Search Results (25)

Cotton micronaire (MIC) is an essential fiber quality index that characterizes both fiber maturity and fineness components. This study compared how MIC affects the fiber high volume instrument (HVI) and advanced fiber information system (AFIS) qualities between Deltapine^® and PhytoGen upland varieties. There were noticeable differences among HVI and AFIS qualities from Deltapine^® fiber samples and PhytoGen samples, with significant differences om HVI strength and elongation. MIC development benefited fiber HVI strength enhancement and also HVI short fiber index (SFI), AFIS neps, AFIS short fiber contents, and AFIS immature fiber content (IFC) reduction, all of which were desired. Adversely, MIC evolution could cause undesired HVI Rd lowering, HVI +b boosting, and AFIS UQL(w), and a decrease in L5%(n) in fiber. Further, MIC values were not related with lint turnout, but they were positively and greatly correlated with algorithmic M_IR values of the attenuated total reflection in Fourier transform infrared (ATR FT-IR) spectra. The results demonstrated the applicability of the ATR FT-IR technique combined with the M_IR approach for rapid laboratory MIC assessment at early MIC testing in remote/breeding locations. Full article

Cotton is the most important natural fiber-producing crop globally. High-quality fiber and early maturity are equally important breeding goals in the cotton industry. However, it remains challenging to synchronously improve these traits through conventional breeding techniques. To identify additional genetic information relating to fiber quality and early maturity, 11 phenotypic traits for the F₂ and F₃ generations were tested, and quantitative trait loci (QTL) mapping was performed. Candidate genes were analyzed using published RNA-seq datasets and qRT-PCR assays. All 11 tested traits showed bi-directional transgressive segregation, and most traits followed an approximately normal distribution. Overall, significant positive and significant negative correlations were observed among these traits. During cotton breeding, varieties with strong boll-setting ability can be selected from early-maturing materials that have high-quality fiber. A total of 102 QTLs were mapped, including 4 major and 3 stable QTLs. qFL-D13-1 was mapped in both the F₂ and F₃ generations, achieving a 3.94% to 11.39% contribution rate to the phenotypic variation. Three genes located in the QTL regions were identified based on their high expression levels in the three evaluated RNA-seq datasets. Ghir_A04G014830.1, covered by qHNFFB-A4-1 and qFU-A4-1, encoded ACLA-1. Ghir_D13G015010.1, encoding VTC2, and Ghir_D13G016670.1, encoding GA2OX1, were in the stable QTL qFL-D13-1 region. The qRT-PCR results suggested that these three genes may be involved in regulating seed development, fiber initiation, and fiber elongation. Overall, these findings contribute additional information for the breeding of high-yield, high fiber quality, and early-maturity varieties, as well as serve as a foundation for research on the underlying molecular mechanisms. Full article

The boll opening rate (BOR) is an early maturity trait that plays a crucial role in cotton production in China, as BOR has a significant effect on defoliant spraying and picking time of unginned cotton, ultimately determining yield and fiber quality. Therefore, elucidating the genetic basis of BOR and identifying stably associated loci, elite alleles, and potential candidate genes can effectively accelerate the molecular breeding process. In this study, we utilized the mixed linear model (MLM) algorithm to perform a genome-wide association study (GWAS) based on 4,452,629 single-nucleotide polymorphisms (SNPs) obtained through whole-genome resequencing of a natural population of 418 upland cotton accessions and phenotypic BOR data acquired from five environments. A total of 18 SNP loci were identified on chromosome D11 that are stable and significantly associated with BOR in multiple environments. Moreover, a significant SNP peak (23.703–23.826 Mb) was identified, and a GH-D11G2034 gene and favorable allelic variation (GG) related to BOR were found in this genomic region, significantly increasing cotton BOR. Evolutionary studies have shown that GH-D11G2034 may have been subjected to artificial selection throughout the variety selection process. This study provides valuable insights and suggests that the GH-D11G2034 gene and its favorable allelic variation (GG) could be potential targets for molecular breeding to improve BOR in upland cotton. However, further research is needed to validate the function of this gene and explore its potential applications in cotton breeding programs. Overall, this study contributes to the advancement of genetic improvement in early maturity and has important implications for the sustainable development of the cotton industry. Full article

Cotton is regarded as one of the significant economic crops in China, and its earliness is defined as one of the crucial traits influencing fiber quality and yield. To study the physiological and biochemical mechanisms related to early-maturing traits of cotton, cotton shoot apexes at the one-leaf, three-leaf, and five-leaf stages of the early-maturing cotton CCRI50 and late-maturing cotton Guoxinmian11 were collected for transcriptome sequencing and metabolomics, respectively. A total of 616, 782, and 842 differentially expressed genes (DEGs) at the one-leaf stage, three-leaf stage, and five-leaf stage were obtained through transcriptome sequencing, respectively. The metabolic detection results showed that 68, 56, and 62 differential metabolites (DMs) were obtained in the three periods, respectively. A total of 10 DMs were detected simultaneously from the one-leaf to five-leaf stage, 4 of which were phenolic acids and down-regulated in the early maturing variety CCRI50. A combined transcriptomic and metabolomic analysis revealed that phenylpropanoid biosynthesis, tyrosine metabolism, and phenylalanine metabolism might be important metabolic pathways in cotton bud differentiation. GhTYDC-A01 was identified in both the tyrosine metabolism and phenylalanine metabolism pathways, and it was highly expressed in pistils. To investigate the function of this gene in flowering, we overexpressed it in Arabidopsis thaliana. Compared to the wild type, the flowering time of the overexpression of GhTYDC-A01 in Arabidopsis was delayed. This study provides valuable resources and new insights into the relationship between metabolites and early-maturing cotton. Full article

The trithorax group (TrxG) complex is an important protein in the regulation of plant histone methylation. The ABSENT, SMALL, OR HOMEOTIC DISCS 1 (ASH1) gene family, as important family members of the TrxG complex, has been shown to regulate tolerance to abiotic stress and growth and development in many plants. In this study, we identified nine GhASH1s in upland cotton. Bioinformatics analysis revealed that GhASH1s contain a variety of cis-acting elements related to stress resistance and growth and development. The transcriptome expression profiles revealed that GhASHH1.A and GhASHH2.A genes expression were upregulated in flower organs and in response to external temperature stress. The results of virus-induced gene silencing (VIGS) indicated that GhASHH1.A and GhASHH2.A genes silencing reduced the ability of cotton to adapt to temperature stress and delayed the development of the flowering phenotype. We also showed that the silencing of these two target genes did not induce early flowering at high temperature (32 °C), suggesting that GhASHH1.A and GhASHH2.A might regulate cotton flowering in response to temperature. These findings provide genetic resources for future breeding of early-maturing and temperature-stress-tolerant cotton varieties. Full article

Flowering in plants is pivotal for initiating and advancing reproductive processes, impacting regional adaptation and crop yield. Despite numerous cloned and identified flowering time genes, research in cotton remains sparse. This study identified GhSWEET42 as a key determinant of the flowering time in cotton, demonstrating that its heterologous expression in Arabidopsis accelerated flowering under LD conditions compared to WT. Transgenic plants exhibited upregulated expression of the flowering inducers AtFT, AtSOC1, AtGI, and AtFKF1, alongside downregulated expression of the repressors AtTSF, AtFLC, and AtRGL2, correlating with the earlier flowering phenotype. GhSWEET42 showed a constitutive expression pattern, with elevated levels in the leaves, petals, and flower buds, and was notably higher in early-maturing cotton varieties. Subcellular localization assays confirmed GhSWEET42’s presence on the cell membrane. Transcriptome analysis between WT and GhSWEET42-overexpressing Arabidopsis plants revealed 2393 differentially expressed genes (DEGs), spanning 221 biological processes, 93 molecular functions, and 37 cellular components according to Gene Ontology (GO) enrichment analysis. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis categorized the DEGs into metabolism and environmental information processing. These findings enhance the understanding of GhSWEET42’s function and provide a foundation for elucidating the molecular mechanisms governing flowering time regulation in cotton. Full article

Cotton (Gossypium hirsutum) requires a long growing period for fruit and fiber maturation, making it vulnerable to insect pests, thus affecting the seed cotton yield and fiber quality. Cotton-feeding thrips (Thysanoptera: Thripidae) are one of the major insects impacting cotton yield throughout the U.S. cotton belt and worldwide. A two-year field research conducted at Texas A&M AgriLife Research farm in west Texas, USA quantified the interactive effect of three cover crops [wheat (Triticum aestivum), rye (Secale cereale), and no cover] and three irrigation regimes [rainfed, deficit irrigation (30%) and full irrigation] on thrips population dynamics across the phenologically susceptible stages of upland cotton and resulting impact on plant growth and yield parameters. Temporal densities of thrips, feeding injury from thrips, cotton growth and reproductive profiles, yield, and fiber quality varied with cover crops and irrigation levels. Thrips densities were conspicuously low due to harsh weather conditions, but the densities decreased with an increase in plant age. Terminated rye and wheat cover versus conventional-tilled, no-cover treatments showed marginal effects on thrips colonization and population dynamics. Similarly, full irrigation treatment supported higher thrips densities compared to rainfed and deficit irrigation treatments. Immature thrips densities increased through the successive sampling periods, indicating increased thrips reproduction following the initial colonization. Thrips feeding injury was significantly greater in no-cover plots in the early seedling stage, but the effect was insignificant across all cover crop treatments in subsequent sampling dates. The results of this study demonstrated increased seedling vigor, plant height, and flower densities in terminated cover crop plots across all irrigation regimes compared to that in no-cover plots. However, the cover crop x irrigation interaction significantly impacted the cotton lint yield, with increased lint yield on cover crop treatments. This study clearly demonstrates the value of cover crops in semi-arid agricultural production systems that are characterized by low rainfall, reduced irrigation capacity, and wind erosion of topsoil. Full article

Saline soils limit plant growth due to high salinity. Straw returning has proven effective in enhancing soil adaptability and agricultural stability on saline lands. This study evaluates the effects of different straw-returning methods—straw mulching (SM), straw incorporation (SI), and straw biochar (BC)—on soil nutrients, water dynamics, and salinity in a barley–cotton rotation system using field box experiments. SM improved soil water retention during barley’s jointing and heading stages, while SI was more effective in its filling and maturation stages. BC showed lesser water storage capacity. During cotton’s growth, SI enhanced early-stage water retention, and SM benefited the flowering and boll opening stages. Grey relational analysis pinpointed significant water relationships at 10 cm and 20 cm soil depths, with SM regulating water across layers. SM and BC notably reduced soil conductivity, primarily within the top 20 cm, and their effectiveness decreased with depth. SI significantly lowered soil conductivity at barley’s jointing stage. SM effectively reduced salinity at 10 cm and 20 cm soil depths, whereas BC decreased soil conductivity throughout barley’s jointing, filling, and heading stages. For cotton, SI lowered soil conductivity at the seedling and boll opening stages. SM consistently reduced salinity across all stages, and BC decreased conductivity in the top 30 cm of soil during all growth stages. Both SM and BC significantly enhanced the total nutrient availability for barley and cotton, especially improving soil organic carbon and available potassium, with BC showing notable improvements. At barley’s heading stage, SI maximized dry matter accumulation, while SM boosted accumulation in leaves, stems, and spikes during the filling and maturation stages. Straw returning increased barley yield, particularly with SM and BC, and improved water use efficiency by 11.60% and 5.74%, respectively. For cotton, straw returning significantly boosted yield and water use efficiency, especially with SI and SM treatments, enhancing the total bolls and yield. In conclusion, straw returning effectively improves saline soils, enhances fertility, boosts crop yields, and supports sustainable agriculture. These results provide a robust scientific foundation for adopting efficient soil improvement strategies on saline lands, with significant theoretical and practical implications for increasing agricultural productivity and crop resilience to salt stress. Full article

Satellite remote sensing data expedite crop yield estimation, offering valuable insights for farmers’ decision making. Recent forecasting methods, particularly those utilizing machine learning algorithms like Random Forest and Artificial Neural Networks, show promise. However, challenges such as validation performances, large volume of data, and the inherent complexity and inexplicability of these models hinder their widespread adoption. This paper presents a simpler approach, employing linear regression models fitted from vegetation indices (VIs) extracted from MODIS sensor data on the Terra and Aqua satellites. The aim is to forecast cotton yields in key areas of the Brazilian Cerrado. Using data from 281 commercial production plots, models were trained (167 plots) and tested (114 plots), relating seed cotton yield to nine commonly used VIs averaged over 15-day intervals. Among the evaluated VIs, Enhanced Vegetation Index (EVI) and Triangular Vegetation Index (TVI) exhibited the lowest root mean square errors (RMSE) and the highest determination coefficients (R²). Optimal periods for in-season yield prediction fell between 90 and 105 to 135 and 150 days after sowing (DAS), corresponding to key phenological phases such as boll development, open boll, and fiber maturation, with the lowest RMSE of about 750 kg ha⁻¹ and R² of 0.70. The best forecasts for early crop stages were provided by models at the peaks (maximum value of the VI time series) for EVI and TVI, which occurred around 80–90 DAS. The proposed approach makes the yield predictability more inferable along the crop time series just by providing sowing dates, contour maps, and their respective VIs. Full article

Cotton is an economically important crop. However, the yield gain in cotton has stagnated over the years, probably due to its narrow genetic base. The introgression of beneficial variations through conventional and molecular approaches has helped broaden its genetic base to some extent. The growth habit of cotton is one of the crucial factors that determine crop maturation time, yield, and management. This study used 44 diverse upland cotton genotypes to develop high-yielding cotton germplasm with reduced regrowth after defoliation and early maturity by altering its growth habit from perennial to somewhat annual. We selected eight top-scoring genotypes based on the gene expression analysis of five floral induction and meristem identity genes (FT, SOC1, LFY, FUL, and AP1) and used them to make a total of 587 genetic crosses in 30 different combinations of these genotypes. High-performance progeny lines were selected based on the phenotypic data on plant height, flower and boll numbers per plant, boll opening date, floral clustering, and regrowth after defoliation as surrogates of annual growth habit, collected over four years (2019 to 2022). Of the selected lines, 8×5-B3, 8×5-B4, 9×5-C1, 8×9-E2, 8×9-E3, and 39×5-H1 showed early maturity, and 20×37-K1, 20×37-K2, and 20×37-D1 showed clustered flowering, reduced regrowth, high quality of fiber, and high lint yield. In 2022, 15 advanced lines (F₈/F₇) from seven cross combinations were selected and sent for an increase to a Costa Rica winter nursery to be used in advanced testing and for release as germplasm lines. In addition to these breeding lines, we developed molecular resources to breed for reduced regrowth after defoliation and improved yield by converting eight expression-trait-associated SNP markers we identified earlier into a user-friendly allele-specific PCR-based assay and tested them on eight parental genotypes and an F₂ population. Full article

Short-season cotton is a type of cotton variety characterized by its abbreviated cycle, rapid development, and concentrated flowering and boll setting. Compared with full-season cotton, short-season cotton facilitates an easier attainment of desirable maturation even when sown relatively late. This advantage of late sowing and early maturation eliminates the necessity for plastic film mulching, thereby creating opportunities for diversified double cropping, such as cotton–wheat, cotton–garlic, cotton–rape, and cotton–triticale systems. This paper provides a comprehensive review of the morphological, physiological, and molecular biological mechanisms underlying early maturity in short-season cotton. Furthermore, the significance and application of short-season cotton is discussed in relation to optimizing planting patterns and methods, promoting its cultivation in saline fields, developing machine-harvested cotton, and encouraging plastic mulch-free cotton planting. Based on these analyses and discussions, the paper proposes future strategies aimed at enhancing the breeding and cultivation of short-season cotton. These findings serve as valuable references for global breeding and cultivation research, and application of short-season cotton in the future. Full article

(1) Background: Mapping QTLs for early-maturing traits is necessary for the development of early-maturing variety breeding. (2) Methods: In this research, a high-density genetic map (HDGM) was constructed using an F₂ population with 100 individuals and single nucleotide polymorphism markers (SNPs) developed using the genotyping-by-sequencing (GBS) method. (3) Results: The HDGM, which covered a total distance of 3167.14 cM, harbored 5454 SNPs with an average marker interval of 0.58 cM. In total, 18 QTLs for four early-maturing characters were detected and explained 11.6–46.4% of phenotypic variation (PV). Two QTLs of the whole growing period (WGP) and height of the node of the first fruiting branch (HNFFB) were identified as stable QTLs. In total, 125 candidate genes were identified in the confidence intervals of these stable QTLs. Presumably, Gh_D03G0857 may play an important role in regulating earliness. (4) Conclusions: This research will provide new information about fine mapping of QTLs for earliness traits, molecular marker assisted selection (MAS) of earliness traits, and pyramiding breeding as well. Full article

Late-sowing and high-density cultivation are typical cotton planting models that are widely applied in the Yellow River Valley of China. The model can easily lead to late maturity and reduced yields. Plant topping and ethephon spraying have been shown to improve cotton earliness and yields. However, the optimal topping date and ethephon concentration are yet to be established. A two-year field experiment (2020–2021) was thus conducted to assess the effects of spraying high-concentration ethephon and early topping on the growth, yield, and earliness of cotton under late-sowing and high-density cultivation models. The experiment employed a split-plot design, in which the main plots were sprayed with varying ethephon concentrations (2000 mL/ha, E₂₀₀₀; 4000 mL/ha, E₄₀₀₀; 6000 mL/ha, E₆₀₀₀), while subplots were plant topping dates (T13, 13 July, early-topped; T20, 20 July, suitable-topped; T27, 27 July, late-topped). Higher ethephon concentrations (E₄₀₀₀) increased the earliness of early-topped (T13) plants. Boll-setting and boll-opening rates increased by 12.00% and 16.83% in T13 plants, respectively, relative to T27 plants. However, the shedding rate for T13 plants decreased by 12.00%. Earliness and harvest index (HI) for the T13 plants were higher than those of the T27 plants by 8.01% and 18.91%, respectively. Even though the T13 plant yield decreased slightly, their boll weight increased by 3.99% and 12.27%, respectively, relative to those of the T20 and T27 plants. Earliness increased with increasing ethephon concentration. In conclusion, early topping and higher ethephon concentrations can effectively improve cotton yield and earliness. Full article

The balance between vegetative and reproductive growth is the central objective in the cotton production system, which is associated with cotton maturity and yield. In China, manual topping (MT) has been performed many years prior to or during the flowering period to inhibit vegetative growth and enhance reproductive growth. MT is gradually being replaced by chemical topping (CT) with mepiquat chloride (MC, 180 g ha⁻¹, 98% soluble powder) due to labor shortages and increasing labor cost. To determine whether CT influences cotton maturity and yield relative to MT, we carried out field experiments at four locations in the Yellow River Valley of China during 2018–2020. The results showed that CT did not alter the boll age, and although it produced taller and slender spatial boll distribution under several environments, it had little effect on the accumulation of boll fraction (the number of bolls in a given period divided by total boll number) over time at the end of blooming across locations. As a result, there were no significant differences between MT and CT in boll opening percentage in the late season. CT did not influence yield or yield components, except under severe drought. Therefore, CT with MC (180 g/ha, 98% soluble powder) during the flowering period will not compromise the maturity or yield of cotton in the Yellow River Valley of China. Similar outcomes would be achieved in other areas with similar ecological conditions and social conditions that require an alternative to extensive manual labor. Full article

Cotton genus Gossypium L., especially its wild species, is rich in genetic diversity. However, this valuable genetic resource is barely used in cotton breeding programs. In part, due to photoperiod sensitivities, the genetic diversity of Gossypium remains largely untapped. Herein, we present a genetic analysis of morphological, cytological, and genomic changes from radiation-mediated mutagenesis that induced plant photoperiod insensitivity in the wild cotton of Gossypium hirsutum. Several morphological and agronomical traits were found to be highly inheritable using the progeny between the wild-type G. hirsutum subsp. purpurascens (El-Salvador) and its mutant line (Kupaysin). An analysis of pollen mother cells (PMCs) revealed quadrivalents that had an open ring shape and an adjoining type of divergence of chromosomes from translocation complexes. Using 336 SSR markers and 157 F₂ progenies that were grown with parental genotypes and F₁ hybrids in long day and short night conditions, five quantitative trait loci (QTLs) associated with cotton flowering were located on chromosomes At-05, At-11, and Dt-07. Nineteen candidate genes related to the flowering traits were suggested through molecular and in silico analysis. The DNA markers associated with the candidate genes, upon future functional analysis, would provide useful tools in marker-assisted selection (MAS) in cotton breeding programs for early flowering and maturity. Full article