The International Rice Research Institute (IRRI) is an international agricultural research and training organization with its headquarters in Los Baños, Laguna in the Philippines, and offices in seventeen countries. IRRI is known for its work in developing rice varieties that contributed to the Green Revolution in the 1960s which preempted the famine in Asia.The Institute, established in 1960 aims to reduce poverty and hunger, improve the health of rice farmers and consumers, and ensure environmental sustainability of rice farming. It advances its mission through collaborative research, partnerships, and the strengthening of the national agricultural research and extension systems of the countries IRRI works in.IRRI is one of 15 agricultural research centers in the world that form the CGIAR Consortium of International Agricultural Research Centers, a global partnership of organizations engaged in research on food security. It is also the largest non-profit agricultural research center in Asia.
Context and objectives The combined application of farmyard manure (FYM) and mineral phosphorus (P) fertilizers is widely promoted within the integrated soil fertility management framework to enhance the P use efficiency (PUE) in highly P-deficient soils. This study analyzed the magnitude and mechanisms of FYM × P interactions across 18 field × year combinations using an ensemble of field trials conducted between 2007 and 2025 in the Malagasy highlands. In parallel, a liming field trial was conducted to test earlier hypotheses that FYM × P interactions are primarily related to the alleviation of aluminium (Al) toxicity. Methods The field trials had been established at four locations using a common design with graded TSP applications in the presence or absence of FYM, combined with non-limiting applications of nitrogen (N) and potassium (K). Treatments were maintained on the same plots over multiple years. The different trials included rice, maize, soybean and Bambara groundnut. Results Crop yield largely responded to P applications, with a mean PUE (grain P uptake above control per unit of P applied) of only 4% in the absence of FYM. On average, FYM addition increased the total PUE (including FYM-derived P) by a factor of 1.6, indicating an overall synergistic effect. This effect was not related to watering regime (rainfed vs irrigated) or initial soil properties such as soil pH, organic carbon content, P status, and clay content. The annual PUE based on cumulative P inputs increased 1.6-fold in later application years compared with the first year, independently of FYM application. This indicates that the PUE is generally underestimated during the establishment phase. The new liming trial showed that soil pH increases may explain the FYM × P synergism in maize, but not in upland rice, which is more Al-tolerant than maize. Foliar composition indicated that FYM alleviated rice zinc deficiency in one field. Conclusions These findings demonstrate that combining mineral P fertilizers with FYM can provide a clear agronomic advantage across a wide range of field conditions in the Malagasy highlands. The benefits of FYM on the PUE are likely related to a combination of mechanisms, including the supply of nutrients beyond N, P, and K and the alleviation of Al toxicity in acid-sensitive crops. Other mechanisms such as reduced P sorption may also play a role, although not directly assessed in this study.
Mid-season rice in the Yangtze River basin was studied to analyze the effects of high-temperature stress during flowering on yield and seed setting rate, using ORYZA(v3) model simulation data (1981–2019). Results indicated that: (1) Under varying high-temperature durations during flowering, rice yield and seed setting rate were less negatively impacted in coastal Jiangsu. (2) In the mid-season rice-producing area of the Yangtze basin, long-duration (≥8 days) low-intensity (≤38 ℃) and short-duration (≤3 days) high-intensity (≥41 ℃) heat stress during flowering induced similar yield and seed setting rate reductions. (3) Yield and seed setting rate reduction trends plateaued when high-temperature duration at anthesis reached 8 days; durations below 2 days showed no significant differential effects on reduction percentages across intensities. Given these findings, under future warming scenarios, extremely high-temperature events in the rice-producing region of the Yangtze River Basin are expected to increase in frequency and persistence. Proactive measures are crucial for mitigating sequential high-temperature events during rice flowering, thereby ensuring stable and high yields in mid-season rice-producing areas of the Yangtze Basin.
Flooding stress is a major adverse condition during the emergence period of direct-seeded rice. This study investigated the use of wood vinegar as a seed soaking treatment to enhance rice seedling rates under flooding stress, exploring both the methodology and physiological mechanisms involved. The optimal seed soaking concentration was determined through a gradient experiment, followed by a multi-cultivar validation test. The physiological mechanism of wood vinegar soaking on seedling emergence was analyzed by measuring the electrical conductivity of the flooding water, the changes in starch and soluble sugar contents in the grains and sprouts, and the dynamics of α-amylase activity and antioxidant-related enzyme activities in the sprouts. The results showed that soaking rice seeds in a wood vinegar solution at a low concentration significantly enhanced the emergence of rice seedlings under flooding conditions, with a 100-fold dilution having the most pronounced effect, increasing seedling rates by 50.6%–60.0%. Further analysis indicated that wood vinegar treatment enhanced seedling establishment by inducing a significant increase in α-amylase activity, leading to a 74.9%–213.6% increase in soluble sugar content in the sprouts during 2–8 d after flooding stress compared with the control. Additionally, the treatment increased superoxide dismutase and peroxidase activities in the sprouts, mitigating lipid peroxidation of the cell membranes, and notably lower water electrical conductivity was observed in wood vinegar-treated seeds compared with the control. In conclusion, soaking rice seeds in a 100-fold diluted wood vinegar solution improves rice seedling rates under flooding stress by mitigating oxidative damage and maintaining energy supply. This approach is valuable for developing cost-effective seed treatment technologies and offering novel strategies to improve seedling rates and uniformity of direct-seeded rice under flooding conditions.
The International Rice Research Institute (IRRI) runs the largest public rice breeding program in the world, playing a crucial role in ensuring global food security. Using a large dataset containing 12,045 yield observations of IRRI elite lines, we estimate the annual genetic gain attributable to IRRI since the release of IR8, the variety that launched the Green Revolution, and the market impacts in Indonesia and the Philippines. Results indicate that since the release of IR8, the genetic gains from IRRI lines have increased by 0.58% annually. The estimated average annual supply increase through producer adoption of IRRI lines in Indonesia and the Philippines was sufficient to feed an additional 25.14 million people's annual rice consumption. An important aspect of this study's findings is to highlight the significant role that public breeders like IRRI play in combating global food insecurity, even in the face of diminishing funding.
Rice (Oryza sativa) is one of the world’s most important cereal crops, contributing to food and financial security, particularly in developing countries. High temperature due to climate change seriously threatens sustainable rice production. Rice crops are adversely affected by heat stress at the morphological, physiological, and molecular levels, resulting in reduced yield and poor grain quality. Rice is highly sensitive to heat during the reproductive phase, causing pollen sterility, impaired pollen dehiscence, pollen germination, and tube growth, ultimately drastically reducing spikelet sterility and yield. High temperature also promotes the accumulation of reactive oxygen species in plant cells, resulting in multiple adverse effects, including damage to chloroplasts and cell membranes, inactivation of photosystems, reduced Rubisco activity, and impaired production of photoassimilates. In this review, we have synthesized the current knowledge on the effects of heat stress on rice and summarized QTLs, genes, and regulatory pathways underlying thermotolerance. We further evaluate conventional breeding, transgenics, and diverse omics-based strategies to breed high-yielding, heat-tolerant rice varieties. The precise molecular insights gained through various omics approaches are expected to advance our understanding of the intricate nature of heat stress tolerance in rice. Additionally, we highlight the emerging roles of microbiome, high-throughput phenotyping technologies, and artificial intelligence as promising tools for accelerating the development of heat-resilient rice.
