Rice Crop Research Articles

Synthesis, antifungal evaluation, two-dimensional quantitative structure-activity relationship and molecular docking studies of isoxazole derivatives as potential fungicides.

Sheath blight and bakanae disease, prominent among emerging rice ailments, exert a profound impact on rice productivity, causing severe impediments to crop yield. Excessive use of older fungicides may lead to the development of resistance in the pathogen. Indeed, a pressing and immediate need exists for novel, low-toxicity and highly selective fungicides that can effectively combat resistant fungal strains. A series of 20 isoxazole derivatives were synthesized using alkoxy/halo acetophenones and N,N-dimethylformamidedimethylacetal. These compounds were characterized by various spectroscopic techniques, namely 1H nuclear magnetic resonance (NMR), 13C NMR and liquid chromatography-high-resolution mass spectrometry, and were evaluated for their fungicidal activity against Rhizoctonia solani and Fusarium fujikuroi. Compound 5n (5-(2-chlorophenyl) isoxazole) exhibited highest activity (effective dose for 50% inhibition [ED50] = 4.43 μg mL-1) against R. solani, while 5p (5-(2,4-dichloro-2-hydroxylphenyl) isoxazole) exhibited highest activity (ED50 = 6.7 μg mL-1) against F. fujikuroi. Two-dimensional quantitative structural-activity relationship (QSAR) analysis, particularly multiple linear regression (MLR) (Model 1), highlighted chi6chain and DistTopo as the key descriptors influencing fungicidal activity. Molecular docking studies revealed the potential of these isoxazole derivatives as novel fungicides targeting sterol 14α-demethylase enzyme, suggesting their importance as crucial intermediates for the development of novel and effective fungicides. All test compounds were effective in inhibiting both fungi, according to the QSAR model, with various descriptors, such as structural, molecular shape analysis, electronic and thermodynamic, playing an important role. Molecular docking studies confirmed that these compounds can potentially replace commercially available fungicides and help control fungal pathogens in rice crops effectively. © 2024 Society of Chemical Industry.

Effects of Grain Sprout Fertilizer Application Rate on Yield and Its Composition of Hybrid Middle Rice–Ratoon Rice System

Enhancing yield and achieving environmental goals represent challenges for the future of agriculture. Rational nitrogen (N) management is one of the most promising ways to meet this challenge. However, complicated nitrogen management strategies and considerable input requirements still exist in rice–ratoon rice production. To address this issue, field experiments were conducted with two main high-yield rice crop genotypes and five fertilization treatments at six sites in Southwest China from 2018 to 2020. The results showed the following: (1) the yield of the main rice crop was extremely significantly affected by the year, location, and fertilization, but not by genotype; (2) the yield of the ratoon rice was extremely significantly affected by year, genotype, location, and fertilization; and (3) the total plant N content (TPN) and leaf SPAD value at the full heading stage of the main crop were significantly positively correlated with the total soil N content (TSN) and soil available N (SAN) content of the basic soil. The highly efficient N application rate of grain- and bud-promoting fertilizer for ratoon rice was 60–120 kg ha−1. The TSN, SAN, TPN, and SPAD values higher than 0.247 kg N kg−1, 298 mg N kg−1, 2.159 kg N kg−1, and 49.94 were, respectively, considered the reference values when not applying grain- and bud-promoting fertilizer. A regression equation was established to predict the amount of high-efficiency grain- and bud-promoting fertilizer based on the TSN and SPAD. Overall, the yield of rice–ratoon rice was significantly affected by year, genotype, location, fertilization, and their interactions. The use of the predicted grain- and bud-promoting fertilizer regression equation can achieve high yields under simplified and reduced N input practices in the rice–ratoon rice systems.

Effect of Planting Geometry and Inorganic Fertilizers with Nano Urea on Growth Indices of Rice Crop (Oryza sativa L.)

An experiment was conducted at Agronomy Research Farm of Acharya Narendra Deva University of Agriculture and Technology, Kumarganj, Ayodhya, Uttar Pradesh, India during Kharif season 2022 and 2023 to find out the effect of planting geometry and inorganic fertilizers with nano urea on growth indices of rice crop. All the growth indices parameters viz. Crop growth rate (g m-2 day-1) Relative growth rate (g g-1 day-1x 10-3), Net Assimilation rate (g m-2 day-1) and yield were significantly higher with the treatment P1 (20 cm × 10 cm) and F2 [100% RDF + foliar spray of nano urea @ 3000 ml ha-1(Tillering and Panicle initiation stage)] at par with treatment combination P1 (20 cm × 10 cm) and F3 [75% RDF + foliar spray of nano urea @ 3000 ml ha-1(Tillering and Panicle initiation stage)] and significantly higher than the other treatments. It can be concluded that treatment C1 (20 cm × 10 cm) with the application of F2 [100% RDF + foliar spray of nano urea @ 3000 ml ha-1 (Tillering and Panicle initiation stage)] proved better during both the year for all growth indices to achieve higher yield and remuneration of rice crop.

The role of OsBZR4 as a brassinosteroid-signaling component in mediating atrazine and isoproturon degradation in rice

Development of a biotechnological system for rapid degradation of pesticides is important to mitigate the environmental, food security, and health risks that they pose. Degradation of atrazine (ATZ) and isoproturon (IPU) in rice crops promoted by the brassinosteroid (BR) signaling component BRASSINAZOLE RESISTANT4 (OsBZR4) is explored. OsBZR4 is localized in the plasma membrane and nucleus, and is strongly induced by ATZ and IPU exposure. Transgenic rice OsBZR4-overexpression (OE) significantly enhances resistance to ATZ and IPU toxicity, improving growth, and reducing ATZ and IPU accumulation (particularly in grains) in rice crops. Genetic destruction of OsBZR4 (CRISPR/Cas9) increases rice sensitivity and leads to increased accumulation of ATZ and IPU. OE plants promote phase I, II, and III metabolic reactions, and expression of corresponding pesticide degradation genes under ATZ and IPU stress. UPLC-Q-TOF-MS/MS analysis reveals increased relative contents of ATZ and IPU metabolites and conjugates in OE plants, suggesting an increased OsBZR4 expression and consequent detoxification of ATZ and IPU in rice and the environment. The role of OsBZR4 in pesticide degradation is revealed, and its potential application in enhancing plant resistance to pesticides, and facilitating the breakdown of pesticides in rice and the environment, is discussed.

Performance of basmati rice (Oryza sativa) under variable irrigation and nitrogen management

A field experiment was conducted during the rainy seasons (kharif) of 2021 and 2022 at research farm of ICAR- Indian Agricultural Research Institute, New Delhi to study the effect of irrigation regimes and integrated use of prilled urea and nano-urea as a source of N, on productivity and profitability of basmati rice (Oryza sativa L.). The experiment was conducted in a three-time replicated split-plot design (SPD) comprised of 3 irrigation regimes, viz. irrigation at 1, 3 and 6 days after disappearance of surface water (DADSW) assigned to main-plots and 4 N-management variants including; 100% RDN (recommended dose of N, 120 kg/ha); 75% RDN + 4% nano-urea (NU) 2 sprays (75% RDN + 2 NU); 50% RDN + 2 NU; and no-N (control) in sub-plots. Irrigating basmati rice 1 DADSW exhibited the highest panicle weight (2.67–3.09 g) and number of grains/panicle (115.9, 109.8), across the years, respectively that were significantly higher than 3 and 6 DADSW. The most delayed irrigation at 6 DADSW caused significant reduction in grain yield, the magnitude of reduction was 13–19% over irrigation at 3 DADSW and substantially by 23–28% over 1 DADSW. Fertilizing rice crop with 100% RDN and 75% RDN + 2 NU resulted in statistically similar yield attributes and grain yield; however, both were, significantly superior to 50% RDN + 2 NU and no-N. Net returns, benefit cost (B:C) ratio and monetary efficiency were significantly higher when crop was irrigated 1 DADSW than 3 and 6 DADSW. The N-management options followed the trend as RDN>75% RDN + 2 NU ˃50% RDN > no-N for all studied economic parameters.

Effects of Sustainable Rice Management on the Behavior and Bioefficacy of Bispyribac-Sodium: A Medium-Term Study

The practices (tillage and flooding) used for rice crops are unsustainable, especially in areas characterized by water shortages, such as the Mediterranean region. Therefore, it is necessary to develop sustainable methods in order to ensure the viability of rice production. However, it is essential to understand the effects that alternative management can have on herbicide behavior. In this context, this paper describes the first field experiment conducted to evaluate the medium-term effects of different agricultural practices on the fate of bispyribac sodium (BPS). Thus, the treatments were as follows: tillage and flooding (TF), tillage and sprinkler (TS), and no-tillage and sprinkler (NTS). In addition, “alperujo” compost (AC) from olive mill waste was used in each treatment (TF-AC, TS-AC, and NTS-AC). The AC was applied only once in 2015 when the TS and NTS treatments were implemented. The AC amendment increased the adsorption of BPS and its irreversibility, thereby decreasing the BPS leaching capacity. Furthermore, throughout this study, the BPS persistence was up to 1.85 times greater with sprinklers than in the flooding condition, which could explain the high values of BPS effectiveness (increased by a factor of 1.45 on average) found with sprinklers. Therefore, the implementation of sprinklers in combination with AC can be considered a sustainable strategy for Mediterranean rice production, at least in the medium term, as it reduces BPS water pollution and increases its weed control efficiency.

Utilization of Rhodopseudomonas palustris in Crop Rotation Practice Boosts Rice Productivity and Soil Nutrient Dynamics

Using beneficial microorganisms, such as purple non-sulfur bacteria (PNSB), has shown enormous potential for improving plant growth and agricultural production. However, the full extent of their benefits and interactions with agricultural practices is yet to be fully understood. The present study aimed to investigate the use of PNSB in crop rotation practice, focusing on its impact on rice growth and yield. The experiment was conducted over two rice cropping seasons, with djulis grown between the rice as a rotation crop. The study shows that PNSB treatment increased the concentration of 5-aminolevulinic acid (5-ALA) in plants, indicating enhanced photosynthesis. Moreover, when combined with crop rotation, PNSB remarkably improved soil fertility. These combined benefits resulted in substantial increases in tiller numbers (163%), leaf chlorophyll content (13%), and lodging resistance (66%), compared to the untreated plants. The combined treatment also resulted in higher productive tillers per hill (112%), average grain per hill (65%), and grain fertility (26%). This led to increased grain yield (65%), shoot dry weight (15%), and harvest index (37%). The findings clearly suggest that the incorporation of PNSB in crop rotation strategies can significantly augment the growth and yield of rice crops. These insights, pivotal for sustainable rice cultivation, hold the potential to simultaneously tackle the pressing issues of global food security and climate change.

Anurans and their contribution to agriculture: a review

Anurans and their contribution to agriculture: a review

Phytocoenology Study of Weeds of Rice Crop with Edaphic Variation: An Analysis from Jhargram, West Bengal, India

Phytocoenology Study of Weeds of Rice Crop with Edaphic Variation: An Analysis from Jhargram, West Bengal, India

Resistance patterns and molecular basis to ACCase-inhibiting herbicides

Abstract Digitaria ciliaris var. chrysoblephara (Fig. & De Not.) R.R. Stewart is an annual xeromorphic weed that severely infests direct-seeded rice fields in China. Herbicide resistance is emerging in D. ciliaris var. chrysoblephara owing to extensive and recurrent use of the acetyl-CoA carboxylase (ACCase)-inhibiting herbicide metamifop. In this study, a total of 53 D. ciliaris var. chrysoblephara populations randomly sampled from direct-seeded rice fields across Jiangsu Province were investigated for metamifop resistance and potential resistance-endowing mutations. Single-dose assays revealed that 17 (32.1%) populations evolved resistance to metamifop and 5 (9.4%) populations were in the process of developing resistance. The resistance index (RI) of metamifop-resistant populations ranged from 2.7 to 32.1. Amino acid substitutions (Ile-1781-Leu, Trp-2027-Cys/Ser, and Ile-2041-Asn) in ACCase genes were detected in resistant D. ciliaris var. chrysoblephara plants and caused various cross-resistance patterns to ACCase-inhibiting herbicides. All of four resistant populations (YC07, YZ09, SQ03, and HA06), with different ACCase mutations, exhibited cross-resistance to the aryloxyphenoxypropionate (APP) herbicides cyhalofop-butyl (RI values: 10.0 to 19.9), fenoxaprop-P-ethyl (RI values: 53.7 to 132.8), and haloxyfop-P-methyl (RI values: 6.2 to 62.6), and the phenylpyrazoline (DEN) pinoxaden (RI values: 2.3 to 5.4), but responded differently to the cyclohexanedione (CHD) herbicides clethodim and sethoxydim. It is noteworthy that four postemergence herbicides used for rice cropping, including bispyribac-sodium, pyraclonil, quinclorac, and anilofos, showed poor control effect against D. ciliaris var. chrysoblephara, suggesting few alternations for managing this weed in rice fields except ACCase inhibitors. In conclusion, this work demonstrated that the D. ciliaris var. chrysoblephara had developed resistance to ACCase-inhibiting herbicides in rice cultivation of China, and target-site amino acid substitutions in ACCase were primarily responsible for metamifop resistance.

Impact of Temperature Variations on Rice Production

The mean temperature might rise up to range of 2.0–4.5°C worldwide by the end of this century. Climatic variables affect the growth and development of the crop differently at different growth stages. The rate of development of a crop depends on the climate. Temperature is the primary factor that influences the growth and productivity of crops. Higher or lower temperatures than the optimum lead to improper crop development and affect rice's phenological stages. Extreme temperature may lead to early maturity of the crop and lower temperature lead to prolonged maturity of the crop which in both cases leads to a decrease in yield. A moderate increase in temperature will not have severe implications, but an increase in average temperature by 20 C will likely have strong negative effects on rice crop production. In several studies, it has been reported that high night temperature decreases the yield potential of rice. Whereas, respiratory losses have been shown to increase due to higher day temperature, leaf conductance and net assimilation rates during the day were reported to be higher.

Effect of Biochar Application on Performance of Rice in a Vertisol of Central India

The present investigation was carried out at the Research Farm of ICAR- Indian Institute of Soil Science (ICAR-IISS), Bhopal (M.P.) during the Kharif seasons of 2021 and 2022 and performance of rice crop under the application of biochar in combinations of farm yard manure and chemical fertilizers was studied. The field experiment consisted of 12 treatments involving three doses of biochar (0, 4 and 8 tha-1) with and without fertilizer (0 or 120:60:40 kg N, P2O5, K2O ha-1) and manure (0, 5 t ha-1) in four replications. Rice (cv. PB 1121) was grown consecutively for two years and various parameters viz., plant height, green seeker, number of tillers, earhead length, grains per earhead, seed index and grain yield, straw yield, total biomass and harvest index were evaluated. The results revealed that, among the parameters studied except harvest index, all parameters were influenced positively upon biochar application.

Genetic Architecture, Studies to Identify the Selection Criteria for Yield in Long Duration Rice Lines (Oryza sativa L.)

Genetic Architecture, Studies to Identify the Selection Criteria for Yield in Long Duration Rice Lines (Oryza sativa L.)

Assessing paddy methane emissions through the identification of rice and winter crop areas using Sentinel-2 imagery in Korea

The global efforts on reducing methane (CH4) emissions was emphasized in COP 28 and the potential for improved estimation became feasible through bottom-up data acquisition with advanced remote sensing technology. The objectives of this study were to extract summer rice and winter crop cultivation areas based on satellite images and to incorporate into estimating CH4 emissions in South Korea for the year 2020. Satellite images of Sentinel-1 and Sentinel-2 were acquired from European Space Agency. Rice paddy was classified with backscattering coefficient from Sentinel-1 images, while the normalized difference vegetation index from Sentinel-2 images was used to identify winter cropping field. The equation of IPCC guidelines was used to estimate CH4 emissions by incorporating the areas of rice paddy and winter crop extracted with the respective satellite image. National farming statistics were used to determine the scaling factors for paddy organic matter and water management practices. The estimated areas for rice paddy and winter crop cultivation were 712,237 ha and 117,840 ha, respectively. The rice paddy areas were primarily concentrated in the western regions of the Korean peninsula, whereas winter crop cultivation was predominantly found in southern part of the country. The total amount of CH4 emissions was 6272 Gg CO2 eq./yr when considering rice straw and winter cropping practices into estimation (modified Tier 2 method). This represents a 7% increase compared to the method that considered solely the rice straw incorporation (current Tier 2 method). The CH4 emissions per unit area were also 8.82 tons CO2 eq./ha/yr with the modified Tier 2 method, indicating a 10% greater compared to the current Tier 2 method. Substantial CH4 emissions were primarily concentrated in western regions where extensive rice paddy cultivation occurs, while greater CH4 emissions per unit area were predominantly found in southern regions with substantial winter crop cultivation. The study findings hold importance for improving the accuracy of CH4 emissions estimation by employing bottom-up approach that utilizes satellite imagery to assess rice paddy and winter cropping areas. Further study would be needed to incorporate field-based data on rice crop management practices, such as rice straw and water management, to further refine CH4 emission estimation method.

Effect of Sesbania sesban L. as a Green Manure on Yield of Rainfed-lowland Rice

Rice (Oryza sativa L.) is the most important grain crop for more than half of the world's population especially in Asia. Nitrogen (N) plays a crucial role in rice production. The incorporation of the cover crop as a pre- rice crop is the potential to improve the nitrogen used by rice crops. The experiment was conducted on the clay loam of Svay Rieng Province Cambodia in 2022 during the rice cropping season. The trial was designed using Spit-Plot design, with 4 levels of nitrogen (N) as main-plot and Cover Crop (CC) as a sub-plot. The CC was either the absence of CC or the use of incorporated Sesbania sesban L. (30 kg ha-1 ) as a pre-rice crop. The application rate of nitrogen was 0, 35, 70 and 105 kg ha–1 , respectively. Direct-seeded rice (DSR) was 100 Kg ha-1 . The size of each plot was 16 m2 (4 m×4 m). The experiment was conducted in 3 replicates. An analysis of variance (ANOVA) on Plants Height revealed a significant difference at 1% (P < 0.01) effect of nitrogen level. N35 had the greatest average height (82.95 cm) and N0 was the shortest plant height (77.15 cm). Additionally, a significant difference at 1% (P < 0.01) of planting (CC). CC1 was the tallest plant height (81.75 cm), while CC0 was the shortest plant height (78.49 cm). However, the interaction between N level and CC was not statistically significant (P > 0.05) on Plant height. An analysis of variance (ANOVA) on Grain yield showed a significant difference at 1% (P < 0.01) N70 had the highest average yield (4.92 tons/ha) and N0 had the lowest yield averaging (3.53 tons/ha). Planting (CC) was a significant difference at 1% (P < 0.01). CC1 had the highest average yield (4.60 tons/ha), while CC0 had the lowest average yield (4.13 tons/ha). the interaction between N level and CC was not statistically significant (P > 0.05) The results suggested that among 4 levels of nitrogen, The application of any rates of fertilizers increased the grain yield compared to non-N application. The grain yield was even higher with the incorporation of CC as a pre-rice crop.

Estimation of greenhouse gas emission due to open burning of rice straw using Sentinel data

In recent decades, Vietnam has gradually become a critical global rice producer. During that production process, residual straw becomes an environmental pollutant due to open burning, raising greenhouse gas emissions. This study combines the optical images of the Sentinel-2 satellite and the radar images of the Sentinel-1 satellite to estimate the dry biomass of rice and to determine gas emissions due to rice straw burning over the fields in Quoc Oai district, Hanoi city for urban environmental management purposes. Sentinel-2 images have been classified into the land covers, thereby identifying the areas of ​​rice cultivation and the areas of ​​burned straw. Meanwhile, the Sentinel-1 radar image has been used to calculate the dry biomass of rice due to its ability to penetrate clouds, an obstacle to optical images in tropical regions. Furthermore, a field trip during harvesting season allows us to measure aboveground dry biomass. Then, the analysis shows a high correlation between the backscatter V.V. and V.H. of the radar image and the in-situ dry biomass (R=0.923 and R2=0.852), with a relatively low average error (RMSE = 6.58 kg/100 m2). By linear regression method, the study found the total rice dry biomass of 28728.5 tons, which was obtained after the Summer rice crop 2020 for the whole Quoc Oai district, of which 2037.91 tons of rice straw have been burned, releasing a large amount of greenhouse gas emission with 2398.6 tons of CO2, 189.5 tons of CO, 18.8673 tons of PM10 dust, 17.2087 tons of PM2.5 dust and some other gases. The identical procedure has also been applied to the western region of Hanoi city center to estimate the amount of gas emissions. This study has proven the effectiveness of an approach and contributed to supporting urban managers in proposing appropriate policies to monitor and protect the environment.

Machine learning-based potential loss assessment of maize and rice production due to flash flood in Himachal Pradesh, India.

Flash floods in mountainous regions like the Himalayas are considered to be common natural calamities. Their consequences often are more dangerous than any flood event in the plains. These hazards not only put human lives at threat but also cause economic deflation due to the loss of lands, properties, and agricultural production. Hence, assessing the impact of such hazards in the existing agricultural system is of utmost importance to understand the probable crop loss. In this paper, we studied the efficiency of the remotely sensed microwave data to map the croplands affected by the flash flood that occurred in July 2023 in Himachal Pradesh, a mountainous state in the Indian Himalayan Region. The Una, Hamirpur, Kangra, and Sirmaur districts were identified as the most affected areas, with about 9%, 6%, 5.74%, and 3.61% of the respective districts' total geographical area under flood. Further, four machine learning algorithms (random forest, support vector regressor, k-nearest neighbor, and extreme gradient boosting) were evaluated to forecast maize and rice crop production and potential loss during the Kharif season in 2023. A regression algorithm with ten predictor variables consisting of the cropland area, two vegetation indices, and seven climatic parameters was applied to forecast the maize and rice production in the state. Amongst the four algorithms, random forest showed outstanding performance compared to others. The random forest regressor estimated the production of maize and rice with R2 more than 0.8 in most districts. The mean absolute error and the root mean squared error obtained from the random forest regressor were also minimal compared to the others. The maximum production loss of maize is estimated for Solan (54.13%), followed by Una (11.06%), and of rice in Kangra (19.1%), Una (18.8%) and Kinnaur (18.5%) districts. This indicated the utility of the proposed approach for a quick in-season forecast on crop production loss due to climatic hazards.

Ameliorants for the Management of Soil Acidity – A Review

Soil acidity is one of the major yield limiting factors in rice crop production. The H+ and Al3+ ions in the soil must be neutralized by the release of OH-ions on application of liming materials for the management of soil acidity. Liming material is the substance, which can increase the soil pH by combining with H+ ions in the soil solution. Lime is the most widely used ameliorant for management of soil acidity. There are alternative products, such as dolomite, rice husk ash, gypsum, phosphogypsum and calcium magnesium silicates having high reactivity than lime in increasing the pH, supply of nutrients like Ca, Mg, Si etc., and have the potential to reduce iron and aluminium toxicity and reduce methane emission. Fineness and chemical purity of the liming material are the major factors affecting the ability of the material to neutralise soil pH. Method and timing of application of liming material depend on the place of origin, nutrients and other elements associated with it, and amount of neutralising power. Relative worth of the liming material also depends on the cost of the same.

Adaptive water management in response to tidal inundation and sea level rise on tidal agricultural lowlands of Katingan, Central Kalimantan

Decreased water management systems and sea level rise cause inundation in the Katingan tidal agricultural lowland. Excessive and prolonged inundation can decrease rice production or even loss of rice land. A study was conducted to provide adaptive water management for controlling water levels in canals and rice crop fields inundation. For this purpose, a combined one- and two-dimensional unsteady flow method was used in HEC-RAS. The scenario of water level control uses sluice and flap gates in secondary canals. Under spring tide conditions, water level control with gates decreases the inundation area by 95.62%. Likewise, in the 25 and 50-year sea level rise scenarios, inundation decreased by 88.51% and 82.25%. In the spring tide condition, the duration of inundation is decreased from 3.5 to 0.9 days. Under 25 and 50-year sea level rise scenarios, the duration of inundation was decreased from 3.7 to 3 days and from 4.3 to 4.1 days. The use of gates significantly decreases inundation in the spring tide condition, but under sea level rise in 25 and 50-year, the depth and duration of inundation are still dangerous for rice crops; therefore, it is necessary to advance water management control for the sustainability of rice fields.

Impact assessment of seed treatment in rice crop in district Auraiya Uttar Pradesh

Impact assessment of seed treatment in rice crop in district Auraiya Uttar Pradesh