Search Results (91)

High nighttime temperature (HNT) due to asymmetric diurnal warming threatens wheat productivity. This study evaluated the effect of HNT on wheat phenology, physiology, and yield through field and controlled environment experiments in Central Queensland, Australia. Two wheat genotypes, Faraday and AVT#6, were assessed under three sowing dates—1 May (Early), 15 June (Mid), and 1 August (Late)—within the recommended sowing window for the region. In a parallel growth chamber study, the plants were exposed to two nighttime temperature regimes, of 15 °C (normal) and 20 °C (high), with consistent daytime conditions from booting to maturity. Late sowing resulted in shortened vegetative growth and grain filling periods and increased exposure to HNT during the reproductive phase. This resulted in elevated floret sterility, lower grain weight, and up to 40% yield loss. AVT#6 exhibited greater sensitivity to HNT despite maturing earlier. Leaf gas exchange analysis revealed increased nighttime respiration (Rn) and reduced assimilation (A), resulting in higher Rn/A ratio for late-sown crops. The results from controlled environment chambers resembled trends of the field experiment, producing lower grain yield and biomass under HNT. Cumulative nighttime hours above 20 °C correlated more strongly with yield losses than daytime heat. These findings highlight the need for HNT-tolerant genotypes and optimized sowing schedules under future climate scenarios. Full article

Under the scenario of global climate warming, meteorological risks affecting sunflower cultivation in Xinjiang’s 10th Division were investigated by developing a meteorological-growth coupling model. Field experiments were conducted at three representative stations (A1–A3) during 2023–2024 to assess temperature and precipitation impacts on yield and quality traits among sunflower cultivars with varying maturation periods. The main findings were: (1) Early-maturing cultivar B1 (RH3146) exhibited superior adaptation at low-temperature station A1, achieving 12% higher plant height and an 18% yield increase compared to regional averages. (2) At thermally variable station A2 (daily average temperature fluctuation ± 8 °C, precipitation CV = 25%), the late-maturing cultivar B3 showed enhanced stress resilience, achieving 35.6% grain crude fat content (15% greater than mid-maturing B2) along with 8–10% increases in seed setting rate and 100-grain weight. These improvements were potentially due to optimized photoassimilated allocation and activation of stress-responsive genes. (3) At station A3, characterized by high thermal-humidity variability (CV > 15%) during grain filling, B3 experienced a 15-day delay in maturation and a 3% reduction in ripeness. Two principal mitigation strategies are recommended: preferential selection of early-to-mid maturing cultivars in regions with thermal-humidity CV > 10%, improving yield stability by 23%, and optimization of sowing schedules based on accumulated temperature-precipitation modeling, reducing meteorological losses by 15%. These evidence-based recommendations provide critical insights for climate-resilient cultivar selection and precision agricultural management in meteorologically vulnerable agroecosystems. Full article

Mungbean is grown as a summer crop in subtropical climates globally. The global demand for mungbean is increasing, and opportunities exist to expand production regions to more marginal environments, such as southern Australia, as an opportunistic summer crop to help meet the growing global demand. Mungbean has the potential to be an opportunistic summer crop when an appropriate sowing window coincides with sufficient soil water. This expansion from subtropical to temperate climates will pose challenges, including low temperatures, a longer day length and a low and variable water supply. To assess mungbean suitability to temperate, southern Australian summer rainfall patterns and soil water availability, we conducted field experiments applying a range of water treatments across four locations with contrasting rainfall patterns within the state of Victoria (in southern Australia) in 2020–2021 and 2021–2022. The water treatments were applied prior to sowing (60 mm), the vegetative stage (40 mm) and the reproductive stage (40 mm) in a factorial combination at each location. Two commercial cultivars, Celera II-AU and Jade-AU, were used. Water scarcity during flowering and the pod-filling stages were important factors constraining yield. Analysis of yield components showed that increasing water availability at critical growth stages, viz. the vegetative and reproductive stages, of mungbean was associated with increases in total biomass, HI and grain number in addition to increased water use and water use efficiency (WUE). Average WUEs ranged from 1.3 to 7.6 kg·ha⁻¹·mm⁻¹. The maximum potential WUE values were 6.4 and 5.1 kg·ha⁻¹·mm⁻¹ for Celera II-AU and Jade-AU across the sites, with the estimated soil evaporation values (x-intercept) of 83 and 74 mm, respectively. Nitrogen fixation was variable, with %Ndfa values ranging from 9.6 to 76.8%, and was significantly affected by soil water availability. This study emphasises the importance of water availability during the reproductive phase for mungbean yield. The high rainfall zones within Victoria have the potential to grow mungbean as an opportunistic summer crop. Full article

In light of current global challenges of climate change, the over-exploitation of natural resources, and increasing demand for livestock products, the exploration of excellent forage crop resources holds great potential for development. Therefore, selecting forage crops that are high-yield, high-quality, and have excellent resistance to pests and diseases can greatly promote the development of the livestock industry. Oat (Avena sativa L.), a dual-purpose crop for grain and forage, plays a vital role in the development of animal husbandry. Autumn-sown oats have a significantly longer growth cycle than spring-sown oats, ensuring a year-round forage supply and achieving higher yields. The agropastoral transitional zone in southwest China is a key region for autumn-sown oats, but the systematic evaluation of oat germplasm there is still limited. Therefore, we conducted a two-growing-season (2022–2024) field experiment across four locations to evaluate nine oat genotypes for growth phenotypes, forage productivity, and nutritional quality through 11 agronomic traits and nutritional parameters during the filling stage (Zadok’s 75). The results revealed the following: (1) agronomic performance: dry matter yield (DMY) ranged from 10.72 to 14.58 t/ha, with line ‘WC109’ achieving the highest DMY (14.58 t/ha) and crude protein (CP, 9.66%); (2) nutritional quality: CP exhibited a significant negative correlation with fiber content (NDF: r = −0.72, p < 0.01; ADF: r = −0.68, p < 0.01), highlighting a yield–quality trade-off; ‘WC109’ demonstrated superior forage value, with the highest relative forage quality (RFQ: 115.45) and grading index (GI: 19.30); (3) environmental adaptation: location-specific climatic conditions significantly influenced productivity, with Wenjiang (WJ) showing optimal performance due to favorable temperature and precipitation. These results position ‘WC109’ as a promising candidate for autumn-sown cultivation in southwest China, addressing winter forage shortages while enhancing livestock nutrition. Our findings further elucidate the mechanisms linking yield and feeding value to growth performance indicators, providing references for trait-based measures to enhance forage oat productivity and quality. Full article

Tartary buckwheat is an important characteristic multigrain crop, mainly planted in Sichuan, Guizhou, Yunnan and Tibet, and other alpine and remote ethnic mountainous areas. In order to clarify the effect of sowing date on the yield and quality of Tartary buckwheat and its relationship with meteorological factors The variety Jinqiao No. 2 was used for a two-year trial at Dingxiang Test Base in Shanxi Province on four sowing dates (15 June, 26 June, 6 July and 17 July 2022 and 19 June, 30 June, 10 July and 21 July 2023) starting from the bud stage. Responses to sowing date were investigated by examining the growth period structure, yield, yield component, quality, and their relationship to climatic factors. The results showed that meteorological factors during the grain grain-filling stage were different when the sowing date was different. Compared with other sowing times, the treatment with the sowing of early and mid-July had less than 13.5~27.9 h of sunshine, less than 28.8~48.5 mm of rainfall, more than 10.5~19 days of ≤15 °C days, but the most serious low-temperature stress (≤15 °C days up to 27 days). The yield of sowing in July was 69.8~77.0% and 69.9~79.1% lower than that of sowing in June in 2022 and 2023 respectively, and the later sowing had a lower yield. Delayed sowing is beneficial to the accumulation of flavonoids and protein in Tartary buckwheat grains, and the average value in 2022 and 2023 is 11.55% and 14.64% higher than that in the first sowing, but the content of fat and starch is significantly reduced. The result of path analysis showed that the low temperature (≤15 °C days up to 27 days) and less solar radiation duration were the key points for attaining high yield and quality, due to the mean daily temperature and ≤15 °C days from flowering to maturity had negative effect on 1000-seed weight, seed setting rate, starch and crude lipid content of Tartary buckwheat, and the direct effect of sunshine duration on the content of protein and flavonoid in Tartary buckwheat was the greatest. The yield of Tartary buckwheat sown in June was higher than that of other treatments, because of avoiding low-temperature stress and long rainy and sunless weather during the grain filling stage, which enabled the blossoming and grain filling normally and finally attained higher yield. Full article

Understanding the spatial–temporal distribution of photosynthetically active radiation (PAR) within crop canopies is crucial for optimizing planting structures to enhance resource use efficiency and improve crop yields. While high planting densities are commonly employed to increase yields, this practice can lead to issues such as early leaf senescence and reduced biomass. This study investigates the impact of varying planting densities on PAR dynamics, canopy structure, and yield formation in maize over two years. Key findings include the following: (1) higher planting density significantly increased grain yield, biological yield, and LAI, although HI decreased; (2) canopy light distribution varied with planting density, with the middle layers intercepting the most light, particularly during the grain filling stage; (3) a density of 83,000 plants·ha⁻¹ was the most efficient for maximizing yield and WUE, although high accumulated temperatures negatively impacted yields. These results suggest that adjusting planting density can enhance resource use efficiency in maize farming, particularly in regions with variable water availability and climate challenges. Future research should explore the long-term effects of planting density on soil health, water use efficiency, and crop resilience under varying environmental conditions. Additionally, studies integrating precision agriculture technologies to fine-tune planting density and water management in response to climate change are essential for ensuring sustainable maize production and food security in the future. Full article

There are many factors affecting rice yield and quality during cultivation, including temperature, light, water, and fertilization, among which high temperature (HT) is one of the main factors affecting rice yield and quality. However, less is known about the effects and potential mechanisms of different durations of HT stress during the grain filling stage on grain quality. In this study, the differences in rice quality and starch rapid viscosity analyzer (RVA) characteristics of eight indica rice varieties under different high-temperature treatment times were studied by simulating high temperature in an artificial climate chamber. The prolonged duration of HT leads to an overall deterioration in the milling quality, appearance quality, and cooking quality of rice. The impact of HT duration on the starch RVA characteristics of rice is more complex and is mainly related to the varieties. Among them, the starch RVA characteristics of R313 were more stable. It is worth noting that there is a significant difference in the sensitivity of the appearance quality of 8XR274 and 5W0076 to HT duration, with 8XR272 being more sensitive and 5W0076 being the opposite. We selected these two varieties for transcriptome analysis after 14 days of HT treatment and found that the number of differentially expressed genes (DEGs) in 8XR274 was significantly less than that in 5W0076. The DEGs of 8XR274 were mainly enriched in pathways related to carbohydrates, while 5W0076 was mainly enriched in pathways related to photosynthesis. Our study provides a new perspective on the molecular response and related genes of different rice varieties under high temperature, as well as the high-quality rice breeding under high temperature. Full article

The trend of global warming is becoming increasingly evident, with frequent extreme high-temperature events posing a severe challenge to food security. Rice (Oryza sativa L.), the world’s primary food crop, is highly susceptible to the adverse effects of high-temperature stress throughout its growth cycle. High temperatures, defined as ambient temperatures exceeding 35 °C during reproductive stages and 33 °C during vegetative stages, can impair seed germination, reduce tillering, disrupt pollination, and diminish grain quality. Notably, heat stress during the grain-filling stage accelerates grain maturation, leading to increased chalkiness, a higher degree of chalky formation, deteriorated cooking and eating quality, and decreased grain weight. To cope with high-temperature stress, rice activates a series of complex physiological and biochemical responses, including heat-related signaling pathways and transcriptional regulatory networks. Although some agronomic practices and genetic improvement methods have been developed to enhance rice’s heat tolerance, the regulatory mechanisms of rice’s response to high-temperature stress, especially the molecular mechanisms during the grain-filling stage, remain poorly understood. This review identifies knowledge gaps in understanding rice’s response mechanisms, emphasizing molecular pathways during the grain-filling stage and provides an outlook on future rice high-temperature defense measures. Full article

In response to the current key issues in the field of smart irrigation for farmland, such as the lack of data sources and insufficient integration, a low degree of automation in drive execution and control, and over-reliance on cloud platforms for analyzing and calculating decision making processes, we have developed nodes and gateways for smart irrigation. These developments are based on the EC-IOT edge computing IoT architecture and long range radio (LoRa) communication technology, utilizing STM32 MCU, WH-101-L low-power LoRa modules, 4G modules, high-precision GPS, and other devices. An edge computing analysis and decision model for smart irrigation in farmland has been established by collecting the soil moisture and real-time meteorological information in farmland in a distributed manner, as well as integrating crop growth period and soil properties of field plots. Additionally, a mobile mini-program has been developed using WeChat Developer Tools that interacts with the cloud via the message queuing telemetry transport (MQTT) protocol to realize data visualization on the mobile and web sides and remote precise irrigation control of solenoid valves. The results of the system wireless communication tests indicate that the LoRa-based sensor network has stable data transmission with a maximum communication distance of up to 4 km. At lower communication rates, the signal-to-noise ratio (SNR) and received signal strength indication (RSSI) values measured at long distances are relatively higher, indicating better communication signal quality, but they take longer to transmit. It takes 6 s to transmit 100 bytes at the lowest rate of 0.268 kbps to a distance of 4 km, whereas, at 10.937 kbps, it only takes 0.9 s. The results of field irrigation trials during the wheat grain filling stage have demonstrated that the irrigation amount determined based on the irrigation algorithm can maintain the soil moisture content after irrigation within the suitable range for wheat growth and above 90% of the upper limit of the suitable range, thereby achieving a satisfactory irrigation effect. Notably, the water content in the 40 cm soil layer has the strongest correlation with changes in crop evapotranspiration, and the highest temperature is the most critical factor influencing the water requirements of wheat during the grain-filling period in the test area. Full article

High temperatures have adverse impacts on the photosynthetic efficiency and yield of many crop plants. This study investigated how high temperatures affect the photosynthetic efficiency parameters and chloroplast ultrastructure of three edamame cultivars (AGS354, UVE17, and UVE14) at the reproductive stages (flowering and pod-filling). Heat stress (HS) treatments were performed under controlled conditions in climate chambers set at 25/18 °C (control), 30/23 °C (HS-I), and 35/28 °C (HS-II). The AGS354 cultivar exhibited the greatest susceptibility under HS-II treatment, characterised by a reduction in the photochemical reactions, decreased chlorophyll-a (chl-a) and carotenoid accumulation, the highest increase in the starch grain traits, and reduced plastoglobule and grana area traits. In UVE 14 and UVE17, the HS-II treatment enhanced chl-a and chl-b accumulation. Elevated carotenoid levels in UVE14 and UVE17 likely protected chlorophyll from degradation and mitigated photooxidative damage. The HS-II treatment also enhanced the grana traits, supporting improved light-harvesting capacity during heat stress in UVE14 and 17. However, heat stress disrupted the photochemical reactions (quantum efficiency of photosystem II, performance index absorbance, and performance index), indicating that elevated carotenoids alone do not exhibit complete tolerance to heat stress. Since plastoglobules play an essential in carotenoid biosynthesis, increased or stabilised plastoglobule traits in UVE14 and UVE17 under HS-II treatment strongly indicate improved heat stress tolerance. Overall, UVE14 and UVE17 emerged as the most heat-tolerant cultivars, with AGS354 being the most susceptible. These findings provide valuable insights into heat stress adaptation mechanisms and suggest the UVE14 and UVE17 cultivars as potential candidates for breeding heat-tolerant edamame cultivars. Full article

Chalkiness in rice is adversely affected by high temperatures during the flowering and grain-filling stages. Potassium (K) is essential for improving grain quality and heat resilience. The effects of split application K fertilizer on rice chalkiness under high temperatures during the flowering and grain-filling stages were investigated in this study. Four treatments, including ambient temperatures with basal K fertilizer (AT-K1), high temperatures with basal K fertilizer (HT-K1), high temperatures with 70% K pre-transplanting and 30% K at the heading stage (HT-K2), and high temperatures with 30% K pre-transplanting and 70% K at the heading stage (HT-K3), were conducted. The results revealed that the chalky grain rate and chalkiness degree were reduced by 9.2–13.72% and 12.16–19.91%, respectively, by the split application of K fertilizer through effectively modulating the sucrose-to-starch conversion process in the rice grains, relative to the single basal application of K fertilizer under high temperatures. Specifically, the split application of K fertilizer reduced the enzymatic activities of SuSy, ADPGase, and SBE by 3.17–34.20% at 5–10 DAA, and GBSS and SSS by 6.48–13.50% at 5 DAA, but enhanced them by 5.50–54.90% from 15 DAA and 2.07–97.10% from 10 DAA. Similarly, the gene expression levels of enzymes involved in this process were decreased by 3.52–24.12% at 5 DAA but increased by 8.61–30.00% at 20 DAA by the split application of K fertilizer. This modulation led to a retardation in the excessive accumulation of starch during the early grain-filling stage but a higher starch accumulation rate during the middle and later stages, combined with a longer duration of starch accumulation, ultimately resulting in higher starch accumulation and reduced rice chalkiness. These results suggest that the application of K fertilizer during the heading stage is effective in compensating the deterioration of rice chalkiness by high temperatures. Full article

Exposure to high temperatures can impair the grain-filling process in rice (Oryza sativa L.), potentially leading to the formation of chalky endosperm, but the molecular regulation mechanism remains largely elusive. Here, we reported that high-temperature (HT) stress (day/night, 35 °C/30 °C) reduces both the grain-filling rate and grain weight of Ningjing 1 variety compared to normal temperatures (NT, day/night, 28 °C/23 °C). Grains under HT stress exhibited an opaque, milky-white appearance, alongside significant alterations in starch physicochemical properties. An integrated transcriptomic analysis of grains under HT revealed up-regulation of genes related to defense mechanisms and oxidoreductase activity, while genes involved in sucrose and starch synthesis were down-regulated, and α-amylase genes were up-regulated. Proteomic analysis of grains under HT echoed this pattern. These results demonstrate that high temperature during the grain-filling stage significantly increases rice chalkiness by down-regulating genes related to sucrose and starch synthesis, while up-regulating those involved in starch degradation. Full article

The Juruena Mineral Province is an emerging world-class mineral province in the southern Amazonian Craton, due to numerous Au-Cu and base metal deposits, such as the Raimunda deposit, related to Novo Mundo 2.03–1.98 Ga I-type calc-alkaline granites. Its hydrothermal alteration zones comprise Na-metasomatism, microclinization, propylitic and sericitic alteration, silicification, a sulfide stage, and late carbonate alteration. The disseminated mineralization, associated with the sulfide stage, the main mineralization stage, is represented by gold inclusions and fracture-filling grains in pyrite, chalcopyrite, and Cu-Bi sulfides. Chlorite geothermometer and fluid inclusion data indicate temperature conditions of 325–380 °C for the mineralization. The coexistence of high-temperature aqueous and aqueous-carbonic fluid inclusions, based on a microthermometric study of fluid inclusions, reveals a mixing of medium-saline hot fluids with cooler and low-saline fluid. The δ¹⁸O_fluid (3.11–7.86‰) and δ³⁴S_py data (−1.4–0.1‰) are coherent to the magmatic origin of the mineralizing fluid. Gold was initially transported as chlorine complexes in a hot, high-salinity, acidic, and oxidized fluid from the magma chamber, and later as H₂S⁻ complexes. The chemical-physical instability during fluid ascent is interpreted as a triggering factor for ore precipitation. The results offer valuable insights into the genesis of porphyry–Au deposits and their implications for prospecting in the Amazonian Craton. Full article

High-temperature (HT) stress frequently affects the early and middle stages of grain filling in hybrid seed production regions. Photo-thermo-sensitive male-sterile (PTMS) wheat lines, which play a critical role as female parents in hybrid seed production, face challenges under HT conditions. However, the mechanisms governing grain filling in PTMS lines under HT stress remain poorly understood. This study used the BS253 line to investigate the effects of HT on grain filling, primarily focusing on the transition from sucrose unloading to starch synthesis. The findings indicated that HT significantly reduced the grain starch content and weight by 7.65% and 36.35% at maturity, respectively. Further analysis revealed that the expression levels of TaSUT1 and TaSWEETs in grains initially increased after HT stress, paralleling the rise in sucrose content during the same period. The activities of ADP-glucose pyrophosphorylase, UDP-glucose pyrophosphorylase, granule-bound starch synthase, and soluble starch synthase were markedly decreased, indicating that impaired starch synthesis was a key factor limiting grain filling immediately after HT exposure. A total of 41 key regulatory genes involved in sucrose-to-starch metabolism were identified, with HT significantly reducing the expression of genes associated with pathways from sucrose unloading to starch synthesis during the middle and late stages post-HT. Based on the observed ultrastructural changes in the abdominal phloem and sucrose transporter expression levels under HT, we concluded that limited sucrose supply, degradation, and inhibition of starch synthesis collectively constrained grain filling during these stages. Additionally, 11 heat shock proteins and two catalase genes were identified and significantly upregulated during the initial phase post-HT, suggesting their potential role in enhancing sucrose supply at this critical time. More importantly, seven key genes involved in the sucrose-to-starch pathway were identified by weighted gene co-expression network analysis (WGCNA), which provides target genes for their functional research for starch synthase. These findings provide a comprehensive understanding of how HT limits grain filling, identify several genes involved in the sucrose-to-starch pathway, and offer a novel perspective for future research on HT-restricted grain filling across the entire process from sucrose unloading to starch synthesis in developing grains. Full article

It is a consensus that Earth’s climate has been warming. The impact of global warming is asymmetric, that is, there is more substantial warming in the daily minimum surface air temperature and lower warming in the maximum surface air temperature. Previous studies have reported diurnal temperature differences greatly affecting winter wheat yield. However, only a few studies have investigated the impact of global warming on the growth and yield of winter wheat, yet the influence of night warming on quality has not been deeply evaluated. In this study, two wheat cultivars were used as materials: Jimai 44 (JM44) with strong gluten and Jimai 22 (JM22) with medium gluten, to explore the effects of high nighttime temperatures (HNTs) on the growth, yield, and quality of wheat. The results show that HNTs significantly shortened seedling emergence and anthesis periods in both cultivars compared with ambient temperatures (ATs). In addition, HNTs increased the respiration rate at anthesis and grain-filling stages, impeding wheat pollination and grain maturity. HNTs also accelerated leaf senescence and increased the number of sterile spikelets and plant height, but decreased the effective tiller number, the number of spikes per unit area, and grains per spike. As a result, the grain yield of JM22 and JM44 was decreased by 24.6% and 21.2%, respectively. Moreover, HNTs negatively influenced the flour quality of the two wheat cultivars. The current findings provide new insights into the effects of HNTs on the growth, development, yield, and quality of different wheat genotypes during the whole growth period. Full article