Papaya yellow leaf curl virus: A newly identified begomovirus infecting Carica papaya L. from the Indian Subcontinent     

Chitra Nehra  Avinash Marwal  Rakesh Kumar Verma  Megha Mishra  Pradeep Sharma 《The Journal of Horticultural Science and Biotechnology》2019,94(4):475-480

India is one of the world’s largest producers of papaya. Viruses, mainly begomoviruses and potyviruses, cause a significant loss in papaya production. The study described here has identified a new species of begomovirus and a new species of betasatellite infecting Carica papaya in India. The sequences of the begomovirus and betasatellite show 90.03% nucleotide sequence identity to an isolate of Radish leaf curl virus and 92.25% identity to an isolate of Tomato leaf curl betasatellite, respectively. Maximum likelihood phylogenetic tree of begomovirus sequence of isolate DP2 (KX353622) showed distant relationships with previously characterised begomoviruses. Recombination analysis proposed six recombination breakpoints in begomovirus genome with other geographical begomovirus isolates.  相似文献   

Technical efficiency of carp production in Nepal: An application of stochastic frontier production function approach*     

Khem R. Sharma  Pingsun Leung 《Aquaculture Economics & Management (Blackwell Science)》2013,17(3):129-140

Abstract

Modern aquaculture is a relatively new activity among Nepalese farmers and a small contributor to the economy. Given the abundance of water resources and fish species, rising demand for fish, and its high profitability, aquaculture has potential for future expansion if it is given appropriate attention from the government. In Nepal, productivity in aquaculture is much lower compared to other countries in the region, which suggests that there is potential for increased fish production through technological progress and improvement in farm‐level technical efficiency. However, no formal analysis has yet been conducted to assess the productive performance of Nepalese aquaculture and its potential for future improvement. Against this background, this paper examines the technical efficiency and its determinants for a sample of fish pond farms from the Tarai region of the country using a stochastic production frontier involving a model for technical inefficiency effects. The estimated mean technical efficiency is 77%, with intensive farms being more efficient than extensive farms. The adoption of regular fish, water, and feed management activities has a strong positive effect on technical efficiency.  相似文献   

Status,structure and environmental variations in semi-arid mangroves of India     

G.A.Thivakaran  Seema B.Sharma  Abhiroop Chowdhury  Arumugam Murugan 《林业研究》2020,31(1):163-173

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Effect of tester on combining ability estimates of maize germplasm complexes     

D. Sharma  J. P. Tandon  J. N. Batra 《Euphytica》1967,16(3):370-376

Eight maize complexes and varieties representing high and low yield levels were tested for their suitability as top cross testers by comparing the performance of the crosses in relation to the combining ability of the parents estimated by diallel analysis. The discriminating ability of the testers was compared by Schumann and Bradley test. In both cases the results clearly showed that the low performing testers were better and more reliable than the high performing complexes. The utility of per se performance as an indication of general combining ability of the complexes has been discussed.  相似文献   

A review of production frontier analysis for aquaculture management     

Khem R. Sharma  Pingsun Leung 《Aquaculture Economics & Management (Blackwell Science)》2013,17(1-2):15-34

Abstract

This paper examines recent advances in production economics with special reference to efficiency measurement using production frontiers and its implications for aquaculture management. Compared with agriculture and other industries, the use of production frontiers in aquaculture is still very limited. However, in recent years several frontier applications in aquaculture have appeared in the literature, suggesting potential applications of these techniques in aquaculture. A synopsis of stochastic frontier production function model and data envelopment analysis (DEA), the two most popular approaches to efficiency measurement, is presented, followed by a review of recent frontier studies in shrimp, carp and tilapia production. The paper concludes with a brief discussion of future development and prospects of frontier applications for aquaculture management.  相似文献   

Food consumption and digestive enzyme activity of Clarias batrachus exposed to various temperatures     

T. Ahmad  S.P. Singh  B.K. Khangembam  J.G. Sharma  R. Chakrabarti 《Aquaculture Nutrition》2014,20(3):265-272

The effect of temperature on the food consumption rate and the digestive enzyme activities of Clarias batrachus (80.60 ± 5.34 g) were evaluated. Fish were exposed to six different temperatures of 10, 15, 20, 25, 30 and 35 °C following an acclimation temperature of 25 °C. The rate of temperature change was 2 °C day^?1. Highest food consumption was recorded at 25 °C. It gradually reduced with decreasing water temperature. Food consumption rate was significantly (P < 0.05) lower at 10 °C compared with other treatments. Hence, 46.67, 8.20–23.58 and 1.02–6.15% reduced food consumptions were recorded in groups exposed at 10, 15 and 20 °C temperatures, respectively, compared with the 25 °C. The consumption rate was not affected in fish exposed at 30 and 35 °C. Total protease, trypsin and chymotrypsin activities were significantly (P < 0.05) higher in fish exposed at 25 °C compared with others. Lipase activity was significantly (P < 0.05) higher in fish exposed at 30 °C compared with others. Lowest enzyme activities were recorded at 10 °C. Water temperature below 25 °C affected the food consumption and digestive enzyme activities in fish that served as indicators of stress in fish.  相似文献   

Effects of Partial and Complete Replacement of Synthetic Cryoprotectant with Carrot (Daucus carota) Concentrated Protein on Stability of Frozen Surimi     

Sanjeev Sharma  K. Siddhnath  N. K. Mehta  Apurba Saha  Shubham Gupta 《Journal Of Aquatic Food Product Technology》2013,22(8):808-820

ABSTRACT

The study aimed to evaluate the effects of carrot concentrated protein (CCP) as additive on the functional and textural properties of surimi from striped catfish (Pangasianodon hypophthalmus) during six months of frozen storage (?20°C). The CCP (82.22% crude protein) was used as an additive either a lone or with a synthetic cryoprotectant (sucrose-sorbitol-sodium tri-polyphosphate). Control was made with synthetic cryoprotectant only. Molecular weight of CCP was found to be 36 kDa. After six months, the results revealed that up to 50% of synthetic cryoprotectants could be replaced by CCP during frozen storage of surimi. Biochemical parameters such as protein solubility, Ca²⁺ATPase activity, and gel strength decreased significantly (p < .05) during storage. Treatment T-3 (CCP 0.5% + 50% of synthetic cryoprotectant) maintained quality of protein significantly superior (p < .05) in respect to denaturation and other functional and sensory attributes compared to all the treatments. The microstructure images of surimi confirmed that addition of CCP modified the ice crystal growth during frozen storage. This study suggests that CCP can be a potential additive to protect protein from denaturation along with partial replacement of chemical cryoprotectants.  相似文献   

Pharmacokinetics of Enrofloxacin and Its Metabolite Ciprofloxacin after Intramuscular Administration of Enrofloxacin in Goats     

Rao GS  Ramesh S  Ahmad AH  Tripathi HC  Sharma LD  Malik JK 《Veterinary research communications》2001,25(3):197-204

The pharmacokinetics of enrofloxacin and its active metabolite ciprofloxacin were investigated in goats after a single intramuscular administration of enrofloxacin at 2.5 mg/kg body weight. The plasma concentrations of enrofloxacin and ciprofloxacin were determined simultaneously by a HPLC method. The peak concentrations (C _max) of enrofloxacin (1.13 g/ml) and ciprofloxacin (0.24 g/ml) were observed at 0.8 and 1.2 h, respectively. The elimination half-life (t _1/2), volume of distribution (V _d(area)), total body clearance (Cl_B) and mean residence time (MRT) of enrofloxacin were 0.74 h, 1.42 L/kg, 1329 ml/h per kg and 1.54 h, respectively. The t _1/2, area under the plasma concentration–time curve (AUC) and the MRT of ciprofloxacin were 1.38 h, 0.74 g h/ml and 2.73 h, respectively. The metabolic conversion of enrofloxacin to ciprofloxacin was appreciable (36%) and the sum of the plasma concentrations of enrofloxacin and ciprofloxacin was maintained at or above 0.1 g/ml for up to 4 h. Enrofloxacin appears to be useful for the treatment of goat diseases associated with pathogens sensitive to this drug.  相似文献   

Growth-inhibiting activity of azadirachtin onCorcyra cephalonica     

G. K. Sharma 《Phytoparasitica》1992,20(1):47-50

The growth-inhibiting properties of azadirachtin, a bioeffective triterpenoid compound isolated from neem (Azadirachia indica A. Juss) seeds, was evaluated on the rice moth,Corcyra cephalonica Staint., a serious pest of stored products. By topical application of various azadirachtin doses (0.5 to 10 μg/larva) in methanol to last-instar spinning stage larvae, development was inhibited. The effect was dose-dependent; at higher doses, many of the insects remained in the larval stage (55% with 10 μg/larva). Disturbance of both larval-pupal and pupal-adult molting is discussed and interpreted as interference with the morphogenetic hormone pool size.  相似文献   

Genetics of soybean-Heterodera glycines system     

S. C. Anand  S. B. Sharma 《Integrated Pest Management Reviews》1995,1(1):65-69

Genetics of resistance to soybean cyst nematode (SCN), Heterodera glycines Ichinohe is very complex. Crosses involving PI 437654, which is resistant to all races of cyst nematodes with other sources of resistance (Peking, PI 88788, and PI 90763) indicated that resistance to race 3 was controlled by four genes, two of which were dominant resistance genes and the other two were recessive resistance genes. For race 5, a four gene model with two recessive and two dominant resistance genes in epistasis has been proposed. For race 14, the results suggested a three gene model with one dominant and two recessive alleles. Several other plant introductions have been isolated which have different genes conditioning resistance. Most of the currently grown soybean varieties derived resistance from Peking and/or PI 88788. Resistance to SCN in these soybean varieties has broken down because of the emergence of several new races and populations of SCN. The use of PI 437654 or Hartwig and other plant introductions with different genes for resistance will broaden genetic diversity and stabilize yield.  相似文献