Authors:H. Khan, S.C. Bhardwaj, O.P. Gangwar, P. Prasad, P.L. Kashyap, S. Savadi, S. Kumar and R. Rathore
A set of forty wheat cultivars comprising bread wheat, durum and triticale identified during 2010–2014 were tested for resistance to Indian pathotypes of leaf, stem and yellow rusts at seedling stage under controlled conditions. Eight Lr genes (Lr1, Lr3, Lr10, Lr13, Lr14a, Lr23, Lr24 and Lr26) were characterized based on differential interactions with specific rust races. Genes Lr23, Lr26 and Lr13 conferred leaf rust resistance in most of the accessions. Three Yr genes (YrA, Yr2 and Yr9) were inferred in 40 genotypes, where Yr2 followed by Yr9 were most frequent in conferring stripe rust resistance. Ten Sr genes, namely, Sr2, Sr5, Sr8a, Sr7b, Sr9b, Sr9e, Sr11, Sr13, Sr24 and Sr31, were postulated in these lines with predominance of Sr11, Sr31 and Sr2. These Lr, Sr and Yr genes were observed singly or in combination. Robust DNA markers were used to identify adult plant resistance genes Yr18/Lr34/Sr57, Lr68 and Sr2 and all stage resistance genes Lr24/Sr24, Sr28 and Yr9/Lr26/Sr31. STS marker iag95 showed presence of Yr9 in four additional cultivars which were resistant to one or more rusts. Gene Sr28 was identified in seven durum cultivars with the wPt7004 marker. This is first report of Sr28 being present in many Indian wheat cultivars. CsGs-STS marker identified Lr68 in nine cultivars.
Authors:B. Kumar, K.S. Hooda, R. Gogoi, V. Kumar, S. Kumar, A. Abhishek, P. Bhati, J.C. Sekhar, K.R. Yathish, V. Singh, A. Das, G. Mukri, E. Varghese, H. Kaur, V. Malik and O.P. Yadav
Maydis leaf blight (MLB), a serious foliar fungal disease of maize, may cause up to 40% losses in yield. The present studies were undertaken to identify the stable sources of MLB resistance, its inheritance study, and testing of MLB resistance linked markers from diverse background in the Indian adapted tropical maize genotypes. A set of 112 inbred lines were screened under artificially created epiphytotics conditions at three hotspot locations. Analysis across multi-locations revealed significant effects of genotypes and environments, and non-significant effects due to genotypes × environment interaction on disease incidence. A total of 25 inbred lines with stable resistance were identified across multi-locations. Inheritance of resistance was studied in six F1s and two F2s of resistant and susceptible parents. The null hypothesis of segregation of resistance and susceptible for mono and digenic ratios in two F2 populations was rejected by Chi-square test. The non-significant differences among the reciprocal crosses depicted the complete control of nuclear genome for MLB resistance. Partial dominance in F1s and normal distribution pattern in F2s of resistant and susceptible parents suggested polygenic nature of MLB resistance. Correlation studies in F2 populations exhibited significant negative correlation between disease score and days to flowering. Five simple sequence repeats (SSRs) markers, found associated to MLB resistance in different studies were unable to differentiate amongst MLB resistance and susceptible parents in our study. This emphasizes the need of fine mapping for MLB resistance in Indian germplasm. The identified stable sources of resistance and information on inheritance study can be used further in strengthening of resistance breeding against MLB.
Authors:R. Batra, P. Kumar, M.R. Jangra, N. Passricha and V.K. Sikka
Adenosine diphosphate glucose pyrophosphorylase (AGPase) is the rate limiting enzyme of starch biosynthesis that directly affects the wheat productivity. AGPase and grain growth rate (GGR) discerned to be following strict temperature regimen in wheat disomic chromosome substitution (DCS) lines. The first half of grain filling period had chromosome 1B and 2D as prominent players, whereas second half was mainly controlled by chromosomes 6A and 5B. Chromosome 2D had major contribution towards yield in a specific temperature range of 23 ± 1.5 °C during initial stages of grain filling which can serve as an effective early screening tool for terminal heat tolerance in wheat. Chromosome 2D with highest amylose content can also be utilized to produce low digestibility flour. Grain yield was found to be significantly associated with spikes/plant, grains/spike, grain weight/spike and plant biomass. Further, path analysis indicated that though grains/spike had less direct effect on grain yield but its indirect impact on grain yield via AGPase-21 activity was high.
Authors:K.G. Mandal, K. Kannan, A.K. Thakur, D.K. Kundu, P.S. Brahmanand and A. Kumar
Three-year (2007/2008–2009/2010) field experiment was conducted at the Directorate of Water Management Research Farm under Deras command in Odisha, India to assess the crop yield, irrigation water use efficiency (WUE), sustainable yield index (SYI), land utilization index (LUI) and changes in soil organic carbon (SOC) for dominant rice systems, viz. rice-maize-rice, rice-cowpea-rice, rice-sunflower-rice, rice-tomato-okra and rice-fallow-rice. Results revealed that crop yield, in terms of total system productivity (TSP) increased by 273, 113, 106 and 58% in rice-tomato-okra, rice-sunflower-rice, rice-maize-rice and rice-cowpea-rice, respectively, when compared to rice-fallow-rice. Irrigation WUE was 49–414% greater in rice-based diversified systems than the existing rice-fallow-rice (2.98 kg ha−1 mm−1). The SYI ranged from 0.65 to 0.75 indicating greater sustainability of the systems. Three crops in a sequence resulted in greater LUI and production efficiency compared to rice-fallow-rice. The gross economic return and benefit-cost ratio was in the order: rice-tomato-okra > rice-maize-rice > rice-sunflower-rice > rice-cowpea-rice > rice-fallow-rice. The SOC storage ranged from 40.55 Mg ha−1 in rice-fallow-rice to 46.23 Mg ha−1 in rice-maize-rice system. The other systems had also very close values of SOC storage with the rice-maize-rice system; there was a positive change of SOC (7.20 to 12.52 Mg ha−1) for every system, with highest in rice-maize-rice system and the lowest in rice-fallow-rice. It is concluded that the appropriate rice-based system would be rice-tomato-okra followed by rice-maize-rice, rice-sunflower-rice and rice-cowpea-rice. Rice-fallow-rice is not advisable because of its lower productivity, lower LUI and economic return.
Authors:N. Raje, K. Swain, S. Kumar, S. Kayasth, R. Parthasarathy and P. Mathur
A simple and efficient method has been developed to preconcentrate natural protactinium from large quantity of monazite (5–10 g) and thorium concentrates (5–100 g), obtained from thorium plant stream on Dowex 1X8 in acid medium. Gamma-spectrometry, a powerful determination technique, has been used for quantitative determination of protactinium and uranium. Various parameters like sample preparation, optimization of the resin and sample size for 231Pa recovery, 231Pa/235U ratio have been studied in detail and are discussed.
Authors:S. Kumar, M. Sivaiah, K. Venkatesan, R. Krishna, G. Murthy and P. Sasidhar
A composite mixture of zirconium molybdate and zirconium tungstate was prepared and studied for the sorption of cesium and strontium as a function of nitric acid, metal ion concentration, time and temperature. The distribution coefficient (Kd) of 7000 ml/g (~90% sorption) and 70 ml/g (~20% sorption) was obtained for the sorption of cesium and strontium in 0.1M nitric acid, respectively. Experimental sorption capacity, b for cesium was found to be 50 mg/g from 0.1M HNO3 and 30 mg/g for strontium from 0.001M nitric acid. The sorption of strontium on the sorbent was accompanied by the absorption of heat but the sorption of Cs+ results in the liberation of heat. Column studies were conducted by following a breakthrough (BT) curve of cesium and strontium up to C/C0=1 and the results are reported.
Authors:Biplab Das, Shekhar Kumar, P. Mondal, U. Kamachi Mudali and R. Natarajan
Red-oil is a mixture of nonspecific composition consisting of extractant, degradation products, nitrated solvent and unidentified
red-coloured nitro-organics. Red-oil formation is coupled with decomposition of extractant and diluent into gases of explosive
nature. If ignited or incinerated, these gases may cause rapid pressurization and endanger the integrity of containment. Such
an event occurred at Tomsk-7 facility in 1993. To ensure safe operation, red-oil formation has to be avoided in the fuel cycle
facilities by a careful combination of several independent measures like strict control over temperature, limiting organic
entrainment in the aqueous streams (which are to be concentrated by evaporation) and control over acidity of aqueous phases.
Since tri-iso amyl phosphate (TiAP) has much lower aqueous solubility as compared to TBP, it is visualized as alternate solvent for PUREX
process. In this work, TiAP red-oil was synthesized and characterized.
Authors:Shekhar Kumar, M. Muthukumar, P. Sinha, U. Kamachi Mudali and R. Natarajan
Phenyl trifluoromethyl sulfone (FS-13) is a polar diluent, proposed in literature as an alternate to nitrobenzene, in UNEX/HCCD-PEG
processes for better physical properties. Its PVT properties and accurate expression for estimation of its vapour pressure
are not available in the literature. Recently PVT properties of FS-13 were estimated by authors and its vapour pressure was
experimentally measured at temperatures ranging from 263.15 to 363.15 K. In this paper, results of these studies are presented.
Authors:C. Kedari, M. Kumar, S. Tripathi, A. Dakshinamoorthy, S. Munshi and P. Dey
Cross-linked hydrogel matrices immobilized with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (HA), were prepared to
investigate their application in the recovery of radionuclide from acidic waste solutions. Gamma-radiation was used to produce
HA immobilized polyvinyl alcohol (PVA) hydrogels (HA-gel). The hydrogels with different characteristics such as: degree of
cross-linking (by varying radiation dose) and quantity of extractant immobilized (by starting with aqueous PVA solution containing
different amounts of HA), were synthesised. These HA-gels were investigated for solid-liquid phase extraction of U(VI), Pu(IV),
Am(III) and some fission products, under various experimental conditions. The concentration of HNO3 in the aqueous phase was found to play an important role in the extraction of these radionuclei. Extraction of U(VI) was
more favourable at lower concentration of HNO3 (∼0.001 to 0.5M), while at higher concentrations (∼0.5 to 3M HNO3), more than 90% of Pu(IV) present in the aqueous phase, could be extracted by the HA-gel. The extraction of Am(III) was also
found predominant only at lower acidities (at pH∼2 and above). Under optimized conditions, maximum metal loading capacities
obtained were 19±0.8 mg, 8±0.4 mg and 11±0.5 mg per gram of swollen HA-gel, for U(VI), Pu(IV) and Am(III), respectively. Under
the experimental conditions, extractions of Cs(I) and Sr(II) were observed to be negligible. No leaching out of HA from the
HA-gel particles was noted even after its repetitive use for the studied ten cycles of extraction and stripping experiments,
as evident from its unchanged extraction efficiency.
Authors:R. Kumar, N. Sivaraman, A. Thiruvenkadasamy, C.R. Venkata Subramani and P.R. Vasudeva Rao
Carrier-free 22Na was separated from bulk quantities of magnesium by both ion exchange and extraction chromatographic techniques. An extraction chromatographic procedure based on di-(2-ethylhexyl) phosphoric acid (HDEHP) coated on to an inert support (Amberlite XAD-7) was developed for the first time for separation of sodium from magnesium. The sorption behavior for sodium and magnesium was studied as a function of percentage of HDEHP loaded on to the inert support as well as pH of aqueous phase. These data were used to arrive at the optimum conditions of separation. In addition, carrier free 22Na was also separated from magnesium using ion exchange chromatographic technique.