Search Results (229)

Improved irrigation guidelines are needed to maximize crop water use efficiency. Combining field data with simulation models can provide information for better irrigation management. The objective of the present study was to evaluate the effects of two flood irrigation treatments on fiber yield (FY) and quality during the 2023 and 2024 growing seasons in Maricopa, Arizona, USA. Two irrigation treatments, denoted as F100% and F80%, were arranged in a randomized complete block design with three replicates. Then, AquaCrop was used to simulate cotton yield (Y_Tot), water use (ET_obs), and total soil water content (WC_Tot) for the two irrigation treatments. Six statistical metrics, including the coefficient of determination (R²), the normalized root-mean-square error (NRMSE), the mean absolute error (MAE), simulation error (S_e), the index of agreement (D_index), and the Nash–Sutcliffe efficiency coefficient (NSE), were employed to assess model performance. The results of the field trial demonstrated that reducing the irrigation rate to 80% of ET_c negatively impacted cotton FY and ET water productivity (ETWP); the FY declined by 45.2% (ETWP = 0.097 kg·ha⁻¹) in 2023 and by 38.1% (ETWP = 0.133 kg·ha⁻¹) in 2024. Conversely, F100% produced a more uniform and stronger fiber than F80%, with the uniformity index (UI) and fiber strength (STR) measuring 81.7% and 29.5 g tex⁻¹ in 2023 and 82.2% and 30.0 g tex⁻¹ in 2024, indicating that UI and STR were well correlated with soil water during both growing seasons. AquaCrop showed an excellent performance in simulating cotton CC during the two growing seasons. The R², NRMSE, D_index, and NSE were between 0.97 and 0.99, 8.45% and 14.36%, 0.98 and 0.99, and 0.96 and 0.98, respectively. Moreover, the AquaCrop model accurately simulated Y_Tot during these seasons, with R², NRMSE, D_index, and NSE for pooled yield data of 0.93, 8.05%, 0.95, and 0.78, respectively. The model consistently overestimated Y_Tot, ET_obs, and WC_Tot, but within an acceptable S_e (S_e < 15%) during both growing seasons, except for WC_Tot under the 80% treatment in 2023 (S_e = 26.4%). Consequently, AquaCrop can be considered an effective tool for irrigation management and yield prediction in arid climates such as Arizona. Full article

Cottonseeds, rich in high-quality protein and fatty acids, represent a vital plant-derived feedstuff and edible oil resource. To systematically investigate genetic variation patterns in nutritional quality and screen superior germplasm, this study analyzed 26 nutritional quality traits and 8 fiber traits across 259 upland cotton (Gossypium hirsutum L.) accessions using multivariate statistical approaches. Results revealed significant genetic diversity in cottonseed nutritional profiles, with coefficients of variation ranging from 3.42% to 26.37%. Moreover, with advancements in breeding periods, the contents of protein, amino acids, and the proportion of unsaturated fatty acids (UFAs) increased, while oil content and C16:0 levels decreased. Correlation analyses identified significant positive associations (p < 0.05) between proteins, amino acids, UFAs, and most fiber traits, except for seed index (SI), fiber micronaire (FM), and fiber elongation (FE). Through a principal component analysis–fuzzy membership function (PCA-FMF) model, 13 elite accessions (F > 0.75) with high protein content, high UFA proportion, and excellent fiber quality were identified. These findings provide both data-driven foundations and practical germplasm resources for value-added utilization of cottonseed and coordinated breeding for dual-quality traits of nutrition and fiber. Full article

Background: Gossypium hirsutum L. is one of the main economic crops worldwide, and increasing the size/weight of its seeds is a potential strategy to improve its seed-related yield. AINTEGUMENTA (ANT) is an organogenesis transcription factor mediating cell proliferation and expansion in Arabidopsis, but little is known about its candidate function in upland cotton seed. Results: In this study, functional characterization of GhANT in the cotton seed development stage was performed. The expression pattern analysis showed that GhANT was predominantly expressed in the ovules, and its expression was consistent with the ovules’ development stage. Heterologous expression of GhANT in Arabidopsis promoted plant organ growth and led to larger seeds. Importantly, specific expression of GhANT by the TFM7 promoter in the cotton ovules enlarged the seeds and increased the cotton seed yield, as compared with the wild-type in a three-year field trial. Furthermore, transcription level analysis showed that numerous genes involved in cell division were up-regulated in the ovules of TFM7::GhANT lines in comparison to the wild-type. These results indicate that GhANT is a potential genetic resource for improving cotton seed yield through its molecular links with cell cycle controllers. Full article

There is a lack of systematic research on the comprehensive regulatory effects of urea and organic fertilizer application on soil quality and cotton yield in summer direct-seeded cotton fields in the Yangtze River Basin. Additionally, there is a redundancy of indicators in the cotton field soil quality evaluation system and a lack of reports on constructing a minimum dataset to evaluate the soil quality status of cotton fields. We aim to accurately and efficiently evaluate soil quality in cotton fields and screen nitrogen application measures that synergistically improve soil quality, cotton yield, and nitrogen fertilizer utilization efficiency. Taking the summer live broadcast cotton field in Jiangxi Province as the research object, four treatments, including CK without nitrogen application, CF with conventional nitrogen application, N1 with nitrogen reduction, and N2 with nitrogen reduction and organic fertilizer application, were set up for three consecutive years from 2022 to 2024. A total of 15 physical, chemical, and biological indicators of the 0–20 cm plow layer soil were measured in each treatment. A minimum dataset model was constructed to evaluate and verify the soil quality status of different nitrogen application treatments and to explore the physiological mechanisms of nitrogen application on yield performance and stability from the perspectives of cotton source–sink relationship, nitrogen use efficiency, and soil quality. The minimum dataset for soil quality evaluation in cotton fields consisted of five indicators: soil bulk density, moisture content, total nitrogen, organic carbon, and carbon-to-nitrogen ratio, with a simplification rate of 66.67% for the evaluation indicators. The soil quality index calculated based on the minimum dataset (MDS) was significantly positively correlated with the soil quality index of the total dataset (TDS) (R² = 0.904, p < 0.05). The model validation parameters RMSE was 0.0733, nRMSE was 13.8561%, and the d value was 0.9529, all indicating that the model simulation effect had reached a good level or above. The order of soil quality index based on MDS and TDS for CK, CF, N1, and N2 treatments was CK < N1 < CF < N2. The soil quality index of N2 treatment under MDS significantly increased by 16.70% and 26.16% compared to CF and N1 treatments, respectively. Compared with CF treatment, N2 treatment significantly increased nitrogen fertilizer partial productivity by 27.97%, 31.06%, and 21.77%, respectively, over a three-year period while maintaining the same biomass, yield level, yield stability, and yield sustainability. Meanwhile, N1 treatment had the risk of significantly reducing both boll density and seed cotton yield. Compared with N1 treatment, N2 treatment could significantly increase the biomass of reproductive organs during the flower and boll stage by 23.62~24.75% and the boll opening stage by 12.39~15.44%, respectively, laying a material foundation for the improvement in yield and yield stability. Under CF treatment, the cotton field soil showed a high degree of soil physical property barriers, while the N2 treatment reduced soil barriers in indicators such as bulk density, soil organic carbon content, and soil carbon-to-nitrogen ratio by 0.04, 0.04, 0.08, and 0.02, respectively, compared to CF treatment. In summary, the minimum dataset (MDS) retained only 33.3% of the original indicators while maintaining high accuracy, demonstrating the model’s efficiency. After reducing nitrogen by 20%, applying 10% total nitrogen organic fertilizer could substantially improve cotton biomass, cotton yield performance, yield stability, and nitrogen partial productivity while maintaining soil quality levels. This study also assessed yield stability and sustainability, not just productivity alone. The comprehensive nitrogen fertilizer management (reducing N + organic fertilizer) under the experimental conditions has high practical applicability in the intensive agricultural system in southern China. Full article

The insect resistance expression of Bacillus thuringiensis (Bt) cotton (Gossypium hirsutum L.) is unstable due to temporal and spatial variations in the Bt protein content in different organs and growth stages. The aim of this study was to improve the Bt protein content in cotton flowers and investigate the underlying physiological mechanism using biochemical analytical methods. In this study, a split-plot design with three replications was used. The main plots included two Bt cotton cultivars (a conventional cultivar, Sikang1 (S1), and a hybrid cultivar, Sikang3 (S3)), while five soil nitrogen application levels (CK (control check): normal level; N1: 125% of the CK; N2: 150% of the CK; N3: 175% of the CK; N4: 200% of the CK) constituted the subplots. The Bt protein content and related nitrogen metabolism parameters were measured. We found that the Bt protein content increased and then decreased with increasing nitrogen rates. It reached its maximum at N3, with significant increases of 71.86% in 2021 and 39.36% in 2022 compared to the CK. Correlation analysis indicated that the Bt protein content was significantly positively related to the soluble protein and free amino acid contents, as well as the GPT (glutamic pyruvic transaminase), GOT (glutamic oxaloacetic transaminase), GS (glutamine synthetase) and GOGAT (glutamate synthetase) activities. On the other hand, negative correlations were found between the Bt protein content and protease and peptidase activities. In addition, stepwise regression and path analysis indicated that the increased Bt protein content was mainly due to the enhanced GS and GOGAT activities. In summary, appropriately increasing nitrogen fertilizer application is a practical way to increase flower Bt protein content and insecticidal efficacy of Bt cotton. These findings provide an actionable agronomic strategy for sustaining Bt expression during the critical flowering period. Full article

Background: Verticillium wilt (VW), caused by the fungal pathogen Verticillium dahliae, is a destructive disease that severely compromises cotton yield and fiber quality. Pyrimidine nucleotides, as essential metabolites and nucleic acid components, play critical roles in plant development and stress responses. However, genes involved in pyrimidine metabolism, especially their roles in disease resistance, remain largely uncharacterized in plants. Methods: Ghir_D05G039120, a gene encoding uridine kinase, shown to be associated with VW resistance in our previous study, was cloned and named as GhUKL4. The differential expression of GhUKL4 between the resistant and susceptible cultivars at multiple time points post-inoculation with V. dahliae was analyzed by quantitative real-time PCR (qRT-PCR), and the uracil phosphoribosyl transferase (UPRT) and uridine 5′-monophosphate kinase (UMPK) domains were verified by analyzing the amino acid sequences of GhUKL4. The role of GhUKL4 in the defense against VW infection was estimated by silencing GhUKL4 in the resistant and susceptible cultivars using virus-induced gene silencing (VIGS) analysis. Results: There were significant differences in the expression level of Ghir_D05G039120/ GhUKL4 among resistant and susceptible cotton lines. GhUKL4 contains UPRTase and UMPK domains, and there was one SNP between the resistant and susceptible cultivars in its 3′-UTR region. The silencing of GhUKL4 reduced cotton’s resistance to VW through mediating hormone signaling (JA) and oxidative stress (ROS) pathways. Conclusions: GhUKL4, encoding UMPK and UPRTase domain proteins, is a new regulatory factor associated with VW resistance in Gossypium hirsutum through fine-tuning JA-signalling and ROS bursting. Full article

Crops and arbuscular mycorrhizal (AM) fungi can enhance nitrogen (N) transformation and utilization efficiency in the soil, and this effect is regulated by soil N application rates. However, it remains unclear whether the N utilization efficiency of cotton can be improved through the symbiosis of cotton with AM fungi under reduced N application rates. Therefore, we conducted ¹⁵N labeling experiments using a compartmentalized culture system with Gossypium hirsutum L. as the experimental plant. We established three N treatments (0.15 g·kg⁻¹, 0.10 g·kg⁻¹ and 0 g·kg⁻¹) to investigate the effects of different fertilization rates on N utilization, soil N priming effects, and differences in N accumulation in various parts of cotton plants within the soil–AM fungi–cotton system. The results indicate that under reduced N application, symbiosis between cotton and AM fungi increased the N fertilizer utilization efficiency and the soil N priming effect. Specifically, reducing the fertilization dosage from 0.15 g·kg⁻¹ to 0.10 g·kg⁻¹ increased the N fertilizer utilization efficiency and soil N priming effect by 8.87% and 11.67%, respectively, and decreased the N loss rate by 7.02%. The symbiosis between cotton and AM fungi after N reduction significantly increased N accumulation in the roots and leaves. Moreover, the N fertilizer content accounted for 5.89% of the total N content in roots. Overall, when N application was reduced, symbiosis with AM fungi effectively promoted the rhizosphere N priming effect, which reconciled the conflict in N nutrient allocation within cotton and thus enabled the efficient utilization of soil N. Full article

Greenhouse gas (GHG) emissions evaluations from agroecosystems are critical, particularly as technology improves. Consistent GHG measurement methods are essential to the evaluation of GHG emissions. The objective of the study was to evaluate potential differences in gas-flux-determination (GFD) options and carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) fluxes and growing-season-long emissions estimates from furrow-irrigated cotton (Gossypium hirsutum) in southeast Arkansas. Four GFD methods were evaluated [i.e., linear (L) or exponential (E) regression models, with negative fluxes (WNF) included in the dataset or replacing negative fluxes (RNF)] over the 2024 growing season using a LI-COR field-portable chamber and gas analyzers. Exponential regression models were influenced by abnormal CO₂ and N₂O gas concentration data points, indicating the use of caution with E models. Season-long CH₄ emissions differed (p < 0.05) between the WNF (−0.51 kg ha⁻¹ season⁻¹ for L and−0.54 kg ha⁻¹ season⁻¹ for E) and RNF (0.01 kg ha⁻¹ season⁻¹ for L and E) GFD methods, concluding that RNF options over-estimate CH₄ emissions. Gas concentration measurements following chamber closure should remain under 300 s, with one concentration measurement obtained per second. The choice of GFD method needs careful consideration to result in accurate GHG fluxes and season-long emission estimates. Full article

Advances in spinning technology have increased the demand for upland cotton (Gossypium hirsutum L.) cultivars with superior fiber quality. However, progress in breeding for traits such as fiber length is constrained by limited phenotypic and genetic diversity within upland cotton. Introgression from Gossypium barbadense, a closely related species known for its superior fiber traits, offers a promising strategy. Sealand 883 is an obsolete upland germplasm developed through G. barbadense introgression and is known for its long and fine fibers. Previous studies have identified a fiber length quantitative trait locus (QTL) on Chromosome 25, designated qFL-Chr.25, in Sealand 883, conferred by an allele introgressed from G. barbadense. This study evaluated the effect of qFL-Chr.25 in near-isogenic introgression lines (NIILs) using Advanced Fiber Information System (AFIS) measurements. Across four genetic backgrounds, NIILs carrying qFL-Chr.25 consistently exhibited longer fibers, as reflected in multiple length parameters, including UHML, L(n), L(w), UQL(w), and L5%. Newly developed TaqMan SNP diagnostic markers flanking the QTL enable automated, reproducible, and scalable screening of large populations typical in commercial breeding programs. These markers will facilitate the incorporation of qFL-Chr.25 into commercial breeding pipelines, accelerating fiber quality improvement and enhancing the competitiveness of cotton against synthetic fibers. Full article

Short fruiting branch cotton (SFBC) has a compact plant architecture suitable for dense planting. Plant population density (PPD) and topping are important agronomic practices to achieve high yielding by optimizing cotton plant structure. However, their individual and interactive effects on SFBC growth and yield are poorly understood. This study aimed to explore cotton growth and yield responses to various combinations of PPD and topping time (TT) and the underlying physio-ecological mechanism. Four combinations were included in a two-year field experiment (2023–2024) involving two PPD levels (5.3 plants m⁻², low density LD; 8 plants m⁻², high density HD) and two TT levels (early topping for leaving ten sympodials per plant ET; late topping for leaving fifteen sympodials per plant LT), and compared in terms of biomass accumulation, photosynthetically active radiation capture, and leaf senescence during entire reproductive growth period. Compared to the other three combinations, the combination of HD and LT (HDLT) achieved a higher lint yield due to a greater biological yield, which was predominantly attributed to the higher average rate during the rapid biomass increasing period. Owing to delayed leaf senescence caused by the HD and the LT, the HDLT performed better in leaf senescence-related attributes at the late growth stage. Moreover, these improved attributes also contributed to a higher radiation interception rate and photosynthetic efficiency at the late growth stage. Taken together, combining high density with later topping tends to increase the lint yield of SFBC through increasing dry matter accumulation, delaying leaf senescence, and enhancing canopy radiation interception rate at the late growth. Full article

Cotton is the most widely consumed natural fiber globally and emits fewer greenhouse gases compared to synthetic alternatives. Brazil is currently the largest cotton exporter, and understanding its potential for sustainable expansion is crucial. This study developed agroclimatic zoning maps for cotton (Gossypium hirsutum L.) across Brazil under current and future climate conditions using data from the World-Clim and MapBiomas platforms. Four climate change scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0, SSP5-8.5) were assessed over multiple time periods. Results showed that rising temperatures and reduced rainfall will likely reduce cotton suitability in traditional producing regions such as Bahia. However, areas with potential for cotton cultivation, especially in Mato Grosso, which currently accounts for 90% of national production, remain extensive, with agroclimatic conditions indicating a theoretical expansion potential of up to 40 times the current cultivated area. This projection must be interpreted with caution, as it does not account for economic, logistical, or social constraints. Notably, Brazilian cotton is cultivated with minimal irrigation, low fertilizer input, and high adoption of no-till systems, making it one of the least carbon-intensive globally. Full article

Aims: Soil compaction is one of the main challenges in agriculture, negatively affecting cotton growth (Gossypium hirsutum L.), nutrition, and productivity. This study evaluated the efficacy of plant growth-promoting bacteria (PGPB), Exiguobacterium sibiricum, and Pantoea vagans in mitigating the effects of different soil compaction levels (65%, 75%, 85%, and 95%) on cotton performance. Methods: Parameters such as plant height, stem diameter, number of leaves, shoot dry matter (SDM), and nutrient content in leaves, stems, and roots were assessed. The methodology included variance analysis and mean clustering to identify significant differences among treatments using R software. Results: The results indicated that PGPB inoculation improved plant growth and nutrition even under high compaction levels. Cotton height increased by up to 45% in compacted soils (95%), while stem diameter and SDM also showed significant gains. Foliar nutrient levels of N (37.2 g kg⁻¹), Ca, and Mg remained within the adequate range for cotton cultivation, reflecting the efficiency of PGPB in enhancing nutrient absorption. Under severe compaction, Ca accumulation dropped to 18.2 g kg⁻¹, highlighting the physical constraints imposed on the roots; however, the bacterial action mitigated this impact. Additionally, bacterial strains increased the availability of N and P in the soil due to their ability to fix nitrogen, solubilize phosphates, and produce exopolysaccharides that improve soil structure. Conclusions: In conclusion, inoculation with Exiguobacterium sibiricum and Pantoea vagans is an effective strategy to mitigate the impacts of soil compaction on cotton. These bacteria promote plant growth and nutrition and enhance the soil’s physical and biological properties. Full article

Phosphorus (P) is an essential nutrient for plant growth, and low-phosphorus (LP) stress significantly limits cotton productivity. Here, we conducted single- and multi-locus genome-wide association studies (GWASs) on four LP-related traits using 419 upland cotton (Gossypium hirsutum L.) accessions genotyped with 2.97 million single-nucleotide polymorphisms (SNPs). Phenotypic analysis reveals substantial variation under LP stress, with LP-SDW showing the highest coefficient of variation (33.69%). The GWASs identified thousands of significant SNPs, including pleiotropic loci associated with multiple traits. Chromosomes A08, D09, and D12 harbored novel associated signals. Multi-locus models significantly enhanced detection sensitivity, identifying 123 SNPs undetected by single-locus approaches. Functional annotations prioritized six candidate genes near associated SNPs, including GhM_A08G1315 (remorin protein) and GhM_D06G1152 (carotenoid cleavage dioxygenase), whose LP-induced expression patterns were validated by qRT-PCR. These genes are implicated in membrane signaling, root architecture modulation, and hormone metabolism. Our findings provide novel genetic insights into LP tolerance and establish a foundation for breeding phosphorus-efficient varieties through marker-assisted selection in cotton. Full article

Root systems are pivotal for nutrient absorption, exhibiting high plasticity in phosphorus (P) acquisition, and significantly influencing soil phosphorus availability. However, the impacts of different P application methods on root parameters and P utilization efficiency in cotton (Gossypium hirsutum L.) under Xinjiang conditions are still not well understood. To identify optimal P fertilization strategies, a consecutive two-year field experiment (2023–2024) under mulched drip irrigation was conducted. Three P application methods were tested: no P (CK), basal P application (PB), and drip P application (PD). Results revealed that P application methods significantly affected cotton dry matter, P use efficiency, root morphology, and yield (p < 0.05). Over the two years, the optimized treatment (25% P applied at bud stage and 25% at flowering-boll stage, PD) increased yield by 13.62% and 9.50% compared to full basal application (PB), with P use efficiency improved by 22.04–31.51% and agronomic efficiency improved by 6.56–9.75 kg kg⁻¹. PB significantly increased soil-available P in 0–20 cm (34.17–70.09%) and 20–40 cm layers (30.37–70.32%) compared to CK. During the bud stage, PD treatment exhibited higher soil-available P in the 20–40 cm layer than PB. PD enhanced P uptake and dry matter accumulation, with increases of 22.43–36.33% and 7.90–15.55% in reproductive organ P accumulation compared to other treatments. Root parameters followed PD > PB > CK across all treatments. At the seedling stage, PB increased total root length by 19.79% compared to CK, while PD increased root volume by 46.15% compared to PB. During the bud stage, PB increased root volume by 53.33% compared to CK, and PD enhanced root surface area and volume by 39.25% and 47.82% compared to PB. Root volume showed a significant positive correlation with phosphorus absorption across growth stages. The PD treatment significantly enhanced soil P availability and P use efficiency and optimized root spatial distribution. This treatment consistently increased cotton yield by 30.41–39.09% (p < 0.05) compared to CK, demonstrating stable positive effects. This study highlights that adjusting P application methods can establish sustainable, high-yield agricultural fertilization systems. Full article

Based on a 2-year in situ nitrogen fertilization experiment, this study aims to establish a critical nitrogen concentration (CNC) dilution curve model for cotton under straw incorporation, analyze the effects of the nitrogen application rate on the cotton yield and nitrogen use efficiency (NUE), and determine the optimal nitrogen application rate by integrating the nitrogen nutrition index (NNI). The experiment setup was a randomized block design with five nitrogen application levels under a straw incorporation: 0, 60, 120, 180, and 240 kg N ha⁻¹ (denoted as N0, N60, N120, N180, and N240, respectively). The cotton dry matter accumulation and nitrogen concentration were measured at the flowering and boll stage, peak boll stage, and boll opening stage. The CNC dilution curve was developed using the data from 2021 and validated with those of 2022. Results showed that the cotton biomass and seed cotton yield at the boll opening stage increased with nitrogen application rates up to 180 kg N ha⁻¹. However, no further increase was found in the yield with an N rate higher than 180 kg N ha⁻¹. The CNC dilution curve was formulated as y = 3.4921x^−0.416 (R² = 0.8741). The validation using 2022 data yielded a root mean square error (RMSE) of 0.21% and a normalized RMSE (nRMSE) of 13.40%, confirming the model’s robustness. The NNI, calculated based on the CNC, indicated that an application rate of 120 kg N ha⁻¹ maintained NNI values close to one across all growth stages, reflecting an optimal nitrogen status. Significant positive correlations were observed between the NNI and both the seed cotton yield and harvest index (p < 0.05). Nitrogen use efficiency parameters, including the agronomic NUE (NUEa), nitrogen partial factor productivity (NPFP), and internal NUE (NUEi), exhibited quadratic declines with the increasing nitrogen input. Within the range of 120–240 kg N ha⁻¹, the highest NPFP was achieved at 120 kg N ha⁻¹. In conclusion, the critical nitrogen dilution curve model combined with the NNI effectively diagnoses the nitrogen status in cotton under straw incorporations. Considering the NNI, yield, and nitrogen utilization efficiency, the recommended nitrogen application rate for cotton in a cotton–rape rotation system with a straw incorporation is 120 kg N ha⁻¹. Full article