Journal of Agronomy and Crop Science最新文献

Maize is a staple crop worldwide due to its extensive food, feed and industrial applications. With climate change, heat waves are becoming more frequent and intense, leading to a significant decrease in maize production. To meet the growing demand for maize products, it is critical to understand the mechanisms by which maize crops respond to heat stress. During anthesis, maize is particularly sensitive to heat, especially in the development of kernels, where kernel number is a major yield component. This sensitivity can vary considerably among different cultivars. However, studies on this topic have been infrequently reported thus far. We comprehensively reviewed controlled experiments from 13 independent, observation-based publications and summarised the negative impacts of heat stress on maize yield and yield components. Our findings indicate that maize is more sensitive to heat stress after silking, particularly during the first 4 days following silking, compared to the period before silking. Moreover, maize yield is further reduced by increased maximum air temperature (T_max) and accumulated heat degree days (HDD) for T_max values exceeding 30°C. Among all the studied maize cultivars, the heating degree days threshold for mild heat stress ranged from 35°C·day in the heat-sensitive cultivar to 59°C·day in the heat-tolerant cultivar. Failing to select the appropriate heat-tolerant cultivars for planting may lead to a significant reduction in maize production. Therefore, we strongly recommend that maize growers select heat-tolerant cultivars or other varieties from the same series before planting to effectively combat climate change.

Salt stress is a major factor limiting the growth, development, and yield of soybeans (Glycine max (Linn.) Merr), yet the regulatory networks underlying soybean resistance to salt stress remain largely unresolved. This study aimed to elucidate the mechanisms of soybean resistance to salt stress by integrating phenotypic, physiological, transcriptomic, and metabolomic analyses of the salt-tolerant soybean cultivar HD6 and the salt-sensitive cultivar ZH929. We found that HD6 exhibited significantly stronger osmotic regulation capacity, enhanced antioxidant capacity, and greater photosynthetic efficiency compared with ZH929. Transcriptomic analysis revealed that differentially expressed genes under salt stress were primarily enriched in pathways related to arginine biosynthesis and isoflavone biosynthesis. Consistently HD6 accumulated higher levels of amino acids and flavonoids. Integrated analysis of transcriptomic and metabolomic data further underscored the critical roles of amino acid and flavonoid biosynthesis regulatory networks in conferring salt resistance. Notably, genes LOC547724 (glutamate decarboxylase, GAD), LOC102661752 (succinate dehydrogenase [ubiquinone] iron–sulfur subunit 2, SDH2), and CHS10 (chalcone synthase 10, CHS), along with metabolites including L-glutamine and rutin, were identified as central components of these networks. Additionally, weighted gene co-expression network analysis highlighted the importance of hub genes such as LOC100820620 (peroxidase) in the salt stress response. Collectively, these findings demonstrate that amino acids and flavonoids are crucial for soybean resistance to salt stress.

Chickpea cultivation during the summer season in the semi-arid tropics offers a potential strategy to enhance cropping intensity, but high temperatures and moisture stress remain major constraints to productivity. A three-year field study was undertaken to assess phenological responses, reproductive efficiency, yield performance and yield stability of nine chickpea genotypes under summer conditions. The short-duration crop recorded substantially reduced grain yield, though with wide genotypic variation ranging from 77 – 651 kg ha⁻¹. Genotypes JG-14 and IPC 06–11 consistently achieved the highest yields (> 540 kg ha⁻¹), primarily due to a higher number of seeds per plant. Reproductive efficiency of the summer crop was impaired, with a mean pollen viability of 63% and pollen germination of 31%. However, JG-14, IPC 06–11 and ICE-15654-A maintained > 70% pollen viability and > 40% pollen germination, coupled with cooler canopy temperatures and relative water content exceeding 60%, indicating superior physiological resilience. Correlation analysis revealed strong negative associations between phenological traits (days to flowering, maturity and reproductive duration) and grain yield, while elevated temperatures during both vegetative and reproductive phases further suppressed productivity. Stability analyses identified JG-14 as the most stable and high-yielding genotype across environments, whereas IPC 06–11 and ICE-15654-A performed comparatively better under relatively cooler and more humid spring conditions. Overall, the study highlights considerable genotypic variability, with JG-14, IPC 06–11 and ICE-15654-A emerging as promising candidates for summer chickpea cultivation in the semi-arid tropics. Further evaluation of a broader germplasm base is warranted to identify lines with stable yield performance under resource-limited summer environments.

Blackgram (Vigna mungo) is an important pulse crop grown mainly under rainfed and partly under irrigated conditions in the North Interior Karnataka region of the Deccan Plateau of India. However, rising temperatures and unpredictable rainfall patterns due to climate change pose a significant threat to its consistent performance and productivity. To assess the effect of projected climates (2021–2040) on blackgram productivity in the region, the DSSAT-CROPGRO model was used, which was calibrated and validated using experimental data recorded at the MULLaRP Scheme, University of Agricultural Sciences, Dharwad, India during the year 2022. The study considered two predominant soil types: black clay and red sandy soils across the study area. Under future climates, blackgram yield in the region is projected to decrease by 19.7% on black clay soils and up to 32.0% on red sandy soils compared to the current climate (2011–2020) period under rainfed situations. Among the 12 districts studied, the highest yield reduction under the projected climate was observed in Gadag (51.5% and 69.2%, respectively, in black clay and red sandy soils), followed by Haveri (43.7% and 56.2%, respectively, in black clay and red sandy soils).

Water stress considerably impairs rice growth and reduces grain yield. Brassinolide (BR) can mitigate the detrimental impacts of various stresses on rice growth. However, the effects of BR on rice root growth under water stress have yet to be studied. This research investigated the impacts of BR application on root morphological and physiological traits, nitrogen accumulation and utilisation, photosynthesis and grain yield in rice subjected to water deficiency. A pool experiment was conducted with two irrigation regimes, namely, continuous watering (W) and water deficit (D) conditions, and four BR concentrations, namely, 0 (B0), 0.1 (B1), 1 (B2) and 5 (B3) μmol L⁻¹, over 2 years. Under the W regime, the application of BR increased the grain yield by 9.6%–54.2% compared with that under WB0. At the same BR level, the grain yield under the D treatment was significantly lower than that under the W treatment. However, compared with DB0, BR application at 0.1 μmol L⁻¹ significantly increased the length, surface area, volume, diameter, activity and total and active absorbing area of the roots; increased the activities of nitrate reductase and glutamine synthetase in the roots; and promoted nitrogen accumulation and utilisation and photosynthesis. Compared with DB0, DB1 resulted in a significantly greater rice yield, with an increase of 67.2%–68.4%. Moreover, the grain yield of DB1 was significantly greater than that of WB0. The grain yield of DB2, which was significantly greater than that of DB0, was similar to that of WB0. DB3 did not result in any yield improvement over DB0. These results suggest that the application of BR at a low concentration promotes the morphological and physiological traits of rice roots under water-deficient conditions, thereby increasing nitrogen uptake, use efficiency and grain yield.

High temperatures during the rice panicle initiation stage can easily lead to yield loss. Although exogenous trehalose has been shown to significantly improve plant tolerance to abiotic stresses, its application in rice remains limited. Therefore, in this study, pot experiments were conducted using two rice varieties with differing heat tolerance to investigate whether exogenous trehalose could alleviate heat stress during the panicle initiation stage and to elucidate the underlying physiological mechanisms. The results demonstrated that exogenous trehalose significantly increased rice yield under high-temperature conditions. In the experiment in 2023, the maximum yield increases for N22 and YR343 were 89.5% and 110.3%, respectively, while in 2024, the increases were 89.2% and 111.6%, respectively. The optimal concentration for exogenous trehalose application was found to be 15 mmol L⁻¹. The yield improvement was primarily attributed to the synergistic effects of exogenous trehalose, which not only enhanced leaf photosynthetic capacity but also improved the activity of key carbohydrate metabolism enzymes, up-regulated the expression of sucrose transporter genes, and enhanced sucrose utilisation in young panicles. Additionally, it elevated endogenous trehalose levels, increased the accumulation of osmoregulatory compounds, and enhanced antioxidant enzyme activity, while reducing membrane lipid peroxidation. Furthermore, the regulation of hormone metabolism contributed to improved high-temperature tolerance in rice. In conclusion, the application of trehalose may provide an effective strategy for mitigating high-temperature damage during the rice panicle initiation stage.