Integrated Physiological, Biochemical, and Molecular Analysis Identifies Important Traits and Mechanisms Associated with Differential Response of Rice Genotypes to Elevated Temperature

In changing climate, heat stress caused by high temperature poses a serious threat to rice cultivation. A multiple organizational analysis at physiological, biochemical and molecular level is required to fully understand the impact of elevated temperature in rice. This study was aimed at deciphering the elevated temperature response in eleven popular and mega rice cultivars widely grown in India. Physiological and biochemical traits specifically membrane thermostability (MTS), antioxidants, and photosynthesis were studied at vegetative and reproductive phases which were used to establish a correlation with grain yield under stress. Several useful traits in different genotypes were identified which will be important resource to develop high temperature tolerant rice cultivars. Interestingly, Nagina22 emerged as best performer in terms of yield as well as expression of physiological and biochemical traits at elevated temperature. It showed lesser relative injury, lesser reduction in chlorophyll content, increased super oxide dismutase, catalase and peroxidase activity, lesser reduction in net photosynthetic rate (PN), high transpiration rate (E) and other photosynthetic/ fluorescence parameters contributing to least reduction in spikelet fertility and grain yield at elevated temperature. Further, expression of 14 genes including heat shock transcription factors and heat shock proteins was analyzed in Nagina22 (tolerant) and Vandana (susceptible) at flowering phase, strengthening the fact that N22 performs better at molecular level also during elevated temperature. This study shows that elevated temperature response is complex and involves multiple biological processes which are needed to be characterized to address the challenges of future climate extreme conditions

Improved Enzymatic Hydrolysis of Pilot Scale Pretreated Rice Straw at High Total Solids Loading

Enzymatic hydrolysis at high solids loading has the potential to reduce both capital and operational expenditures. Here, pretreatment of rice straw (PRS) with dilute acid was carried out at a pilot scale (250 kg per day) at 162°C for 10 min and 0.35% acid concentration, followed by enzymatic hydrolysis at different total solids loadings. It showed that although the total sugar concentration increased from 48 to 132 g/l, glucan conversion reduced by 27% (84–66.2%) with increasing solids from 5 to 20% in batch mode. Therefore, two different fed-batch approaches were evaluated to improve the glucan conversion by the sequential addition of a substrate and/or enzyme. At 20% solid loadings and a 3 filter paper units/g enzyme dosage, the highest glucan conversion obtained was 66% after 30 h of hydrolysis in batch mode. However, in an optimized fed-batch approach, the glucan yield was improved to 70% by simply dividing the substrate feeding into three batches, that is, 50% at 0 h, 25% each after 4 h, and 8 h of hydrolysis reaction. The addition of surfactant (Ecosurf E6) further improved the conversion to 72% after 30 h. The role of critical factors, that is, inhibitors, enzyme–lignin binding, and viscosity, was investigated during the course of hydrolysis in the batch and fed-batch approaches. This study suggests a sustainable approach for improved hydrolysis at high solids loadings by fine-tuning a simple process

Participatory research for assessing the suitability of potential innovations: A case study on high-yielding varieties options for rice farmers in north east India

This study examines the potential of participatory research to investigate the suitability and performance of high yielding rice varietal technologies with farmers of both hill and valley districts of Manipur based on front line demonstrations (FLDs) conducted from 2005 to 2012. Demonstrations were carried out in all the 9 districts (4 valley and 5 hill) in coordination with Krishi Vigyan Kendras to demonstrate the performance of RC Maniphou 10 on the farmers’ fields. Leimaphou a very popular variety among the farmers was grown as a check variety. The average yield of check variety ranged from 3.3 to 4.8 tonnes/ha, whereas the demonstrated variety RC Maniphou 10 recorded yield ranging from 4.6 to 6.2 tonnes/ha and yield gain over the check variety ranged from 27 to 43% in different districts. It was found that net returns have increased from 34% (in Imphal West) to 69% in Tamenglong- under improved practice (IP) than farmer’s practice (FP). The crop profitability has also increased by 40% in Imphal West and 75% in Tamenglong. The technology gap analysis revealed highest gap in the demonstration yield over potential yield in Senapati and Chandel districts (3.89 tonnes/ha), whereas it was lowest in Thoubal district (2.36 tonnes/ha). High extension gap of 1.52 tonnes/ha was recorded in Churachandpur followed by Tamenglong district. The technology index was minimum in Thoubal (27.7%) as compared to other districts. From this participatory research, farmers were convinced about the performance of RC Maniphou 10 and neighbouring farmers have taken seed which helped in spread of the variety. The variety was found suitable for both valley and hill areas

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Not AvailableAbiotic stresses such as drought, salt, heat, and cold are serious threats to the sustainability of rice yield. As rice is considered one of the major food crops, the development of enhanced abiotic stress tolerance using breeding and transgenic approaches will undoubtedly have a serious impact on global food security. Significant genetic variation in rice germplasm for resistance/tolerance to abiotic stresses makes plant breeding as a viable option of stress tolerance development. Though high-yielding rice cultivars with enhanced tolerance to abiotic stresses have been released, the progress made by conventional breeding was considerably slow due to multigenic nature of the traits and other associated problems. Biotechnology tools like molecular breeding and genetic engineering have accelerated the efforts of developing abiotic stress-tolerant crops. Further, the progress in identification of new genes and QTLs involved in abiotic stress response has supplemented the breeding and transgenic approaches of stress tolerance. The transgenic approach offers an alternative to breeding approaches for the genetic improvement of rice germplasm. In recent years, a number of stress-related genes have been identified and transferred in rice to improve its tolerance against abiotic stresses. Several transgenic rice lines with enhanced abiotic stress tolerance have been generated and evaluated. This chapter highlights the updates of breeding and transgenic approaches for the development of abiotic stress tolerance in rice with illustrations from research targeted at drought, salinity, heat, cold, and submergence.Not Availabl

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Not AvailableTwenty three new plant type (NPT) wheat derivatives with three checks were evaluated for grain yield and stability under timely (TSI) and late-sown irrigated environments (LSI).The experiment was conducted in six environments at two locations in 2006-07 and 2007-08. Analysis of variance of stability for grain yield through Eberhart and Russell’s model and AMMI analysis revealed highly significant differences among genotypes and environments and significant genotype x environment (G x E) interaction (GEI). Highly significant mean squares due to environment + genotype x environment interactions (E + G x E) in the Eberhart and Russell model revealed that genotype interacted considerably with environmental conditions that existed under TSI and LSI condition. Further partitioning of E + G x E effects indicated that E (linear), G x E (linear) component, and pooled deviation were highly significant for grain yield. Some genotypes showed linear effects over environments, while others showed significant deviation from a linear relationship. Partitioning of G x E interaction into principal components in AMMI analysis revealed that the two interaction principal component axes accounted for 90.4% of the total GEI variation. Genotypes DL 893, DL 901, DL 966 and PBW 343 exhibited high per se performance under TSI, whereas DL 880, DL 882, DL 886, DL 892, DL 893, DL 901 and DL 927 recorded high per se performance under LSI at both locations. Based on per se performance, regression coefficient, and deviations from regression as well as AMMI analysis, genotypes DL 886, DL 901, DL 924, DL 927, DL 966 and DL 960 were found to be stable and are adaptable to both TSI and LSI. Both Eberhart and Russell and AMMI results are comparable in identifying stable genotypes for the test environments.Not Availabl

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Not AvailableSUMMARY Twenty three new plant type (NPT) wheat derivatives with three checks were evaluated for grain yield and stability under timely (TSI) and late-sown irrigated environments (LSI).The experiment was conducted in six environments at two locations in 2006-07 and 2007-08. Analysis of variance of stability for grain yield through Eberhart and Russell's model and AMMI analysis revealed highly significant differences among genotypes and environments and significant genotype x environment (G x E) interaction (GEI). Highly significant mean squares due to environment + genotype x environment interactions (E + G x E) in the Eberhart and Russell model revealed that genotype interacted considerably with environmental conditions that existed under TSI and LSI condition. Further partitioning of E + G x E effects indicated that E (linear), G x E (linear) component, and pooled deviation were highly significant for grain yield. Some genotypes showed linear effects over environments, while others showed significant deviation from a linear relationship. Partitioning of G x E interaction into principal components in AMMI analysis revealed that the two interaction principal component axes accounted for 90.4% of the total GEI variation. Genotypes DL 893, DL 901, DL 966 and PBW 343 exhibited high per se performance under TSI, whereas DL 880, DL 882, DL 886, DL 892, DL 893, DL 901 and DL 927 recorded high per se performance under LSI at both locations. Based on per se performance, regression coefficient, and deviations from regression as well as AMMI analysis, genotypes DL 886, DL 901, DL 924, DL 927, DL 966 and DL 960 were found to be stable and are adaptable to both TSI and LSI. Both Eberhart and Russell and AMMI results are comparable in identifying stable genotypes for the test environments.Not Availabl

Screening of Rice (Oryza sativa L.) Genotypes for Anaerobic Germination

The present investigation was carried out to screen the set of 2000 rice genotypes including germplasm, released varieties, INGER nurseries and elite lines for anaerobic germination trait. Based on initial screening of 2000 genotypes, five hundred lines were selected for further to study the trait based on parameters namely germination percentage, seedling length and vigour index. Frequency distribution was calculated for the three observations under study. Out of five hundred genotypes under study, 16 genotypes were not germinated, while 100 % germination was recorded by 17 genotypes. The seedling length of the germinated seeds was in the range of 1 cm (E 199 and E 282) to 62 cm (E 480), While vigour index was ranged from 20 (E199, E282 and E532) to 4880 (E1777). After repeated screening, 13 entries namely E775, E1810, E596, E1786, E 753, E773, E1846, E1195, E1049, E1772, E1723, E1701 and E1777 were recorded 100% anaerobic germination with high seed vigour index, was identified as tolerant genotypes for the anaerobic germination. These genotypes could be used as parents to introduce anaerobic germination tolerance into improved cultivars to utilize under direct seeded condition

Typhoid ileal perforation: a 13-year experience

Typhoid fever is endemic in many developing countries with a high rate of complications. Aim of this study is to analyse epidemiological features, clinical presentations, complications and therapeutic outcomes of enteric perforation peritonitis diagnosed and treated in our hospital. Records of total number of 646 patients, who presented with perforation peritonitis due to enteric fever in the surgical emergency unit of Dr Ram Manohar Lohia hospital, New Delhi between January 2001 and December 2013, were reviewed retrospectively. Descriptive statistics was used to analyze the data. Out of 646 patients, 62 (9.59%) presented in shock. Stomal, peristomal, local and systemic complications were high in these patients. Primary closure was done in 212 (33.12) patients, primary ileostomy was created in 410 (64.06) patients, and resection and anastomosis was done in 24 (3.75) patients. Thirteen patients (2.01%) died of typhoid intestinal perforation. To prevent complications of typhoid fever, in addition to control sanitation, it is also important to control quackery and malpractices. Awareness and education about the disease, its nature and complications will also be of great help

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Not AvailableIn changing climatic conditions, heat stress caused by high temperature poses a serious threat to rice cultivation. A multiple organizational analysis at physiological, biochemical, and molecular levels is required to fully understand the impact of elevated temperature in rice. This study was aimed at deciphering the elevated temperature response in 11 popular and mega rice cultivars widely grown in India. Physiological and biochemical traits specifically membrane thermostability (MTS), antioxidants, and photosynthesis were studied at vegetative and reproductive phases, which were used to establish a correlation with grain yield under stress. Several useful traits in different genotypes were identified, which will be an important resource to develop high temperature-tolerant rice cultivars. Interestingly, Nagina22 emerged as the best performer in terms of yield as well as expression of physiological and biochemical traits at elevated temperature. It showed lesser relative injury, lesser reduction in chlorophyll content, increased super oxide dismutase, catalase and peroxidase activities, lesser reduction in net photosynthetic rate (P N ), high transpiration rate (E), and other photosynthetic/fluorescence parameters contributing to least reduction in spikelet fertility and grain yield at elevated temperature. Furthermore, expression of 14 genes including heat shock transcription factors and heat shock proteins was analyzed in Nagina22 (tolerant) and Vandana (susceptible) at flowering phase, strengthening the fact that N22 performed better at molecular level also during elevated temperature. This study shows that elevated temperature response is complex and involves multiple biological processes that are needed to be characterized to address the challenges of extreme conditions of future climate.Not Availabl

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Not AvailableComputational prediction of potential miRNAs and their target genes was performed to identify the miRNAs and genes associated with temperature response in rice. The data of temperatureresponsive miRNAs of Arabidopsis, and miRNAs and whole genome data of rice were used to predict potential miRNAs in O. sativa involved in temperature response. A total of 55 miRNAs were common in both the species. A total of 27 miRNAs were predicted at the first time in rice. Target genes were searched for these 27 miRNAs in rice genome following stringent criteria. Real time PCR based on expression analysis of nine miRNAs showed that majority of the miRNAs were down regulated under heat stress for rice cultivar Nagina 22. Furthermore, miR169, miR1884 and miR160 showed differential expression in root and shoot tissues of rice.Identification and expression studies of miRNAs duringheat stress will advance the understanding of gene regulation under stress in rice.Not Availabl