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- Author or Editor: R. K. Sharma x
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In India wheat is conventionally planted on flat-bed and irrigation is applied by flooding, which results in low water-use efficiency. Efficient use of irrigation water is a major researchable issue in most command areas for improving crop productivity. Resource conservation technologies aimed at improving productivity and water-use efficiency such as raised-bed planting have been found useful in wide row crops like maize, cotton, sunflower, sugarcane, etc. However, such information is not available for a relatively narrow row crop like wheat. A field experiment was conducted during 2002–04 at New Delhi on a sandy loam soil to evaluate the performance of wheat crop under resource conservation techniques (RCTs), viz. furrow-irrigated raised-bed (FIRB), broad-bed and furrow (BBF), raised-bed and sunken-bed (RBSB) and conventional flat-bed (FB) in main plots, and 4 irrigation regimes, viz. irrigation only at crown root initiation (CRI); irrigation at 0.9 and 1.2 IW/CPE (irrigation water/cumulative pan evaporation) ratio and irrigations at six critical physiological growth stages in subplots. Wheat performed equally well under all the RCTs with respect to grain yield. The maximum grain yield was recorded under 1.2 IW/CPE ratio, which was at par with 6 irrigations at critical growth stages, but significantly higher than 0.9 IW/CPE and one irrigation at CRI. Bed planting techniques involving FIRB and BBF recorded significantly lower consumptive use (CU) of water than RBSB and FB. There was saving of 18.2 to 19.5% irrigation water by adopting FIRB compared to FB with flood irrigation. Water-use efficiency under FIRB and BBF was 8.3–22.8 and 4.9–24.8% higher respectively over the FB with flooding.
The hydrolytic behavior of thorium(IV) and dioxo-uranium(VI) was studied in the absence as well as in the presence of small concentration of fluoride in the pH range of 2.0 to 4.0 and 2.0 to 5.5, respectively. Effects of metal ion concentration and time dependence of the hydrolytic process were also investigated. The log values of 11 * and 13 * computed from the best model of species distribution were found to be -3.51±0.03, and -10.75±0.14 for thorium(IV). Similarly, the best model for dioxo-uranium consisted of 22 *, 46 * and 47 * species having values -6.15±0.05-18.43±0.09 and -23.36±0.07, respectively. Recently developed HYPERQUAD computer program was used for analyzing the various aspects of solution equilibrium species. Different models of chemically possible species distribution were invoked to identify the best model for which HYPERQUAD yields the best fitting of experimental data with least errors. The best model was also decided on the basis of chemical feasibility of the reaction. The species distribution of hydrolytic product remained unaffected in the presence of small quantity of fluoride ions (~1% of thorium and uranium concentration). Moreover, fluoride was found to be helpful in suppressing the early polymerization and colloid formation at the metal ion concentrations investigated. The small amounts of fluoride did not seem to affect the response of glass electrode significantly. The formations of fluoride containing ternary complexes were also not observed at 1% fluoride concentration.
Nitrogen (N) movement in the soil resulting from the long-term application of fertilizer N is an environmental concern when it reaches the groundwater. The distribution of N in the profile of an alkaline sandy loam soil (Typic Haplustept) and its relationship with N uptake by plants was studied after 22 years of continuous cultivation in an annual crop rotation involving maize (Zea mays L.) and wheat (Triticum aestivum L.). Soil samples were collected to a depth of 1.2 m from the 0-0.15, 0.15-0.30, 0.30-0.45, 0.45-0.60, 0.60-0.90 and 0.90-1.20 m layers and analysed for alkaline KMnO4-oxidisable N (available N) and mineral N (NH4-N and NO3-N). The continuous addition of increasing levels of N resulted in an increase in N content, whereas the combined application of N, P and K caused a decline in its availability. Mineral N (2 M KCl-extractable NH4-N and NO3-N) was the lowest in the N120P35K33.2 treatment plot. The available N and NH4-N decreased with increasing soil depth. However, variations in NO3-N concentration due to differential rates of fertilizer application were observed only to a depth of 0.45 m. This effect was more pronounced in the N180P17.5K33.2 plot. Regression equations were used to predict N uptake by wheat using the N status in different soil layers as independent variables. Multiple regression analysis indicated that the predictability of the relationship between N uptake and available N improved considerably when its status to a soil depth of 0.45 m was included. In the case of NH4-N, a noticeable increase in the coefficient of determination (R2) occurred to a depth of 0.90 m. The R2 value of NO3-N with the N uptake by wheat was quite low in the top layers (to a depth of 0.30 m). However, an increase in the R2 value was observed when lower depths (beyond 0.30 m) were included in the regression analysis, suggesting that the inclusion of subsoil N status is important to achieve better and profitable N supply systems in crop production.
High yielding, stable wheat (Triticum aestivum L.) cultivars are needed for the diverse environments in West Asia to improve rural livelihoods. This study was conducted to determine the performance of elite wheat breeding lines developed by CIMMYT, to analyze their stability for grain yield across diverse environments, and to identify superior genotypes that could be valuable for varietal release. Genetically diverse 196 advanced breeding lines were evaluated across different sites in Afghanistan. Grain yield, days to heading and plant height were analyzed. Genotypic superiority for grain yield was determined using genotype and genotype × environment (GGE) biplot analysis. The experimental genotypes showed arrays of variation for grain yield in each year, with mean values ranging from 3908 to 7209 kg/ha. A set of 20 experimental genotypes superior to the check based on their high mean yield and stability across environments as assessed by the GGE rank was identified. The most stable high yielding genotypes were HD 2687; Elvia/5/Cndo/R143//Ente/Mexi75/3/AE. sq./4/2*Oci; Quaiu; Whear/Vivitsi//Whear; Kiritati/2*Trch; Waxwing; Munal#1; Whear//Inqalab 91*2/Tukuru and Snb//Cmh79A.955/3*Cno79/3/Attila/4/Chen/A.sq.(Taus)//Bcn/3/2*Kauz. These superior genotypes also had acceptable maturity and plant height. The findings of this study provides information on adaptation of the internationally important wheat genotypes, valuable for wheat improvement program in Afghanistan and its neighbouring countries in West, Central and South Asia.
The phase diagram of 1,4-dibromobenzene (DBB) with pyrogallol (PG) shows the formation of a monotectic and a eutectic alloys at 0.12 and 0.99 mol fractions of DBB, respectively. The phase equilibrium shows the large miscibility gap region with the upper consolute temperature 159.0 °C at 0.55 mol fraction of DBB. Growth kinetics of pure compounds and their monotectic and eutectic at different undercooling (ΔT) obey Hillig–Turnbull's equation: v = u (ΔT) n . Thermodynamic parameters such as enthalpy of mixing, entropy of fusion, interfacial energy, roughness parameters and excess thermodynamic functions were computed based on enthalpy of fusion values obtained from DSC studies. The Cahn wetting condition is applicable for monotectic alloy. The optical microphotographs of binary alloys show lamellar and dendritic features.
In this paper we describe a sensitive and reproducible reversed-phase high-performance liquid chromatography (HPLC) method with photodiode-array detection for isolation and quantification of the bioactive hydrophilic constituent 7-(1-O-β-d-galacturonide-4′-(1-O-β-d-glucopyranosyl)-3′,4′,5,7-tetrahydroxyflavone, 1, from the seeds of Cuminum cyminum. Compound 1 was separated isocratically on a C18 preparative column, in high purity, after removal of solvents. The purity and identity of the compound were established by use of LC-mass spectrometry and by spectroscopic techniques (1H and 13C NMR). The purity of 1 was also confirmed by HPTLC.
Field experiments were conducted over two years under low input conditions to know the influence of bio-inoculants, namely arbuscular mycorrhiza fungi (AMF, Glomus fasciculatum ) and Azotobacter chroococcum (Azc) on the performance and gene effects for important root and plant characters in three crosses of wheat (WH147×WH157, WH147×PBW175 and WH147×WH542). Six generations representing P 1 , P 2 , F 1 , F 2 , BC 1 and BC 2 populations of each cross were grown in randomized block design with three replications. The estimate of means (m) indicated that bio-inoculants enhanced the mean performance of most of the characters and root length density and grain yield in some crosses only. Crop season also showed considerable effect on impact of bio-inoculants. The joint scaling test revealed adequacy of additive-dominance model of gene effects for root biomass, root length density, flag leaf area, tillers/plant, grain weight and grain yield in all the crosses and bio-inoculants treatments in both years. The AMF treatment brought about changes in the magnitude and significance of additive component for root biomass, plant height, flag leaf area in all the three crosses. Both additive (d) and dominance (h) components were affected with respect to grain yield in WH147×WH157 and WH147×WH542. The dominant component was important for tillers/plant, grain yield, root length in control, as well as bio-inoculants treated populations of WH147×PBW175 but treatment of AMF and AMF+ Azc reduced the magnitude of h and increased the magnitude of d. Digenic interactions were prominent for grains/spike in WH147×WH157. Magnitude of digenic interactions was higher under bio-inoculation. Simple pedigree and bulk pedigree methods are suggested to capitalize on adequate additive gene effects for developing bio-inoculants responsive wheat genotypes.
Maize cultivars (4 composites, 14 inbreds and 7 hybrids) cultivated in Punjab were characterized using a set of 70 Simple Sequence Repeat (SSR) markers with a total of 199 alleles. Out of these, 67 markers produced polymorphic profiles, 3 were monomorphic. Eight SSR primers detected eight unique alleles in three genotypes. These unique SSR alleles provide an opportunity for unambiguous differentiation of the respective genotypes. SSR profiles were analyzed by using computer softwares NTSYS-pc and DARwin 5.0. Both of them classified the genotypes in four distinct groups.
The present study reports the effects of pre-treatment with ferulic acid (FA) on antioxidant response of wheat seedlings. In comparison to hydropriming, 100 and 150 ppm of FA significantly enhanced seedling growth of wheat at 6th day after germination (DAG). However, 1000 ppm of FA led to reduction in seedling growth. Roots and shoots of wheat seedlings pre-treated with 100 ppm of FA showed significant upregulation of peroxidase (POX), ascorbate peroxidase (APX) activities. Although catalase (CAT) remained unaffected in the roots, but showed about 2-fold increase in the shoots. Despite of low glutathione reductase (GR) and high polyphenol oxidase (PPO) activities in the shoots and roots, respectively, ascorbic acid and total phenolic contents also increased at 6th DAG which may be due to the activation of their biosynthetic pathways in seedlings pre-treated with 100 ppm of FA. Proline content of wheat seedlings pre-treated with 100 ppm of FA remained unaffected. Results signify the role of FA pre-treatment in augmenting the antioxidant response of wheat and thereby suggest that at lower concentrations, it can be used for improving performance of wheat under various environmental constraints.
The dissolution of UO2 in carbonate-bicarbonate solutions containing sodium hypochlorite as an oxidant has been investigated. The effect of temperature, sodium hypochlorite concentration and stirring speed was examined. In the temperature range of 303 to 318 K, the leaching reaction displayed linear kinetics. Apparent activation energy obtained from the differential approach was found to be 57 kJ mol–1. This relatively high activation energy value indicates a chemically controlled behavior of UO2 dissolution. The order of reaction with respect to sodium hypochlorite concentration was found to be unity.