spatial resampling was performed to obtain six different resolutions of multispectral images, vegetation index and texture features were extracted, and the texture index was constructed with texture features. Using the vegetation index, texture index and the combination of the two indices as input quantities, the cotton LAI prediction model based on the partial least squares regression (PLSR), support vector machine (SVM) and random forest algorithm (RF) were constructed and the prediction performance of the three input features and the models were compared under different resolutions, respectively. [Results] (1) The correlation between the two indices and LAI tended to increase and then decrease when the resolution of the multispectral image decreased, and the correlation between the two indices and LAI reached maximum when the image resolution was under the 1.0 m. The estimation performance of the three models were first increased and then decreased with the reduction of image resolution, and the estimation performance was the best under the 1.0 m resolution. (2) When the multispectral image was under the 1.0 m resolution, the RF algorithm model has the best estimation results, followed by the SVM algorithm model, and the PLSR algorithm model has the worst results. (3) The order of the accuracy of three input feature quantities were the follow: vegetation index and texture index, vegetation index, and texture index. [Conclusion] The RF algorithm model constructed by vegetation index and texture index extracted from UAV remote sensing image with 1.0 m spatial resolution had the highest accuracy in estimating cotton LAI at flowering and boll-setting stage.

[Objective] The unmanned aerial vehicle (UAV) multi-spectral remote sensing technology was used to monitor the severity of cotton Verticillium wilt, which will provide theoretical guidance for the precise prevention and control of cotton Verticillium wilt. [Method] By analyzing the spectral characteristics of canopy in cotton field affected by Verticillium wilt, the best vegetation index, the best wavelength combination and the best time phase for multi-spectral identification of Verticillium wilt by UAV were selected. The images of cotton fields differing in the severity of Verticillium wilt were established based on the optimal time phase. Parallelepiped method, maximum likelihood method and support vector machine radial basis function classification method were used to classify and evaluate the accuracy of the images. [Result] The results showed that the canopy spectral reflectance of cotton plants differing with occurrence of Verticillium wilt increased obviously with the increase of wavelength at 710-760 nm, the spectral reflectance of cotton canopy decreased obviously with the aggravation of Verticillium wilt at the wavelength of 760-950 nm. With the aggravation of Verticillium wilt, the chlorophyll content of leaves, fresh mass of aerial tissue per plant, dry mass of aerial tissue per plant, plant water content and leaf area index of cotton plants were all decreased. The best vegetation index and best band combination for UAV multi-spectral remote sensing to identify cotton Verticillium wilt were difference vegetation index (DVI) and B_3-5-8 (the corresponding wavelengths are 550 nm, 656 nm and 800 nm). Mid to late August was the best time to identify the occurrence degree of cotton Verticillium wilt by UAV multi-spectral remote sensing. Support vector machine radial basis function classification method, best band combination B_3-5-8 and DVI integrated image had the highest classification accuracy for Verticillium wilt in cotton field (classification accuracy was 96.64%, and Kappa coefficient was 95.61%). The classification results of Verticillium wilt severity in cotton fields corresponded to the changes in canopy spectral reflectance and agronomic parameters of cotton plants, and were consistent with the field investigation results. [Conclusion] It is feasible to classify the severity of Verticillium wilt in cotton field by using support vector machine radial basis function classification method, optimal band combination B_3-5-8 and DVI integrated images. The results can provide theoretical ground for monitoring similar crop pests and diseases by remote sensing technology.

[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.

The ontogenesis of the cotton mealybug Phenacoccus solenopsis feeding on six varieties of transgenic or non-transgenic Bt cotton was investigated. Correlations between the development and reproduction of Ph. solenopsis and the amounts of soluble sugar, soluble protein and gossypol in cotton were also analyzed. The results showed that the cotton mealybug could complete its life cycle on both transgenic and non-transgenic cotton plants, but there were significant differences among the six cotton varieties in the development time, fecundity, and mortality of Ph. solenopsis. Variety CCRI 41 was the best for cotton mealybug, which had the best fecundity, longevity, net reproductive rate(R₀), intrinsic rate of increase(r_m), and finite rate of increase(λ) and the lowest doubling time(DT) on this strain. In contrast, CCRI 59 was the most unsuitable variety for cotton mealybug, which had the lowest fecundity, longevity, R₀, r_m, and λ and the highest mortality and DT on this cultivar. There was a positive correlation between gossypol content of tender leaves and the duration of 2^nd instar nymphs and negative correlations between gossypol content of both tender and mature leaves and adult longevity and fecundity, which implied that gossypol slowed the growth and development of Ph. solenopsis and inhibited both reproduction and survival of the mealybug.

To investigate the resistance of Amaranthus retroflexus and Portulaca oleracea to glyphosate, 18 collection sites were selected from cotton fields in seven provinces, and then the level of resistance of these two weed species to glyphosate was evaluated by seed and whole plant bioassays. Additionally, differences of shikimic acid content in A. retroflexus and P. oleracea were measured by ultraviolet spectrophotometry. The results showed that A. retroflexus and P. oleracea from different collection sites had different levels of resistance to glyphosate, and the two detection methods showed the same resistance tendency. A. retroflexus from the collection site of Xi'an, Shaanxi and P. oleracea from Shule, Xinjiang were the most sensitive to glyphosate. The highest resistance level for both A. retroflexus were found in plants from the collection site of Quzhou, Hebei. The shikimic acid content in the plants was associated with their resistance level; in general, less resistant plants accumulated more shikimic acid than more resistant ones.

In order to apply software engineering to monitor the water and salinity content of cotton in saline soil, we developed a remote sensing monitoring system by integrating an estimation model for the water and salinity content of cotton leaf with a soil dielectric properties' model based on remote ground sensing. Through inputting hyper-spectral reflectance for functional leaves and microwave dielectric properties for saline soil as essential parameters, we were able to calculate and predict the water and salinity content of these systems. The running result was output, demonstrating the simple but reliable operation of this system. This system can provide digital and scientific decision support in cotton farming for farmers, agronomists, and researchers.

The purpose of this paper was to identify the potential value of a novel glyphosate-resistant cotton mutant comprising a new glyphosate resistance gene and to evaluate its agricultural production as glyphosate-resistant germplasm for breeding and utilization. At genomic and transcriptional levels, polymerase chain reaction (PCR) assay was used to exclude possible contamination by theCP4-EPSPS gene in this mutant cotton. The relative content of shikimic acid was determined to evaluate the typical physical characteristics of glyphosate resistance of this mutant. The phenotype of this cotton mutant under glyphosate treatment was observed at the seedling stage in pot cultures. No significant accumulation of shikimic acid was detected with different concentration or without glyphosate treatment in the mutant treated leaves, which indicated the typical physical characteristic of glyphosate resistance. The glyphosate-resistant phenotype of this cotton mutant was consistent with glyphosate-resistant cotton of Monsanto at the two-leave stage during glyphosate treatment. PCR showed that the CP4-EPSPS gene was not present in the genomic DNA or RNA of this mutant; thus, the glyphosate resistance of this mutant was not caused by the CP4-EPSPS gene. The results of similar exclusion tests for other reported glyphosate-resistant genes, indicated a new molecular mechanism existed in this mutant cotton.

To genetically transform cotton shoot tips, we established a biolistic genetic transformation system though the plant shoot tip culture technique and the gene gun-mediated transformation method, using the shoot tips of brown cotton Xincaimian No.5, a Gossypium hirsutum L. variety cultured in Xinjiang as materials. Several critical factors of the system were assessed, including the type of coagulant, the activated charcoal concentration, the kanamycin concentration, the penetration processing time, and the bombardment pressure and distance. Results showed that each factor clearly influenced the transformation rate of brown cotton shoot tips. An optimal biolistic genetic transformation technology system was determined: (1) shoot tips were cultured for 4 h before being bombarded in the osmotic medium; (2) the shoot tips were bombarded with helium pressure of 7.586 MPa (1100 psi), and a bombardment distance of 9 cm; (3) after culturing for 4 d in the recovery medium, shoot tips were moved to MSB screening medium containing 8 g·L^－1 agar powder and 125 mg·L^－1 kanamycin and then screened for 25 d to obtain the resistant germs; (4) then, 1 g·L^－1 activated charcoal was added to the induction medium to induce rooting of the resistant germs to obtain resistant regenerating plants. After PCR and qPCR detections, 16 plants positive for the transgene were obtained from 5200 shoot tips, with a transformation rate of 0.31%. The establishment of this technology system lays a foundation for the genetic transformation of brown cotton and provides new materials for naturally-colored cotton breeding.

[Objective] This study aims to characterize the GhROP6 and study its roles of resistance to Verticillium wiltin upland cotton (Gossypium hirsutum L.). [Method] The bioinformatics analysis was used to identify Rho-related guanosine triphosphatase from plants (ROP) genes in upland cotton. The chromosome distributions, expression pattern analysis of GhROP genes were investigated. The function of GhROP6 gene was studied by quantitative real-time polymerase chain reaction (qRT-PCR), virus-induced gene silencing (VIGS), plant genetic transformation and metabolism analysis. [Result] Totally, 28 ROP genes were identified in upland cotton. And the corresponding amino acid sequence contained the ROP protein specific structures, including four GTP/GDP binding domains, effector domain binding to downstream target proteins and variable C-terminal regions. Chromosomal mapping analysis showed that 24 ROP genes were symmetrically distributed in subgenome A and subgenome D, and 3 genes specifically distributed in subgenome D. qRT-PCR analysis showed that the transcript levels of GhROP6 varied in different organs, and showed higher expression level in petals, stigma, fiber of 10 days post anthesis. Meanwhile, the transcript level of GhROP6 was upregulated in cotton by methyl jasmonate (MeJA). Knock-down of GhROP6 through VIGS weakened the cotton resistance to Verticillium wilt, and reduced the expression of GhLOX1, GhOPR3-1, GhOPR3-3, GhAOC1, GhAOS involved in jasmonic acid (JA) synthesis, and the expression of GhMYC2 involved in JA signaling pathway, and the expression of GhCCR-1, GhF5H-1, GhCCoAOMT-2, and GhCCoAOMT-3 genes involved in lignin synthesis. However, constitutively activated GhROP6 in Arabidopsis enhanced the plants resistantce to V. dahliae. Further analysis showed that the contents of JA-isoleucine and lignin in transgenic Arabidopsis were higher than those of wild type. [Conclusion] GhROP6 may involve in the resistance of cotton to Verticillium wilt through JA synthesis and signaling pathway and lignin synthesis.