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A set of 75 rice genotypes were evaluated under reproductive stage drought stress and controlled conditions during kharif 2011 and 2012 to identify stress tolerant genotypes. Drought tolerance indices like stress susceptibility index (SSI), drought tolerance efficiency (DTE), stress tolerance index (STI) and stress tolerance (TOL) and physio-morphological traits responses were employed in screening of the genotypes. Significant yield reduction was observed under drought stress in majority of the rice genotypes studied. Drought stress at reproductive stage caused reduction in grain yield (55.31%), leaf area (34.87%), number of spikelet (15.9%), spikelet fertility (17.13%), plant height (8.87%), relative water content (31.57%), harvest index (29.2%), while increase in sterility percentage (51.5%) and proline content (55.9%). The variation in SSI values ranged from 0.39 - 1.34, DTE from 26.10-78.54%, STI ranged from 0.22-0.74 and TOL varied from 0.91 -3.54. The genotypes with high DTE and STI and low SSI and TOL were identified as drought tolerant genotypes. Based on preliminary screening, rice genotypes IR55419-04, IR84895-B-B-127-CRA-5-1-1, IR83376-B-B-24-2, IR83387-B-B-40-1 and IR83373-B-B-24-3 showed low SSI and TOL and high DTE and STI values were identified as drought tolerant genotypes. These drought tolerant genotypes also showed superior performance with respect to grain yield and desired physiological and biochemical traits viz., relative water content (RWC), chlorophyll content, proline content, stomatal conductance and photosynthetic rate. Significant negative correlation found between grain yield with leaf rolling, leaf drying and spikelet sterility under stress condition. The present study indicate that selection based on stress tolerance indices likes DTE, SSI, STI and TOL will results in identification of drought tolerant genotypes for rainfed ecosystem. [ABSTRACT FROM AUTHOR]

The complexity of genotype × environment interactions under drought reduces heritability, which determines the effectiveness of selection for drought tolerance and development of drought tolerant varieties. Genetic progress measured through changes in yield performance over time is important in determining the efficiency of breeding programmes in which test cultivars are replaced each year on the assumption that the new cultivars will surpass the older cultivars. The goal of our study was to determine the annual rate of genetic gain for rice grain yield in a drought-prone rainfed system in a series of multi-environment trials conducted from 2005 to 2014 under the Drought Breeding Network of Indian sites in collaboration with the International Rice Research Institute (IRRI). Our results show a positive trend in grain yield with an annual genetic yield increase of about 0.68 % under irrigated control, 0.87 % under moderate reproductive stage drought stress and 1.9 % under severe reproductive stage drought stress due to breeding efforts. The study also demonstrates the effectiveness of direct selection for grain yield under both irrigated control as well as managed drought stress screening to improve yield in typical rainfed systems. IRRI's drought breeding programme has exhibited a significant positive trend in genetic gain for grain yield over the years under both drought stress as well as favorable irrigated control conditions. Several drought tolerant varieties released from the programme have outperformed the currently grown varieties under varied conditions in the rainfed environments on farmers' fields., Competing Interests: 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., (© 2020 The Authors.)

Rice is a staple cereal of India cultivated in about 43.5Mha area but with relatively low average productivity. Abiotic factors like drought, flood and salinity affect rice production adversely in more than 50% of this area. Breeding rice varieties with inbuilt tolerance to these stresses offers an economically viable and sustainable option to improve rice productivity. Availability of high quality reference genome sequence of rice, knowledge of exact position of genes/QTLs governing tolerance to abiotic stresses and availability of DNA markers linked to these traits has opened up opportunities for breeders to transfer the favorable alleles into widely grown rice varieties through marker-assisted backcross breeding (MABB). A large multi-institutional project, "From QTL to variety: marker-assisted breeding of abiotic stress tolerant rice varieties with major QTLs for drought, submergence and salt tolerance" was initiated in 2010 with funding support from Department of Biotechnology, Government of India, in collaboration with International Rice Research Institute, Philippines. The main focus of this project is to improve rice productivity in the fragile ecosystems of eastern, northeastern and southern part of the country, which bear the brunt of one or the other abiotic stresses frequently. Seven consistent QTLs for grain yield under drought, namely, qDTY1.1, qDTY2.1, qDTY2.2, qDTY3.1, qDTY3.2, qDTY9.1 and qDTY12.1 are being transferred into submergence tolerant versions of three high yielding mega rice varieties, Swarna-Sub1, Samba Mahsuri-Sub1 and IR 64-Sub1. To address the problem of complete submergence due to flash floods in the major river basins, the Sub1 gene is being transferred into ten highly popular locally adapted rice varieties namely, ADT 39, ADT 46, Bahadur, HUR 105, MTU 1075, Pooja, Pratikshya, Rajendra Mahsuri, Ranjit, and Sarjoo 52. Further, to address the problem of soil salinity, Saltol, a major QTL for salt tolerance is being transferred into seven popular locally adapted rice varieties, namely, ADT 45, CR 1009, Gayatri, MTU 1010, PR 114, Pusa 44 and Sarjoo 52. Genotypic background selection is being done after BC2F2 stage using an in-house designed 50K SNP chip on a set of twenty lines for each combination, identified with phenotypic similarity in the field to the recipient parent. Near-isogenic lines with more than 90% similarity to the recipient parent are now in advanced generation field trials. These climate smart varieties are expected to improve rice productivity in the adverse ecologies and contribute to the farmer's livelihood., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Maternal pneumomediastinum and subcutaneous emphysema is a rare, alarming but relatively benign complication of labor. It usually manifests itself during the second stage. Once it is diagnosed, further bearing down should be avoided and labor shortened. Due to its rarity, a case is reported with a review of literature. In this case pneumomediastinum and pneumothorax occurred in the newborn, also. To our knowledge, this is the first reported case of simultaneous pneumomediastinum in mother and neonate.

Angiotensin-converting enzyme (ACE) was measured in tissue homogenates from the African lungfish and six species of air-breathing teleosts (Heteropneustes fossilis, Clarias batrachus, Channa gachua, Anabas testudineus, Notopterus chitala, and Monopterus cuchia) using a standard spectrophotometric assay. In most species, the highest levels of ACE activity were found in the respiratory organs (gills and/or accessory respiratory organs). ACE was also found in heart and kidney tissues from most species and occasionally in liver. Converting enzyme was not found in skin or skeletal muscle from any species and only in blood from H. fossilis and brain from C. batrachus. Captopril, a potent inhibitor of mammalian ACE, inhibited enzymatic activity from all tissues except C. gachua heart and liver and A. testudineus heart. As fish make the transition from aquatic to aerial respiration the gill microcirculation is usually reduced in size and the accessory respiratory organs become elaborated and occupy a more central position in the vascular tree. The presence of ACE in accessory respiratory organs of air-breathing fish appears to greatly enhance the metabolic efficiency of this enzyme on circulating substrates.