Rice blast, caused by Magnaporthe oryzae, poses a significant threat to rice cultivation worldwide, particularly in Bangladesh where rice is a major staple cereal. This study explores the biocontrol potential of bacterial isolates against rice blast disease, with an emphasis on in vitro and field efficacy. Thirty bacterial isolates from indigenous rice varieties and rhizospheric soils were evaluated using dual culture techniques to assess their antagonistic effects on M. oryzae. Six isolates demonstrating significant antifungal activity were further tested in field trials through seed and seedling priming methods. Results indicated that these bacterial isolates significantly reduced leaf blast incidence and severity, with specific isolates (Isolate 2 and Isolate 5) showing notable efficacy. Yield was significantly influenced by bacterial treatments, with seed priming using Isolate 5 (358.20 g/m²) and seedling priming using Isolate 2 (342.98 g/m²) achieving the highest yields, significantly outperforming the control (128.72 g/m²). This study highlights the effectiveness of biocontrol agents in enhancing rice production and offers a sustainable strategy for disease management in rice. Bangladesh J. Nuclear Agric,39(2): 123-135, 2025

Synergistically enhancing both photosynthetic rate (A) and intrinsic water use efficiency (iWUE) in rice remains a major challenge for achieving high productivity in the future. In this study, 37 cultivated rice (Oryza sativa) varieties with significant variation in stomatal morphological traits were selected for pot experiments. Among these, the two highest and two lowest stomatal density varieties were further subjected to drought treatments. Under well-watered conditions, stomatal density was identified as a key factor coordinating stomatal conductance (gs) and mesophyll conductance (gm) among rice varieties by influencing mesophyll cell arrangement through stomatal development. Although increased stomatal density enhanced A, it did not synergistically improve iWUE. Under water stress, however, stomatal aperture decreased rapidly as drought intensified, gradually diminishing the positive effect of high stomatal density on gs until it disappeared. Notably, varieties with high stomatal density maintained higher gm than those with low stomatal density across the entire range of leaf water potentials measured, enabling simultaneous enhancement of both A and iWUE under drought conditions. Our study demonstrates that high stomatal density can synergistically enhance both AandiWUE under drought conditions, underscoring its potential utility in breeding drought-tolerant rice varieties.

The rapid variation of avirulence genes in Magnaporthe oryzae (M. oryzae) undermines the resistance function in rice varieties carrying cognate resistance genes. Monitoring the variation of these avirulence genes is crucial for deploying resistant rice cultivars in the field. AVR-Pita3 is known as a gene that lacks avirulent activity to rice carrying Pi-ta. However, its distribution, evolution, and avirulence function in M. oryzae populations remain poorly understood. In this study, we analyzed the distribution and variation of the AVR-Pita3 in M. oryzae and examined its avirulence function. Among 262 isolates collected from five hosts in rice-producing regions in Southwest China, 188 isolates of M. oryzae, including one isolate in Eleusine indica (E. indica), carried AVR-Pita3. A total of 31 nucleotide variations and 19 amino acid variations were identified, along with 5 haplotypes, the majority of isolates belonged to the haplotype H2. The isolates carrying AVR-Pita3 from rice and E. indica hosts clustered into distinct evolutionary clades, and the gene was under negative selection. Pathogenicity assays showed that a monogenic line rice carrying Pi-ta was resistant to 103 isolates, susceptible to 60 isolates, and had an unknown response to remain 25 isolates carrying AVR-Pita3. This study provides the first report on the distribution and variation of the AVR-Pita3 in M. oryzae populations across rice-growing regions in Southwest China. AVR-Pita3 is widely distributed in these populations, with a high frequency of occurrence, particularly in isolates from Guizhou. The findings indicate that Pi-ta monogenic line remains effective against most pathogen stains carrying AVR-Pita3 in these regions, which highlights its potential for disease management in rice cultivation.

Endophyte-induced physiological adjustments to improve drought tolerance in rice.

This study aimed to investigate the effects of hydrocolloid combinations and milling methods on the quality of gluten-free bread (GFB) prepared with rice flours from different rice varieties. Physicochemical and microstructural analyses were conducted to assess the impact of flour type and formulation on the quality properties of GFB. Dry-milled rice flour, characterized by moderately damaged starch (3.63%) and lower amylose content (14.95%), was found to result in GFB with delayed retrogradation during 4days of storage compared with wet-milled rice flour. The use of hydrocolloids, particularly the combination of hydroxypropyl methylcellulose (HPMC) and propylene glycol alginate (PGA), further improved crumb texture, moisture retention, and structural integrity. Of the tested rice flours, "Baromi2" DR showed a more favorable starch composition and baking performance, supporting its suitability for gluten-free product applications. These findings confirmed the importance of selecting appropriate milling techniques and functional hydrocolloids to optimize GFB quality and market potential.

Subspecies-specific epigenetic remodeling drives differential cold adaptation in geng/xian rice.

Genetic diversity and genome-wide association mapping for salt stress tolerance in diverse parental lines of hybrid rice.

Multi-year water and carbon flux contrasts between high-yielding and conventional rice cultivars

Rice NH2 functions as a positive regulator of salicylic acid-mediated defense responses against sheath blight disease.

Innovation of Batiah: The Role of Rice Varieties and Enrichment with Cassiavera-Morel Berry Extract and Pumpkin Seed Flour

The opportunistic fungal pathogen Nigrospora oryzae poses a growing threat to global rice production, especially given its enhanced virulence in co-infections with other pathogens. This study aimed to characterize the pathogen and identify effective integrated disease management strategies. Isolates from Indonesia were identified using morphological and molecular markers, including the ITS and ACT genes, which confirmed a strong genetic link to a rice-native strain from China, ruling out a recent host jump from oil palm. Pathogenicity assays demonstrated the fungus’s opportunistic nature, as its virulence and disease progression were significantly heightened when co-inoculated with Curvularia lunata. In vitro fungicide tests revealed a high sensitivity to methyl thiophanate (EC50 ~250 ppm ) but a lower sensitivity to azoxystrobin. Furthermore, silicon application effectively suppressed the disease, highlighting that some rice varieties responded better than others; the IPB 3S variety experienced a 30% reduction in disease incidence compared to 16% in Situ Bagendit. These findings establish a comprehensive framework for integrated disease management, combining varietal selection and silicon application with targeted chemical control to combat this emerging threat.

Metabolic remodeling and sucrose transporter modulation in source-sink tissues conserve pollen germination and spikelet fertility in rice under concomitant heat and drought stress.

A novel aldo-keto reductase gene, OsAKR1, negatively regulates P reutilization in P deficient rice (Oryza sativa) root cell wall via a NO dependent manner.

A comprehensive deep learning framework for rice variety classification with real-time deployment

Rice production stability is essential to maintain Indonesia’s food security, yet it is increasingly affected by climate variability. This study quantified thermal time as growing degree days (GDD) and radiation use efficiency (RUE) to evaluate rice performance across wet-season planting windows and to identify a suitable planting period for tropical lowland ecosystems. The field investigation was carried out in Sidoarjo, East Java, Indonesia, during the 2023–2024 wet season using three representative varieties: Pandan Wangi, Inpari 32, and Intani 602. Rice was transplanted at three planting periods representing early (November), mid (January), and late (March) wet season planting. The experiment applied a randomized block design with two factors with combine anlyzed. Data were analyzed using analysis of variance and regression. The results indicated that planting time significantly affected all yield components. The hybrid Intani 602 achieved the highest panicle number, grain weight, and grain yield (7.56 to 9.54 t ha⁻¹), demonstrating superior adaptability and physiological performance. Regression analysis showed a significant negative relationship between GDD and grain yield and a positive relationship between RUE and grain yield. The findings emphasize the importance of matching variety selection with planting time to enhance productivity and resilience under tropical climates. Developing suitable agroclimatic-based planting calendars is recommended to support sustainable rice production systems.

Natural high-vitamin B parboiled rice malt from Thai rice varieties

Guangxi boasts extensive selenium-rich soils, creating favorable conditions for screening high-quality rice varieties that can be cultivated in this region and determining the optimal selenium fertilizer spraying concentrations for their growth. In this study, three major rice varieties predominantly grown in the area were selected for evaluation (Ge68 Superior 9938, Guiyu 9 and Yexiang Youlisi). A clear water control (CK), Treatment 1 (T1, with the application of 100 g•hm-2 amino acid-based organic selenium), and Treatment 2 (T2, with the application of 200 g•hm-2 amino acid-based organic selenium) were established. Rice yield, brown rice percentage, selenium content in different plant parts, and the levels of certain rice quality indicators were measured. Additionally, the entropy weight-TOPSIS method was employed to evaluate the comprehensive performance of the eight indicators under different treatments. Results indicate that foliar application of selenium (Se) fertilizer significantly increased rice yield by over 8.7% compared to the control group (CK), but had no significant effect on brown rice rate. Under selenium treatment, selenium content in stems, leaves, panicle stems, and grains of all three rice varieties significantly exceeded the control group, with maximum increases of 0.33, 1.12, 0.38, and 0.26 mg/kg, respectively. Regarding nutritional quality, treatment 2 (T2) significantly elevated protein, amylose, lipid, and amino acid content across all three rice varieties. Entropy-weighted TOPSIS analysis indicated that for the rice variety YexiangYouLisi cultivated in Guangxi’s selenium-enriched region, foliar application of selenium fertilizer at a concentration of 200 g•hm-2 was optimal. This concentration not only yielded the highest grain yield and grain quality for this variety but also maintained selenium levels in stems, leaves, panicle stems, and grains within suitable ranges.

Rice is a primary staple crop and a key contributor to food security in Bangladesh; however, rice production in coastal regions is increasingly threatened by climate variability, particularly fluctuations in temperature and precipitation. Despite growing concern, district-level analyses linking climatic factors with rice production in coastal Bangladesh remain limited. This study therefore examines the influence of major climatic parameters on rice production across 19 coastal districts using data from the Bangladesh Bureau of Statistics (BBS) and the Bangladesh Meteorological Department (BMD) covering 2006-2020. Descriptive statistics were used to assess production trends, while unit root tests and fixed and random effects (FE/RE) panel data regression were applied to evaluate the relationship between climatic variables and rice production. The results reveal clear spatial variation in seasonal rice cultivation, with Aus predominating in Chattogram, Aman in Jessore, and Boro in Bhola districts. Climate-yield relationships were found to be complex: moderate temperature increases supported Aus and Aman production by accelerating crop growth, whereas excessive heat during critical growth stages reduced yields. Increased rainfall and cultivated land availability were positively associated with production across all major rice seasons. The findings emphasize the importance of adaptive strategies, including improved water management and stress-tolerant cultivation practices, to reduce climate-related risks. Policy recommendations include promoting climate-resilient rice varieties, targeted water management, and extension services to strengthen coastal food security under changing climatic conditions.

Integrating traditional knowledge and field monitoring to assess insect pest tolerance in indigenous rice varieties of Wayanad, Kerala

The effects of nitrogen (N) application rates and N topdressing at different leaf growth stages on the yield, N absorption, and utilization of japonica rice cultivar Nanjing 9108 were studied to screen the optimal N management mode for high yield and high N use efficiency. A field experiment was conducted from 2023 to 2024, with nine N regulation treatments (94-351 kg ha-1) established through dynamic allocation of basal, tillering, and topdressing fertilizers. The results showed that with the increase of N application rate, the yield and N use efficiency of Nanjing 9108 first increased and then decreased. At a total N application rate of 270 kg ha-1, the N6 treatment (basal N + tiller N + topdressing at the 13th leaf stage) demonstrated optimal overall performance, achieving the highest yield and N use efficiency. Topdressing at the 13th leaf stage (coinciding with young panicle differentiation) promoted spikelet differentiation and large panicle formation, increasing grains per panicle by 2.36-2.20% compared to other treatments under the same N rate. The N6 treatment exhibited enhanced N uptake and utilization: N accumulation increased by 39.27-67.12% during the elongating to heading stage and by 7.14-62.24% during heading to maturity, while N apparent efficiency and agronomic efficiency rose by 3.51-14.68% and 29.22-58.25%, respectively. At heading, the proportion of high-effective leaf area in N6 was 1.52-7.05% higher than in N4, N5, and N7 treatments, accompanied by a slower leaf area decay rate. These traits provided sustained photosynthetic support for dry matter accumulation in mid-to-late growth stages. Consequently, dry matter accumulation in N6 increased by 5.85-33.44% (elongating to heading) and 0.42-26.98% (heading to maturity), leading to a yield advantage of 3.8-17.2% over other treatments. In summary, the N management strategy combining basal, tiller, and 13th-leaf topdressing at 270 kg ha-1 is most effective for achieving both high yield and high N efficiency in Nanjing 9108.