Swarna Sub1 Research Articles

Breeding for flooding tolerance in rice: Advancements and future perspectives

Rice, the resilient grain, is cultivated in different types of ecosystems, from seacoast to hilly areas. Unfortunately, due to climate change, it frequently suffers from submergence stress during its growth period. Anoxic stress at the germination phase, flash flooding during the vegetative phase and water stagnation in low-lying areas are the major types of flooding in rice. When floodwaters rise, rice adapts. Some varieties stretch their stems toward the surface, gasping for air. Others remain dormant, conserving energy, like the FR13A landrace, SUB1 equips rice with underwater endurance. It orchestrates a genetic symphony, fine-tuning metabolic pathways and signalling survival. Some of the promising quantitative trait locus (QTLs) identified are qAG-9-2, which is responsible for anaerobic germination tolerance; qSUB1 for vegetative stage submergence tolerance, and qTIL12 for deep water adaptation. Identifying other novel QTLs and donors helps to breed varieties tolerant to different types of submergence stress. Along with Swarna SUB1, many mega-submergence-tolerant varieties have been developed and released for cultivation in Asia. As we cultivate these versatile survivors, we sow hope for a food-secure future.

Performance of different rice genotypes cultivated under submergence and normal growing conditions

Abstract Submergence negatively affects the plant growth and yield of rice genotypes, which in turn results in huge financial loss. Thus, identification of submergence tolerance rice genotypes is needed for sustainable rice cultivation in flood-prone areas. Keeping this in view, a two-year (2019 and 2020) field study was undertaken at Rice Research Farm of Bihar Agricultural College, Bihar Agricultural University, Sabour, Bhagalpur to investigate and compare the yield responses of rice genotypes under submergence and normal growing conditions. Twenty-five days old seedlings of 25 rice genotypes were transplanted in a randomized complete block design in two replicates, which were allowed to grow under normal practice for the next 25 days. Thereafter, the 50-day old plants were completely submerged with turbid water of 1.5 m height for the next 18 days. After de-submergence, all the recommended agronomic practices were adopted during the rest of the crop period. Under submergence, higher grain yield was recorded under all the genotypes during 2020 as compared to 2019 mainly due to higher temperature and lesser rainfall during 2020. Under submergence conditions, Jalmagna, Nona Bokra and Swarna Sub 1 were the best performers having produced average yields of 3,167, 2,786 and 2,741 kg/ha, respectively. Whereas under normal growing practice, Swarna Sub 1, Jalmagna and Sudha were the first three best performing genotypes producing average yields of 5,063, 4,565 and 4,456 kg/ha, respectively. Therefore, Jalmagna should be preferred for cultivation in the flood-prone regions of the state, however in non-flooded areas; Swarna Sub 1 may be cultivated.

Screening of Rice Genotypes for Submergence Stress Tolerance

The experiment was conducted at Department of Rice, Tamil Nadu Agricultural University, Coimbatore to study the effect of submergence on growth of various genotypes of paddy. The genotypes viz., AC1303, AC42088, AC38575, SABITA, NAVEEN, SWARNA Sub1, BLACK GORA, BAJKANI, SWARNA, PARUAT, PAU9, BRAHMANNAKHI, MAHULATA, BVD109, IET-18720, IET-18727 and IC-516009 lines were used for submergence screening. The seeds should be pre-heated at 50°C for 2-3 days for breaking the seed dormancy before sowing. The seeds were directly sown inside the tanks using wet-bed direct sowing method. Each genotype was sown in 2 rows (min.) with 3 replications with a row to row spacing of 20 cm and plant to plant spacing of 15 cm. Germinated seedlings were allowed to grown normally till 20–25 days without submergence stress. The observations like plant height (before and after submergence), Number of plants survived (before and after submergence), survival percentage and total starch content were recorded. The genotypes IET-18727, PAU9 and AC38575 had better survival percentage (80.0 to 86.7%) with higher starch content (6.3 to 6.9 mg g-1) under submerged stress conditions. The genotypes of BVD109 and SWARNA registered lesser survival percentage (26.7% and 26.3%) with starch content of 2.1 mg g-1 among the rice genotypes.

Utilizing Arthrospira platensis for the fabrication of zinc oxide nanoparticles: Analysis and assessment for enhancing drought tolerance in Sub1A QTL bearing rice seedlings

In the present study, the underlying pathways for zinc oxide nanoparticles (ZnO-NPs) mediated modulation of oxidative stress under drought were evaluated in rice seedlings. Principally, rice cultivar (cv. Swarna Sub1) was used to assess the potential of the Sub1A QTL for its drought sensitivity in response to bio-fabricated ZnO-NPs. ZnO-NPs were synthesized from algal (Arthrospira platensis) extract and characterized for their opto-physical properties, confirming size (54 nm), hydrodynamicity (-18.54), amorphous-cubic shape and others features. Fifteen-day-old rice seedlings were primed with 25 ppm ZnO-NPs and exposed to 12 % polyethylene glycol (PEG) mediated drought stress (DS) for 7-days under laboratory conditions. Primarily, Sub1A QTL responded to drought-induced anoxic stress with a significant increase in the activities of alcohol dehydrogenase (447.41 %) and pyruvate decarboxylase (96.51 %) through ZnO-NPs sensitization. Plants recorded a significant reduction in root growth, which regained 89.25 % with ZnO-NPs treatments. ZnO-NPs also recovered relative water content (49 %), proline (99.2 %), and improved chlorophyll fluorescence (90.9 %) under stress. Furthermore, drought-induced membrane leakage was stabilized by reducing ionic conductivity through the distribution of wall-bound polyamines. A characteristic feature of fluorescence also reinforced the sustenance of photosynthetic activities by ZnO-NPs under drought. Alternatively, rice seedlings showed regulation of oxidative stress, where lipid peroxidation and protein carbonylation were reduced by 270 % and 178.2 %, respectively. This was observed with the minimization of superoxide and hydrogen peroxide concentrations by regulating apoplastic oxidase activity (117.64 %) with distinct polymorphisms in proteins. These observations suggest that ZnO-NPs can ameliorate drought-induced oxidative stress in rice, providing insights for improved nano-fertigation.

Effect of biotic and abiotic factors on the population dynamics of Nilaparvata lugens in the middle Gangetic Plains of India

Aim: To investigate the effect of biotic and abiotic factors on the population dynamics of brown planthopper Nilaparvata lugens (Stal) (Hemiptera: Delphacidae) in the middle Gangetic plains of India. Methodology: Field trials were conducted in the middle Gangetic plains of India at Agricultural Research Farm, B.H.U., Varanasi, Uttar Pradesh, India during Kharif season of 2018 and 2019 on the variety Swarna sub-1 to study the population dynamics and certain biotic and abiotic interaction with brown planthopper. Results: During Kharif 2018 and 2019, the highest mean number of brown planthopper population (45.00 ± 2.31 and 39.33 ±1.82 nos., respectively) were recorded during September in both seasons. Abiotic factors such as rainfall (r = - 0.556), relative humidity in the morning (r = 0.476), maximum temperature (r = 0.511), and sunshine hour (r = - 0.546) influenced planthopper population dynamics, and predictions were made with reasonable accuracy (R2 = 0.89) using the principal component regression analysis technique. Crop phenology was the most influential biotic factor on pest population density. The crop's booting stage had the highest incidence of planthoppers. Three different predatory populations (wolf spider, damselfly and ladybird beetle) were observed to feed on planthoppers in Kharif 2018 and four different predatory populations (wolf spider, damselfly, ladybird beetle and green mirid bug) were observed to feed on planthoppers in Kharif 2019, resulting in a reduction in crop pest density. Interpretation: These findings can be used to develop the precise management strategies for brown planthopper in the rice ecosystem. Key words: Abiotic, Biotic factors, Brown planthopper, Crop phenology, Middle Gangetic Plains, Natural enemies, Rice

Evaluation of Sheath Blight Resistance in Diverse Rice Varieties Under Artificial Inoculation and Field Conditions

Rice (Oryza sativa L.) a vital food crop for nearly half of the global population, facing significant threats from various biotic and abiotic stresses. Among biotic stresses, diseases pose the most common challenge. Sheath blight, caused by soil-borne fungal pathogen Rhizoctonia Solani Kühn (R. solani), is a major concern, leading to substantial damage to rice and cereal crops worldwide. This study evaluated sheath blight resistance across diverse rice varieties, including short grain, long grain, aromatic, hybrid, and wild types, under both artificial inoculation and field conditions. Ten host plant species were assessed for resistance to sheath blight caused by Rhizoctonia Solani, using physiological screening one-week post-inoculation. The highly virulent R. solani isolate (AG-1 IA anastomosis group) was cultured on PDA media, covering the entire plate 3 to 5 days. Screening of cultivated rice varieties, was conducted using field conditions and humidified chamber methods, with results confirmed through molecular characterization. Among the ten cultivated rice varieties, Arize 6444 and Dhanya 748 exhibited the lowest disease index, classifying them as moderately resistant. In contrast, Kalanamak and Pusa Basmati were highly susceptible, displaying high disease indices. Among wild rice accessions, Oryza rufipogon showed a disease index of five or less. Visual ratings indicated the highest susceptibility in Kalanamak, followed by Pusa Basmati and Swarna sub-1, while the lowest visual ratings were observed in wild rice accessions Oryza australiensis and Oryza rufipogon across all tested hosts. The findings underscore the importance of identifying resistant rice varieties to manage sheath blight effectively. The moderately resistant cultivars and wild rice accessions identified in this study offer valuable genetic resources for breeding programs aimed at enhancing sheath blight resistance in rice.

Comparative Analysis of Peroxidase and Catalase Isoenzymes via Native-PAGE Electrophoresis and SDS-PAGE Profiling of Leaf Proteins in Rice Varieties under Infection Stress

Rice (Oryza sativa L.) is a staple food for over half of the world's population. However, rice productivity is significantly hindered by various diseases, including sheath blight caused by Rhizoctonia solani. This study aims to evaluate the resistance of different rice varieties and wild rice accessions to sheath blight and to analyze the biochemical responses, specifically peroxidase and catalase activities, under infection stress. The results revealed that Kalanamak and Pusa Basmati were highly susceptible, with high disease indices and visual ratings. Conversely, wild rice accessions such as O. rufipogon and O. australiensis exhibited lower disease indices, indicating moderate resistance. Peroxidase activity varied significantly among the rice leaves, ranging from 148.83 to 182.44 mg/g fresh weight/min. Dhanya 748 showed the highest peroxidase activity, followed by O. australiensis and O. rufipogon. Native-PAGE electrophoresis of peroxidase isoenzymes demonstrated high-intensity bands in O. rufipogon, BPT 5204, and Swarna Sub-1, while minimal or no bands were observed in other genotypes, indicating varying levels of peroxidase activity. Catalase activity also showed significant variation, ranging from 138.18 to 152.14 mg/g fresh weight/min. BPT-5204 exhibited the highest catalase activity, followed by O. australiensis and Pusa Basmati. Isoenzyme analysis via Native-PAGE revealed high-intensity catalase bands in O. australiensis, Dhanya 748, NDR 118, and Pusa Basmati, while no bands were observed in O. rufipogon, CSR 13, Arize 6444, and Swarna Sub-1. SDS-PAGE analysis of leaf proteins showed variability in banding patterns. Non-infected leaves of Swarna Sub-1, Arize 6444, Kalanamak, and Pusa Basmati had minimal bands, while O. australiensis and Dhanya 748 showed maximum bands. Infected leaves of CSR 13, NDR 118, Arize 6444, Kalanamak, Dhanya 748, and Pusa Basmati had minimal bands, whereas O. australiensis exhibited maximum bands. Overall, the study highlights the potential of wild rice species in enhancing disease resistance and provides insights into the biochemical responses of rice varieties under pathogen stress.

Effectiveness of local isolates of Trichoderma spp. in imparting drought tolerance in rice, Oryza sativa

Rice is a crop that requires high amount of water, and the drought is a major constraint in paddy cultivation. Water stress condition frequently prevails due to shortage of rain which results in significantly reduced plant growth and yield of rice. In the present study capability of Trichoderma spp. in imparting drought tolerance to rice, Oryza sativa was explored. Eleven local strains of Trichoderma spp. were applied to rice cv. Swarna Sub-1 through soil application (2 g/kg soil) and seed treatment (20 g/kg seed) under 0, 25, 50 and 75% less watering of the recommended amount. The soil application of T. harzianum AMUTHZ84 significantly promoted the shoot and root length (23.6 and 21.3%) followed by seed treatment (19.7 and 18.2%) under recommended level of irrigation condition (100% irrigation). Next in effectiveness was T. viride AMUTVR73 (21.5 and 18.1%) over untreated control. However, under 75% water availability, soil application with T. harzianum AMUTHZ82 was found superior over other isolates in enhancing shoot and root length (17.7 and 16.4%). The same isolate was also recorded to be superior under 50% (12.4 and 10.1%) and 25% water availability (9.3 and 8.1%) in enhancing the plant growth and biomass of rice cv. Swarna Sub-1. The isolate also significantly enhanced the leaf pigments, and photosynthesis in the rice plants grown under 25–75% water stress condition. In general, soil application of Trichoderma isolates was found more effective than seed treatment, and the T. harzianum AMUTHZ82 provided 8–17% enhancement in the plant growth, biomass, leaf pigments and photosynthesis of rice cv. Swarna Sub-1 grown under 25–75% water stress condition.

Enhancing rice productivity through holistic nutrient management: integrating vermicompost and Azolla for improved agronomic performance and sustainability

A three-year multi-location trial on the farmer’s field was conducted in West Bengal, India to evaluate the impact of integrated nutrient management (INM) on the performance of kharif rice cv. Swarna Sub 1. The experiment employed a randomized block design (RBD) across eleven farmers’ fields with similar soil properties, texture, topography, and historical fertilizer application patterns. Three treatments were tested: T1 – common practice of applying N:P:K @ 55:32:27 kg ha−1, T2 – soil test-based application (STA) of ∼75% recommended N dose through chemical fertilizer + ∼ 25% through Azolla, and T3 – soil test-based application of ∼ 75% recommended N dose through chemical fertilizer + 20% N from vermi-compost + 5% N through Azolla. The result of the experiment revealed that the T3 exhibited significant improvements in plant height, leaf area index (LAI), effective tillers meter−2, number of panicles plant−1, and 1000-grain weight compared to T2 and T1. Among the different nutrient management practices, the T3 recorded maximum rice grain productivity than the T1, and T2, Further, the benefit-cost ratio was noticed significantly higher under T3 (1.29) followed by T2 (1.27) and T1 (1.23). The soil organic carbon (SOC), available nutrient was enhanced by the soil test-based application of ∼75% recommended N dose through chemical fertilizer + 20% N from vermicompost + 5% N through Azolla. Thus, our study indicated that the balanced nutrient application through combined sources (T3) could improve crop growth; and sustain rice productivity, besides enhancing the farm income, and soil different soil properties.

Effect of Different Levels of Zinc on Yield of Various Varieties of Rice (Oryza sativa L.)

A field experiment was conducted to study the effect of different level of zinc on various variety of rice during two consecutive kharif seasons year 2022 and 2023 respectively. The experiment was laid out in split plot design with four variety of rice (Sarju-52, NDR-2064, NDR-2065 and Swarna Sub-1) in Main plot. Each main plot was further divided in five Sub plot i.e (Control, Zn @ 2.5 kg/ha, Zn @ 5 kg/ha, Zn @ 7.5 kg/ha and Zn @ 10 kg/ha).the result recorded that the variety NDR 2065 maximum panicle length (24.8cm ,25.3), number of panicles m-2 ( 134.1, 137.5), number of grains per panicles (149.1 ,152.6), test weight (23.6g, 23.7g) grain yield (44.19, & 46.01) q ha-1,straw yield (67.31 & 70.13) q ha-1,and biological yield (111.50 &116.14) q ha-1during 2022 and 2023 respectively. Among Zn level Maximum value of yield attributes and yield was recorded under Zn @10 kg/ha which was at par with 7.5 kg/ha, and 5 kg/ha for number of panicles, number of grains per panicle, 1000 grain seed weight, grain yield, straw yield, biological yield during both years.

Genetic Variability Analysis for Yield and Its Attributing Traits in Rice (Oryza Sativa L.) under Phosphorus-sufficient and Deficient Field Conditions

Aim: The present study aims to identify phosphorus deficiency tolerant rice genotypes under both phosphorus-sufficient and deficient conditions. Materials and Methods: Two kinds of fields (high and low phosphorus content) were selected based on their soil phosphorus availability. Hundred diverse rice germplasm was collected and planted in an augmented design along with four local checks namely, Swarna sub-1, MTU 1153, MTU 7029 and Uttar Sona. The data was recorded for 14 traits and subjected to different types of variability analysis. Place and Season of Study: The experiment took place at instructional Farm of Uttar Banga Krishi Vishwavidyalaya, Cooch Behar, West Bengal, India during the Kharif season of 2021. Results: The variability analysis revealed that phosphorus uptake showed a high genotypic coefficient of variation (GCV) under phosphorus-deficient condition and high phenotypic coefficient of variation (PCV) under both conditions. Grain yield showed high GCV and PCV under both the phosphorus conditions. Heritability was moderate whereas high Genetic advance as percentage of mean was observed under both the conditions for both phosphorus uptake and grain yield. Strong positive correlations were observed between days to flowering and various yield-related traits under both the conditions. Positive correlation was observed between phosphorus uptake and grain yield under phosphorus-sufficient condition, but a weaker correlation under phosphorus-deficient condition.

Physiological and antioxidant responses associated with Sub1 gene introgressed rice (Oryza sativa L.) lines under complete submergence.

Rice is the only crop which is well adapted to aquatic environment but, it is unable to survive if completely submerged for several weeks. Breeding rice varieties with submergence tolerance is one of the best approaches to alleviate the adverse effect of submergence which requires the introgression of Sub1 gene into elite rice varieties. Hence, the study was undertaken to introgress submergence tolerant gene into the rice variety Jaya through Marker-Assisted Backcross Breeding. Also the physiological and biochemical responses like survival percentage, underwater shoot elongation, total carbohydrate content and superoxide dismutase activity were also studied in Sub1 introgressed lines. We could develop twenty Sub1 introgressed lines with Sub1 region of 3.1-5.1mb and with 80.0- 95.3% recurrent parent genome recovery. Sub1 introgressed Jaya lines and the tolerant checks FR13A and Swarna Sub1 had lower shoot elongation under water, higher superoxide dismutase activity (about 5 times) upto 4h after de-submergence which resulted in higher survival percentage. The reduced shoot elongation of tolerant varieties reduced the utilization of stored carbohydrate. Through our research we introgressed Sub1 gene into rice variety Jaya through Marker-Assisted Backcross Breeding and could study the physiological responses under submergence by which we confirmed the presence of Sub1 gene in these lines. These lines could be field evaluated and could be released as a new variety thus helping the farmers of flood prone areas of Kerala.

Impact of Climate Resilient Technology on Growth and Yield of Paddy (Oryza sativa L.) under Submergence Condition

The submergence of rice fields is a significant issue in India's rice production, which is further aggravated by the unpredictable monsoon rain patterns and the impact of climate change. Larger variation in rainfall patterns affected by the timing of nursery raising and transplanting later in the main field therefore, we adopted Climate Resilient Technology (CRT) for rice production, Extended seedbed durations for rice seedlings allow for adequate rainfall during the monsoon season. So that the experiment was conducted at 30 farmer’s fields of NICRA village, Khana Bari, Kishanganj, Bihar, India, in 2022 under the supervision farm science Center, Kishanganj, the experiment was framed in randomized block design with ten replications. All plots received the recommended dose of fertilizers (120:60:40 kg ha-1 N.P.K.) in equal amounts. Urea, di-ammonium phosphate, and muriate of potash were used as the sources of nitrogen, phosphorus, and potassium, respectively. To determine the growth characters i.e., plant height (cm) at harvest stage, number of effective tillers hill-1, LAI, Chlorophyll concentration (SPAD) and days to 50 per cent flowering were recorded at 90 days. Yield attributes viz., After the completion of the harvest, various observations were recorded, such as the number of panicles/m2, the number of grains per panicle, the number of filled and unfilled grains per panicle, the test weight in grams, and the yield. This encompassed grain yield, straw yield, biological yield in quintals per hectare, and harvest index percentage. During the field experiment, both the climate-resilient technology Swarna Sub1 and Sabour Sampans paddy varieties were tested. Swarna Sub1 was found to be significantly superior in terms of plant growth, yield attributes, and yield characteristics. under submergence conditions. The significant maximum grain yield (48 q ha-1), straw yield (84 q ha-1), biological yield (153 q ha-1), and harvest index (45%) were recorded in Swarna Sub-1.

Submergence Tolerance in Rice (Oryza sativa L.) Genotypes at the Seedling Stage: A Combined Approach of Morphological and Molecular Characterization

Background: Rice (Oryza sativa L.) is the major cereal crop often suffers from submergence in the rainfed growing situation of India and South East Asia. Developing rice cultivars with tolerance to submergence is the best strategy to circumvent the situation. In Eastern India a vast reservoir of rice genotypes exists grown in diverse agro-climatic situation under rainfed condition. Screening rice genotypes under submergence stressed condition by observing morphological traits combined with molecular marker approach helps to identify the genotypes having innate capacity to survive under flooding condition more precisely than either of the approach alone. The present study was framed to identify the landraces and genotypes having the presence of desired genes which will helpful for future breeding program. Methods: Fifty rice (Oryza sativa L.) genotypes were evaluated for submergence tolerance using both morphological and molecular characterization in the field and laboratory respectively. Six stress indices, namely elongation%, survival%, mortality%, relative growth index, dry mass% and recovery rate, were examined in the field seven days and fourteen days after submergence. The genotypes were screened with SSR markers to identify the presence of the desired gene. Result: Based on morphological and molecular screening, out of all rice genotypes, Brahmabalak, Jaladhi 1-2, Jaldubi, Kerala Sundary, China IRRI, Sonachur, Pravat, Pankaj, Ranjit SUB1 and Bahadur SUB1 showed higher levels of tolerance to submergence than the tolerant control Swarna SUB1. They have one or more loci different from the SUB1 locus, which can be bred to create improved submergence-tolerant rice varieties with high yield in the rainfed lowland agroecosystem.

Characterization of Rice Genotypes for SNORKEL1 (SK1) and SNORKEL2 (SK2) Gene

The present study was performed in kharif (June-December) 2019 at Bihar Agricultural College, Sabour, Bhagalpur, Bihar, India to screen gene specific markers developed from SNORKEL1 (SK1) and SNORKEL2 (SK2) gene and identify the rice genotypes for the presence of SNORKEL genes. A total of 13 rice genotypes were used out of which 8 genotypes Vaidehi, RYC743, FR13A, Desaria, Dudhi, Birar, Kalaladora and Kajargod indicated the presence of both SNORKEL1 (SK1) and SNORKEL2 (SK2) gene using SK1-1, SK1-2, SK2-1 and SK2-2 markers. Therefore, these genotypes have tolerance ability of deep water flooding due to higher rates of elongation where water stagnates for longer than two weeks. However, results from the present study also revealed that the genotype Desaria and RYC743 had higher rates of elongation and Satyam, Sudha, Purnendu, FR13A, Pansoradhan and Swarna Sub1 had lower shoot elongation rate compared to other genotypes. This study provides gene specific markers for the identification of varieties/donors tolerant to deep water flooding as well as donors to be used in deep water rice breeding programs. Thus, the marker developed and validated in this study will aid rice breeders in quickly and efficiently identifying and introgressing the SNORKEL genes. The results would be a helpful in the development of rice varieties with both submergence tolerance and elongation ability in order to improve the yield stability in flood-prone areas.

Projection of Yield of Rice Crop over Prayagraj with Future Climatic Scenario

The purpose of this study was to evaluate the effects of climate change on productivity of rice cultivars Swarna sub-1, Sarjoo-52, Pant Dhan 4, and NDR-359 for the years 2030, 2050, 2070, and 2090 for the Prayagraj district of Uttar Pradesh using the Marksim and DSSAT crop simulation model under four different climate change scenarios, namely RCPs 2.6, 4.5, 6.0, and 8.5. The model evaluation indicated good performance with both calibration (PE=2.43,6.26,4.31,3.79, RMSE= 132.79, 345.13, 237.44, 237.85, nRMSE = 2.53, 7.31, 4.46, 3.97) and validation (PE =3.58, 10.03, 4.28, 6.09, RMSE = 197.88, 456.35, 238.37, 366.52, nRMSE = 3.95, 10.55, 4.67, 6.39) for Swarna sub-1, Sarjoo-52, Pant Dhan 4 and NDR-359 cultivars respectively, which showed good agreement between anticipated and observed values. For the Prayagraj region, NDR-359 yields the most among the four varieties, followed by Pant Dhan 4, Swarna Sub-1, and Sarjoo-52. By examining the future climate data that MarkSim's weather generator downloaded, it was noticed that all other weather variables, such as solar radiation, average maximum and minimum temperature increases while rainfall decreases. The findings of the study reveal that, among all projection scenarios, the grain yield is greater for RCP 2.6 and lowest for RCP 8.5. Analysis of the expected climate scenario data with yield revealed that the yield was higher in 2030 and lower in 2050. Additionally, it was observed that again in 2090 the yield gets increased for RCP 2.6 & decreased for RCP 4.5,6.0 & 8.5. Among all the four cultivars the yield of Sarjoo-52 will be reduced for RCP 4.5,6.0 & 8.5 for the year of 2050,2070 & 2090.These findings may offer insightful information about possible climate change effects on rice yield and suitable adaptive strategies to minimize the negative effects of future climate change.

Improvement of Local Speciality Rices as a Boon to Health, Wealth and Export Diversity: Case of Kalanamak Rice

A blessing from Lord Buddha some 3,000 years ago, and now a heritage rice of Uttar Pradesh, India is valued for its aroma, taste and nutritive quality. Its cultivation declined from 50,000 ha to less than 2,000 ha and was at the verge of extinction. No attention was paid for improving Kalanamak and it survived as landrace due to the mercy of the farmers. PRDF collected, catalogued and conserved 250 accessions of Kalanamak, and the best one, through Pureline selection, was released in 2007 and notified in 2010 as KN 3. Mutation breeding using gamma rays and EMS gave many academically interesting mutants but no high yielding dwarfs. Hybridization of KN 3 with Swarna Sub1 and Improved Sambha Mahsuri yielded varieties like Bauna Kalanamak 101, Bauna Kalanamak 102 and Kalanamak with shorter duration and 50% higher yield, released and notified in years 2016, 2017 and 2019 respectively. Protocol for organic production with higher yield was developed and certification under PGS arranged. Kalanamak is sugar-free with 49 to 52% Glycemic Index, 11% protein, 3 times higher Iron and 4 times higher Zinc. It is unique rice to have Vitamin A in form of Beta Carotene. Kalanamak is backed by Geographical Indication and PPV and FRA, and selling at five times higher price of common rice tripling farmers’ income. Now exported to Singapore, Nepal and Dubai has opened door to prosperity and added diversity to Basmati for export. This success story can be repeated for other land rices of speciality status.

Pyramiding Submergence Tolerance and Three Bacterial Blight Resistance Genes in Popular Rice Variety Hasanta through Marker-Assisted Backcross Breeding

Flash flooding (FF) along with bacterial blight (BB) outbreak are very destructive for rice production in the rainfed shallow-lowland (RSL) ecosystem. The presence of dynamic Xoo races with varying levels of genetic diversity and virulence renders their management extremely challenging under RSL. In this context, the marker-assisted improvement of plant resistance/tolerance has been proven as one of the most promising strategies towards the development of sustainable cultivars. The present study demonstrates the marker-assisted introgression of the submergence tolerant (Sub1) and three bacterial blight resistant genes (Xa21 + xa13 + xa5) into the genetic background of Hasanta, a long duration popular rice variety in the eastern coastal region of India. The rice genotypes, Swarna Sub1 (carrying Sub1) and IRBB66 (carrying Xa21 + xa13 + Xa7 + xa5 + Xa4) had maximum genetic similarity (0.84 and 0.73, respectively) with Hasanta; recurrent parent (RP) was used as donor. The forward analysis of target genes in F1s, IC1F1s and backcross (BC) generations was performed by linked/genic markers (Sub1bc2; pTA248, xa13prom and RM122), whereas background recovery of RP in each BC and segregating generations was performed utilizing 108 hypervariable SSR markers. Intervened speed breeding (SB) strategy and intensive phenotyping could lead the development of near isogenic lines (NILs) as to the RP in all basic traits. The performance of the near isogenic lines (NILs, BC2F3 and BC2F4), HS 232-411-391-756-37, HS 232-411-391-809-8, HS 232-411-391-756-18, HS 110-224-197-10-36, HS 232-411-391-809-81, HS 110-224-197-10-41 and HS 232-411-391-809-63 establishes the utility of marker-assisted backcross-breeding (MAB) and SB in accelerated trait introgression. The introgressed lines carrying Sub1 + Xa21 + xa13 + xa5 showed 76% to 91% survival under 14 days of submergence and durable BB resistance (percent disease index-PDI of 2.68 ± 0.26 to 6.22 ± 1.08 and lesion length, LL of 1.29 ± 0.12 to 4.2 ± 0.64 cm). Physiological analysis revealed that improved NILs, carrying Sub1 gene conquered adaptive physiological modulations, had reduced the consumption of soluble sugar and the degradation of total chlorophyll contents (TCC), and an enhanced level of Alcohol Dehydrogenase activity (ADH) and proline accumulation in all submergence regimes. The pyramided lines attained complete product profile of RP, that will contribute to sustainable rice production under RSL, particularly in the coastal region that has substantial acreage under the variety Hasanta.

Management of sulphur for yield augmentation in rice (Oryza sativa) under rice fallow system

Sulphur (S) is ranked as 4th most essential nutrient after nitrogen, phosphorous and potassium which plays a vital role in crop production. Its uses have declined in recent years. S-deficiency in soils of Odisha has increased from 36% during 2008–09 to 44% in 2018–19. A field experiment was conducted at farmers’ field in Ankurda village, Goindia block of Dhenkanal district, for two years (2018–19 and 2019–20) in order to study the effect of different sources of sulphur in rice (Oryza sativa L.) (cv. Swarna Sub 1) under mid-central table land zone of Odisha. The experiment was conducted in RBD with 10 treatments and 3 replications. Four different sources of sulphur (SSP, calcium sulphate, elemental S0 and navaratna as (20-20-0-13) were used with two methods, viz. basal and top dressing to rice crop during rainy (kharif) season. A mixture source was formulated with (CaSO4 + SSP) @1:1 ratio which was applied as basal only. Among the sources of sulphur applied, highest biomass yield was recorded with spilt method of ES which followed the order as: ESo>mixture source>navaratna>SSP>gypsum. Due to S fertilization, the biomass yield increased by 16% over the control (T1). Spilt application of sulphur fertilizer exerted a beneficial effect on yield attributing character, higher grain and straw yield, nutrient uptake, sulphur use efficiency and sulphur harvest index, quality parameters and B:C ratio of Swarna Sub-1 in comparison to basal application of fertilizers during rainy (kharif) season.

EVALUATION OF THE TOLERANCE OF RICE (ORYZA SATIVA) FOR SUBMERGENCE AND DROUGHT USING VARIOUS YIELD RELATED STRESS INDICES

Rice genotypes were evaluated under submergence stress and drought stress in two separate field conditions under Split Plot design consisting of water stress as the main plots, and rice genotype as the sub-plot treatments. Grain yields under non-stress and stressed conditions were used to calculate stress indices. In the first experiment, four rice genotypes (Swarna Sub1, Ciherang Sub1, IR-07-F289 Sub1 and IR-44 Sub1) along with two high yielding local varieties (KSK-133 and Super Basmati) were evaluated under submergence stress in field conditions. Submergence stress was applied at tillering stage for 21 days. Results of stress indices under submergence revealed that yield stability index was the only stress index which showed strong and positive correlation with crop yield under submergence. Biplot graph exhibited that harmonic mean, geometric mean productivity, mean productivity; stress tolerance index and yield index were the best stress indices among all other indices to identify submergence tolerant genotypes. Based on the stress indices and their correlation results, the genotypes can be classified in different groups. Super Basmati performed well under submergence and normal conditions, KSK-133 performed well under normal conditions, IR-44 Sub1 and Swarna Sub1 performed well under submerged conditions. While in the second experiment drought stress was applied for 30 days on four Sub1 genotypes along with Nagina-22 (Drought tolerant check) and IR-64 (drought susceptible check). Harmonic mean and yield index showed strong positive correlation with the yield under drought stress. Biplot graph exhibited that mean productivity, tolerance index, and stress susceptibility index were the best stress indices among all other indices to identify drought tolerant genotypes. Based on the stress indices and their correlation results it was observed that Nagina-22 performed well under drought and normal conditions, IR-64 performed well only under normal conditions, Swarna Sub1 and IR-07-F289 performed well under drought as compare to the normal conditions. As a whole, the findings of this study indicate that classification and selection of superior genotypes under severe stress conditions is more reliable by using stress indices as a base for selection.