Journal of Agronomy and Crop Science最新文献

The crop productivity in rainfed regions is driven by the quantum and distribution of rainfall during the crop growth period. The dry spell index (DSI) was used in the present investigation to quantify the cumulative impact of dry spells on major rainfed crops of the kharif season (June–September) in India's semi-arid regions of Andhra Pradesh. The effect of DSI on the yield of major rainfed crops, i.e., groundnut, pigeon pea, cotton, maize and pearl millet was estimated and compared with the widely used standard precipitation index (SPI). Our results revealed that among the various districts, a higher DSI (> 16.1) was noticed in Anantapur that experienced a DSI of 8.1–16.0 in 77% of the years during the study period (1998–2019), which indicated that the crop suffered stress conditions during the season affecting the crop yields. Moreover, a significant negative correlation was observed between the yields of various crops (groundnut, pigeon pea, maize and pearl millet) and DSI. On the other hand, SPI analysis showed that 74%–83% of the years experienced normal (−0.99 to 0.99) to moderately dry (−1.00 to −1.49) conditions, indicating normal rainfall status during the season. At the same time, no significant correlation was found between the SPI and crop yields. Therefore, the present study revealed that the DSI performed better in quantifying the dry spells and their impact on crop yields, especially under rainfed conditions in the semi-arid regions of south-east India.

The increasing concentrations of ground-level ozone (O₃) resulting from industrialisation and anthropogenic activities present a substantial environmental threat to agricultural productivity, particularly affecting O₃-sensitive crops such as soybeans. The effects of acute O₃ exposure on soybean yield attributes and seed quality and whether soybean showed different detoxification mechanisms in response to moderate and severe O₃ stress are not extensively explored. In this study, soybean seedlings were exposed to moderate (80 nmol mol⁻¹) and acute severe (200 nmol mol⁻¹) O₃ stress, and then growth parameters, yield attributes, reactive oxygen species (ROS) levels, enzymatic and non-enzymatic antioxidant properties and associated gene expression in the leaves were assessed. The results revealed that moderate O₃ exposure enhanced growth parameters but reduced the 100-grain weight, while acute severe exposure sharply depressed growth parameters, yield attributes and the 100-grain weight. Moderate O₃ fumigation significantly increased hydrogen peroxide (H₂O₂) levels and catalase (CAT) activity from 4 to 32 h. Acute severe O₃ stress induced the overproduction of superoxide anions (O₂^.−) and H₂O₂ during nearly the whole experiment period, but only enhanced superoxide dismutase (SOD) activity at 32 h, and showed no stimulatory effects on CAT activity. Additionally, the relative expression levels of the SOD and CAT gene family in soybean leaves exposed to elevated O₃ were upregulated, peaking at 8 h. Moderate O₃ treatment enhanced reduced glutathione (GSH) and ascorbate (AsA) levels and increased the activities of AsA–GSH cycle-related enzymes. In contrast, acute severe O₃ exposure inhibited GSH and AsA contents and markedly suppressed AsA–GSH cycle-related enzymes, particularly from 8 to 32 h. Redundancy analysis indicated that CAT and AsA play crucial roles in scavenging O₃-induced ROS under moderate stress, while ascorbate peroxidase (APX) and GSH were more effective under acute severe stress conditions. These findings provide insights into the differential impacts of acute O₃ stress on soybeans, emphasising the importance of considering both crop yield and grain quality in assessing O₃ risks to crops.

Globally, climate changes have significantly shifted the phenological phases and stages of rice, altered the duration of the growing season and negatively affected rice productivity due to flooding and drought. However, in the present study, the positive and negative impacts of inter-annual climate variability on rice crops during phenological stages in agro-climatic zones of Punjab for the period from 1989 to 2018. Initially, first difference approach was applied to minimise the impact of technological factors. Then, skewness and kurtosis tests were used to check the normalisation of the data. The standardisation method was used to normalise the data. Pearson correlation was used to determine the significant effects of climate variables on rice yield. The residuals were formed to confirm the effects of inter-annual climate variability on rice yield in the phenological phases. The analysis revealed that a high variability of rice yields was investigated in the western region compared to the southern and western regions. The results showed a negative impact of heavy rainfall (flooding) on the years with low yields (2010, 2013 and 2016) in the Central region. Similarly, the years with low rice yields (1996, 2010, 2013 and 2014) in the Southern region were negatively affected by flooding at the time of sowing. A positive effect of rainfall was observed in the years with high rice yields (1995, 2002, 2009 and 2018) in the Western region. In contrast, the low-yielding years 1994, 2003 and 2010 were negatively affected by flooding in the same years during the tillering stage. A high interannual maximum temperature variability was analysed in the Southern > Western > Central regions, leading to yield losses due to biotic stress during tillering and stem elongation stages. This is due to the immense reason of drought stress. The minimum temperature negatively affects the low-yield years (2001, 2008, 2013 and 2016) in the central zone and the low-yield years (2014, 2015 and 2016) in the southern zone during the reproductive stage. This research will help to develop new rice varieties that are more productive at high temperatures and require less water, leading to sustainable development in arid and semi-arid regions.

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.