Stress Tolerant Rice Varieties Research Articles

Multi-omics approaches for abiotic stress tolerance in rice (Oryza sativa L.)

Rice, one of the world's staple crops, faces significant challenges due to abiotic stresses such as drought, salinity and extreme temperatures, which threaten global food security. Traditional breeding methods have limitations in developing stress-tolerant rice varieties within a short time frame. Thus, there is a growing interest in employing multi-omics approaches, integrating genomics, transcriptomics, proteomics, metabolomics and epigenomics, to unravel the complex molecular mechanisms underlying abiotic stress tolerance in rice. In contrast to a single-omics method, this combination of multi-dimensional approaches provides an extensive understanding of cellular dynamics under abiotic stress conditions. This review discusses recent advances in multi-omics technologies and their applications in dissecting the molecular responses of rice to abiotic stresses. It highlights the integration of multi-omics data to identify critical genes, pathways and regulatory networks involved in stress responses and tolerance mechanisms.Furthermore, it explores the potential of multi-omics-assisted breeding strategies for developing stress-tolerant rice varieties with improved agronomic traits. The challenges and future perspectives in utilizing multi-omics approaches to enhance rice's abiotic stress tolerance are also discussed. Overall, multi-omics approaches offer a comprehensive platform to understand the molecular basis of stress tolerance in rice and accelerate the development of resilient varieties to ensure global food security.

Physiological Responses of Stress Tolerant Rice Varieties across Different Cropping Systems under Rainfed Stress

Rice, sustaining half of the world's population, is traditionally cultivated through transplanting, particularly in Asia. However, challenges like excessive water use, labour demands, and environmental stresses like drought prompt the search for alternatives. Our study evaluates the impact of various crop establishment methods (CEs) – conventional puddled transplanting, direct drill seeding on flatbeds (DSR), and direct seeding on raised beds (FIRB) – on five stress-tolerant rice varieties (V): DRR 42, DRR 44, Sukha Dhan 5, Sukha Dhan 6, and Sarjoo 52. The key physiological parameters like Relative Water Content, Membrane Stability Index, and Chlorophyll content were analysed across different CE and V combinations. Notably, FIRB consistently surpasses other methods, suggesting its potential in bolstering stress tolerance and yield. Among the five varieties, Sukha Dhan 5 (V3) displays the highest RWC, Sarjoo 52 (V5) in MSI, and DRR 44 (V2) demonstrates superior chlorophyll content. These varieties underscore their pivotal role in maintaining plant water status, facilitating robust photosynthesis, and enhancing stress resilience, thereby ensuring stable yields. Our findings underscore FIRB's promise in curbing water waste and mitigating drawbacks associated with conventional transplanting practices.

Assessment of Biochemical Parameters and Yield Performance in Rice under Different Crop Establishment Methods

Rice (Oryza sativa L.), a staple food for half of the global population, is cultivated using various methods, with transplanting being conventional in many Asian countries. However, challenges such as high-water consumption, labour intensiveness, and environmental degradation have prompted the exploration of alternative methods. In this study, we assessed the impact of various crop establishment methods (CE) i.e. conventional puddled transplanting, direct drill seeding on flatbed (DSR), and direct seeding on raised beds (FIRB) on five stress-tolerant rice varieties (V) i.e. DRR 42, DRR 44, Sukha Dhan 5, Sukha Dhan 6 and Sarjoo 52 by analysing biochemical parameters i.e. total sugar content, starch content, MDA content, SOD content and yield outcomes. Our findings reveal significant variations in biochemical parameters and yield across different CE and V combinations. Notably, FIRB consistently outperformed other CEs, indicating its potential for enhancing stress tolerance and yield. Similarly, DRR 44 exhibited superior performance across most growth stages. Our study highlights the potential advantages of FIRB method in mitigating water wastage and addressing the limitations of conventional transplanting practices.

Marker-assisted breeding accelerates the development of multiple-stress-tolerant rice genotypes adapted to wider environments.

Rice, one of the major staple food crops is frequently affected by various biotic/abiotic stresses including drought, salinity, submergence, heat, Bacterial leaf blight, Brown plant hopper, Gall midge, Stem borer, Leaf folder etc. Sustained increase of yield growth is highly necessary to meet the projected demand in rice production during the year 2050. Hence, development of high yielding and multiple stress tolerant rice varieties adapted to wider environments will serve the need. A systematic MAB approach was followed to pyramid eight major QTLs/genes controlling tolerance to major abiotic/biotic stresses viz., drought (qDTY1.1 and qDTY2.1), salinity (Saltol), submergence (Sub1), bacterial leaf blight (xa13 and Xa21), blast (Pi9) and gall midge (Gm4) in the genetic background of an elite rice culture CBMAS 14065 possessing high yield and desirable grain quality traits. Two advanced backcross derivatives of CBMAS 14065 possessing different combinations of target QTLs namely #27-1-39 (qDTY1.1+qDTY2.1+Sub1+xa13+Xa21+Gm4+Pi9) and #29-2-2 (qDTY1.1+qDTY2.1+Saltol+Xa21+Gm4+Pi9) were inter-mated. Inter-mated F1 progenies harboring all the eight target QTLs/genes were identified through foreground selection. Genotyping of the inter-mated F4 population identified 14 progenies possessing all eight target QTLs/genes under homozygous conditions. All the fourteen progenies were forwarded up to F8 generation and evaluated for their yield and tolerance to dehydration, salinity, submergence, blast and bacterial leaf blight. All the 14 progenies exhibited enhanced tolerance to dehydration and salinity stresses by registering lesser reduction in their chlorophyll content, relative water content, root length, root biomass etc., against their recurrent parent Improved White Ponni/CBMAS 14065. All the 14 progenies harboring Sub1 loci from FR13A exhibited enhanced survival (90 - 95%) under 2 weeks of submergence /flooding when compared to their recurrent parent CBMAS 14065 which showed 100% susceptibility The inter-mated population showed a enhanced level of resistance to bacterial leaf blight (Score = 0 to 2) against blast (Score - 0) whereas the susceptible check CO 39 and the recurrent parent CBMAS 14065 recorded high level of susceptibility (Score = 7 to 9). Our study demonstrated the accelerated development of multiple stress tolerant rice genotypes through marker assisted pyramiding of target QTLs/genes using tightly linked markers. These multiple stress tolerant rice lines will serve as excellent genetic stocks for field testing/variety release and also as parental lines in future breeding programs for developing climate resilient super rice varieties.

Crop Intensification through Short Duration Stress-Tolerant Rice Varieties with Green Gram for Fostering Agricultural Resilience and Sustainability

Rice stands as a critical cornerstone in the pursuit of food security due to its unparalleled significance as a staple crop for billions of people worldwide. Rice in India, is cultivated within diverse cropping systems that harness the nation's rich agro-climatic variations. Eastern India has emerged as a significant contributor to the country's overall rice production. Nevertheless, most of the existing cropping systems of rice in this region suffer from some drawbacks, primarily due to monoculture practices and limited crop diversity. An experiment was conducted in the Eastern Indian State of Odisha to evaluate the efficiency and profitability of promoting a rice-green gram-rice cropping system. The experiment consists of two major interrelated interventions viz., awareness regarding short-duration stress-tolerant rice varieties (STRV) and the introduction of the new crop for higher economic returns. Varietal awareness programs were organized before the onset of the wet season of 2020 and the potential benefits of cultivating STRV over the popular traditional cultivars were communicated to the target farmers, besides advocating the rice-green gram-rice cropping system. The study employed a field experiment design to compare the performance of existing and new cropping systems. The impact evaluation was carried out after recording the comments of the farmers followed by a thorough comparison between the new and existing cropping systems. The available evidence suggests that the introduced short-duration STRVs are better than the already existing varieties and have the potential to change the cropping system of the region. The most desirable trait of these varieties as reported by the farmers is their short maturity duration. The results do unequivocally demonstrate the superior performance of the new cropping system over the existing system in terms of crop yield, diversification, and profitability. This remarkably underscores the potential of the new system to address food security challenges and enhance agricultural productivity.

Comparison of the Morpho-Physiological and Molecular Responses to Salinity and Alkalinity Stresses in Rice.

Rice is a major food crop that has a critical role in ensuring food security for the global population. However, major abiotic stresses such as salinity and alkalinity pose a major threat to rice farming worldwide. Compared with salinity stress, there is limited progress in elucidating the molecular mechanisms associated with alkalinity tolerance in rice. Since both stresses coexist in coastal and arid regions, unraveling of the underlying molecular mechanisms will help the breeding of high-yielding stress-tolerant rice varieties for these areas. This study examined the morpho-physiological and molecular response of four rice genotypes to both salinity and alkalinity stresses. Geumgangbyeo was highly tolerant and Mermentau was the least tolerant to both stresses, while Pokkali and Bengal were tolerant to only salinity and alkalinity stress, respectively. A set of salinity and alkalinity stress-responsive genes showed differential expression in the above rice genotypes under both stress conditions. The expression patterns were consistent with the observed morphological responses in these rice genotypes, suggesting the potential role of these genes in regulating tolerance to these abiotic stresses. Overall, this study suggested that divergence in response to alkalinity and salinity stresses among rice genotypes could be due to different molecular mechanisms conferring tolerance to each stress. In addition to providing a basis for further investigations into differentiating the molecular bases underlying tolerance, this study also emphasizes the possibilities of developing climate-resilient rice varieties using donors that are tolerant to both abiotic stresses.

Training and seed production spillovers and technology adoption: The case of seed producer groups in Nepal

AbstractRice farmers in developing countries are often vulnerable to drought which can drastically reduce yields. Stress‐tolerant rice varieties (STRVs) can mitigate this vulnerability, as can having a high seed replacement rate (SRR) and using best management practices (BMPs) in rice cultivation. However, access to high‐quality STRV seed is often limited. This article uses propensity‐score weighted regressions to estimate the spillover effects of seed producer groups (SPGs) in Nepal. It compares adoption rates of STRVs and BMPs, and the SRR of non‐member households in villages with SPGs and in villages adjacent to these compared to other control villages in the region. According to a range of results from weighted models, non‐members in SPG villages and adjacent villages are 24–32 percentage points more likely to have adopted an STRV compared to non‐members in control villages. Non‐members in SPG and adjacent villages have a higher SRR, and households in SPG villages are more likely to use some BMPs compared to non‐members in control villages. Results suggest that SPGs have the potential to improve the resilience of communities in the face of climate change.

Tools for using the International Rice Genebank to breed for climate-resilient varieties.

Traditional rice varieties have been critical for developing improved stress-tolerant rice varieties. Tools to analyze the genome sequences of traditional varieties are accelerating the identification and deployment of genes conferring climate change resilience.

Factors Affecting the Adoption of Stress-Tolerant Rice Varieties: Evidence from Bangladesh

Climate change, through exposure to submergence, salinity, and droughts, affects crop production and leads to food insecurity, particularly in developing countries. Various climate-stress–tolerant rice varieties have been developed in many countries in the world to mitigate climate-related production losses. Despite the benefits of stress-tolerant rice varieties (STRVs), adoption rates are still low. This paper uses panel data from Bangladesh to analyse the factors influencing the adoption of STRVs. A random-effects probit model with the Mundlak approach is used to control for the farmer- and plot-level heterogeneities and to avoid the incidental parameters problem. The study finds that smallholder farmers are more inclined to adopt STRVs, proving that this technology is related to a type of adaptation in the form of adoption. The main drivers for adopting STRVs are information and knowledge transferred by extension workers, sharing knowledge by membership in an organisation, and learning from peers. Policy measures such as providing capacity enhancement activities, strengthening social capacity and local institutions, and implementing a site-specific policy are suggested to encourage the adoption of STRVs in climate-stress-prone areas.

Do farmers pay for climate-resilient technology? Evidence from bidding experiments in eastern India

Using an experimental auction, we estimate demand for stress-tolerant rice varieties (STRVs) in eastern India, where frequent covariate production risks are affecting the welfare of smallholder farmers. STRVs have the potential to cope with low- to medium-intensity abiotic stresses and stabilize rice productivity in stress-prone rice ecosystems. The experiment involves a series of farmers’ decision-makings in the context of STRV seed purchase, set in an environment with minimal social frictions and improved information availability. Survival analysis, double hurdle, and sequential logit models are employed to understand farmers’ bidding and buying behavior. The results indicate that the demand for STRVs is highly elastic and is in line with reported market behavior. Willingness to pay (WTP) estimates for initial and latent buyers are coinciding, we find evidence of strategic underbidding by latent buyers in the experiment. Information asymmetry resulting from lack of awareness and previous experience in using STRVs is found to be the major reason for such decisions. Given the high elasticity of demand, STRV seed market distortion through subsidy, price cue, and an information campaign on variety characteristics and benefits could be an effective policy mix for overcoming the constraints related to price and asymmetric information and thereby increase adoption.

Rice Responses to Water Limiting Conditions: Improving Stress Management by Exploiting Genetics and Physiological Processes

Water-limiting conditions can severely affect rice yield. Therefore, increasing plant tolerance to water stress is a priority for many rice breeding programs. However, improving rice tolerance to this abiotic stress comes with several complications related to the seeding practices, the adopted water management system and the growth stage where water stress occurs. For this reason, it is challenging to outline single ideotypes showing traits suitable for overcoming drought at different times during the life cycle of rice in diverse cropping ecosystems. The current knowledge of genomics and biochemicals can contribute to drawing rice ideotypes flexible towards diverse water availability conditions. Traits identified in accessions of the wild ancestor of cultivated rice, as well as other wild rice species, in Oryza glaberrima and weedy rice were demonstrated to confer enhanced tolerance to water stress, while screenings of cultivated rice germplasms identified several genes/loci improving water stress resistance. New frontiers are represented by the dissection of the epigenetic control of stress tolerance and the implementation of the contribution of favorable microbiota. Innovative breeding technologies, whose feasibility is related to advancements in genomic analyses, are contributing to enhancing the knowledge-based development of water stress-tolerant rice varieties.

Enabling Adoption of Stress-Tolerant Rice Varieties and Associated Production Management Technologies by Smallholder Farmers in Cambodia

Smallholder rice farmers in four target provinces surrounding Tonle Sap Lake in Cambodia face problems of crop failures and low yields due to biotic and abiotic factors and a lack of suitable seeds and technologies. This paper reviews the status of rice production in the four areas and discusses the approaches to foster wide-scale dissemination and adoption of high-yielding, stress-tolerant rice varieties (STRVs) with resistance to biotic factors and tolerance to drought or floods. Baseline and endline surveys were conducted as well as extensive linkages with stakeholders, capacitybuilding activities, quality seed production at institutional level, field demonstration, and seed dissemination. The study summarizes data from 1,220 baseline respondents on demographic details, varietal use, knowledge assessment, and needs. The survey showed an aging profile, of which almost 25 percent are women, use of traditional and modern varieties with low yields of 2.5 t/ha, abiotic stress occurrence, and that only 14 percent of farmer respondents have heard about STRVs. In 30 months, training activities, varietal information, and diffusion of seeds reached 13,080 farmers. Results from 339 field trials showed the yield advantage of 1.0 to 1.5 t/ha of STRVs compared with those of farmer’s varieties. An endline survey from 424 farmers in 2018 showed recognition for government extension, better awareness of STRVs, high willingness to adopt STRVs at 92.4 percent of the respondents, preferred varietal traits, and additional training activities are needed. The barriers to adoption that were identified were concerns on low market price and marketability. Participatory trials and farmers’ field days were effective for early adoption as the visual performance of STRVs increased interest among farmer groups. Key government agencies are needed to promote and sustain registered seed production, availability of STRVs, and crop suitability. The support of the Royal Government of Cambodia and its new seed policy address problems on seed quality and availability.

Association Between Socio-Economic Characteristics and Information Seeking Behaviour of STRVs Growers of Odisha

The study was conducted purposively in the state of Odisha with a view to analyze the relationship between socioeconomic characteristics of STRVs (Stress Tolerant Rice Varieties) growers and their overall information seeking behaviour. The sample size covered 210 respondents from 3 districts & response was obtained from each individual respondent with the help of a structured interview schedule pretested with 10 per cent samples other than the respondents of the study. The fi ndings of the study revealed that majority of the STRVs growers were middle-aged (53.82%) and 30.95 per cent had middle school education. The majority (50%) of respondents were having small land holding size, 29.05 per cent respondents were involved in Agriculture+ horticulture both, majority (45.24%) had 10 – 20 years of farming experience, 41.91 per cent of the respondents had annual income of Rs 50,001 to 1,00,000, majority (73.81%) had medium social participation and 59.05 per cent had medium extension participation. The detailed study of information seeking behaviour of the respondents showed that in case of Personal localite information sources own family members o ccupied the highest mean score 2.738 a nd ranked fi rst followed by neighbour farmers having mean score 2.728, in personal cosmopolite sources krishak sathi occupied the highest mean score 2.219 and ranked fi rst followed by VAW having mean score 2.133 and in case of impersonal cosmopolite mobile occupied the highest mean score 2.585 and ranked fi rst. Education, family type, family size, land holding, experience, annual income, social participation and extension participation had a positive and signifi cant association with the information seeking behaviour of respondents

Coping with Climatic Stress in Eastern India: Farmer Adoption of Stress-Tolerant Rice Varieties

Cultivating stress-tolerant rice varieties (STRVs) is widely cited as a strategy of rice farmers to cope with climate-induced stresses. In India, dissemination of STRVs started in 2008 through international development initiatives, but only 5 percent of farmers have adopted it after seven years. Using a double-hurdle model, this study estimated the factors influencing simultaneous decisions on land selection and allocation for cultivating STRVs. It developed a framework for assessing the risks faced by farm households due to adverse climatic conditions vis-à-vis the decision to adopt STRVs. Results show that perceived and actual experiences of climate stress are important parameters influencing the decision to adopt STRVs. Farmers who have adopted such varieties are more likely to cultivate them on only a small portion of their land. These farmers are risk takers and very patient. The study recommends the use of a targeted approach to scale up the adoption of STRVs. Farmers affected by climate stresses should be identified and educated about the benefits of STRVs through demonstration. In addition, the accessibility of the seeds must be ensured.

Molecular characterization and varietal identification for multiple abiotic stress tolerance in rice (Oryza sativa L.)

Coexistence of two or more abiotic stresses is common in most of the rainfed lowland and upland rice growing areas of India and worldwide. Rice production under these conditions is not sustainable. Identification and development of multiple abiotic stress tolerant rice varieties are to be addressed. Here we tried to identify multiple abiotic stress tolerant varieties from a collection of earlier identified varieties for single stress and validated the known SSR markers for stress tolerance. Twenty rice genotypes were evaluated for individual abiotic stress such as drought, salinity and temperature initially and the tolerant three genotypes in each case were further evaluated for combination of stresses various physio-morphological and biochemical parameters were recorded. Among the genotypes evaluated for combination of stresses, PTB-7 was found to be tolerant for drought and salinity, Nagina-22 was tolerant against high temperature and salinity. However, the seeds did not germinate in the presence of all three stresses simultaneously. Twenty rice varieties viz., Chomala, MO-16, PTB-35, PTB-60, PTB-39, PTB-55, PTB-30, PTB-7, CRdhan307, Apo, Vyttila-3, Vyttila-4, Vyttila-5, Vyttila-6, Vyttila-7, Vyttila-8, Vyttila-9, Vyttila-10, Nagina-22 and NL-44 were further investigated using microsatellite markers to confirm the genotypic level of tolerance to combination of abiotic stresses. Rice genotypes were screened using 30 reported simple sequence repeat (SSR) markers that are linked to drought, salinity and temperature. Molecular marker analysis of rice genotypes also confirmed that RM8904 and RM1287 were associated with salinity tolerance, RM2612, RM6100 and RM5749 were linked to high temperature tolerant trait. Population analysis also revealed that there is five subpopulation among rice genotypes.

Smallholder adaptation to flood risks: Adoption and impact of Swarna-Sub1 in Eastern India

Climate change and the consequent increase in the incidence of drought and flood will remain a major threat to smallholders. Hence, it is crucial to adopt an appropriate adaptation strategy to overcome this threat and increase farmers’ income. Because seed is a primary input, the adoption of stress-tolerant rice varieties is a potential mitigation strategy to combat climate risks. In this context, the present study is carried out among paddy farmers in the flood-prone region of Eastern India to understand the adoption and impact of submergence-tolerant rice variety Swarna-Sub1 on yield and income. The study reveals that the adoption of Swarna-Sub1 varies significantly across eastern India. Education, primary occupation, credit, social group, cultivated land, and access to information on stress-tolerant rice varieties significantly influence the adoption decision. Endogenous switching regression estimates revealed that the expected paddy yield of Swarna-Sub1 adopters in an actual scenario and for non-adopters in a counterfactual scenario is significantly higher than for their counterparts. The average treatment effect confirms that the benefit of cultivating Swarna-Sub1 is much higher in submergence conditions than in normal conditions. An additional 19.0% and 48.2% of paddy yield and income is obtained respectively by cultivating Swarna-Sub1 in flooded conditions.

Improving the Climate Resilience of Rice Farming in Flood-Prone Areas through Azolla Biofertilizer and Saline-Tolerant Varieties

Rice farming in coastal areas is often victim to flooding as a result of climate change. Low-cost adaptation strategies are required to increase resilience and rice productivity in these flood-prone coastal areas. In this study, enriched Azolla extract (EAE) liquid biofertilizers, combined with selected stress-tolerant rice varieties, were tested in farmers’ fields in Pangandaran, West Java from June to October 2020. This study aimed to investigate the effectiveness of EAE in increasing the yield of different rice varieties. The research was arranged as a split-plot design with five replications. The main plot was the EAE application (T1 = 3 ton ha−1 compost and T2 = 3 ton ha−1 compost + 10 L ha−1 of EAE), and the sub-plots were stress-tolerant rice varieties (V1 = Inpari 43, V2 = Mawar, V3 = Inpari 30, V4 = Inpara 03, V5 = Mendawak). The application of EAE of 10 L ha−1 significantly affected the rice grain yield, which was 37.06% higher than that of the control plot. The average grain yield of the five varieties under EAE treatment (5.51 ton ha−1) was greater than the grain yield of local farmers’ fields (3.78−4.97 ton ha−1). Inpari 43 had the highest grain yield with 5.90 ton ha−1, but the yield was not significantly different from the Mendawak variety (4.90 ton ha−1). This result suggests that EAE and selected stress-tolerant rice varieties (Inpari 43 or Mendawak) are an effective adaptation strategy to increase rice farms’ resilience and productivity in coastal areas prone to flooding.

Challenges and opportunities in productivity and sustainability of rice cultivation system: a critical review in Indian perspective.

Rice–wheat cropping system, intensively followed in Indo-Gangetic plains (IGP), played a prominent role in fulfilling the food grains demand of the increasing population of South Asia. In northern Indian plains, some practices such as intensive rice cultivation with traditional method for long-term have been associated with severe deterioration of natural resources, declining factor productivity, multiple nutrients deficiencies, depleting groundwater, labour scarcity and higher cost of cultivation, putting the agricultural sustainability in question. Varietal development, soil and water management, and adoption of resource conservation technologies in rice cultivation are the key interventions areas to address these challenges. The cultivation of lesser water requiring crops, replacing rice in light-textured soil and rainfed condition, should be encouraged through policy interventions. Direct seeding of short duration, high-yielding and stress tolerant rice varieties with water conservation technologies can be a successful approach to improve the input use efficiency in rice cultivation under medium–heavy-textured soils. Moreover, integrated approach of suitable cultivars for conservation agriculture, mechanized transplanting on zero-tilled/unpuddled field and need-based application of water, fertilizer and chemicals might be a successful approach for sustainable rice production system in the current scenario. In this review study, various challenges in productivity and sustainability of rice cultivation system and possible alternatives and solutions to overcome such challenges are discussed in details.Graphic abstract

Recent Advances in Rice Varietal Development for Durable Resistance to Biotic and Abiotic Stresses through Marker-Assisted Gene Pyramiding

Abiotic and biotic stresses adversely affect rice growth, development and grain yield. Traditional rice breeding techniques are insufficient in modern agriculture to meet the growing population’s food needs on a long-term basis. The development of DNA markers closely linked to target genes or QTLs on rice chromosomes, and advanced molecular techniques, such as marker-assisted selection (MAS), have encouraged the evolution of contemporary techniques in rice genetics and breeding, such as gene pyramiding. Gene pyramiding refers to the act of combining two or more genes from multiple parents into a single genotype, which allows the overexpression of more than one gene for broad-spectrum abiotic and biotic stress resistance. Marker-assisted pedigree, backcrossing and pseudo-backcrossing methods can increase the conventional breeding speed by reducing the number of breeding generations in order to enhance the pyramiding process. Pyramiding is affected by several factors: the number of transferred genes; the range within gene and flanking markers; the number of chosen populations in every breeding generation; the features of genes and germplasms; and the potentiality of breeders to identify the target genes. Modern breeding methods, such as the marker-assisted backcrossing approach, have made gene pyramiding more precise and reliable for the development of stress-tolerant rice varieties in the coming decades. This review presents up-to-date knowledge on gene pyramiding schemes, marker-assisted gene pyramiding techniques, the efficiency of marker-assisted gene pyramiding and the advantages and limitations of gene pyramiding methods. This review also reports on the potential application of marker-assisted selection breeding to develop stress-tolerant rice varieties that stabilize abiotic and biotic stresses. This review will help rice breeders to improve yields by increasing rice productivity under abiotic and biotic stress conditions.

Assessment of Stress Tolerant Rice Varieties under Rain Fed Condition in North Eastern Ghat of Odisha

A field experiment was conducted during kharif 2019 at NICRA villages viz. Nada, Chikili and Chopara of Krishi Vigyan Kendra, Ganjam1 through technology demonstration to analyse the performance of stress tolerant rice varieties under rainfed condition. Three different drought tolerant rice varieties i.e. MTU-1010, Sahabhagidhan and Swarna Shreya with ten replications were taken in random block design with improved package of practices compared to farmers’ practice. The results of technology demonstration revealed that growing of Swarna Shreya recorded higher growth parameters compared to other treatments with ten days delayed maturity. Improved practice of Swarna Shreya (T3) recorded higher number of filled grains panicle-1 (135.4±5.41), spikelet fertility (95.0±0.33 %), panicle length (24.8±1.45 cm) and 1000 grain weight (25.7±0.52 g) compared to other two treatments. Significantly higher grain yield (3588±169.5 kg ha-1) and straw yield (7591±236.9 kg ha-1) were recorded compared to farmers’ practice (2632±125.1 kg ha-1 and 5934±366.4 kg ha-1, respectively). Swarna Shreya recorded higher gross return (Rs 67037±2980.2 ha-1), net return (Rs 37037±2980.2 ha-1), B: C ratio (2.23±0.20) and profitability (Rs. 101.5±8.16 ha-1 days) with as compared to farmers’ practice of growing MTU 1010.