Journal of Agronomy and Crop Science最新文献

Crop lodging is recognised as one of the yield-limiting factors in agricultural production. Therefore, better understanding to improve lodging resistance and to prevent lodging-induced losses in agronomic crops is necessary. Besides yield losses, lodging severely affects the crop harvesting process and increases the production cost. However, achieving the objective of higher crop yields and yield quality without increasing lodging risk is quite challenging. To this end, it is essential to interpret the underlying mechanism of plant stem buckling and failure of root anchorage and optimise the fundamental trade-off between lodging resistance and yield performance in agronomic crops. In the present review, we made an effort to discuss recent and innovative research insights that guarantee greater lodging resistance along with advanced lodging prevention strategies while sustaining higher crop yield and yield quality.

Plant growth regulators (PGRs) improve crop growth and mitigate the adverse effects of drought stress. This study explores the effects of various PGRs including melatonin (MT), indole-butyric acid (IBA) and gibberellic acid (GA₃) on drought-tolerant Zhongzhe 9 (ZZ9) and Xintaitang 22 (ROC22), as well as drought-sensitive varieties Guitang-44 (GT44) and Funong 41 (FN41) varieties. A pot experiment was conducted to evaluate the foliar application of these hormones alone or in combination on sugarcane seedlings under drought stress conditions. At the sixth leaf stage, drought stress was induced by reducing soil moisture to 40%–45% field capacity. Results showed that the drought-sensitive variety GT44 had the highest plant height (17.97 cm), while PGRs application enhanced the relative water content (RWC) in FN41 by 0.96%. PGRs treatment also increased plant height by 33.98% and RWC by 3.26% compared to controls. MT application significantly increased chlorophyll a and b contents in FN41 by 4.82% and 4.51%, respectively. Antioxidant enzyme activities superoxide dismutase and peroxidase increased by 16.39% and 12.57%, respectively, indicating enhanced oxidative stress defence. Moreover, PGRs applications reduced hydrogen peroxide and malondialdehyde (MDA) accumulation, signifying decreased oxidative damages. The combinations of MT + GA₃ and MT + IBA + GA₃ significantly improved the plant growth attributes, antioxidant enzymes, osmolytes and reduced the accumulation of ROS and MDA content in both tolerant and sensitive varieties under drought stress. Thus, combined application of MT + GA₃ and MT + IBA + GA₃ treatments effectively mitigated drought stress in sugarcane seedlings, providing valuable insights for sustainable agricultural practices.

Grain-filling rate and duration largely affect the grain-filling capacity, which determines the grain yield of maize (Zea mays L.). Nevertheless, there is little about the mechanism of how various soil mulching practices affect the leaf photosynthetic potential and subsequent grain-filling capacity of maize. Field experiments were undertaken on rainfed summer maize in northwest China under flat cultivation without mulch (FNM), flat cultivation with straw mulch (FSM), flat cultivation with transparent film mulch (FTF), flat cultivation with black film mulch (FBF), ridge-furrow cultivation with transparent film mulch (RTF) and ridge-furrow cultivation with black film mulch (RBF) in 2021 and 2022. This study explored the impact of various soil mulching patterns on soil hydrothermal condition, leaf growth, photosynthetic potential, aboveground dry matter growth and grain-filling process of rainfed maize. The dynamics of leaf area index (LAI) and grain-filling were fitted with growth equations, and the relationships of grain-filling rate, leaf area duration and LAI withering rate were quantified. The results showed that, compared with FNM, other five soil mulching practices improved soil hydrothermal condition, the maximum LAI and leaf expansion rate but reduced leaf withering rate, thereby increasing radiation interception rate (RI) at the grain-filling stage. The soil mulching practices also increased leaf SPAD value, net photosynthetic rate, photosynthetic nitrogen use efficiency and the aboveground dry matter. Compared with FNM, other five practices extended the effective grain-filling period and the active period of grain-filling, increased the maximum and mean grain-filling rates, improved the 100-kernel weight and the average kernel per ear (KPE), thereby increasing grain yields by 9.2%, 33.7%, 38.0%, 46.3% and 58.6%, respectively. The functional relationships of grain-filling rate and accumulated leaf area duration (y = a/(1 + b*exp(−kx))), and the functional relationships of grain-filling rate and LAI withering rate (y = (a + cx + ex²)/(1 + bx + dx²)) were first proposed. In conclusion, various soil mulching practices improved the soil hydrothermal condition, green leaves growth process and RI, which improved the leaf photosynthetic potential and the grain-filling capacity, thereby increasing the 100-kernel weight, KPE and grain yield. This study can help us quantitatively describe and better understand the maize grain-filling process under various mulching practices.

Maize, a cereal crop of global significance, encounters cultivation challenges in the subtropical regions of Guangxi, mainly due to variable rainfall and low soil fertility, exacerbating the effects of drought. This study evaluated the effects of irrigation and nitrogen fertilisation on overcoming these challenges and improving maize growth and yield. Between 2020 and 2021, a split-plot experiment was conducted. The main plots were assigned to two irrigation treatments: irrigated and rainfed. Within each main plot, subplots were treated with different nitrogen levels (0, 150, 200, 250 and 300 kg ha⁻¹). The results showed that nitrogen levels and water regime significantly impacted several key factors, including the net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), intercellular carbon dioxide concentration (Ci), photosynthetically active radiation (PAR), carbon-metabolising enzymes and total carbon (TC) content accumulation. Under drought-like rainfed conditions, the application of nitrogen, RN300 (rainfed application nitrogen 300 kg ha⁻¹), IN250 (irrigated application nitrogen 250 kg ha⁻¹) significantly enhanced the Pn (10.0%), Tr (3.17%), Ci (3.41%) and Gs (2.6%). Additionally, PAR was significantly influenced by the water regime and nitrogen levels. Under IN250, the capture ratio (Ca) increased (2.36%), while the penetration ratio (Pe) and reflectance ratio (Re) decreased by 13.12% and 46.36%, respectively, compared to RN300. The levels of carbon metabolism enzymes (sucrose phosphate synthase and phosphoenolpyruvate carboxylase) and the TC content were higher under RN300 compared to IN250; however, these differences were not statistically significant. Path analysis revealed that thousand kernel weight had the most significant impact on yield under both water regimes. The effect was stronger under irrigated conditions, with a path coefficient of 0.647, compared to 0.459 under rainfed conditions. Correlation analysis indicated that plant height (0.938), stem diameter (0.906), ear diameter (0.928) and ear length (0.803) were positively correlated with nitrogen levels. In conclusion, maize under IN250 exhibited superior photosynthetic performance and carbon accumulation. This suggests that balanced irrigation and nitrogen management can effectively mitigate the adverse impacts of drought on maize, optimising growth and yield sustainably.

The Crop Water Stress Index (CWSI) is a widely used method for quantifying crop water status and predicting yield. However, its evaluation across different irrigation methods and its stage-specific response to crop yield is rarely evaluated. In this study, controlled field experiments were conducted on winter wheat using drip irrigation (DI) and flood irrigation (FI) during the 2021–2022 and 2022–2023 seasons in western Uttar Pradesh, India. The irrigation treatments included 50% MAD (maximum allowable depletion) (DI), 55% MAD (DI), 60% MAD (DI), 50% MAD (FI), local farmer's field replication (FI), rain-fed, and well-watered treatment (DI). The derived mean CWSI values for the irrigation treatments ranged from 0.03 to 0.66 in season 1 and 0.06 to 0.57 in season 2 across treatments. The seasonal mean CWSI for 50% MAD (DI) was 0.12 (season 1) and 0.11 (season 2), while 50% MAD (FI) yielded higher mean CWSI values of 0.29 (season 1) and 0.22 (season 2). The 50% MAD (DI) treatment produced the highest grain yield and water use efficiency in both seasons. A comprehensive analysis of stage-specific CWSI values and grain yields revealed that grain yield was more sensitive to post-heading CWSI as compared to pre-heading CWSI values. Among the growth stages, CWSI values during the flowering stage were the most critical for predicting wheat yield. The study recommends that the CWSI values in the flowering and post-heading stages are more relevant in predicting wheat yield accurately as compared to the pre-heading and seasonal mean CWSI.

Elevated CO₂ concentration (eCO₂) can modulate the response of crop plants to drought stress (DS). This study aimed to investigate the response of leaf gas exchange, chlorophyll fluorescence, antioxidant activities, osmotic adjustment substance, phytohormone and signal transduction regulatory enzymes, as well as related genes in foxtail millet to DS (water stress for 10 days), ambient condition (aCO₂, 400 μmol mol⁻¹) and eCO₂ (600 μmol mol⁻¹). eCO₂ significantly increased the net photosynthetic rate, maximum net photosynthetic rate, chlorophyll a content, transpiration rate and stomatal conductance, but did not affect leaf instantaneous water-use efficiency under DS. eCO₂ also significantly enhanced the quantum yield of Photosystem II (PSII), photosynthetic electron transport, and proportion of open PSII reaction centers under DS. Moreover, eCO₂ significantly increased abscisic acid (ABA) content, proline content, and the activities of peroxidase, superoxide dismutase, and calcium-dependent protein kinase under DS, leading to a significant reduction in malondialdehyde content. eCO₂ significantly increased the expressions of gene encoding ABA-, stress- and ripening-induced proteins and ABA-responsive element binding factor under DS. Our results clearly demonstrated the vital role of eCO₂ in mitigating the drought-induced damage over ambient CO₂ grown foxtail millet.

Rice, a staple food crop for over half of the global population, is facing a serious threat of rising temperature due to climate change, especially in the areas producing Basmati rice. The main objectives of the study were to compare the promising cultivars of Basmati rice for heat stress tolerance and to assess how elevated temperature affects leaf physiological and morphological parameters of fine rice at seedling stage. A 2-year-controlled pot experiment was carried out to evaluate how different Basmati rice varieties respond to heat stress. The experiment was carried out at the Agronomic research area, University of Agriculture Faisalabad, Pakistan, during 2022 and 2023. The design of experiment was completely randomised design (CRD) with split treatment structure and four replications. Plant morphology, leaf temperature, chlorophyll contents, relative cell injury and relative water contents were evaluated for both experimental years. Heat stress significantly affected all morphological and physiological attributes such as chlorophyll contents, relative water contents and relative cell injury across different varieties. There was variation in the behaviour of different varieties under stress conditions as compared to no heat, but from the results it was very clear that Kisan Basmati and PK-1121 Aromatic constantly showed poor performance under both conditions for all the recorded parameters. However, in almost each parameter evaluated, Basmati-515, Super Basmati and NIAB-16 exhibited Superior thermo tolerance and better performance. On the basis of observed morphological and physiological attributes, Kisan and PK-1121 Aromatic Basmati were graded as sensitive varieties, while Basmati-515, Super Basmati and NIAB-16 showed tolerance to heat stress as compared to other varieties. However, further research is needed to explore the underlying mechanisms and genetic factors contributing to the sensitivity or tolerance observed in these varieties.

Cereal crops are cultivated across diverse regions globally, facing numerous environmental challenges, with salinity posing a significant threat to their growth and productivity. Plants respond to salinity stress (SS) through various morphological and physiological mechanisms. Notably, root system architecture (RSA) has emerged as a crucial factor in aiding nutrient uptake and ensuring efficient water supply, reshaping plant responses, particularly under SS. However, assessing and visualizing RSA and growth patterns in different crops is more challenging than aboveground parts, often leading to neglect in research. Roots serve a dual role in SS: preventing Na⁺ (sodium) uptake from soil and its accumulation into shoots. This review highlights the impact of SS on remodeling RSA, encompassing phenology, cytology, and genetic regulation. It offers comprehensive insights into root architecture, functionalities, hormonal crosstalk, and agronomic strategies tailored for cereals crops. These insights aim to optimize resource capture, mitigate Na⁺ uptake—known to reduce yield in saline conditions—and explore potential avenues for engineering roots to circumvent SS.

Waterlogging during the anthesis, exacerbated by continuous rainy weather and heavy soil, has become a primary limiting factor affecting wheat yield in southern China's rice-wheat rotation regions. Previous research indicates that utilizing exogenous 6-benzylaminopurine (6-BA) can effectively alleviate the adverse effects of continuous rain on wheat yield, while the fundamental process is yet to be fully understood. In this research, two wheat varieties with contrasting waterlogging sensitivities were selected, which were exposed to waterlogging and shading for 7, 11, and 15 days after anthesis. Subsequently, three different concentrations of 6-BA solution (15, 25, and 35 mg L⁻¹) were applied through spraying. The application of 6-BA significantly increased the total soluble sugar and starch content in grains during the filling process, as well as enhanced the activities of starch synthesis-related enzymes: sucrose synthase (SuS, EC 2.4.1.13), ADP-glucose pyrophosphorylase (AGPase, EC 2.7.7.21), and starch phosphorylase (Pho, EC 2.4.1.1). Moreover, the application of 6-BA notably enhanced the transfer and transport rate for non-structural carbohydrates (NSC) in the stem and sheath. It resulted in a notable increase in the distribution ratio of dry matter in the grain, ultimately leading to higher grain weight and yield. Applying 6-BA through spraying mitigated the adverse effects of waterlogging and shading on starch accumulation and dry matter transport in grains, thereby improving grain weight. The most effective concentration in this experiment was 25 mg L⁻¹.