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Chitinase genes, as a class of cell wall hydrolases, are essential for the development and pathogenesis of Fusarium oxysporum f.sp. vasinfectum (F. ox) in cotton, but related research focused on chitinase genes are limited. This study explored two island cotton root secretions from the highly resistant cultivar Xinhai 41 and sensitive cultivar Xinhai 14 to investigate their interaction with F. ox by a weighted correlation network analysis (WGCNA). As a result, two modules that related to the fungal pathogenicity emerged. Additionally, a total of twenty-five chitinase genes were identified. Finally, host-induced gene silencing (HIGS) of FoChi20 was conducted, and the cotton plants showed noticeably milder disease with a significantly lower disease index than the control. This study illuminated that chitinase genes play crucial roles in the pathogenicity of cotton wilt fungi, and the FoChi20 gene could participate in the pathogenesis of F. ox and host-pathogen interactions, which establishes a theoretical framework for disease control in Sea Island cotton.
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Quitinasas , Resistencia a la Enfermedad , Fusarium , Gossypium , Enfermedades de las Plantas , Fusarium/patogenicidad , Fusarium/genética , Gossypium/microbiología , Quitinasas/genética , Quitinasas/metabolismo , Resistencia a la Enfermedad/genética , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/genética , Interacciones Huésped-Patógeno/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulación de la Expresión Génica de las Plantas , Raíces de Plantas/microbiologíaRESUMEN
The elucidation of genetic architecture and molecular regulatory networks underlying complex traits remains a significant challenge in life science, largely due to the substantial background effects that arise from epistasis and gene-environment interactions. The chromosome segment substitution line (CSSL) is an ideal material for genetic and molecular dissection of complex traits due to its near-isogenic properties; yet a comprehensive analysis, from the basic identification of substitution segments to advanced regulatory network, is still insufficient. Here, we developed two cotton CSSL populations on the Gossypium hirsutum background, representing wide adaptation and high lint yield, with introgression from G. barbadense, representing superior fibre quality. We sequenced 99 CSSLs that demonstrated significant differences from G. hirsutum in fibre, and characterized 836 dynamic fibre transcriptomes in three crucial developmental stages. We developed a workflow for precise resolution of chromosomal substitution segments; the genome sequencing revealed substitutions collectively representing 87.25% of the G. barbadense genome. Together, the genomic and transcriptomic survey identified 18 novel fibre-quality-related quantitative trait loci with high genetic contributions and the comprehensive landscape of fibre development regulation. Furthermore, analysis determined unique cis-expression patterns in CSSLs to be the driving force for fibre quality alteration; building upon this, the co-expression regulatory network revealed biological relationships among the noted pathways and accurately described the molecular interactions of GhHOX3, GhRDL1 and GhEXPA1 during fibre elongation, along with reliable predictions for their interactions with GhTBA8A5. Our study will enhance more strategic employment of CSSL in crop molecular biology and breeding programmes.
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Seeds play a crucial role in plant reproduction, making it essential to identify genes that affect seed development. In this study, we focused on UDP-glucosyltransferase 71C4 (UGT71C4) in cotton, a member of the glycosyltransferase family that shapes seed width and length, thereby influencing seed index and seed cotton yield. Overexpression of UGT71C4 results in seed enlargement owing to its glycosyltransferase activity on flavonoids, which redirects metabolic flux from lignin to flavonoid metabolism. This shift promotes cell proliferation in the ovule via accumulation of flavonoid glycosides, significantly enhancing seed cotton yield and increasing the seed index from 10.66 g to 11.91 g. By contrast, knockout of UGT71C4 leads to smaller seeds through activation of the lignin metabolism pathway and redirection of metabolic flux back to lignin synthesis. This redirection leads to increased ectopic lignin deposition in the ovule, inhibiting ovule growth and development, and alters yield components, increasing the lint percentage from 41.42% to 43.40% and reducing the seed index from 10.66 g to 8.60 g. Our research sheds new light on seed size development and reveals potential pathways for enhancing seed yield.
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Glucosiltransferasas , Gossypium , Semillas , Gossypium/genética , Gossypium/crecimiento & desarrollo , Gossypium/metabolismo , Semillas/crecimiento & desarrollo , Semillas/genética , Semillas/metabolismo , Glucosiltransferasas/genética , Glucosiltransferasas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Lignina/metabolismo , Regulación de la Expresión Génica de las PlantasRESUMEN
KEY MESSAGE: Different kinship and resistance to cotton leaf curl disease (CLCuD) and heat were found between upland cotton cultivars from China and Pakistan. 175 SNPs and 82 InDels loci related to yield, fiber quality, CLCuD, and heat resistance were identified. Elite alleles found in Pakistani accessions aided local adaptation to climatic condition of two countries. Adaptation of upland cotton (Gossypium hirsutum) beyond its center of origin is expected to be driven by tailoring of the genome and genes to enhance yield and quality in new ecological niches. Here, resequencing of 456 upland cotton accessions revealed two distinct kinships according to the associated country. Fiber quality and lint percentage were consistent across kinships, but resistance to cotton leaf curl disease (CLCuD) and heat was distinctly exhibited by accessions from Pakistan, illustrating highly local adaption. A total of 175 SNP and 82 InDel loci related to yield, fiber quality, CLCuD and heat resistance were identified; among them, only two overlapped between Pakistani and Chinese accessions underscoring the divergent domestication and improvement targets in each country. Loci associated with resistance alleles to leaf curl disease and high temperature were largely found in Pakistani accessions to counter these stresses prevalent in Pakistan. These results revealed that breeding activities led to the accumulation of unique alleles and helped upland cotton become adapted to the respective climatic conditions, which will contribute to elucidating the genetic mechanisms that underlie resilience traits and help develop climate-resilient cotton cultivars for use worldwide.
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Gossypium , Polimorfismo de Nucleótido Simple , Gossypium/genética , Pakistán , China , Resistencia a la Enfermedad/genética , Enfermedades de las Plantas/genética , Mutación INDEL , Adaptación Fisiológica/genética , Genoma de Planta , Alelos , Fitomejoramiento , Fibra de Algodón , FenotipoRESUMEN
The excellent Upland cotton (Gossypium hirsutum) cultivars developed since 1949 have made a huge contribution to cotton production in China, the world's largest producer and consumer of cotton. However, the genetic and genomic basis for the improvements of these cotton cultivars remains largely unclear. In this study, we selected 16 Upland cotton cultivars with important historical status in Chinese cotton breeding and constructed a multiparent, advanced generation, intercross (MAGIC) population comprising 920 recombinant inbred lines. A genome-wide association study using the MAGIC population identified 54 genomic loci associated with lint yield and fiber quality. Of them, 25 (46.30%) pleiotropic genomic loci cause simultaneous changes of lint yield and/or fiber quality traits, revealing complex trade-offs and linkage drags in Upland cotton agronomic traits. Deep sequencing data of 11 introduced ancestor cultivars and publicly available resequencing datasets of 839 cultivars developed in China during the past 70 years were integrated to explore the historical distribution and origin of the elite or selected alleles. Interestingly, 85% of these elite alleles were selected and fixed from different American ancestors, consistent with cotton breeding practices in China. However, seven elite alleles of native origin that are responsible for Fusarium wilt resistance, early maturing, good-quality fiber, and other characteristics were not found in American ancestors but have greatly contributed to Chinese cotton breeding and wide cultivation. Taken together, these results provide a genetic basis for further improving cotton cultivars and reveal that the genetic composition of Chinese cotton cultivars is narrow and mainly derived from early introduced American varieties.
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Fibra de Algodón , Gossypium , Gossypium/genética , Estudio de Asociación del Genoma Completo , Fitomejoramiento , GenómicaRESUMEN
Structural variations (SVs) have long been described as being involved in the origin, adaption, and domestication of species. However, the underlying genetic and genomic mechanisms are poorly understood. Here, we report a high-quality genome assembly of Gossypium barbadense acc. Tanguis, a landrace that is closely related to formation of extra-long-staple (ELS) cultivated cotton. An SV-based pan-genome (Pan-SV) was then constructed using a total of 182 593 non-redundant SVs, including 2236 inversions, 97 398 insertions, and 82 959 deletions from 11 assembled genomes of allopolyploid cotton. The utility of this Pan-SV was then demonstrated through population structure analysis and genome-wide association studies (GWASs). Using segregation mapping populations produced through crossing ELS cotton and the landrace along with an SV-based GWAS, certain SVs responsible for speciation, domestication, and improvement in tetraploid cottons were identified. Importantly, some of the SVs presently identified as associated with the yield and fiber quality improvement had not been identified in previous SNP-based GWAS. In particular, a 9-bp insertion or deletion was found to associate with elimination of the interspecific reproductive isolation between Gossypium hirsutum and G. barbadense. Collectively, this study provides new insights into genome-wide, gene-scale SVs linked to important agronomic traits in a major crop species and highlights the importance of SVs during the speciation, domestication, and improvement of cultivated crop species.
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Estudio de Asociación del Genoma Completo , Gossypium , Gossypium/genética , Genoma de Planta/genética , Fenotipo , TetraploidíaRESUMEN
Genome-wide association studies (GWAS) of fiber quality traits of upland cotton were conducted to identify the single-nucleotide polymorphic (SNP) loci associated with cotton fiber quality, which lays the foundation for the mining of elite] cotton fiber gene resources and its application in molecular breeding. A total of 612 upland cotton accessions were genotyped using the ZJU Cotton Chip No. 1 40K chip array via the liquid-phase probe hybridization-based genotyping-by-target-sequencing (GBTS) technology. In the present study, five fiber quality traits, namely fiber length, fiber strength, micronaire, uniformity and elongation, showed different degrees of variation in different environments. The average coefficient of variation of fiber strength was the greatest, whereas the average coefficient of variation of uniformity was the least. Significant or extremely significant correlations existed among the five fiber quality traits, especially fiber length, strength, uniformity and elongation all being significantly negative correlated with micronaire. Population cluster analysis divided the 612 accessions into four groups: 73 assigned to group I, 226 to group II, 220 to group III and 93 to group IV. Genome-wide association studies of five fiber quality traits in five environments was performed and a total of 42 SNP loci associated with target traits was detected, distributed on 19 chromosomes, with eight loci associated with fiber length, five loci associated with fiber strength, four loci associated with micronaire, twelve loci associated with fiber uniformity and thirteen loci associated with fiber elongation. Of them, seven loci were detected in more than two environments. Nine SNP loci related to fiber length, fiber strength, uniformity and elongation were found on chromosome A07, seven loci related to fiber length, fiber strength, micronaire and elongation were detected on chromosome D01, and five loci associated with fiber length, uniformity and micronaire were detected on chromosome D11. The results from this study could provide more precise molecular markers and genetic resources for cotton breeding for better fiber quality in the future.
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Oilseed crops are used to produce vegetable oil to satisfy the requirements of humans and livestock. Cotton (Gossypium spp.) is of great economic value because it is used as both an important textile commodity and a nutrient-rich resource. Cottonseed oil is rich in polyunsaturated fatty acids and does not contain trans fatty acids; hence, it is considered a healthy vegetable oil. However, research on the genetic basis for cottonseed protein content, oil production, and fatty acid composition is lacking. Here, we investigated the protein content, oil content, and fatty acid composition in terms of oleic acid (C18:1) and linoleic acid (C18:2) in mature cottonseeds from 318 Gossypium hirsutum accessions. Moreover, we examined the dynamic change of protein content and lipid composition including palmitic acid (C16:0), stearic acid (C18:0), oleic acid (C18:1), linoleic acid (C18:2), and linolenic acid (C18:3) in developing seeds from 258 accessions at 10 and 20 days post-anthesis. Then, we conducted a genome-wide association study and identified 152 trait-associated loci and 64 candidate genes responsible for protein and oil-related contents in mature cottonseeds and ovules. Finally, six candidate genes were experimentally validated to be involved in the regulation of fatty acid biosynthesis through heterologous expression in Arabidopsis. These results comprise a solid foundation for expanding our understanding of lipid biosynthesis in cotton, which will help breeders manipulate protein and oil contents to make it a fully developed 'fiber, food, and oil crop'.
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Arabidopsis , Gossypium , Humanos , Gossypium/genética , Gossypium/metabolismo , Aceite de Semillas de Algodón/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Estudio de Asociación del Genoma Completo , Semillas/genética , Semillas/metabolismo , Ácidos Grasos/metabolismo , Ácido Oléico/metabolismo , Ácido Linoleico/metabolismo , Aceites de Plantas/metabolismo , TextilesRESUMEN
Verticillium, representing one of the world's major pathogens, causes Verticillium wilt in important woody species, ornamentals, agricultural, etc., consequently resulting in a serious decline in production and quality, especially in cotton. Gossupium hirutum and Gossypium barbadense are two kinds of widely cultivated cotton species that suffer from Verticillium wilt, while G. barbadense has much higher resistance toward it than G. hirsutum. However, the molecular mechanism regarding their divergence in Verticillium wilt resistance remains largely unknown. In the current study, G. barbadense cv. Hai7124 and G. hirsutum acc. TM-1 were compared at 0, 12, 24, 48, 72, 96, 120, and 144 h post-inoculation (hpi) utilizing high throughput RNA-Sequencing. As a result, a total of 3,549 and 4,725 differentially expressed genes (DEGs) were identified, respectively. In particular, the resistant type Hai7124 displayed an earlier and faster detection and signaling response to the Verticillium dahliae infection and demonstrated higher expression levels of defense-related genes over TM-1 with respect to transcription factors, plant hormone signal transduction, plant-pathogen interaction, and nucleotide-binding leucine-rich repeat (NLR) genes. This study provides new insights into the molecular mechanisms of divergence in Verticillium wilt resistance between G. barbadense and G. hirsutum and important candidate genes for breeding V. dahliae resistant cotton cultivars.
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After polyploidization originated from one interspecific hybridization event in Gossypium, Gossypium barbadense evolved to produce extra-long staple fibres than Gossypium hirsutum (Upland cotton), which produces a higher fibre yield. The genomic diversity between G. barbadense and G. hirsutum thus provides a genetic basis for fibre trait variation. Recently, rapid accumulation of gene disruption or deleterious mutation was reported in allotetraploid cotton genomes, with unknown impacts on fibre traits. Here, we identified gene disruptions in allotetraploid G. hirsutum (18.14%) and G. barbadense (17.38%) through comparison with their presumed diploid progenitors. Relative to conserved genes, these disrupted genes exhibited faster evolution rate, lower expression level and altered gene co-expression networks. Within a module regulating fibre elongation, a hub gene experienced gene disruption in G. hirsutum after polyploidization, with a 2-bp deletion in the coding region of GhNPLA1D introducing early termination of translation. This deletion was observed in all of the 34 G. hirsutum landraces and 36 G. hirsutum cultivars, but not in 96% of 57 G. barbadense accessions. Retrieving the disrupted gene GhNPLA1D using its homoeolog GhNPLA1A achieved longer fibre length in G. hirsutum. Further enzyme activity and lipids analysis confirmed that GhNPLA1A encodes a typical phospholipase A and promotes cotton fibre elongation via elevating intracellular levels of linolenic acid and 34:3 phosphatidylinositol. Our work opens a strategy for identifying disrupted genes and retrieving their functions in ways that can provide valuable resources for accelerating fibre trait enhancement in cotton breeding.
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Fibra de Algodón , Fitomejoramiento , Genes de Plantas/genética , Gossypium/genética , Fosfolipasas/genéticaRESUMEN
Cotton fiber is an excellent model for studying plant cell elongation and cell wall biogenesis as well because they are highly polarized and use conserved polarized diffuse growth mechanism. Fiber strength is an important trait among cotton fiber qualities due to ongoing changes in spinning technology. However, the molecular mechanism of fiber strength forming is obscure. Through map-based cloning, we identified the fiber strength gene GhUBX. Increasing its expression, the fiber strength of the transgenic cotton was significantly enhanced compared to the receptor W0 and the helices number of the transgenic fiber was remarkably increased. Additionally, we proved that GhUBX regulates the fiber helical growth by degrading the GhSPL1 via the ubiquitin 26S-proteasome pathway. Taken together, we revealed the internal relationship between fiber helices and fiber stronger. It will be useful for improving the fiber quality in cotton breeding and illustrating the molecular mechanism for plant twisted growth.
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Interspecific genomic variation can provide a genetic basis for local adaptation and domestication. A series of studies have presented its role of interspecific haplotypes and introgressions in adaptive traits, but few studies have addressed their role in improving agronomic character. Two allotetraploid Gossypium species, Gossypium barbadense (Gb) and G. hirsutum (Gh) originating from the Americas, are cultivated independently. Here, through sequencing and the comparison of one GWAS panel in 229 Gb accessions and two GWAS panels in 491 Gh accessions, we found that most associated loci or functional haplotypes for agronomic traits were highly divergent, representing the strong divergent improvement between Gb and Gh. Using a comprehensive interspecific haplotype map, we revealed that six interspecific introgressions from Gh to Gb were significantly associated with the phenotypic performance of Gb, which could explain 5%-40% of phenotypic variation in yield and fibre qualities. In addition, three introgressions overlapped with six associated loci in Gb, indicating that these introgression regions were under further selection and stabilized during improvement. A single interspecific introgression often possessed yield-increasing potential but decreased fibre qualities, or the opposite, making it difficult to simultaneously improve yield and fibre qualities. Our study not only has proved the importance of interspecific functional haplotypes or introgressions in the divergent improvement of Gb and Gh, but also supports their potential value in further human-mediated hybridization or precision breeding.
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Gossypium , Fitomejoramiento , Mapeo Cromosómico , Fibra de Algodón , Domesticación , Gossypium/genética , FenotipoRESUMEN
As two cultivated widely allotetraploid cotton species, although Gossypium hirsutum and Gossypium barbadense evolved from the same ancestor, they differ in fiber quality; the molecular mechanism of that difference should be deeply studied. Here, we performed RNA-seq of fiber samples from four G. hirsutum and three G. barbadense cultivars to compare their gene expression patterns on multiple dimensions. We found that 15.90-37.96% of differentially expressed genes showed biased expression toward the A or D subgenome. In particular, interspecific biased expression was exhibited by a total of 330 and 486 gene pairs at 10 days post-anthesis (DPA) and 20 DPA, respectively. Moreover, 6791 genes demonstrated temporal differences in expression, including 346 genes predominantly expressed at 10 DPA in G. hirsutum (TM-1) but postponed to 20 DPA in G. barbadense (Hai7124), and 367 genes predominantly expressed at 20 DPA in TM-1 but postponed to 25 DPA in Hai7124. These postponed genes mainly participated in carbohydrate metabolism, lipid metabolism, plant hormone signal transduction, and starch and sucrose metabolism. In addition, most of the co-expression network and hub genes involved in fiber development showed asymmetric expression between TM-1 and Hai7124, like three hub genes detected at 10 DPA in TM-1 but not until 25 DPA in Hai7124. Our study provides new insights into interspecific expression bias and postponed expression of genes associated with fiber quality, which are mainly tied to asymmetric hub gene network. This work will facilitate further research aimed at understanding the mechanisms underlying cotton fiber improvement.
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Xinjiang has been the largest and highest yield cotton production region not only in China, but also in the world. Improvements in Upland cotton cultivars in Xinjiang have occurred via pedigree selection and/or crossing of elite alleles from the former Soviet Union and other cotton producing regions of China. But it is unclear how genomic constitutions from foundation parents have been selected and inherited. Here, we deep-sequenced seven historic foundation parents, comprising four cultivars introduced from the former Soviet Union (108Ф, C1470, 611Рand KK1543) and three from United States and Africa (DPL15, STV2B and UGDM), and re-sequenced sixty-nine Xinjiang modern cultivars. Phylogenetic analysis of more than 2 million high-quality single nucleotide polymorphisms allowed their classification two groups, suggesting that Xinjiang Upland cotton cultivars were not only spawned from 108Ф, C1470, 611Рand KK1543, but also had a close kinship with DPL15, STV2B and UGDM. Notably, identity-by-descent (IBD) tracking demonstrated that the former Soviet Union cultivars have made a huge contribution to modern cultivar improvement in Xinjiang. A total of 156 selective sweeps were identified. Among them, apoptosis-antagonizing transcription factor gene (GhAATF1) and mitochondrial transcription termination factor family protein gene (GhmTERF1) were highly involved in the determination of lint percentage. Additionally, the auxin response factor gene (GhARF3) located in inherited IBD segments from 108Ф and 611Рwas highly correlated with fibre quality. These results provide an insight into the genomics of artificial selection for improving cotton production and facilitate next-generation precision breeding of cotton and other crops.
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Allotetraploid cotton is an economically important natural-fiber-producing crop worldwide. After polyploidization, Gossypium hirsutum L. evolved to produce a higher fiber yield and to better survive harsh environments than Gossypium barbadense, which produces superior-quality fibers. The global genetic and molecular bases for these interspecies divergences were unknown. Here we report high-quality de novo-assembled genomes for these two cultivated allotetraploid species with pronounced improvement in repetitive-DNA-enriched centromeric regions. Whole-genome comparative analyses revealed that species-specific alterations in gene expression, structural variations and expanded gene families were responsible for speciation and the evolutionary history of these species. These findings help to elucidate the evolution of cotton genomes and their domestication history. The information generated not only should enable breeders to improve fiber quality and resilience to ever-changing environmental conditions but also can be translated to other crops for better understanding of their domestication history and use in improvement.
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Genoma de Planta/genética , Gossypium/genética , Cromosomas de las Plantas/genética , Fibra de Algodón , Domesticación , Expresión Génica/genética , Variación Genética/genética , Estudio de Asociación del Genoma Completo/métodos , Secuencias Repetitivas de Ácidos Nucleicos/genéticaRESUMEN
In cotton, the formation of fruiting branches affects both plant architecture and fiber yield. Here, we report map-based cloning of the axillary flowering mutation gene (GbAF) that causes bolls to be borne directly on the main plant stem in Gossypium barbadense, and of the clustered boll mutation gene (cl1) in G. hirsutum. Both mutant alleles were found to represent point mutations at the Cl1 locus. Therefore, we propose that the GbAF mutation be referred to as cl1b. These Cl1 loci correspond to homologs of tomato SELF-PRUNING (SP), i.e. Gossypium spp. SP (GoSP) genes. In tetraploid cottons, single monogenic mutation of either duplicate GoSP gene (one in the A and one in the D subgenome) is associated with the axillary cluster flowering phenotype, although the shoot-indeterminate state of the inflorescence is maintained. By contrast, silencing of both GoSPs leads to the termination of flowering or determinate plants. The architecture of axillary flowering cotton allows higher planting density, contributing to increased fiber yield. Taken together the results provide new insights into the underlying mechanism of branching in cotton species, and characterization of GoSP genes may promote the development of compact cultivars to increase global cotton production.
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Gossypium/crecimiento & desarrollo , Gossypium/genética , Proteínas de Plantas/genética , Gossypium/metabolismo , Mutación , Proteínas de Plantas/metabolismoRESUMEN
Fiber quality is an important economic index and a major breeding goal in cotton, but direct phenotypic selection is often hindered due to environmental influences and linkage with yield traits. A genome-wide association study (GWAS) is a powerful tool to identify genes associated with phenotypic traits. In this study, we identified fiber quality genes in upland cotton (Gossypium hirsutum L.) using GWAS based on a high-density CottonSNP80K array and multiple environment tests. A total of 30 and 23 significant single nucleotide polymorphisms (SNPs) associated with five fiber quality traits were identified across the 408 cotton accessions in six environments and the best linear unbiased predictions, respectively. Among these SNPs, seven loci were the same, and 128 candidate genes were predicted in a 1-Mb region (±500 kb of the peak SNP). Furthermore, two major genome regions (GR1 and GR2) associated with multiple fiber qualities in multiple environments on chromosomes A07 and A13 were identified, and within them, 22 candidate genes were annotated. Of these, 11 genes were expressed [log2(1 + FPKM)>1] in the fiber development stages (5, 10, 20, and 25 dpa) using RNA-Seq. This study provides fundamental insight relevant to identification of genes associated with fiber quality and will accelerate future efforts toward improving fiber quality of upland cotton.