Abstract Background Indeterminate cotton is capable of prolonged vegetative growth and increased fruiting; however, excessive plant height is often associated with fruit abscission, uneven nutrient supply, and difficulties in mechanized harvesting. Therefore, developing early-maturing, machine-harvestable cotton varieties with compact growth remains a long-standing objective for breeders. Members of the phosphatidylethanolamine-binding protein (PEBP) gene family play central roles in maintaining indeterminate growth in cotton. Results In this study, molecular docking coupled with molecular dynamics (MD) simulations was employed to characterize protein–protein interactions among PEBP family members FLOWERING LOCUS T (FT), SELF PRUNING (SP), and the bZIP transcription factor FLOWERING LOCUS D (FD) in Gossypium hirsutum . Docking analysis of Complex I (FD-SP) revealed a strong hydrogen bond (H-bond) and salt bridge between the GLU-242 residue of FD and the ARG-102 residue of SP, whereas in Complex II (FT-FD), the same FD residue (GLU-242) formed an H-bond and a salt bridge with the ARG-111 residue of FT, indicating that SP and FT compete for GLU-242 at FD’s interface. Complex III (FT-SP) displayed comparatively weaker interactions between FT GLU-166 and SP’s LYS-50 through hydrogen bonding and salt bridge formation, suggesting a less favorable interaction. Binding free energy (Δ G ) = –14.1 kcal·mol⁻ 1 and dissociation constant ( K D ) = 4.5 × 10 –11 M, represented consistent values for Complex I and Complex II, while Complex III indicated substantially weaker binding interactions with Δ G = 10.9 kcal·mol⁻ 1 and a K D score of 1.0 × 10 –8 M. Furthermore, MD simulations of the docked complexes (I and II) revealed a stable hydrogen-bonding network, low root mean square deviations (RMSDs) of 0.04 nm, and H-bond distances within 0.3 nm throughout the simulation period. In contrast, Complex III exhibited a reduced H-bond network and a late-stage RMSD spike, indicating structural instability compared to the stronger FD-mediated Complexes I and II. Conclusions These findings provide a structural framework for understanding the competitive interplay among PEBP family members, highlighting potential candidates for future functional validation and the development of improved cotton ideotypes.
Abstract This paper systematically reviews breakthrough advances in research on cotton secondary cell wall (SCW) regulation and illustrates a novel four-tiered “MYB–NAC–MYB–structural gene” regulatory cascade orchestrated by GhMYB44. GhMYB44-interacting protein complexes sequentially activate key downstream genes related to fiber formation, establishing an efficient “initiation–amplification–execution” regulatory system, which represents an adaptive evolutionary module unique to Malvaceae. This review also discusses current research limitations and proposes future strategies that integrate multi-omics approaches and germplasm resource exploration.
Abstract Background The one-time combined application of conventional urea (U) with controlled-release urea (CRU), manure (M), or nitrification inhibitors (NIs) offers sustainable nitrogen (N) management options. However, their comparative performance under equivalent N inputs remains unclear. We conducted a two-year micro-plot field experiment to evaluate their effects on cotton yield, yield stability, nitrogen use efficiency (NUE), and soil mineral nitrogen (N min ) dynamics. Treatments included a control (CK, no N) and four iso-N strategies: U (conventionally split-applied, with 40% applied basally and 60% at the first flowering), U + CRU (30% U + 70% CRU, one-time basal application), U + M (70% U + 30% M, one-time basal application), and U + NI (one-time basal application). Results Both the U + CRU and U + M treatments increased shoot biomass by 53%–155% relative to the CK treatment. The highest biomass was observed in the U + M treatment in 2020 and in the U + CRU treatment in 2021. Under heavy rainfall in 2021, U + CRU enhanced N uptake in reproductive organs by 31.9%–56.1% compared with other treatments, suggesting greater resilience to high-precipitation conditions. Although U + CRU and U + M performed similarly in 2020, U + CRU outperformed all other treatments in 2021, increasing yield by 6.7%–42.3%, largely through a higher boll number, and exhibiting greater yield stability across both years. Soil data revealed consistently higher N min from flowering to boll opening under U + CRU, consistent with increased shoot N uptake and biomass. In contrast, residual N min in the 0–0.6 m soil layer was 10.4%–24.0% lower under U + CRU across both years, indicating a reduced risk of N loss. U + CRU achieved the highest NUE in 2021, exceeding that of other treatments by 43.4%–74.6%. Conclusions Overall, at the evaluated N application rate, the one-time basal application of U with CRU (30% U + 70% CRU) synchronized N supply with crop demand, thereby improving yield and yield stability while reducing residual soil N min . This strategy represents a potential climate-resilient approach for sustainable cotton production under high-precipitation conditions.
Abstract Background India is one of the leading cotton producers, with more than 11 million hectares of cotton acreage worldwide. Despite this, productivity (461 kg·hm −2 ) has remained volatile and far below the global average, shaped by biotic and abiotic stresses, policy shifts, and technological interventions. This study is a unique effort to understand spatial variations in area, production, and yield across all major districts of India’s North, Central, and South Cotton Zones, which is vital for designing targeted interventions to enhance productivity and competitiveness. Results The study examined 211 cotton-growing districts across the Cotton Cultivation Zones (CCZs) from 2013–2014 to 2023–2024. The Compound Annual Growth Rate (CAGR) was calculated using log-transformed area, production, and yield values, wherein the slope of the regression line was used to estimate annual growth rates. The analysis revealed an uneven growth trend in area, production, and yield across the zones. Certain districts of the Central Zone exhibited stable expansion and productivity acceleration, while some districts in the Northern Zone showed stagnation or negative growth, which might be due to climatic variability and pest incidence. Further, the districts have been mapped in four quadrants based on performance in both horizontal (acreage under cotton) and vertical (cotton yield) dimensions, such as High Area-High Yield (HA-HY), High Area-Low Yield (HA-LY), Low Area-High Yield (LA-HY), and Low Area-Low Yield (LA-LY), highlighting spatial disparities and identifying clusters requiring differentiated policy interventions. Conclusions The findings revealed substantial variations in cotton performance across the CCZs, necessitating zone-specific and cluster-based strategies. High-performing districts require optimization through advanced technologies and best management practices, whereas targeted interventions, a comprehensive approach, or a dual strategy that includes horizontal and vertical interventions are recommended for underperforming districts. The proposed diagnostic framework provided actionable insights for policymakers to enhance cotton productivity, bridge yield gaps, and strengthen India’s position in the global cotton sector. The analysis indicated that productivity gains are closely associated with improved input and technological adoption, irrigation access, and agronomic practices.
Abstract Background Short fruiting branch cotton (SFBC) has normal main-stem growth. However, the growth of fruiting branches is compromised by a short sympodial internode of 2–5 cm, which is suitable for a high-density cropping system. Increasing plant population density (PPD) combined with late topping (LT) has been proven to increase yield for SFBC, but the underlying physiological mechanism remains unclear. An SFBC line, P4D, was employed to examine the dynamics of source-sink attributes and leaf carbon metabolism in the fourth main-stem leaf from the apex during peak flowering (PF) to boll opening (BO) stages in 2023 and 2024. The experiment involved a factorial design with two PPD levels (LD: 5.33 plants·m −2 , HD: 8 plants·m −2 ) and two topping times (ET: early topping for leaving ten sympodial branches; LT: late topping for leaving fifteen sympodial branches). Results Compared with the three other combinations, the combination of HD with LT (HDLT) produced higher lint and seed cotton yields by increasing biological yield and boll density. Averaged across the PF to BO stages and over two years, the greatest leaf area index (LAI) and reproductive biomass per unit ground area (RBGA) were recorded in the HDLT, with increases of 46.30% to 78.52% for LAI and 6.77% to 40.18% for RBGA compared with others. Additionally, the HDLT exhibited the lowest reproductive biomass per unit leaf area (RBLA), with a reduction of 15.20% to 42.74%. The above results showed that the HDLT was characterized by the greatest source and sink strengths as well as the strongest anti-senescence ability among the four treatments. Compared with the ET, the LT improved the activities of adenosine diphosphate glucose pyrophosphorylase and sucrose phosphate synthase and, in turn, increased leaf starch and total nonstructural carbohydrate (TNC) concentrations during the PF to BO stages in both years. Relative to the HD, the LD presented greater starch and TNC levels. Thus, the combination of LT and LD (LDLT) achieved the greatest starch and TNC concentrations, followed by the HDLT. Conclusion The higher cotton yield in HDLT is attainable through increasing both source and sink ability, delaying leaf senescence, and improving carbon production capacity. Increasing plant density combined with later topping for SFBC is a promising alternative for sustainable cotton production in Jiangxi province, China and other areas with similar ecology.
