Search Results

You are looking at 1 - 10 of 27 items for :

  • Author or Editor: B. Singh x
  • Biology and Life Sciences x
  • Refine by Access: All Content x
Clear All Modify Search

Aphids have acquired the status of major pest in North-western plains of India. A complex of five species infests the wheat in this part of the country. The diatomaceous earth (DE) has the potential to substitute the most widely used method of chemical control. Laboratory and field investigations were conducted to evaluate the effectiveness of DE either as soil or foliar application for suppression of wheat aphids during 2013–2014 and 2014–2015. The fecundity, adult longevity and total developmental duration of Rhopalosiphum padi decreased with the increasing dosage of soil application of DE in laboratory evaluation. However in field studies, no significant difference in aphid population was observed among different levels of DE application in soil. Foliar application of DE 150 kg/ha and higher dosages significantly reduced aphid population for initial two days but thereafter it had no effect on aphid prevalence. Wheat plant dusted with different dosages of DE did not show any visible injury but the reduction in chlorophyll content was observed in them. Overall, poor field efficacy coupled with loss of chlorophyll and safety issues relating to foliar application of DE proved against its use for control of sucking insect pests.

Restricted access

The CERES-rice model (version 4.0) was calibrated and validated using the data from a field experiment carried out during the rainy season of 2004 and 2005 at Shalimar, Srinagar (35° 5′ N latitude and 74° 89′ E longitude, 1587 m above the mean sea level, India. The experiment included six rice cultivars each transplanted on 25 May, 10 June and 25 June. Data of 25 May transplanting was used for model calibration and development of the genetic coefficients of the rice cultivars. The predicted and observed dates of phenological events were in close agreement with root mean square error (RMSE), mean absolute error (MAE) and D-index of 5.0 days, 4.3 days and 0.91, respectively, for anthesis and 3.7 days, 3.1 days and 0.91, respectively, for physiological maturity of the crop. The predicted and observed grain yields were also very close with a RMSE of 0.63 Mg ha −1 , MAE of 0.58 Mg ha −1 and D-index of 0.89, respectively. Corresponding values for above ground biomass was 1.17 Mg ha −1 , 1.01 Mg ha −1 and 0.82. Sensitivity test showed that simulated yield responded to temperature and atmospheric CO 2 concentration. Nitrogen 240 kg ha −1 at 25 May transplanting, recorded highest simulated grain yield (9.71 Mg ha −1 ). Further, 3 seedlings hill −1 produced highest simulated grain yield. The results suggest that the model can be applied in the temperate Kashmir to estimate crop productivity and optimize the management practices.

Restricted access

Germinated brown rice received great attention as healthy ingredient and can be used as an alternative source in the malting and brewing industry. The germination capacity, physico-nutritional properties, sugars, and diastase enzyme activity of brown rice affected by germination times and temperature were determined and compared with control. Soaking in water increased the moisture content of brown rice. Germination rate of brown rice was also increased by higher germination time and temperature and reached maximum after 48 h of germination at 35 ºC. However, dry matter loss, grain weight, and density are affected to a lesser extent. Germination significantly (P<0.05) affects the crude protein, fat, fibre, and ash contents. Total carbohydrates content showed linear relationship with germination time and temperature. During germination, hydrolytic enzymes act on starch, reducing its concentration and resulting in higher total and reducing sugars amounts. Increase in germination time and temperature also increased diastase enzyme activity.

Restricted access

The High Molecular Weight Glutenin Subunits (HMW GS) in bread wheat landraces were studied using the SDS-PAGE technique. Out of the 32 landraces, 23 were homogeneous while nine showed heterogeneity with respect to the HMW glutenin subunits. Novel variants were observed in HMW GS in four of the landraces. One novel subunit coded by the Glu-B1x locus and two novel subunit pairs at the Glu-D1 locus were identified. A modified system of nomenclature over that of Payne and Lawrence (1983) is suggested for numbering the new subunits. Accordingly, the novel subunits are numbered as 7 1 ( Glu-B1x ) and 2+12 2 ; 5 1 +12 2 ; 5 2 +12 3 and 5 3 +12 3 ( Glu-D1x + y ) and the allelic designations are given as Glu-B1 bh for 7 1 +9; Glu-D1bp for 2+12 2 . Glu-D1bq for 5 1 +12; Glu-D1br for 5 1 +12 2 ; GluD1br for 5 2 +12 3 and GluD1bt for 5 3 +12 3 .

Restricted access

Floral anatomy of Actinomeris squarrosaand Bidens biternatahave been described. The presence of pappus is an important structural feature of the Asteraceae. It has been considered by some as phyllome and by others a trichome structure. The presence of vascular supply to the pappus scales shows that it is a phyllome structure. Once the pappus is considered as a phyllome structure, two major lines of specialization can be established in this family from a primitive type of five vascular scales. In ome line of evolution there has been increase in the number of pappus from five to twenty and finally indefinite in number and the vascular supply is totally suppressed. In another line of evolution there has been a reduction in the number of pappus scales from five to two and finally total reduction of the scales. The disc-florets of Bidens biternataare pentamerous but occasionally tetramerous florets are also observed. In Actinomeris squarrosa disc-florets are tetramerous florets are derived from pentamerous floret by complete fusion of the two anterior alternipetalous strands is discussed. In the Asteraceae, the pistillate ray florets are derived from disc florets by formation of a deep sinus in the corolla on the posterior side, followed by gradual suppression of the androecium. The neutral ray-florets are derived from ray-florets by complete reduction of an ovule, loculus and style along with its vascular supply is also discussed.

Restricted access

The application of ultrasound during extraction of oil from apricot kernels using hexane was evaluated and compared with conventional methods (mechanical extraction and Soxhlet extraction). Results show that ultrasound assisted extraction (UAE) yields more oil with less solvent consumption. The oil yield from UAE, SE, and ME were 44.72%, 44.33%, and 35.06%, respectively. It is noteworthy that it took 44 min to extract oil by UAE method, while alike yield was obtained from SE in 6 hours. Oil extracted by UAE exhibited significantly higher peroxide and ester values. The functional groups of apricot kernel oil were analysed using Fourier transform infrared spectroscopy. Untreated and treated kernel powders were studied by scanning electron microscopy, and the development of microstructures and disruption of cell walls were evaluated. Our study suggests that ultrasound assisted extraction may be an effective method to extract edible oils by achieving higher efficiency in shorter extraction time.

Restricted access

Awareness of the environmental aspects of the quality of crop production has increased in recent decades, leading to renewed interest in organics such as crop residues, green manures and organic manures. The effect of organics on urea transformation was investigated by conducting a laboratory incubation experiment in alluvial clay loam soil (Typic Ustifluvents) at 33±1°C with two moisture levels (1:1 soil:water ratio and field capacity). The rate of urea hydrolysis decreased as the time of incubation increased and the disappearance of urea N was associated with a corresponding increase in the (NH 4 + + NO 3 )-N content in soils treated with crop residues (rice straw and wheat straw), organic manures (poultry manure and farmyard manure) and green manures (cowpea and sesbania). In untreated soil, the time taken for the complete hydrolysis of the applied urea (200 μg urea N g −1 soil) was more than 96 h at both the moisture levels, whereas in amended soils it was completed in 48 h. The rate of urea hydrolysis was more rapid at field capacity than at the 1:1 soil:water ratio. Urea hydrolysis was higher in sesbaniatreated soils, followed by cowpea, poultry manure, farmyard manure, rice straw and wheat straw at both the moisture levels. At field capacity, 85.5% urea was hydrolysed in sesbania-treated soil as compared to 32% in untreated soil after 24 hours of incubation, while at the 1:1 soil:water ratio the corresponding values were 81.5 and 27.5%. Urea hydrolysis followed first order reaction kinetics at both the moisture levels.

Restricted access

Ascochyta blight (Ascochyta rabiei) is one of the most devastating diseases of chickpea. The biocontrol potential of fungal antagonists, Chaetomium globosum, Trichoderma viride, Acremonium implicatum were explored under in vitro and in vivo. A. implicatum isolate-1 overgrew the host mycelium and caused lysis, while A. implicatum isolate-2 produced inhibition zone. C. globosum profusely overgrew the mycelium of A. rabiei and T. viride showed overgrowth and profuse sporulation. Bioassay with culture filtrates of all the antagonists resulted in significant inhibition of pycnidiospore germination and reduction in colony development of A. rabiei. Syringe filtered culture filtrate when amended in liquid broth medium also significantly reduced the mycelial growth. Bioassay of culture filtrates under glass house conditions, although brought reduction in disease development in both pre- and post-inoculation sprays, but C. globosum was the most effective antagonist causing 73.12% reduction in disease index when used as post inoculation spray. Under in vitro conditions C. globosum caused 48.59% reduction in colony diameter and 70.86% reduction in pycnidiospore germination.

Restricted access

Abstract

Brown rice was germinated for different times (12, 24, 36, and 48 h) at different temperatures (25, 30, and 35 °C) with the aim to improve the in vitro digestibility and antioxidant potential of the flour made from it. Results showed that increase in germination time and temperature increased in vitro digestibility of starch and protein during germination of brown rice owing to depolymerisation of starch and protein molecules by enzymatic activity. After germination under varying conditions, antioxidant activity increased from 50.19 to 95.58%, total phenolic and flavonoid contents from 0.88 to 2.02 mg GAE/g and 34.06–62.94 mg QE/100g, respectively. Germination at elevated temperature (35 °C) for prolonged time (48 h) also increased the reducing power by 60.49% and metal chelating activity by 114.50% as a result of structural breakdown of bound phenolics. Increased activity of hydrolytic enzymes with progress in the germination time and temperature also results in continuous reduction in the pasting properties and lightness values (L), while increasing a* and b* values of the flour of germinated brown rice. Tailored germination, therefore, can be offered as a tool to increase nutrient digestibility and bioactive potential of brown rice as compared to non-germinated brown rice, thus, producing naturally modified flour with enhanced functionality.

Restricted access

A set of 286 recombinant inbred lines (RILs) along with the parents and a popular wheat variety in India were grown for two consecutive years at three locations belonging to the two major wheat growing zones of India and evaluated for four grain quality traits. Rare recombinants with high trait value appeared for protein content (PC), thousand-kernel weight (TKW), sedimentation value (SV), and kernel hardness (KH). The magnitude of environmental effects was more pronounced than genotypic effects and genotype-environment interaction (GEI). The cumulative contribution of environment and GEI components to the total variance was highest in the expression of PC followed by TKW, SV, and KH. The top five percent (14 RILs) of genotypes with high trait value were subjected to Eberhart and Russell (1966) (ER), genotype and genotype-environment (GGE) and additive main effects and multiplicative interaction (AMMI) stability models. Five RILs were identified as stable in all the three stability models. RIL61 with 38.8%, RIL101 with 8.9%, RIL226 with 26.1% superiority over check variety were the most stable genotypes in all the three stability models for PC, TKW and KH, respectively. RIL113 was found to be stable genotype in ER and GGE models, whereas, RIL231 was the most stable genotype in AMMI and GGE models in the expression of SV. These common stable genotypes with high trait value identified through ER, AMMI and GGE models could be potential donors in active breeding programs to develop high yielding wheat varieties with improved PC, TKW, SV and KH.

Restricted access