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Rice is a high-silica (SiO2·nH2O) accumulator. Silicon (Si) is designated as a beneficial element associated with multiple positive effects on crops. However, the presence of high silica content is detrimental to rice straw management, hampering its use as animal feed and as raw material in multiple industries. Rice straw management is a serious concern in north-western India, and it is eventually burned in situ by farmers, contributing to air pollution. A practical solution could lie in reducing the silica content in rice while also attaining sound plant growth. A set of 258 Oryza nivara accessions along with 25 cultivated varieties of Oryza sativa was used to assess the variation in straw silica content using the molybdenum blue colorimetry method. A large continuous variation was observed for straw silica content in O. nivara accessions, ranging from 5.08% to 16%, while it varied from 6.18% to 15.81% in the cultivated varieties. The O. nivara accessions containing 43%-54% lower straw silica content than the currently prominent cultivated varieties in the region were identified. A set of 22,528 high-quality single nucleotide polymorphisms (SNPs) among 258 O. nivara accessions was used for estimating population structure and genomewide association studies (GWAS). A weak population structure with 59% admixtures was identified among O. nivara accessions. Further, multi-locus GWAS revealed the presence of 14 marker-trait associations (MTAs) for straw silica content, with six of them co-localizing with previously reported quantitative trait loci (QTL). Twelve out of 14 MTAs showed statistically significant allelic differences. Thorough candidate gene analyses revealed the presence of promising candidate genes, including those encoding the ATPbinding cassette (ABC) transporter, Casparian thickening, multi-drug and toxin extrusion (MATE) protein, F-box, and MYB-transcription factors. Besides, ortho-QTLs among rice and maize genomes were identified, which could open ways for further genetic analysis of this trait. The findings of the study could aid in further understanding and characterizing genes for Si transport and regulation in the plant body. The donors carrying the alleles for lower straw silica content can be used in further marker-assisted breeding programs to develop rice varieties with lower silica content and higher yield potential. [ABSTRACT FROM AUTHOR]

Rice is one of the most widely consumed staple food for more than half of the population in the world. Brown spot caused by Helminthosporium oryzae accounts for 5% yield loss worldwide annually. Adversely affected fields show yield loss as high as 45%. The present study focuses on the several management aspects that are currently used to curb out the disease incidence and measures to be taken in near future for designing effective disease management protocol. The disease is of historic significance and a devasting outbroke in the Bengal Province during 1943 ended as the Great Bengal Famine resulting in starvation and an estimated demise of 2.1 to 3 million people. Brown spot is still devastating on looking the present scenario of damage to rice. Different approaches have been adopted ranging from the use of brown spot resistant rice cultivars, chemical ameliorations and biological control measures for the management of the disease. But, still the disease seems to be chronic and adverse in the current scenario. In this review, we have highlighted epidemiology, control measures practiced and several quantitative and qualitative gaps with respect to disease management, which if rectified, would lead to a strong impact on crop disease control and the sustainable Rice production that are pertinent to the present situation of farmers. [ABSTRACT FROM AUTHOR]

The genomes of an elite rice restorer line KMR3 (salinity-sensitive) and its salinity-tolerant introgression line IL50-13, a popular variety of coastal West Bengal, India, were sequenced. High-quality paired-end reads were obtained for KMR3 (147.6 million) and IL50-13 (131.4 million) with a sequencing coverage of 30X-39X. Scaffolds generated from the pre-assembled contigs of each sequenced genome were mapped separately onto the reference genome of Oryza sativa ssp. japonica cultivar Nipponbare to identify genomic variants in terms of SNPs and InDels. The SNPs and InDels identified for KMR3 and IL50-13 were then compared with each other to identify polymorphic SNPs and InDels unique and common to both the genomes. Functional enrichment analysis of the protein-coding genes with unique InDels identified GO terms involved in protein modification, ubiquitination, deubiquitination, peroxidase activity, and antioxidant activity in IL50-13. Linoleic acid metabolism, circadian rhythm, and alpha-linolenic acid metabolism pathways were enriched in IL50-13. These GO terms and pathways are involved in reducing oxidative damage, thus suggesting their role in stress responses. Sequence analysis of QTL markers or genes known to be associated with grain yield and salinity tolerance showed polymorphism in 20 genes, out of which nine were not previously reported. These candidate genes encoded Nucleotide-binding adaptor shared by APAF-1, R proteins, and CED-4 (NB-ARC) domain-containing protein, cyclase, receptor-like kinase, topoisomerase II-associated protein PAT1 domain-containing protein, ion channel regulatory protein, UNC-93 domain-containing protein, subunit A of the heteromeric ATP-citrate lyase, and three conserved hypothetical genes. Polymorphism was observed in the coding, intron, and untranslated regions of the genes on chromosomes 1, 2, 4, 7, 11, and 12. Genes showing polymorphism between the two genomes were considered as sequence-based new candidates derived from Oryza rufipogon for conferring high yield and salinity tolerance in IL50-13 for further functional studies. [ABSTRACT FROM AUTHOR]

Global climate change has seriously threatened agriculture and connected sectors, especially in developing countries like India. The Brahmaputra Valley in Assam, Northeast India, is vulnerable to climate change due to its agrarian economy, fragile geo-ecological setting, recurrent floods and droughts, and poor socioeconomic conditions of the farmers. The climate-induced hindrances faced by the rice farming community of this region and the local adaptation practices they employ have not been adequately studied. Therefore, we carried out a survey among 635 rice farmers across four agro-climatic zones of Assam, namely the Upper Brahmaputra Valley Zone, North Bank Plain Zone, Central Brahmaputra Valley Zone, and Lower Brahmaputra Valley Zone, to understand how they perceive and respond to climatic changes. The survey revealed that all the respondents have perceived an increase in ambient temperature, and 65% of the respondents have perceived a slight change in rainfall characteristics over the years. Most farmers reported adjusting the existing farming practices and livelihood choices to adapt to the changing climate. Farming adjustments were made mainly in terms of field preparation and management of water, rice variety, nutrients, and pests. Environmental variables like rainfall, flood, drought, and pest level, and socioeconomic variables like family size, education, farming experience, training, digital media exposure, and land area were found to influence farmers' adaptation choices. The findings imply that policies to strengthen flood, drought, pest management, education, land-use planning, agricultural training, and digital media applications in agriculture are needed for effective climate change adaptation in this region., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

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 R 2 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., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The present study was conducted to evaluate the arsenic (As) contamination and possible associated health hazards to exposed population in four villages of two districts (Nadia and North 24 Parganas) of West Bengal, India. The study included two villages each from Nadia (Jaguli and Kugacchi) and North 24 Parganas (Chamta and Byaspur) districts. Groundwater, surface water, soil, rice grains and rice-based food samples were collected from these villages. The results revealed the presence of As in high concentrations in groundwater (35.00 to 186.00 µg L -1 ), surface water (30.00 to 61.00 µg L -1 ), soil (46.17 to 66.00 mg kg -1 ), rice grains (0.017 to 1.27 µg g -1 ) and rice-based food products (0.012 to 0.40 µg g -1 ). The maximum As levels were recorded in all types of samples collected from Kugacchi village. The rice grain samples included high-yielding and local varieties, and the level of As in high-yielding varieties was found to be higher (0.72 to 1.27 µg g -1 ) than in local varieties (0.25 to 1.06 µg g -1 ). The data of As concentrations was used for understanding the hazard quotient (HQ) and incremental lifetime cancer risk (ILCR) to the As-exposed population, and significant non-carcinogenic and carcinogenic risks were revealed considering consumption of rice grains at 400 g per day. The study demonstrates the severity of As contamination in the surveyed villages, which may pose a hindrance to attainment of sustainable development goals (SDGs) by 2030 and proposes the implementation of requisite safety measures., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Management of agri-residues generated in large quantities necessitates for its accurate estimation. Data analysis using machine learning methods can predict the agri-residues generation. The objective of the study was to forecast agri-residues generation from rice, wheat, and oilseed crops in India using ML methods and their sustainable uses. Prediction of agri-residues was done first by forecasting the crop production via the application of ML techniques for the period 2022 to 2030, and then the amount of crop residues generation calculated by multiplying the crop productions with the residues-to-product-ratio (RPR) values of the respective crops. RPR was estimated by using the gravimetric ratio of the residue to the actual crop production. The crop-specific RPR values were taken from various earlier studies in Indian context. The RPR values of 1.73 for the rice, 1.65 for wheat, and 2.6 for the oilseed crop were used as a conversion factor for residues calculation. Machine learning models linear regression, sequential minimal optimization regression (SMOreg), M5 Rule, and Gaussian process were used in the study. SMOreg performed better in models tested by coefficient of determination, root mean square error, and mean absolute error. The models predicted the generation of residues in 2030 as rice straw and husk 195.76 Mt to 277.68 Mt, wheat straw 188.62 Mt to 266.95 Mt, and oilseed stalk and oil cakes 55.61 Mt to 96.30 Mt in India. An overview of the management of agri-residues discussed. Estimation of agri-residues can provide an opportunity to utilize them with the best possible ways, lessen pollution and promote a zero-waste strategy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Several energy-related strategies and scenarios have been suggested to address concerns about rising global temperatures. In addition to using renewable energy, the improvement in energy efficiency of conventional systems is also in focus. Policies are already in place in many countries, including India, to address the energy needs of rural and small-scale enterprises by gasifying locally available, diverse agricultural leftovers. Although rice husk and groundnut shell are two commonly used agricultural leftovers in the southern part of India, their appropriate blending must be studied to improve their conversion efficiency in co-gasification. Therefore, the primary objective of this research is to construct a statistical model utilizing response surface methodology (RSM) to analyze the thermochemical co-gasification of the aforementioned biomass materials. Since RSM can predict optimum performance with limited experimental data, this could contribute to the identification of the performance and operating parameters of an open-core gasifier. The model predicts that the mixture containing 20% rice husk and working at an ER of 0.25 and a reduction zone inlet temperature of 879.9 °C will be CO-23.53%, H 2 -13.97%, and CH 4 -3.56%. In addition, the lower heating value and gas yield can be as high as 6.17 MJ/Nm 3 and 2.369 m 3 /kg, respectively. This outcome can contribute to the effective utilization of biomass for energy supply in rural areas. However, the economic parameters must be analyzed to implement the same in any region., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

In response to the continuing high prevalence of anaemia recorded in the National Family Health Survey-5, the Indian government launched a policy for mandatory iron fortification of the rice provided through public nutrition programmes in India. This was done even though a rigorous evidence analysis had already concluded that rice fortification was not effective in preventing anaemia or iron deficiency at the population level. Fortification also poses a potential risk of iron toxicity over time, but there is no stated time period for the policy's implementation. The risk is particularly high in segments of the population who already have a high habitual iron intake, and who could be exposed to simultaneous fortification in different staples and food commodities along with the ongoing weekly Iron and Folic Acid tablets supplementation programme. Finally, this fortification policy also requires significant additional funding and resources to implement. It is crucial to examine such mandatory health actions, and to weigh the benefits and risks of harm, using the principles of public health ethics.

Sheath blight caused by soil borne necrotrophic fungus Rhizoctonia solani [teleomorph-Thanatephorus cucumeris (Frank) Donk.] is a major disease of rice. The disease is increasing over the year in India and cause up to 69% yield loss under favourable conditions. A total of 67 accessions of Oryza nivara were screened to identify resistance against sheath blight during 2015. Out of these, 16 accessions were found moderately resistant (MR) which were further evaluated during the year 2016 and 2017. After three years of screening, 12 of them were found to have a consistent moderate resistant reaction whereas four of the O. nivara accessions namely, IRGC81941, IRGC102463C, CR100097 and CR100110A have shown moderately susceptible to susceptible reaction against sheath blight. A correlation study revealed that different disease variables measured were significantly (P < 0.05) correlated. All the genotypes and genotype × environment interaction had a significant (P < 0.001) effect on all the disease variables. Cluster analysis showed that all the accessions were clustered into four groups which showed resistant, MR, moderately susceptible and susceptible reactions. Among all the O. nivara accessions IRGC81941A showed the maximum potential against sheath blight due to a least relative lesion height of 22.80%. None of the accession had complete resistance to the disease. The identified promising accessions such as IRGC81835, IRGC81941A, CR100008 and CR100111B can be utilized in a sheath blight resistance breeding program. [ABSTRACT FROM AUTHOR]

Postharvest crop residue burning (CRB) is a major policy issue in several developing countries because of harmful environmental and public health consequences. While the literature has extensively examined the reasons for rice CRB, much less is known about wheat residue management. This paper explores the drivers of CRB of wheat in India and relates it to farmers' prior decisions related to CRB of rice in the preceding season. Using primary data on residue management practices of 301 Indian farmers, whom we tracked over two consecutive harvests of rice (2018) and wheat (2019), we find that farmers are significantly more likely to burn wheat residue if they had previously burned rice residue. The possibility of this linkage or spillover increases the likelihood of wheat residue burning by 15.6 to 21 percent. Furthermore, farmers are undertaking wheat CRB despite the positive net benefit of choosing non-burning alternatives to manage crop residue. Our results suggest that ensuring well-functioning markets for crop residue, awareness campaigns, and recognition of spillover effects of residue management across crops over time can enable policies to promote pro-environmental postharvest choices., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Lopes et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Rice-growing districts in Uttar Pradesh, India, were surveyed during the months of July and October to record the frequency of occurrence and disease incidence of sheath blight caused by Rhizoctonia solani in paddy. A total of 180 paddy fields were surveyed at the block level of 21 districts, where almost all the rice varieties were found highly susceptible to R. solani and exhibited severe yield loss compared with low-infested fields. The district Muzaffarnagar had the highest rate of disease occurrence, while maximum disease severity was recorded in the district Saharanpur. This district also had the highest soil population of R. solani , followed by Mathura, Muzaffarnagar, Barabanki, Aligarh, Sultanpur, Mainpuri, and Rampur. The greatest relative yield loss attributed to sheath blight infestation was recorded in Mathura (40%). The yield loss was linearly correlated with soil population of R. solani and disease incidence. Disease occurrence, incidence, severity, and yield loss to paddy were all significantly greater in the area which experienced relatively higher temperatures (25 to 38°C) and relative humidity (49 to 100%) during the months of June to August. Furthermore, the fields applied with a total dose of 250 to 280 kg nitrogen/ha exhibited higher disease severity (2.9 to 3.3 score) compared with fields that received a moderate dose of 140 to 180 kg N/ha (0.9 to 1.8 disease severity score). The rice nursery fields were found almost free from the sheath blight, but the disease was quite prevalent in the paddy fields with 7.2 to 38.9% disease incidence which resulted in 14.3 to 39.7% yield loss to rice., Competing Interests: The author(s) declare no conflict of interest.

Rice yellow stem borer (Scirpophaga incertulas W), a monophagous pest, is the most destructive pest causing 3 to 95% yield losses in India. Though it accounts for 50 per cent of insecticides used in rice fields, their typical internal feeding behaviour necessitates other management options. In the present study, evaluation of various wild rice lines-wild rice magic population (WRM), derivative of crosses from six species viz., Oryza rufipogon, O.nivara, O.meridionalis, O.glumaepatula, O.barthi, O.gaberrima, O.longistaminata and O.sativa has been carried out. The results of field screening carried out in 38 wild rice introgressed lines, the entries WRM 2, WRM 6, WRM 10, WRM 12, WRM 14, WRM 43, WRM 44, WRM 45 and WRM 76 were moderately resistant to yellow stem borer. The morphological characters of the entries were recorded and correlated with stem borer damage. It revealed a significant negative correlation for plant height and top internode length for their resistant to yellow stem borer. [ABSTRACT FROM AUTHOR]

Purpleputtu (Oryza sativa ssp. indica cv. Purpleputtu) is a unique rice landrace from southern India that exhibits predominantly purple color. This study reports the underlying genetic complexity of the trait, associated domestication and de-domestication processes during its coevolution with present day cultivars. Along-with genome level allelic variations in the entire gene repertoire associated with the purple, red coloration of grain and other plant parts. Comparative genomic analysis using 'a panel of 108 rice lines' revealed a total of 3,200,951 variants including 67,774 unique variations in Purpleputtu (PP) genome. Multiple sequence alignment uncovered a 14 bp deletion in Rc (Red colored , a transcription factor of bHLH class) locus of PP, a key regulatory gene of anthocyanin biosynthetic pathway. Interestingly, this deletion in Rc gene is a characteristic feature of the present-day white pericarped rice cultivars. Phylogenetic analysis of Rc locus revealed a distinct clade showing proximity to the progenitor species Oryza rufipogon and O. nivara. In addition, PP genome exhibits a well conserved 4.5 Mbp region on chromosome 5 that harbors several loci associated with domestication of rice. Further, PP showed 1,387 unique when SNPs compared to 3,023 lines of rice (SNP-Seek database). The results indicate that PP genome is rich in allelic diversity and can serve as an excellent resource for rice breeding for a variety of agronomically important traits such as disease resistance, enhanced nutritional values, stress tolerance, and protection from harmful UV-B rays. [ABSTRACT FROM AUTHOR]

Lowland rice in tropical and subtropical regions can be detected precisely and its crop growth can be tracked effectively through Synthetic Aperture Radar (SAR) imagery, especially where cloud cover restricts the use of optical imagery. Parameterised classification with multi-temporal features derived from regularly acquired, C-band, VV and VH polarized Sentinel-1A SAR imagery was used for mapping rice area. A fully automated processing chain in MAPscape-Rice software was used to convert the multi-temporal SAR data into terrain-geocoded σ0 values, which included strip mosaicking, co-registration of images acquired with the same observation geometry and mode, time-series speckle filtering, terrain geocoding, radiometric calibration and normalization. Further Anisotropic non-linear diffusion (ANLD) filtering was done to smoothen homogeneous targets, while enhancing the difference between neighbouring areas. Multi-Temporal Features viz., max, min, mean, max date, min date and span ratio were extracted from VV and VH polarizations to classify rice pixels. Rice detection was based on the analysis of temporal signature from SAR backscatter in relation to crop stages. About sixty images across four footprints covering 16 samba (Rabi) rice growing districts of Tamil Nadu, India were obtained between August 2017 and January 2018. In-season site visits were conducted across 280 monitoring locations in the footprints for classification purposes and more than 1665 field observations were made for accuracy assessment. A total rice area of 1.07 million ha was mapped with classification accuracy from 90.3 to 94.2 per cent with Kappa values ranging from 0.81 to 0.88. Using ORYZA2000, a weather driven process based crop growth simulation model developed by IRRI, yield estimates were made by integrating remote sensing products viz., seasonal rice area, start of season and backscatter time series. By generating average backscatter for each time series and dB stack for each SoS, LAI values were estimated. The model has generated rice yield estimate for each hectare which were aggregated at administrative boundary level and compared against CCE yield. Yield Simulation accuracy of more than 86–91% at district level and 82–97% at block level from the study indicates the suitability of these products for policy decisions. SAR products and yield information were used to meet the requirements of PMFBY crop insurance scheme in Tamil Nadu and helped in identifying or invoking prevented/failed sowing in 529 villages and total crop failure in 821 villages. In total 303703 farmers were benefitted by this technology in getting payouts of INR 9.94 billion through crop insurance. The satellite technology as an operational service has helped in getting quicker payouts. [ABSTRACT FROM AUTHOR]

Rice has been cultivating and utilizing by humans for thousands of years under diverse environmental conditions. Therefore, tremendous genetic differentiation and diversity has occurred at various agro-ecosystems. The significant indica–japonica differentiation in rice provides great opportunities for its genetic improvement. In the present investigation, a total of 42 polymorphic InDel markers were used for differentiating 188 rice landraces and two local varieties of Chhattisgarh, India into indica and japonica related genotypes based on ‘InDel molecular index’. Frequency of japonica alleles varied from 0.11 to 0.89 among landraces. Results revealed that 104 rice landraces have indica type genetic architecture along with three tested indica cultivars Swarna, Mahamaya and Rajeshwari. Another 60 landraces were placed under ‘close to indica’ type. It was found that three rice landraces i.e. Kalajeera, Kapri, Tulsimala were ‘close to japonica’ type and 21 landraces were ‘intermediate’ type. The result from the calculation of ‘InDel molecular index’ was further verified with STRUCTURE, AMOVA, PCA and cluster analysis. Population structure analysis revealed two genetically distinct populations within the 190 rice landraces/genotypes. Based on AMOVA, ‘intermediate’ type, ‘close to japonica’ type and Dongjinbyeo (a japonica cultivar from Republic of Korea) displayed significant genetic differentiation (ɸPT = 0.642, P = 0.000) from ‘indica’ and ‘close to indica’ groups. The PCA scatter plot and dendrogram demonstrated a clear pattern of two major group differentiations. ‘Close to japonica’ type and ‘intermediate’ type landraces/genotypes were grouped with Dongjinbyeo and formed a separate cluster at 30% Jaccard’s similarity level from rest of the landraces/genotypes which were ‘close to indica’ or ‘indica’ type. Such a significant genetic differentiation among the locally adapted landraces could be exploited for the development of rice varieties introgressing higher yield potential and better plant types of japonica type as per the need of consumers and rice traders. [ABSTRACT FROM AUTHOR]

The aims of the present study were to determine the optimum sowing time of newly developed rice genotypes for high crop water productivity in non-flooded dry-seeded rice (DSR) in north-west India, and to identify the factors underlying high yielding genotypes by comparing their sink production in DSR. We evaluated differences in dry matter, nitrogen accumulation, translocation, yield formation and evapo-transpiration requirement of the selected genotypes developed for DSR (two cultivars; PR-115 and PR-121, two recombinant inbred lines; RIL-367 and RIL-1649) under three sowing dates (1, 10, and 20 June), for two years in the rainy seasons of 2014 and 2015 in north-west India. RIL-1649 sown on 1 June had higher grain yield (9.4 t ha −1 ) and similar or higher water productivity (1.3 kg m −3 ) than the other sowing date x genotype combinations. Delaying sowing from 1 to 10 June reduced yield of all genotypes except PR-121, and there was no further decrease in yield with delay to 20 June of PR-115 and RIL-1649. The yield of RIL-1649 sown on 20 June (7.9 t ha −1 ) was similar to that of PR-115 sown on 1 June.The high grain yield of RIL-1649 (7.9 t ha −1 ) for the late sowing was due to high pre- and post-anthesis dry matter accumulation, coupled with greater contribution of dry matter translocation to grain yield. RIL-367 not only produced similar yield (8.5 t ha −1 ) to the check variety PR-115 (8.3 t ha −1 ) for the 1 June sowing, but also matured 13 days earlier than PR-115.These results suggest that RIL-367 could be useful for DSR-based intensive cropping systems in north-west India, and with higher crop water productivity (1.32 kg m −3 ) than PR-115 (1.20 kg m −3 ). In the late sown condition, grain yield had a positive relationship with harvest index, leaf area index at flowering, preanthesis dry-matter accumulation, and dry matter translocation. A greater amount of dry matter and nitrogen uptake at anthesis, in combination with an increased harvest index, resulted in a greater amount of translocated material during the grain filling period. This, in turn, contributed to higher grain yield during late sowing. This study suggests that, for widening the sowing window, and for sustained yields of DSR in north-west India, high dry matter and nitrogen accumulation at anthesis, together with high harvest index, are useful selection traits. [ABSTRACT FROM AUTHOR]

Rice arsenic (As) contamination and its consumption poses a significant health threat to humans. The present study focuses on the contribution of arsenic, micronutrients, and associated benefit-risk assessment through cooked rice from rural (exposed and control) and urban (apparently control) populations. The mean decreased percentages of As from uncooked to cooked rice for exposed (Gaighata), apparently control (Kolkata), and control (Pingla) areas are 73.8, 78.5, and 61.3%, respectively. The margin of exposure through cooked rice (MoE cooked rice ) < 1 signifies the existence of health risk for all the studied exposed and control age groups. The respective contributions of iAs (inorganic arsenic) in uncooked and cooked rice are nearly 96.6, 94.7, and 100% and 92.2, 90.2, and 94.2% from exposed, apparently control, and control areas. LCR analysis for the exposed, apparently control, and control populations (adult male: 2.1 × 10 -3 , 2.8 × 10 -4 , 4.7 × 10 -4 ; adult female: 1.9 × 10 -3 , 2.1 × 10 -4 , 4.4 × 10 -4 ; and children: 5.8 × 10 -4 , 4.9 × 10 -5 , 1.1 × 10 -4 ) through cooked rice is higher than the recommended value, i.e., 1 × 10 -6 , respectively, whereas HQ > 1 has been observed for all age groups from the exposed area and adult male group from the control area. Adults and children from rural area showed that ingestion rate (IR) and concentration are the respective influencing factors towards cooked rice As, whereas IR is solely responsible for all age groups from urban area. A vital suggestion is to reduce the IR of cooked rice for control population to avoid the As-induced health risks. The average intake (μg/day) of micronutrients is in the order of Zn > Se for all the studied populations and Se intake is lower for the exposed population (53.9) compared to the apparently control (140) and control (208) populations. Benefit-risk assessment supported that the Se-rich values in cooked rice are effective in avoiding the toxic effect and potential risk from the associated metal (As)., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The present study, covering a period of 52 years (1966-2017), explores changes in agricultural land use and its consequences on crop productivity, diversity, and food availability in Haryana, an agriculturally developed state of India. The time series data on different parameters (area, production, yield, etc.) were collected from the secondary sources and analyzed with the help of compound annual growth rate, trend tests (simple linear regression and Mann-Kendall), and change point detection tests such as Pettitt, standard normal homogeneity, Buishand range, and Neumann ratio. Apart from above, the relative share of area and yield to total change in output was determined using decomposition analysis. The results revealed that agricultural land use became intensive and underwent significant alteration with multifold shifting in area from coarse cereals (maize, jowar, and bajra) to fine food grains (wheat and rice). The yield of all crops, especially wheat and rice witnessed a significant increase which subsequently led to an upsurge in their production. However, the production of maize, jowar, and pulses recorded negative growth despite of an increase in their yield. The results also revealed manifold increase in use of modern key inputs during the first two periods (1966-1985), but afterwards input use rate slowed down. Additionally, the decomposition analysis revealed that yield effect remained positive in changing the production of all crops, but area contributed positively only in wheat, rice, cotton, and oilseeds. The major findings of this study imply that the production of crops can be enhanced only through improvement in yield because there is no further scope left for horizontal expansion in cultivable area of the state., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Rice ( Oryza sativa ) is India's major crop. India has the most land dedicated to rice agriculture, which includes both brown and white rice. Rice cultivation creates jobs and contributes significantly to the stability of the gross domestic product (GDP). Recognizing infection or disease using plant images is a hot study topic in agriculture and the modern computer era. This study paper provides an overview of numerous methodologies and analyses key characteristics of various classifiers and strategies used to detect rice illnesses. Papers from the last decade are thoroughly examined, covering studies on several rice plant diseases, and a survey based on essential aspects is presented. The survey aims to differentiate between approaches based on the classifier utilized. The survey provides information on the many strategies used to identify rice plant disease. Furthermore, model for detecting rice disease using enhanced convolutional neural network (CNN) is proposed. Deep neural networks have had a lot of success with picture categorization challenges. We show how deep neural networks may be utilized for plant disease recognition in the context of image classification in this research. Finally, this paper compares the existing approaches based on their accuracy., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2023 V. Balaji et al.)

Water and carbon footprint assessment can be a good indicator of sustainable agricultural production. The present research quantifies the potential impact of near-future (2026-2050) climate change on water footprint (WF) and carbon footprint (CF) of farm-level kharif rice production of three locally grown varieties (Khandagiri, Lalat, and Swarna) in Odisha, India, under the two RCP scenarios of 4.5 and 8.5. The crop yield, water resources utilization, and greenhouse gas (GHG) emissions were estimated using the calibrated and validated DSSAT crop simulation model. The precipitation and temperature estimates from three regional climate models (RCM), namely HadGEM3-RA, RegCM4, and YSU-RSM were downscaled using the quantile mapping method. The results revealed a considerably high increase in the total WF of the Khandagiri, Lalat, and Swarna rice varieties elevating up to 101.9%, 80.7%, and 71.8% respectively during the mid-century for RCP 4.5 scenario, and 67.3%, 66.6%, and 67.2% respectively for RCP 8.5 scenario relative to the baseline WF. Moreover, compared to the green WF, the blue WF was projected to increase significantly (~ 250-450%) in the future time scales. This could be attributed to increasing minimum temperature (~ 1.7 °C) and maximum temperature (~ 1.5 °C) and reduced precipitation during the rice-growing periods. Rice yield was projected to continually decline in the future period (2050) with respect to the baseline (1980-2015) by 18.8% and 20% under RCP 4.5 and 8.5 scenarios respectively. The maximum CF of Swarna, Lalat, and Khandagiri rice were estimated to be 3.2, 2.8, and 1.3 t CO 2 eq/t respectively under RCP 4.5 and 2.7, 2.4, and 1.3 t CO 2 eq/t respectively under RCP 8.5 scenario. Fertilizer application (40%) followed by irrigation-energy use (30%) and farmyard manure incorporation (26%) were the three major contributors to the CF of rice production. Subsequently, management of N-fertilizer dose was identified as the major mitigation hotspot, simultaneously reducing carbon footprint and grey water footprint in the crop production process., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

-Enhancing the productivity of rainfed crops, especially rice, while coping with climate adversities and saving critical natural resources is essential for ensuring the food and nutrition security of a growing population. With this context, the present study was undertaken to validate promising farm innovation and adaptation practices used by small-medium landholding farmers for rice cultivation in eastern Uttar Pradesh (UP), north India, as well as to examine the sustainability of innovative practices for large-scale adoption. For this, a 3-year study comprising extensive field surveys and experiments was undertaken to compare single transplantation (ST) and double transplantation (DT) in rice along with organic addition (farm-yard manure, FYM) on crop growth, yield, climate resilience, soil quality, and overall sustainability i.e., social (women involvements and labour productivity), environmental (water productivity and nutrient use efficiency), and economic (benefit:cost ratio) dimensions of sustainability. Field experiments were conducted in triplicate using two local rice varieties (MotiNP-360 and Sampurna Kaveri) in two agroclimatic zones, namely the middle Gangetic plains and the Vindhyan zone, in the Mirzapur district of eastern Uttar Pradesh. The DT practices of rice with and without farm yard manure (FYM) (replacing at a dose of 25% NPK) were evaluated over conventional methods of rice cultivation (i.e., ST, as control) and analysis was done periodically. The DT practice improved growth (p < 0.05), percent fertile tiller and grain (p < 0.05), and rice yield (15-20% higher than ST), while also improving soil quality, yield indices, water and labour productivity, and the benefit-cost ratio. The DT practice also resulted in early maturity (10-15 days earlier than ST), created more labour days for women, decreased lodging and pest/disease incidence, as well as a subsequent reduction in the use of synthetic chemical pesticides and associated environmental costs. Importantly, the residual effects of FYM application significantly improved (p < 0.05) the grain yield in subsequent years of cropping. Optimizing DT cultivation practices, preferably with FYM input for various agro-climatic regions, is essential for large-scale sustainable rice production under changing climatic conditions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Hybrid rice requires adequate nitrogen (N) management in order to achieve good yields from its vegetative and reproductive development. With this backdrop, a field experiment was conducted at Regional Research Station (Coastal Saline Zone), Bidhan Chandra Krishi Viswavidyalaya, Kakdwip, West Bengal (India) to record growth and yield performance of hybrid rice (cv. PAN 2423) under varied N-fertilizer doses. A modelling approach was adopted for the first time in hybrid rice production system under coastal ecosystem of West Bengal (India). In the present study, the Agricultural Production Systems Simulator (APSIM) model was calibrated and validated for simulating a hybrid rice production system with different N rates. The APSIM based crop simulation model was found to capture the physiological changes of hybrid rice under varied N rates effectively. While studying the relationship between simulated and observed yield data, we observed that the equations developed by APSIM were significant with higher R 2 values (≥0.812). However, APSIM caused an over-estimation for calibrate data but it was rectified for validated data. The RMSE of models for all the cases was less than respective SD values and the normalized RMSE values were ≤20%. Hence, it was proved to be a good rationalized modelling and the performance of APSIM was robust. On the contrary, APSIM underestimated the calibrated amount of N (kg ha -1 ) in storage organ of hybrid rice, which was later rectified in case of validated data. A strong correlation existed between the observed and APSIM-simulated amounts of N in storage organ of hybrid rice (R 2 = 0.94** and 0.96** for the calibration and validation data sets, respectively), which indicates the robustness of the APSIM simulation study. Scenario analysis also suggests that the optimal N rate will increase from 160 to 200 kg N ha -1 for the greatest hybrid rice production in coming years under elevated CO 2 levels in the atmosphere. The APSIM-Oryza crop model had successfully predicted the variation in aboveground biomass and grain yield of hybrid rice under different climatic conditions., Competing Interests: Sukamal Sarkar is an Academic Editor for PeerJ., (© 2023 Sarkar et al.)

Surface ozone is a damaging pollutant for crops and ecosystems, and the ozone-induced crop losses over India remain uncertain and a topic of debate due to a lack of sufficient observations and uncertainties involved in the modeled results. In this study, we have used the observational data from MAPAN (Modelling Air Pollution And Networking) for the first time to estimate the relative yield losses, crop production losses, and economic losses for the two major crops (wheat and rice). The detailed estimation has been done focusing on three individual suburban sites over India (Patiala, Tezpur, and Delhi) and compared with other related studies over the Indian region. We have used the concentration-based metric (M7, 7-h average from 09:00 to 15:59 h) along with the cumulative ozone exposure indices (AOT40, accumulated exposure over a threshold of 40 ppb) and applied the exposure-response (E-R) functions for the calculation of the crop losses. Our study shows that the yearly crop losses can reach the level of 12.4-40.8% and 2.0-11.1% for the wheat and rice crops, respectively, at certain places like Patiala in India. The annual economic loss can be as high as $4.6 million and $0.7 million for wheat and rice crops, respectively, even at individual locations in India. Our estimated %RYL (relative yield loss) lies in the range of 0.3 + /0.6 times the recent regional model estimates which use only the AOT40 metric. Region-specific E-R functions based on factors suitable for the Indian region needs to be developed., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Rice is a staple food for over half of the world's population and has the second largest cereal production after maize. Rice yield has experienced many fold jumps since the 1950s. This happened primarily as the result of genetic improvement and increasing harvest index by reducing plant height using the semi-dwarf genes and utilization of heterosis by producing hybrids. Hybrid rice technology is one of the strongest tools to break the yield barrier. To make hybrid rice technology practically feasible it needs strong system of hybrid seed production at commercial rate. Unlike maize, rice is a self-pollinated crop and needs special techniques, like utilization of male sterility system for hybrid seed production. The first hybrid rice variety for commercial cultivation was released by China in 1976. Seeing the China's success many countries started the hybrid rice breeding programme. India also started this programme in 1989. In about two decades of efforts India released 65 hybrid rice varieties till 2013. Though, China is cultivating about 50% of its rice area under hybrid rice varieties, India is still struggling to enhance its acreage under hybrid rice from 4% to more. Because of complicated seed production system, higher seed cost and less preferred qualities of hybrid varieties it could not cover more area under cultivation in India. In 1998, China started work for developing super hybrid rice by combining an ideotype approach with the use of inter-sub specific heterosis. Till 2011, the Ministry of Agriculture, China approved 56 hybrid cultivars with great yield potential as super hybrid rice. Hence, India and China still have to work hard for developing high yielding super hybrids coupled with good cooking qualities and resistance/tolerance to major biotic and abiotic stresses. Suitable technology should also be developed to make hybrid seed production easier and cheaper. © 2015 Friends Science Publishers [ABSTRACT FROM AUTHOR]

Paddy, Oryza sativa L. (Poales: Poaecea) is infested by a series of lepidopteran, coleopteran, hemipteran, and acarine pests in India. Of the long list, the species Rice Leaf-Roller Pelopidas mathias (Fabricius, 1798) (Lepidoptera: Hesperiidae) is one of most encountered defoliators on paddy. Here we record and describe with illustrations, a new parasitic complex comprising of two new species of parasitic wasps, viz. Brachymeria eastwoodi Binoy, sp. nov. and Sympiesis eastwoodi James & Santhosh, sp. nov. on the pupae of P. mathias from southern India. The parasitoid complexes on P. mathias are also augmented., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Competing Interests: None

India has recently enacted Distinctiveness, Uniformity and Stability (DUS) characterization for rice. This paper focuses on DUS characterization using morphological descriptors for 21 rice varieties planted in a randomized block design during two kharif seasons (2007 and 2008). Data were recorded for 60 DUS descriptors (46 qualitative and 14 quantitative) folloiving guidelines from the International Union for the Protection of New Varieties of Plants (UPOV) and the Protection of Plant Varieties and Farmer's Rights Authority (PPV & FRA). Data on quantitative traits were subjected to Combined Over Years Distinctness (COYD) and Combined Over Years Uniformity (COYU) analyses. The descriptors offering the most discrimination were time to 50% heading, decorticated grain shape, and the colour of lemma and palea. The cultivar Sathi, an improved landrace entry, was observed to be the most distinct, with the rarest morphological features. Eight of the 21 qualitative and 8 of the 14 quantitative traits exhibited uniformity as determined by UPOV-recommended levels. Tivelve of the quantitative traits were relatively stable as judged by seasonal variation in Phenotypic Coefficient of Variation (PCV) and Genotypic Coefficient of Variation (GCV) values. Finally, the varieties were clustered following the eight grouping characteristics recommended by PPV & FRA. All the approaches clustered the improved landrace entities separately from the conventionally bred varieties. [ABSTRACT FROM AUTHOR]

India is the second largest producer of rice however rice productivity is the lowest among the top five rice growing countries in the world. Recent price rise of rice commodity and retirement of rice lands for non agriculture purposes necessitate analyzing the yield response and net returns in rice and suggesting measures to improve upon the existing situation in the country. This paper is an attempt to unravel the facts on yield response, returns and production growth in rice using time series data. The study reveals that there has been deceleration in growth rate of rice production and productivity in India. It is important to focus on yield breakthrough technologies to enhance the yield growth in rice. The study used decomposition model to disaggregate the effects of yield and area on production growth and found that yield effect is more in eastern states like West Bengal, Orissa, and Assam and therefore requires special emphasis for promotion of high yielding variety technology in the region. Rice yield response analysis evidently exhibited that irrigation has significant influence on rice yield and hence needs to be accorded top priority in improving the irrigation infrastructure. Net return over C2 cost is found to be too low and even negative in some of the major rice growing states in the country and hence efforts are required to enhance the profit level otherwise may have an impact on food security. [ABSTRACT FROM AUTHOR]

Climate change influences the current tropospheric ozone (O 3 ) budget due to industrialization and urbanization processes. In recent years, the impact of elevated O 3 on crop development and yield loss has emerged as one of the most important environmental issues, particularly in rural and suburban areas of the lower Indo-Gangetic Plains of India. The impact of the current tropospheric ozone (O 3 ) on the crop yield, photosynthetic yield, and enzymatic antioxidants of six rice (Oryza sativa L.) cultivars (IR 36, MTU 1010, GB 3, Khitish, IET 4786, and Ganga Kaveri) was investigated with and without the application of ethylenediurea (EDU). The results revealed that O 3 stress significantly affected crop yield, photosynthetic yield, and antioxidant enzymes. The findings showed that O 3 toxicity induces oxidative stress biomarkers, i.e., malondialdehyde (MDA) content, and was manifested by increasing the enzymatic antioxidants, i.e., superoxidase dismutase (SOD) and catalase (CAT) in four rice cultivars (IR 36, GB 3, IET 4786, and Ganga Kaveri). At the same time, the results also illustrated that the rice cultivars MTU 1010 and Khitish are more tolerant to O 3 stress as they had less oxidative damage, greater photosynthetic SPAD value, SOD and CAT activities, and lower MDA activity. The results also elucidated that the application of EDU decreased O 3 toxicity in sensitive cultivars of rice by increasing antioxidant defense systems. The current O 3 level is likely to show an additional increase in the near future, and the use of tolerant genotypes of rice may reduce the negative impacts of O 3 on rice production., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Rice agroecosystems are inhabited by a number of Steneotarsonemus species worldwide with various host plant relationships and taxonomic identities. To clarify this situation, a large-scale survey was initiated in rice growing belts of eastern India and this revealed the presence of four species of Steneotarsonemus viz. S. furcatus, S. konoi, S. spinki and S. subfurcatus. However, only S. spinki and S. subfurcatus were found infesting rice while the other species were found associated with a number of graminaceous weeds. We found three intraspecific variants within the population of S. spinki which are differentially distributed in nine separate locations covering four states across eastern India. A new subgenus Linzhangia is proposed for inclusion of exceptionally unique S. subfurcatus possessing setaceous v2 on prodorsum of female. Additionally, the population of S. spinki and S. subfurcatus were found to be differentially distributed across five different agroclimatic zones of West Bengal with S. spinki being the dominant species.

In recent years, environmental change has arisen as a ubiquitous problem and gained environmentalist's attention across the globe due to its long-term harmful effects on agricultural production, food supply, water supply, and livelihoods of rural households. The present study aims to explore the asymmetrical dynamic relationship between climate change and rice production with other explanatory variables. Based on the time series data of India, covering the period 1991-2018, the current study applied the nonlinear autoregressive distributed lag (NARDL) model and Granger causality approach. The results of the NARDL reveal that mean temperature negatively affects rice production in the long run while positively affecting it in the short run. Furthermore, positive shocks in rainfall and carbon emission have negative and significant impacts on rice production in the long and short run. In comparison, negative rainfall shocks significantly affect rice production in the long and short run. Wald test confirms the asymmetrical relationship between climate change and rice production. The Granger causality test shows feedback effect among mean temperature, decreasing rainfall, increasing carbon emission, and rice production. While no causal relationship between increasing temperature and decreasing carbon emission. Based on the empirical investigations, some critical policy implications emerged. Toward sustainable rice production in India, there is a need to improve irrigation infrastructure through increasing public investment and to develop climate-resilient seeds varieties to cope with climate change. Along with, at the district level government should provide proper training to farmers regarding the usage of pesticides, the proper amount of fertilizers, and irrigation systems., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Random amplified polymorphic DNA fingerprinting was performed to assess the genetic diversity among rarely cultivated traditional indica rice (Oryza sativa L.) varieties collected from a tribal hamlet of Kerala State, India. A total of 664 DNA bands amplified by 15 primers exhibited 72.9% polymorphism (an average of 32.3 polymorphic bands per primer). The varieties Jeerakasala and Kalladiyaran exhibited the highest percent (50.19%) polymorphism, while Thondi and Adukkan showed the lowest (9.85%). Adukkan (78 bands) and Jeerakasala (56 bands) yielded the highest and the lowest number of amplicons, respectively. Unweighted Pair Group Method with Arithmetic mean analysis using the Dice similarity coefficient showed the highest value of similarity coefficient between the varieties Adukkan and Thondi, both shared higher level of similarity (0.81), followed by Kanali and Thondi (0.88). Of the three subclusters, the varieties of Adukkan, Thondi, Kanali, Mannuveliyan, Thonnuranthondi, and Chennellu grouped together with a similarity of 0.77. The second group represented by Navara, Gandhakasala, and Jeerakasala with a similarity coefficient of 0.76 formed a cohesive group. The variety Kalladiyaran formed an isolated position that joined the second cluster. The Principal Coordinate Analysis also showed separation of Kalladiyaran from the other varieties. [ABSTRACT FROM AUTHOR]

Weed infestation is a major constraint to widespread adoption of aerobic, direct-seeded rice (Oryza sativa L.). Higher than optimum initial seeding density for obtaining more panicles/m2 is often accompanied by reduced panicle size and 1,000-grain weight, and high rate of spikelet sterility. On the other hand, weeds in plots with a lower seeding rate have a better chance to emerge, grow and build up a strong population and thus pose a serious crop-weed competition. Experiments were conducted during kharif (rainy season) 2008 and 2009 to determine the optimum seed rate that can substantially reduce rice-yield loss caused by weed competition under aerobic conditions. A factorial-treatment arrangement was used with factors consisting of five seed rates (15, 30, 60, 120, and 240 kg/ha) and two weed-pressure treatments (weedy-check and weed-free). Weed pressure caused a significant reduction in yield; there was up to 36.2% reduction in yield for weedy check as compared with the weed-free treatment. Seeding rate was inversely correlated to weed interference. The results suggested that higher seed rates caused significant reductions in weed dry matter, whereas higher than optimum seed rate (15-30 kg/ha) caused reduction in yield. Of all the seeding rates used, 15-30 kg/ha had the lowest grain-yield losses caused by weeds. Therefore, it was concluded that optimum seed rate in direct-seeded rice would minimize the effect of weed competition on rice growth and grain yield and thus would reduce herbicide use, promoting integrated-weed management. Further, this proposition improves economy of the farmers who are thinking to shift to hybrid rice, whose seed is very costly. This investigation supports use of hybrid rice cultivars in DSR using a seed rate of 15-30 kg/ha. [ABSTRACT FROM AUTHOR]

Porteresia coarctata (Syn = Oryza coarctata) is a tetraploid wild rice growing abundantly in the coastal region of India and some other Asian countries. The salt tolerance property of this mangrove associate has been dealt with by a number of workers earlier. The distinct morphology and leaf architecture enabling the plant to exclude salt is a characteristic feature of Porteresia in comparison with Oryza sp. A number of genes have been isolated and characterized from Porteresia that are related to the salt-tolerance property of the plant. Evidence have accumulated that some pathways critical to salt tolerance are in operation in Porteresia of which the inositol metabolic pathway has been recently elaborated. Some of the enzymes of Porteresia have been shown to function as salt-tolerant under in vitro studies giving a clue that this wild halophytic rice may have evolved genes and proteins capable of functioning under a salt environment. Bioprospecting of such genes and proteins coupled with genomic and proteomic approaches remain an exciting area of research in evaluating this plant as a model for salt tolerance for the rice plant. [ABSTRACT FROM AUTHOR]

Out of twenty-eight Oryza species, only two are cultivated. The indigenous practices of different regions vary. But the essence of the indigenous practices are low external input (LEI) based farming system, organic produce, preferences for taste and quality, and a number of innovations involved. The present paper elucidates the traditional organic rice farming in Uttarakhand, India and its commonalities with the System of Rice Intensification (SRI). In SRI, six principles of rice cultivation are followed: use of small young seedlings, single plant transplantation, wide spacing in square geometty, use of organic manure, limited irrigation instead of flood irrigation, and mechanical weeding. The yield obtained is 60% higher in comparison to conventional transplanting. The cost savings are through the operations such as low seed rate (7.5 kg ha-1), water saving, and mechanical weeding. The increased drudgery in transplanting operations is compensated by other complementary operations like saving of time in weeding, watering, and disease and pest control. The added benefits are higher yield and reduction in emission of greenhouse gases. [ABSTRACT FROM AUTHOR]

The northeastern hills of India are endowed with rich source of rice germplasm, which may be safely estimated about 9,000 accessions, excluding the redundancies. Even though much of the germplasm have been collected, studies on nutritional aspects of these local cultivars are still lacking. Fifteen important indigenous rice genotypes collected from different rice growing ecosystem of this region were studied for physical and nutritional qualities. Kernel color of the genotypes varied from white to dark purple. All the genotypes except Manipuri were of bold-grain type. Most of the genotypes studied have fat contents more than 2.0%. The protein content was found higher in Chahou angouba and Naga special. Five cultivars were identified as high-protein cultivars of rice, with 10–12.07% protein content. Amylose content varied from 2.27 to 24.5%. Most of long-grained genotypes recorded lesser amylose than short grained. Chahou varieties were found aromatic and glutinous, which demand higher market prices in local market. PRACTICAL APPLICATION The north-eastern hills of India are endowed with rich source of rice germplasm, and much of the germplasm have been collected, but studies on basic and advanced nutritional aspects of these local cultivars are still lacking. This part of India has valuable rice genotypes of strong aroma, glutinous characters and slender grains with high amount of protein, fat and fiber. Having not known to the rest of the world and even to indigenous end users, some of such cultivars have already been lost, and some more are at the verge of extinction. Quality evaluation done in the present study provided useful information on their commercial exploitation and utilization in breeding programs of nutritional enhancement of rice to fight malnutrition among rice-consuming population, which is largest in the world. [ABSTRACT FROM AUTHOR]

Arsenic (As) contamination of rice plants can result in high total As concentrations (t-As) in cooked rice, especially if As-contaminated water is used for cooking. This study examines two variables: (1) the cooking method (water volume and inclusion of a washing step); and (2) the rice type (atab and boiled). Cooking water and raw atab and boiled rice contained 40 μg As l-1 and 185 and 315 μg As kg-1, respectively. In general, all cooking methods increased t-As from the levels in raw rice; however, raw boiled rice decreased its t-As by 12.7% when cooked by the traditional method, but increased by 15.9% or 23.5% when cooked by the intermediate or contemporary methods, respectively. Based on the best possible scenario (the traditional cooking method leading to the lowest level of contamination, and the atab rice type with the lowest As content), t-As daily intake was estimated to be 328 μg, which was twice the tolerable daily intake of 150 μg. [ABSTRACT FROM AUTHOR]

The Asian rice gall midge, Orseolia oryzae (Wood-Mason) (Diptera: Cecidomyiidae), is a major pest of rice [ Oryza sativa L. (Poaceae)] in India. Breeding resistant varieties and their cultivation has been the main approach to manage this pest. However, the breakdown of resistance conferred by the major genes, deployed one at a time, through evolution of virulent biotypes has become a major setback to this approach. Development of polymerase chain reaction-based molecular markers for eight of the 10 resistance genes and their possible use in marker-assisted selection has enabled breeders to pyramid resistance genes for achieving durable resistance. However, the choice of resistance genes needs to be made with a better understanding of the virulence composition of the pest populations in the target area and the genetics of plant resistance and insect virulence, as the rice–gall midge interaction is a gene-for-gene one. We adopted a single-female test and coupled it with a modified F2 screen test to note the virulence composition of gall midge populations and estimated the frequency of virulence alleles for adaptation at three pest endemic locations in India, namely, Warangal, Ragolu, and Raipur. Results on biotype composition showed heterogeneous pest populations in all the tests and at all the locations. Tests at Warangal repeated after 8 years showed a rapid increase in frequency of the virulence allele conferring adaptation to the plant resistance gene Gm2 as compared to that of the allele for adaptation to the resistance gene Gm1. This is probably the first direct measurement of a durability parameter of plant genes conferring insect resistance. Results supported earlier observations that sex-linked virulence against Gm2 makes it less durable. The sex ratio did not deviate from the expected 1:1 ratio at Warangal, but at Ragolu females outnumbered males. [ABSTRACT FROM AUTHOR]

In the present study, pressurised liquid extraction and ultrasound probe sonication, for the latter in combination with a mixed enzymatic treatment in case of rice and straw samples, were applied as sample preparation prior to arsenic speciation analysis by high pressure liquid chromatography coupled to inductively coupled plasma mass spectrometric detection (HPLC-ICP-MS). A significant number of samples as different as rice, straw, soil, nail and hair, all coming from the heavily arsenic-contaminated Middle and Lower Ganga plain area, could be investigated with validated methods, supported by high speed extraction methods. For rice and paddy samples, inorganic arsenic counted up to 70-98% of the total arsenic content, being the major species As (III). The levels of arsenic obtained from straw and soil samples are significantly higher than the background levels, being the major species As (V), thus increasing human exposure to arsenic via the soil-plant-animal-human pathway. Concentrations found in hair and nails were significantly higher than their background levels: 39- and 20-fold for hair and nails, respectively. These samples contained mainly inorganic arsenic in its tri- and pentavalent forms. Results indicate that, under the local frame conditions, arsenic mainly enters into the food chain via its more problematic inorganic forms. Arsenic speciation analysis proves to be a powerful tool for a complete analytical assessment in epidemiological studies covering the endemic areas. [ABSTRACT FROM AUTHOR]

Cyanobacteria comprise a large group of structurally complex and ecologically significant gram-negative prokaryotes which flourish in rice paddies, and play a major role in sustaining the fertility of this ecosystem. This study aimed to characterize the abundance of cyanobacteria in various rice ecologies of India, identify the isolates and determine diversity indices in relation to the genera wise distribution. Average population counts (measured as MPN) of various locations clearly brought out the tremendous diversity among the locations sampled. Soil samples from Jeypore (Orissa state) recorded highest diversity and 20 cyanobacterial forms, spanning 9 genera were isolated. Nostoc and Anabaena were found to be the dominant genera in all the locations, in terms of their abundance and exhibited highest diversity indices. Our results suggest the need for practical utilization of these organisms towards developing region-specific inocula–which can establish better in their niche and provide maximum benefits to the crop. [ABSTRACT FROM AUTHOR]

An understanding of the dynamics of carbon (C) stock in soils, as impacted by management strategies, is necessary to identify the pathways of C sequestration in soils and for maintaining soil organic C (SOC) at a level critical for upkeeping soil health and also for restraining global warming. This is more important in tropical and subtropical region where soils are inherently low in organic C content and the production system is fragile. We evaluated the long-term role of crop residue C inputs to soil in SOC sequestration and also the critical value of C inputs for maintenance of SOC across five different rice-based cropping systems and four soil management practices including a fallow (no cultivation since initiation of the experiments) using five long-term (7–36 years) fertility experiments in subtropical India. Cropping per se always caused a net depletion of SOC. Such depletion was inversely proportional to the amount of crop residue C incorporated into the soils ( r=−0. 92, P=0. 001). Balanced fertilization with NPK, however, caused an enrichment (9. 3–51. 8% over the control) of SOC, its extent being influenced by the cropping systems. Long-term application of organic amendments (5–10 Mg ha−1 yr−1) through farmyard manure (FYM) or compost could increase SOC hardly by 10. 7% constituting only 18% of the applied C, the rest getting lost through oxidation. The total quantity of soil C sequestered varied from −11. 5 to 14. 5 Mg C ha−1 and was linearly related ( r2=0. 40, P=0. 005) with cumulative crop residue C inputs to the soils. On an average, the rate of its conversion to SOC came out to be 6. 4%. This was more in presence of added organics (6. 9%) than in its absence (4. 2%). For sustenance of SOC level (zero change due to cropping) we found that a minimum quantity of 2. 9 Mg C is required to be added per hectare per annum as inputs. The cropping systems and the management practices that could provide C input higher than the above critical level are likely to sustain the SOC level and maintain good soil health in the subtropical regions of the Indian subcontinent. [ABSTRACT FROM AUTHOR]

Crop growth simulation models provide a means to quantify the effects of climate, soil and management on crop growth and biogeochemical processes in soil. The Denitrification and Decomposition (DNDC) model was evaluated for its ability to simulate methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2) emissions from Indian rice fields with various management practices. The model was calibrated and validated for field experiments in New Delhi, India. The observed yield, N uptake and greenhouse gas (GHG) emissions were in good agreement with the values predicted by the model. The model was then applied for estimation of GHG emissions from rice fields in India using a newly compiled soil/climate/land use database. Continuous flooding of rice fields (42.25 million ha) resulted in annual net emissions of 1.07-1.10, 0.038-0.048 and 21.16-60.96 Tg of CH4-C, N2O-N and CO2-C, respectively, with a cumulated global warming potential (GWP) of 130.93-272.83 Tg CO2 equivalent. Intermittent flooding of rice fields reduced annual net emissions to 0.12-0.13 Tg CH4-C and 16.66-48.80 Tg CO2-C while N2O emission increased to 0.056-0.060 Tg N2O-N. The GWP, however, reduced to 91.73-211.80 Tg CO2 equivalent. The study suggests that the model can be applied for studying the GHG related issues in rice cropping systems of India. [ABSTRACT FROM AUTHOR]

Bacterial Blight (BB) caused by Xanthomonas oryzae pv. oryzae is a major disease of rice in tropical Asia. Since all the Basmati varieties are highly susceptible and the disease is prevalent in the entire Basmati growing region of India, BB is a severe constraint in Basmati rice production. The present study was undertaken with the objective of combining the important Basmati quality traits with resistance to BB by a combination of phenotypic and molecular marker-assisted selection (MAS). Screening of 13 near-isogenic lines of rice against four isolates of the pathogen from Basmati growing regions identified the Xa4, xa8, xa13 and Xa21 effective against all the isolates tested. Two or more of these genes in combination imparted enhanced resistance as expressed by reduced average lesion length in comparison to individual genes. The two-gene pyramid line IRBB55 carrying xa13 and Xa21 was found equally effective as three/four gene pyramid lines. The two BB resistance genes present in IRBB55 were combined with the Basmati quality traits of Pusa Basmati-1 (PB-1), the most popular high yielding Basmati rice variety used as recurrent parent. Phenotypic selection for disease resistance, agronomic and Basmati quality characteristics and marker-assisted selection for the two resistance genes were carried out in BC1F1, BC1F2 and BC1F3 generations. Background analysis using 252 polymorphic amplified fragment length polymorphism (AFLP) markers detected 80.4 to 86.7% recurrent parent alleles in BC1F3 selections. Recombinants having enhanced resistance to BB, Basmati quality and desirable agronomic traits were identified, which can either be directly developed into commercial varieties or used as immediate donors of BB resistance in Basmati breeding programs. [ABSTRACT FROM AUTHOR]

A method was developed for determining the surface area and volume of rice mesophyll cells of elaborate configuration. The method was employed to calculate these indices in several types of rice mesophyll cells found in seventy samples (53 species) of diverse origin coming from Japan, China, Korea, India, Nepal, Australia, France, Italy, Uzbekistan, Afghanistan, and Krasnodar and Primorskii regions. The cultivars of diverse geographic origin varied in cell shape and size due to the number, size, and arrangement of chloroplasts. When the volumes and surface areas of leaf mesophyll cells were compared using the method reported herein and a simple empirical model of the cell as a single ellipsoid, the two methods produced relatively similar data for cell volume; however, the surface area calculated by the former method was about two times larger than in the latter case. The method described in this paper allows for accurate calculations of the volume and surface area of rice mesophyll cells when data are available on the cell shape and linear dimensions and the number of chloroplasts per cell. [ABSTRACT FROM AUTHOR]

Oryza malampuzhaensis Krish. et Chand., one of the tetraploid taxa in the genus Oryza (Poaceae), is geographically restricted to Western Ghats, southern India. This is one of the poorly understood taxa in the genus, and not much is known about the nature and distribution of its genetic diversity. Five individuals each were selected randomly from 11 populations of O. malampuzhaensis from different altitudinal habitats and were grown in a common-garden experiment for 3 years (1994-1997). Sixty morphological traits and 87 random amplified polymorphic DNA (RAPD) markers, generated by 14 random primers, were used to study the genetic variation among the populations. Elevation-dependent phenotypic variation was observed for a suite of metric traits. A scatterplot of mean values for these traits separated the populations from low, middle, and high altitudes into distinct groups. Cluster analysis using RAPD distance grouped the populations according to their altitudinal habitat, and a similar pattern of clustering was observed with respect to morphological distance also. The mean of both RAPD- and morphology-based pairwise genetic distance of populations belonging to similar altitudinal levels differed significantly. These estimates also depicted a significant decrease in genetic distance with increasing altitude. The results demonstrate that (i) effective isolation from gene flow coupled with natural selection governs genetic structure in O. malampuzhaensis and (ii) ecological heterogeneity associated with elevational gradient has a crucial role in the evolution of O. malampuzhaensis.Key words: Oryza malampuzhaensis, altitude, RAPD, morphological traits, genetic variations, molecular ecology.L'Oryza melampuzhaensis Krish. et Chand., un des taxons tétraploïdes du genre Oryza (Poaceae), est géographiquement restreint aux Western Ghats, dans le sud de l'Inde. Il s'agit d'un des taxons mal compris de ce genre, et on sait peu de choses à propos de la nature et de la distribution de sa diversité génétique. Cinq individus, sélectionnés au hasard à partir de chacune de 11 populations de l'O. melampuzhaensis provenant d'habitats situés à diverses altitudes, ont été cultivés dans un jardin expérimental commun, pendant 3 ans (1994-1997). Pour étudier la variation génétique au sein des populations, les auteurs ont utilisé 60 caractères morphologiques et 87 marqueurs RAPD (amplification aléatoire du polymorphisme de l'ADN), générés à l'aide de 14 amorces aléatoires. La variation phénotypique dépendante de l'élévation se révèle dans un ensemble de caractères quantitatifs. Un graphique de distribution des valeurs moyennes obtenues pour ces caractères sépare les populations en groupes distincts selon les altitudes faibles, moyennes et élevées. L'analyse par regroupements à l'aide des distances RAPD groupe les populations selon leur habitat altitudinal, et on observe un patron similaire de regroupement en relation avec la distance morphologique également. Les moyennes de la distance génétique des populations appartenant à des altitudes similaires, basée sur les paires RAPD-morphologie, diffèrent significativement. Ces valeurs estimées montrent également une diminution significative de la distance génétique avec une augmentation de l'altitude. Ces résultats démontrent : (i) qu'une isolation réelle par rapport au flux génétique, couplée avec la sélection naturelle, dicte la structure génétique chez l'O. melampuzhaensis et (ii) que l'hétérogénéité écologique associée avec le gradient d'élévation joue un rôle déterminant dans l'évolution de l'O. melampuzhaensisMots clés : Oryza melampuzhaensis, altitude, RAPD, caractères morphologiques, variation génétique, écologie moléculaire.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Climate change induced heat stress is predicted to negatively impact wheat yields across the Indo-Gangetic Plains (IGP) of India. Research suggests that early sowing of wheat can substantially reduce this impact. However, a large proportion of farmers sow wheat late across this region, likely resulting in large-scale yield loss. We examined the extent of late wheat sowing across the IGP and which perceptional, management, biophysical, and socio-economic factors are associated with delayed sowing using household survey data from 2429 farmers and the cumulative logit model. Our results indicate that despite understanding that early sowing can be helpful to avoid terminal heat stress, over 50% of farmers sow wheat later than their perceived ideal wheat sowing date. We find that variables related to how wheat fields are prepared prior to sowing are associated with wheat sowing date. Specifically, farmers who had shorter fallow periods prior to sowing wheat and those who used zero tillage were 95% and 65% more likely to sow wheat earlier, respectively. In addition, we found that how farmers managed their rice crop in the preceding cropping season impacted wheat sowing date - farmers who transplanted and harvested rice later and/or planted longer duration rice varieties sowed their wheat later. Our results suggest that policies that promote earlier sowing of rice, such as improved access to irrigation and direct seeding machinery, and reduced field preparation time, such as wider adoption of zero tillage technologies, can help farmers across the IGP sow wheat earlier. This is critical given that warming temperatures will only increase the negative impacts of terminal heat stress on wheat yields across this region over the coming decades., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Global warming and food security have led to increasing concern about agricultural crop production efficiency, especially wheat and rice farming. The purpose of the current study is to measure wheat and rice production efficiency scores with environmental quality in China, India, and Pakistan by using a data envelopment analysis (DEA) model. The DEA results show that China and India are more efficient in wheat and rice production but it is not efficient in the environment in the study period. The results also show that Pakistan has also relatively small wheat and rice efficiency compared with China and India and increased the efficiency with the passage of time. The practical outcomes also show that Pakistan has the most efficient and effective states from the periods 2008 to 2019 in terms of wheat and rice efficiency and also a small increase in carbon emission. Based on the findings, policymakers should pay attention to the role of green technology in reducing agricultural CO2 emissions., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

When public health programs with single nutrients are perceived to have a poor impact on the target health outcome, the policy response can be to supply more, by layering additional mandatory programs upon the extant programs. However, we argue for extreme caution, because nutrients (like medicines) are beneficial in the right dose, but potentially harmful when ingested in excess. Unnecessary motivations for the reactionary layering of multiple intervention programs emerge from incorrect measurements of the risk of nutrient inadequacy in the population, or incorrect biomarker cutoffs to evaluate the extent of nutrient deficiencies. The financial and social costs of additional layered programs are not trivial when traded off with other vital programs in a resource-poor economy, and when public health ethical dilemmas of autonomy, equity, and stigma are not addressed. An example of this conundrum in India is the perception of stagnancy in the response of the prevalence of anemia to the ongoing pharmacological iron supplementation program. The reaction has been a policy proposal to further increase iron intake through mandatory iron fortification of the rice provided in supplementary feeding programs like the Integrated Child Development Services and the School Mid-Day Meal. This is in addition to the ongoing pharmacological iron supplementation as well as other voluntary iron fortifications, such as those of salt and manufactured food products. However, before supplying more, it is vital to consider why the existing program is apparently not working, along with consideration of the potential for excess intake and related harms. This is relevant globally, particularly for countries contemplating multiple interventions to address micronutrient deficiencies. Supplying more by layering multiple nutrient interventions, instead of doing it right, without thoughtful considerations of social, biological, and ethics frameworks could be counterproductive. The cure, then, might well become the malady., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.)