World Rice Research Articles

Accurate Paddy Rice Mapping Based on Phenology-Based Features and Object-Based Classification

Highly accurate rice cultivation distribution and area extraction are essential to food security. Moreover, Inner Mongolia, whose slogan is “from scientific rice to world rice”, is an essential national rice production base. However, high-quality rice mapping products at high resolutions are still scarce around the Inner Mongolia Autonomous Region. This condition is not conducive to rational planning of farmland resources, maintaining food security, and promoting sustainable growth of the local agricultural economy. In this study, the rice backscattering intensity difference index from the vertically polarized backscatter intensity of Sentinel-1 and the phenology differential index from the spectral indices of two critical rice phenological phases of Sentinel-2 images were constructed. Other spectral features, including spectral indices, tasseled cap, and texture features, were computed using simple non-iterative clustering (SNIC) to achieve image segmentation. These variables served as input features for the random forest (RF) algorithm. Results reveal that employing the RF with the SNIC segmentation algorithm and combining it with optical and synthetic aperture radar data is an effective way to extract data on rice in mid-latitude regions. The overall accuracy and kappa coefficient are 0.98 and 0.967, correspondingly. The accuracy for rice is 0.99, as proven by empirical data. These results meet the requirements of regional rice cultivation assessment and area monitoring. Furthermore, owing to its resilience against longitude-associated influences, the model discerns rice across diverse regions and multiple years, achieving an R2 of 0.99. This capability significantly bolsters efforts to improve regional food security and the pursuit of sustainable development.

New Dynamics in the World Rice Market

In the last four decades of the 20th century, the world rice market was highly unstable, with price volatility greater than that on world wheat and maize markets. In the 21st century, however, new dynamics (a thicker world rice market, more irrigation, milder export restrictions) have contributed to a reduction in price volatility that is now lower than that on world wheat and maize markets. In addition, the El Niño events that are responsible for many shocks to the world rice market are largely predictable several months in advance. The reduced volatility on the world rice market and the predictability of El Niño events make it easier to use international trade as an instrument for food security. The recent experience with rice trade liberalization by Asian rice importers has been largely positive, helping to improve food security and the affordability of healthy diets, with little impact on domestic price volatility.

Studies on Genetic Variability and Heritability in Rice Genotypes (Oryza sativa. L.) under Salinity

Rice (Oryza sativa L.) is one of the most important staple food crops in the world because more than half of the world's population depends on rice for their livelihood. By 2050, the world's rice productivity will need to double in order to keep up with population growth. Narrow genetic base in the released variety has made the improvement in plateaus. In order to go more than the yield barrier, the genetic base must be broadened. Heritability and genetic variability were measured in eighty-six rice genotypes in terms of yield and yield contributing traits under saline soils. Significant differences were found between the genotypes for all of the studied traits according to analysis of variance. High PCV and GCV were recorded for the traits viz., mortality percentage (%), total number of grains per panicle, number of un-filled grains per panicle, sterility percentage (%) and seed yield per plant (g). The traits showed a significant degree of genetic advancement together with high heritability were mortality percentage (%), 1000 grain weight (g) and seed yield per plant (g). Genetic advance over mean were high for mortality percentage (%), number of productive tillers/m2, total number of grains per panicle (g), number of un-filled grains per panicle (g), sterility percentage (%), 1000 grain weight (g) and seed yield per plant (g). This study provides information about the variability and heritability measures which may supplement the breeding program to break the yield plateaus.

Authentication of premium Asian rice varieties: Stable isotope ratios and multi-elemental content for the identification of geographic fingerprints

Over 90 percent of the world's rice is produced and consumed in the Asia-Pacific region. Varieties such as Thai Jasmine rice and Paw San (or “Myanmar pearl rice”) are globally recognised as premium, while more local high-grade varieties include the Indonesian Ciherang and Inpari. Being able to trace the origin of these products has become necessary, since they are marketed at relatively higher prices compared to other cultivars, and they often become the target of fraudulent activities. In this work, we aimed to identify variables that could distinguish the premium-producing regions within each country, by Isotope Ratio Mass Spectrometry (IRMS) and Inductively Coupled Plasma- Mass Spectrometry (ICP-MS). Low-Level Data Fusion (LLDF) followed the analysis of more than 300 authentic samples, and (O)PLS-DA models yielded very high accuracy values. The most important geo-differentiating variables (VIP>1.4) were identified as: δ13C, δ18O, δ2H, δ34S, Co, Rb, Cu, Ba and Zn.

Screening of NIAS World Rice Core Collection for Seeds with Long Longevity as Useful Potential Breeding Materials Focusing on the Stability of Embryonic RNAs.

Seed longevity is a crucial trait for the seed industry and genetic resource preservation. To develop excellent cultivars with extended seed lifespans, it is important to understand the mechanism of keeping seed germinability long term and to find useful genetic resources as prospective breeding materials. This study was conducted to identify the best cultivars with a high and stable seed longevity trait in the germplasm of rice (Oryza sativa L.) and to analyze the correlation between seed longevity and embryonic RNA integrity. Seeds from 69 cultivars of the world rice core collection selected by the NIAS in Japan were harvested in different years and subjected to long-term storage or controlled deterioration treatment (CDT). The long-term storage (4 °C, RH under 35%, 10 years) was performed on seeds harvested in 2010 and 2013. The seeds harvested in 2016 and 2019 were used for CDT (36 °C, RH of 80%, 40 days). Seed longevity and embryonic RNA integrity were estimated by a decrease in the germination percentage and RNA integrity number (RIN) after long-term storage or CDT. The RIN value was obtained by the electrophoresis of the total RNA extracted from the seed embryos. Seeds of "Vandaran (indica)", "Tupa 729 (japonica)", and "Badari Dhan (indica)" consistently showed higher seed longevity and embryonic RNA integrity both under long-term storage and CDT conditions regardless of the harvest year. A strong correlation (R2 = 0.93) was observed between the germination percentages and RIN values of the seeds after the long-term storage or CDT among nine cultivars selected based on differences in their seed longevity. The study findings revealed the relationship between rice seed longevity and embryo RNA stability and suggested potential breeding materials including both japonica and indica cultivars for improving rice seed longevity.

Preliminary Evaluation of The Performance of Micro Combine Harvesters in Rice Farming

Rice is the most widely used staple food, especially in Asia, accounting for about 90% of the world's rice production. In Malaysia, the cultivated area is as much as 730,016 hectares, and the show was about 3.3 million metric tons throughout the country in 2016. Currently, big combine harvesters are used in Malaysia to harvest rice, allowing for quicker harvesting. However, harvesting with a big combine harvester is impossible in areas with soft soil. As a result, employing a micro combine harvester is one of the options for harvesting in areas with soft soil problems. This study aims to evaluate the performance of a micro combine rice harvester. Performance evaluations were conducted at the MARDI Seberang Perai, Penang research plot. The pedestrian-type micro combines harvester with a triangular rubber crawler type was used in this study. The working width of the machine is 1 meter. The rate of harvesting losses is also evaluated as part of the study. The performance test results of the micro combine harvester show that the farm's efficiency is about 70 percent, with a work rate of 0.10 ha/hour. By keeping the harvester's speed at 1.5 km/h, this micro combine harvester's potential work rate is 0.15 hectares per hour. The losses during the harvesting operation were calculated to be 2.2 per cent. The study's results show that using micro combine harvesters can assist in carrying out rice harvesting work in areas where soft soil issues make it challenging to use the standard large combine harvesters. Farmers that grow rice on a small scale also benefit from using this micro combine harvester. The small percentage of losses demonstrated the effectiveness of this micro combine harvester.

The Impact of Multinational Grain Export Restrictions on China

India is an important exporter of rice in the world. In 2022, India's total rice exports accounted for over 40% of the world's rice exports. With India's announcement of restrictions on rice exports, the import price of rice has also increased. As a populous country, although China has high grain production, due to factors such as food security and balancing international trade, China also imports a large amount of grain from other countries every year. Since 2022, many countries, including Russia, Brazil, and others, have also chosen to restrict grain exports due to certain factors. Although China's rice production can make it self-sufficient, the situation for other agricultural products is not the same. If the largest exporting country of some crops with low yields China restricts their export, it will undoubtedly have an impact on China's imports and market, as the difficulty of importing these crops has increased. This article aims to analyze the impact of grain export constraints on China through literature review to demonstrate the impact of grain export restrictions from other countries on China in order to draw attention to the impact of grain export restrictions on China.

CLIMATE-SMART RICE PRODUCTION: A REVIEW

‌Rice is one of the world's most important crops and the primary source of nutrition for the world's more than half population. Currently, the world rice production is 495.78 million tons, while it will increase to 525 tons in 2050, which is not sufficient for the world's increasing population. At the same time, various climatic factors affect rice production, such as air temperature, atmospheric CO2, light, water, and soil nutrients. For instance, high temperature was the main climate factor that caused yield variation by affecting the rice maturity periods, spikelet fertility, and spikelet number. Thus, it is an urgent need to improve rice production and reduce the negative effects of climate change on rice production. In order to solve above-mentioned problem, one of the most important options is using climate-smart practices, which are planting improved rice varieties, soil and water conservation techniques, and adjusting planting and harvesting dates. The importance of adapting climate smart practices is an increase in rice yield by 15.87%. Climate-smart rice production and climate-smart practices in rice needs still to be investigated widely. The review objective is to describe climate-smart practices in rice cultivation, in order to mitigate the negative effects of climate change on rice production.

How does climate change affect potential yields of four staple grain crops worldwide by 2030?

Global food security basically depends on potential yields of staple grain crops worldwide, especially under climate change. However, most scholars use various models of production function in which climatic factors are often considered to estimate crop yield mostly at local or regional level. Therefore, in this paper: Potential yields of rice, wheat, maize and soybean worldwide by 2030 are projected creatively using Auto-regressive Integrated Moving Average and Trend Regressed (ARIMA-TR) model in which actual yields in recent two years are used for testing the reliability of projection and Gray System (GS) model for validating the test; Especially individual impacts of climate change on the productions of rice, wheat, maize and soybean worldwide since 1961 are analyzed by using unary regression model in which global mean temperature and land precipitation are independent variable while the yield of crop being dependent one, respectively. Results show that: by 2030, the ratio between average and top yields of world rice is projected to be 50.6% increasing, while those of world wheat, world maize and world soybean are projected to be 38.0% increasing, 14.7% decreasing and 72.5% increasing, respectively. Since 1961 global warming has exerted a negative impact on average yield of world rice less than on its top, a positive effect on average yield of world wheat while a negative impact on its top, a positive effect on average yield of world maize less than on its top, and a positive influence on average yield of world soybean while a negative one on its top, which might be slightly mitigated by 'Carbon Peak' target. The fluctuation of global rainfall contributes to the productions of these crops much less than global warming during same period. Our findings indicate that: to improve global production of four staple grain crops by 2030, the priorities of input should be given to either rice or wheat in both high and low yield countries, whereas to maize in high yield countries and to soybean in low yield countries. These insights highlight some difference from previous studies, and provide academia with innovative comprehension and policy-decision makers with supportive information on sustainable production of these four staple grain crops for global food security under climate change in the future.

THE EFFECT OF EXPORT OF RICE ON THE ECONOMY OF INDIA

THE EFFECT OF EXPORT OF RICE ON THE ECONOMY OF INDIA

Back in the Soup: Now What?

This article for AJAD presents the outlook for the world rice market as of early September 2023. It builds on my AJAD article from a year ago (Timmer 2022) and on multiple articles in the East Asia Forum (see Editorial Board, ANU 2023a, b). A year ago, the world was facing a severe food crisis. All the ingredients for significant shortages of food grains and vegetable oils were already boiling. An article in this journal at the time asked how to manage such a crisis (Timmer 2022). The answer was a series of steps designed to build confidence in the availability of supplies. Leadership was sought from Indonesia, chair of the G20 in 2022, and soon to be chair of ASEAN. Indonesia delivered (Editorial Board, ANU 2023a). World food markets remained relatively calm, rice prices actually declined for several months, and the world’s consumers breathed a bit easier. But the breathing space was short-lived. A combination of factors, especially the rampedup attacks by Russia on Ukrainian food export infrastructure and the emergence of a vigorous El Niño in Asian rice bowls, has led to renewed concerns about an impending food crisis. This time the focus is on rice, rather than wheat, maize, and vegetable oils. But rice is increasingly the “food of the poor” in Asia and in Africa (Timmer 2013). A spike in rice prices will cause widespread hunger.

Biochemical changes of rice genotypes against blast (Magnaporthe oryzae) disease and SSR marker validation for resistance genes

Rice blast caused by Magnoporthe oryzae is a major devastating fungal disease and represents a potential threat to world rice productions. However, information about the genetic and biochemical basis of disease tolerance is still limited. In this study, we tested the presence and diversity of resistant R genes using SSR markers, and the antioxidant enzymes catalase (CAT), ascorbate peroxidise (APX) and guaicol peroxidise (POD), activity and also the concentration of hydrogen peroxide (H2O2) and malondialdehyde (MDA) in resistant (BAUdhan 3) and susceptible (BRRIdhan 28) genotype. Molecular marker analysis reveals the presence of all ten studied resistant genes in BAUdhan 3. Among the markers studied, three markers namely RM224, RM72 and RM206 produce distinct band only in resistant genotype BAUdhan 3, which might be used to screen resistant genotypes. The enzymatic activity of APX, CAT and POD increased in the inoculated plant for both cultivars but the increase was more prominent for BAUdhan 3. The M. oryzae infections significantly increased the H2O2 content in BRRIdhan 28 and not much changed in BAUdhan 3. The MDA concentration was higher in the leaves of inoculated plants of BRRIdhan 28. The higher activities of APX and POD in the leaves of the inoculated plants of BAUdhan 3 resulted in lower H2O2 accumulation which can minimize the cellular damages possibly caused by reactive oxygen species. The result shows that the presence of more resistance genes and an effective antioxidative system in BAUdhan 3, which limits the damage caused due to fungal infection and thus contributes to greater resistance.

Twenty-meter annual paddy rice area map for mainland Southeast Asia using Sentinel-1 synthetic-aperture-radar data

Abstract. Over 90 % of the world's rice is produced in the Asia–Pacific region. Synthetic-aperture radar (SAR) enables all-day and all-weather observations of rice distribution in tropical and subtropical regions. The complexity of rice cultivation patterns in tropical and subtropical regions makes it difficult to construct a representative data-relevant rice crop model, increasing the difficulty in extracting rice distributions from SAR data. To address this problem, a rice area mapping method for large regional tropical or subtropical areas based on time-series Sentinel-1 SAR data is proposed in this study. Based on the analysis of rice backscattering characteristics in mainland Southeast Asia, the combination of spatiotemporal statistical features with good generalization ability was selected and then input into the U-Net semantic segmentation model, combined with WorldCover data to reduce false alarms, finally the 20 m resolution rice area map of five countries in mainland Southeast Asia in 2019 was obtained. The proposed method achieved an accuracy of 92.20 % on the validation sample set, and the good agreement was obtained when comparing our rice area map with statistical data and other rice area maps at the national and provincial levels. The maximum coefficient of determination R2 was 0.93 at the national level and 0.97 at the provincial level. These results demonstrate the advantages of the proposed method in rice area mapping with complex cropping patterns and the reliability of the generated rice area maps. The 20 m annual paddy rice area map for mainland Southeast Asia is available at https://doi.org/10.5281/zenodo.7315076 (Sun et al., 2022b).

Biomass estimation of World rice (Oryza sativa L.) core collection based on the convolutional neural network and digital images of canopy

ABSTRACT Above-ground biomass (AGB) is an important indicator of crop productivity. Destructive measurements of AGB incur huge costs, and most non-destructive estimations cannot be applied to diverse cultivars having different canopy architectures. This insufficient access to AGB data has potentially limited improvements in crop productivity. Recently, a deep learning technique called convolutional neural network (CNN) has been applied to estimate crop AGB due to its high capacity for digital image recognition. However, the versatility of the CNN-based AGB estimation for diverse cultivars is still unclear. We established and evaluated a CNN-based estimation method for rice AGB using digital images with 59 diverse cultivars which were mostly in World Rice Core Collection. Across two years at two locations, we took 12,183 images of 59 cultivars with commercial digital cameras and manually obtained their corresponding AGB. The CNN model was established by using 28 cultivars and showed high accuracy (R2 = 0.95) to the test dataset. We further evaluated the performance of the CNN model by using 31 cultivars, which were not in the model establishment. The CNN model successfully estimated AGB when the observed AGB was lesser than 924 g m−2 (R2 = 0.87), whereas it underestimated AGB when the observed AGB was greater than 924 g m−2 (R2 = 0.02). This underestimation might be improved by adding training data with a greater AGB in further study. The present study indicates that this CNN-based estimation method is highly versatile and could be a practical tool for monitoring crop AGB in diverse cultivars.

Пирикуляриоз риса и методы борьбы

Поражения риса, вызываемые Magnaporthe grisea, являются основной болезнью, наносящей ущерб почти во всех странах, выращивающих рис. Экономическая значимость риса огромная, для более по-ловины населения мира рис служит как основной источник калорий. В годы эпифитотий пирикуляри-оз может нанести разрушительное влияние на производство риса в мире. На данный момент этот па-тоген превратился в новаторскую модельную систему для исследования взаимодействия «хозяин–патоген». Вспышка заболевания зависит от климатических условий различных регионов. Возникнов е-ние болезни и симптомы варьируются от страны к стране. Восприимчивые сорта несут огромные по-тери урожая риса. Основной причиной нарушения устойчивости риса к пирикуляриозу является высокая способность патогена к изменчивости. Вирулентные патотипы вызывают тяжелую форму заболеваемости. При исследовании патогенности возбудителя можно определить патотипы, используя коллекцию различных сортов риса, которые обычно отличаются друг от друга, неся различные гены устойчивости. В настоящее время селекционерами мира широко практикуется полигенная (пирамидирование генов) устойчивость вместо традиционной моногенной. Выращивание сортов, полученных путем скрещивания устойчивых сортов с восприимчивыми, с использованием молекулярного контроля перехода генов на каждом этапе, может служить высокоэффективным методом борьбы с пирикуляриозом. Генетическая гетерогенность M. grisea должна учитываться при скрининге устойчивых к пирикуляриозу генотипов риса с помощью морфологического, фитопатологического анализов и молекулярной характеристики.

A developed system to extract specific responses of increment length in rice shoots under gradient changes in nitrogen concentration regimes.

Nitrogen (N) fertilization is one of the most crucial factors that contribute to increasing food production requiring the generation of rice cultivars with improved N use efficiency (NUE) to maintain yield during low N fertilizer application. To assay NUE extent, we developed a screening system to evaluate shoot growth of each rice cultivar under gradient changes in N concentrations. This system comprises a gradient hydroponic culture and growth visualization systems. The former allows gradient changes in ammonium concentrations, while the latter records the increment in shoot length of individual rice seedlings at given time periods using a fixed-point camera. We chose 69 cultivars including two controls (Oryza sativa L. cv. Nipponbare [WRC01] and Kasalath [WRC02]) from the World Rice Core Collection to investigate shoot growth responses under ammonium-sufficient, ammonium-limited, and low ammonium concentration gradients without transplanting stress. We observed three growth patterns in response to different ammonium concentrations. Subsequently, we selected three representative cultivars (Kasalath, WRC03, and WRC05) for the characteristic responses under the different ammonium environments. Distinct expression patterns of glutamine synthetase 1;2 (OsGS1;2) but OsGS1;1 were observed in response to varying ammonium concentration regimes, indicating that the expression patterns of OsGS1;2 may be a growth marker in terms of shoot growth when transitioning from ammonium-limited to low ammonium concentrations. This system with the level of OsGS1;2 allows us to screen for candidate cultivars that return high NUE in low N environments.

Integrated Insect Pest Management Techniques for Rice

In modern agriculture, climate change, environmental degradation, and natural resource depletion constitute one of the major potential issues for sustainable crop production and environmental management. Integrated pest management (IPM) is a promising technology for the environment. Insect pests and weeds have long posed a danger to rice production systems, resulting in severe output losses. Although insect, pest, and weed control has remained the most efficient plant protection tool, environmental risks have prompted scientists to propose alternate pest management options. The understanding of sustainable conventional agriculture prompted the broad deployment of integrated pesticide management (IPM). IPM is a multimodal pesticide management method that aims to avoid negative environmental impacts. This method is critical for delivering healthy, sustainable food to the world’s rising population. Rice is a staple crop that many developing countries rely upon for national stability and economic progress. On the other hand, rice pests represent a major biotic barrier to world rice production. This review aims to provide information on major rice pests, their identification, biology, and various IPM treatments, particularly biological management strategies. To create a sustainable rice agroecosystem, continual research and training on IPM technologies will be required.

ПРОГНОЗИРОВАНИЕ ИСПАРЕНИЯ С ВОДНОЙ ПОВЕРХНОСТИ С ПОМОЩЬЮ МАШИННОГО ОБУЧЕНИЯ

In studies carried out at the Krasnodar Rice Institute, as well as according to data from world rice cultivation centers, it has been shown that evaporation has the greatest effect on rice yield from climatic factors. Evaporation without any significant errors can be taken as evaporation from the waters of water bodies, while the value of rice transpiration most often has a fairly significant correlation or functional relationship with evaporation from water bodies. From the short-term weather forecasts issued by regional subjects of Roshydromet and other organizations, it is possible to obtain forecast values of temperature, wind speed and precipitation with a five-day (pentad) advance. It was on their basis that a method for predicting evaporation for the future pentad was developed. In this paper, the hypothesis of the possibility of predicting the values of evaporation from the water surface of rice checks by the main predicted meteorological elements using neuro-machine learning technologies is tested. In the course of the work, a machine learning algorithm was compiled aimed at approximating the amount of evaporation from the water surface based on forecast data of meteorological parameters. This technology can be used as a new technique for medium-term forecasting of evaporation for the pentad period. In order to obtain the amount of evaporation, it is quite possible to obtain a forecast dependence on the values of air temperature and wind speed, provided there is no precipitation, when such a forecast is most important.

Effect of different nano-fertilizer on growth and yield of summer rice

In the developing world rice (Oryza sativa L.) is the most important cereal crop and it is the staple food of over half of the world’s population. More than 90% of rice is produced and consumed in Asia. Extensive use of chemical fertilizers causes a great alteration in soil physiology and reduce the soil fertility, damages the flora and causes soil erosion and reduce NUE (Nutrient Use Efficiency). A field experiment was conducted in the year 2019-20 in summer rice at the institutional farm, Jaguli, B.C.K.V, Nadia, West Bengal on “Effect of different nano-fertilizer on growth and yield of summer rice” to study the effect of nano-fertilizers on growth, yield and yield components of summer rice. In case of plant height and dry matter accumulation (g/m2), the highest value was observed in T8 treatment (50% Recommended dose of Zn + 100% N - P - K+ Foliar application of Nano Zn). In LAI also the same trend follows as like DMA. Maximum grain yield and straw yield was recorded from T8 treatment (5.61 t/ha and 6.18 t/ha respectively) followed by T9 treatment. It was observed that highest B:C ratio was also seen in T8 treatment followed by T9 and T3 treatment. From the economic analysis of different treatments, it was observed that highest B:C ratio was seen in T8 treatment followed by T9 and T3 treatment. So, T8 treatment is beneficial in economical aspect also.

Competitiveness and Policy Analysis of Potato Production in Different Agro-ecological Zones of Northern Areas: Implications for Food Security and Poverty Alleviation

Potato (L. Solanum tuberosum) belongs to Solanaceae family. It is the most important dicotyledonous tuber crop and possesses major socio-economic importance worldwide. It is the fourth most cultivated food crop after wheat, rice and maize in world. Potato is a good and cheaper source of carbohydrates, vitamins, minerals and proteins and also provides most of the trace elements, which can meet the energy requirement of the people living in the developing countries like Pakistan [Rahman (1986)]. About 325 million metric ton of potato is produced annually throughout the world [World Book (2001)]. This crop is financially more remunerative than cereals from food security and can be recommended as a partial replacement of cereals.