Journal of Agronomy and Crop Science最新文献

Canopy resistance (r_c) is a vital parameter for further estimating crop evapotranspiration (ET_c), and Jarvis model is one of the most widely used models to estimate r_c with parameterizations based on the environmental factors and leaf area index (LAI). However, previous researches on the Jarvis model mainly focused on optimising environmental parameters, which could not explain the great fitting disparity for the r_c estimations of distinct crop species and the uncertain model performances in different growing stages. Therefore, we modified the effective leaf area index (LAI_e) in Jarvis model using a multi-layer method in which we measured stomatal resistance (r_s) and LAI at different layers (0–50, 50–100, 100–150 and 150–200 cm of plant height) of greenhouse cucumber to calculate LAI_e to describe the influences of leaf spatial distribution and photosynthesis efficiency. We compared the performances of the improved and the original Jarvis models on r_c estimation and found the coefficient of determination (R²) and root mean squared error (RMSE) of 0.68 and 163 s m⁻¹, 0.64 and 171 s m⁻¹, respectively, the corresponding errors for hourly ET_c calculation were 0.81 and 0.10 mm h⁻¹, 0.88 and 0.098 mm h⁻¹, respectively. The accuracy of both models gradually raised with the increasing in LAI, and an obvious improvement on ET_c estimation appeared when LAI ≤ 1 m² m⁻² with R² = 0.81 for the improved Jarvis model while R² = 0.77 for the original Jarvis model. Although the accuracy of the improved Jarvis model was not prominently increased for all growing stages, the improved Jarvis model is of great significance in considerations of crop physiological and growth diversity to enhance the model adaptability for distinct crops and reduce the uncertainty of model performance for different growing stages.

Drought resilience strategies are needed to tackle the escalating issue of water scarcity and to sustain crop productivity under water deficit conditions. There is a gap in identifying the most effective consortium of microbial biostimulants and understanding the underlying physiological and antioxidant mechanisms involved in the drought resilience of wheat (Triticum aestivum L.) crop. To address this, three experiments were carried out in laboratory and wire house conditions to identify and optimise the response of drought-tolerant microbial biostimulants for wheat genotypes. Three drought-tolerant microbial biostimulants: Bacillus subtilis, Bacillus megaterium and Trichoderma harzianum were selected from a laboratory study. The two wheat genotypes: Dilkash-2021 and Bakhar Star (drought tolerant and sensitive, respectively) were selected from a wire house experiment. Afterwards, the response of individual and consortium of selected drought-tolerant microbial biostimulants was evaluated in drought-tolerant and sensitive wheat genotypes under well-watered and water deficit regimes. Results indicated that seed inoculation of drought-tolerant genotype with the microbial consortium of Bacillus subtilis, Bacillus megaterium and Trichoderma harzianum significantly increased relative water contents (58%), stomatal conductance (39%), sub-stomatal conductance (70%), water use efficiency (38%) and net leaf photosynthetic rate (34%) as compared with the un-inoculated control under water deficit. Furthermore, a significant reduction in malondialdehyde concentration (36%) and an improvement in proline contents (77%), superoxide dismutase (82%) and peroxidase (51%) were observed with this microbial consortium under water deficit. Therefore, seed inoculation of drought-tolerant wheat genotypes with the microbial consortium might be considered in formulating the best agricultural practices for alleviating the adverse effects of water deficit on the wheat crop.

Cowpea is a valuable legume known for its high-quality protein and multiple uses, but it often suffers from sub-optimal moisture during different growth stages. While the effects of drought at certain stages are studied, comprehensive studies across all growth stages are limited. This study evaluated drought tolerance of two cowpea genotypes by examining morphophysiological, pigments, biomass, yield and quality traits under contrasting soil moisture conditions: control and drought during critical vegetative (V2 and V4) and reproductive (R1 and R4) stages. Gas exchange traits were more affected by drought during the vegetative stages than the reproductive stage, with photosynthesis declining by 86% at the vegetative stage, compared to a 68% reduction at the reproductive stage. The chlorophyll index declined by 54% in the R4 stage, while the V2 stage showed no significant changes under drought. Drought at the R1 stage led to a substantial decrease in seed yield by 46%, followed by 35% in R4, 33% in V2 and 27% in V4. The yield reduction at R1 correlated with an 82%, 68% and 44% drop in stomatal conductance, photosynthesis rate and chlorophyll index, respectively, followed by a 3.4°C increase in leaf temperature. Drought stress during reproductive stages led to an increase in hundred-seed weight and seed protein, while starch content decreased, indicating a shift in resource allocation under stress conditions. Based on seed number and weight, the order of cowpea growth stage resilience to drought stress followed the order of R1 < R4 < V2 < V4. These findings suggest that breeding for a multi-stage drought-resilient genotype is needed to sustain yield under rainfed conditions.

The estimation of water requirement for specific climatic conditions is a challenging but inevitable need for saving unnecessary water losses, and it becomes irrepressible in semi-arid regions. Development of crop coefficient (Kc), the ratio of crop evapotranspiration (ETc) to reference evapotranspiration (ET_O), can enhance ETc estimates in relation to specific crop phenological stages. This research was conducted to determine growth-stage-specific Kc and crop water use for cotton (Gossypium hirsutum) in the Marathwada region (Central India). The FAO Penman-Monteith equation was used to calculate ETo using data of meteorological variables from a nearby standard Meteorological Observatory, while ETc was measured using a weighing lysimeter installed near the centre of a cotton field seeded with cotton, as in the rest of the surrounding field. The average daily ETc of cotton over the complete growing season was figured out as 3.8, 4.0, and 3.7 mm day⁻¹ in 2019, 2020 and 2021, respectively. The values ranged from 1.26 to 7.32 mm day⁻¹ in 2019, 1.7 to 8.8 mm day⁻¹ in 2020 and 1.3 to 7.3 mm day⁻¹ in 2021. For early, mid-season, and end-of-season phases of cotton, respectively, stage-specific K_c values averaged over 3 years were 0.51, 1.24 and 0.95. The computed Kc values differed significantly from the reported FAO-56 values. This result can be useful for agricultural planning and efficient irrigation management and provides precise water applications for cotton cultivation in semi-arid areas.

Abiotic and biotic stress is a staid confront for nourishing global agriculture yields and food supply. Nanoparticles (NPs) are thought to be a key tool for raising agricultural yields in present drastic environmental variations. NPs' application improves amalgamation of the hormones, osmoprotectants, bioactive compounds, free radical scavenging efficacy and expression of genes, thus assisting plants to effectively defend themselves under various stresses. Nanoproducts such as nanopesticides, nanocarriers and nanosensors hold considerable potential for smart and sustained delivery of agrochemicals, genetic material and rapid disease detection, in addition to dynamic and precise crop water monitoring. NPs manifest pesticidal and insecticidal properties by altering the porosity of cell membranes, denaturing nucleic acid, arresting the cell cycle and generating oxidative stress. Furthermore, NPs strengthen plant resistance to stresses by boosting water and mineral uptake, improving ROS-scavenging enzymes, improving the photosynthetic rate and gas exchange parameters. Plants use intricate processes to organise absorption and mobilise NPs. However, there is keen urgency for the incorporation and use of multiomics in plants to get mechanistic insights at molecular levels to comprehend the signalling pathways initiated in response to NPs and for understanding phytotoxicity. In conclusion, this study not only emphasises the relevance of nanoenabled techniques in enhancing wheat health, but it also demonstrates their potential to address global food security issues.

Elevated CO₂ enhances photosynthesis and yield in rice, with indica rice generally displaying a stronger yield response than japonica. However, uncertainty remains about the key yield components driving this difference, which limits breeding strategies for enhancing japonica rice yield. To identify critical factors in yield responses to elevated CO₂ and to explore potential improvements in japonica rice yield, we conducted a meta-analysis of FACE (Free-Air Carbon dioxide Enrichment) data from China and Japan to examine yield component contributions. Additionally, we investigated whether rice lines with enlarged root systems could enhance yield response to elevated CO₂ (+200 μmol mol⁻¹). Our results indicated that, under elevated CO₂, Chinese indica rice genotypes achieved a substantial grain yield increase, averaging around 31.1%. On the other hand, the Chinese and Japanese japonica along with the Japanese indica demonstrated more moderate increases, measuring about 10.3%, 13.7% and 12.5%, respectively. Among yield components, spikelets per panicle (SPP), often a lagging indicator, was identified as a crucial factor in further increasing yield potential. OsERF3-overexpressing rice lines not only expanded root growth but also stimulated root vigour under elevated CO₂ conditions. These enlarged-root lines demonstrated improved nutrient uptake, nitrogen-content stability, increased photosynthesis rates and greater grain weight, effectively avoiding the SPP reductions typically seen in Chinese japonica under elevated CO₂. As a result, these lines achieved a 38.6% yield increase under elevated CO₂, outperforming wild-type japonica responses. These findings suggest that enlarged-root rice lines could be a promising breeding platform for enhancing rice production and developing climate-resilient rice cultivars.