Population dynamics of citrus leaf miner on different varieties of citrus in correlation with abiotic environmental factors in Sargodha District,Punjab, Pakistan     

Irfan Mustafa  Muhammad Arshad  Abdul Ghani  Iftikhar Ahmad  Abu Bakar Muhammad Raza  Farzana Saddique  Saira Asif  Mobushir Riaz Khan  Haroon Ahmed 《Phytoparasitica》2014,42(3):341-348

From January 2010 to December 2011, samples of leaves from citrus varieties Kinnow, Musambi and Feutral were taken from the five tehsils (administrative subdivisions) of Sargodha District in Pakistan including Sargodha, Bahalwal, Silanwalli, Sahiwal and Kotmomin, to study the population trends in citrus leaf miner (CLM), Phyllocnistis citrella (Stainton) (Lepidoptera: Gracillariidae), and its correlation with various environmental factors: (temperature, humidity and rainfall); plant morphological factors: moisture contents of leaves, leaf thickness, surface area (cm ² ), and biochemical percentage of calcium, potassium and magnesium in leaves. The maximum population of CLM was observed on Kinnow and Feutral, followed by Musambi. The effect of these factors on the larval population was 8.39- 2.30(Mg)+2.73(K)-0.398(Ca)-0.100(Temp)0.038(Humidity)+0.567(Rain)+0.07(Moist) 1.01 (Thickness)-0.022(Surface area). This equation revealed that magnesium, calcium, temperature, humidity, leaf thickness and leaf surface area are negatively correlated with larvae population, whereas potassium, rainfall and moisture are positively correlated with larvae population.  相似文献   

Seed Priming Influence on Early Crop Growth,Phenological Development and Yield Performance of Linola (Linum usitatissimum L.)          下载免费PDF全文

Hafeez ur Rehman  Muhammad Qaiser Nawaz  Shahzad Maqsood Ahmed Basra  Irfan Afzal  Azra Yasmeen  Fayyaz ul-Hassan 《农业科学学报》2014,13(5):990-996

Reduced early crop growth and limited branching are amongst yield limiting factors of linola. Field response of seed priming treatments viz. 50 mmol L⁻¹ salicylic acid (SA), 2.2% CaCl₂ and 3.3% moringa leaf extract (MLE) including untreated dry and hydropriming controls was evaluated on early crop growth and yield performance of linola. Osmopriming with CaCl₂ reduced emergence time and produced the highest seedling fresh and dry weights including Chl. a contents. Osmopriming with CaCl₂ reduced crop branching and flowering and maturity times and had the maximum plant height, number of branches, tillers, pods and seeds per pod followed by MLE. Increase in seed weight, biological and seed yields was 9.30, 34.16 and 39.49%, harvest index (4.12%) and oil contents (13.39%) for CaCl₂ osmopriming. Positive relationship between emergence and seedling vigor traits, 100-seed weight, seed yield with maturity time, 100-seed weight and seed yield were found. The study concludes that seed osmopriming with CaCl₂ or MLE can play significant role to improve early crop growth and seed yields of linola.  相似文献   

Effect of density on growth and feed consumption of the abalones Haliotis discus discus, H. gigantea, H. madaka and their hybrids     

Faruq Ahmed  Yasuyuki Koike  Carlos Augusto Strüssmann  Seiichi Watanabe 《Aquaculture International》2013,21(5):969-986

Effect of stocking density was studied in three abalone species Haliotis discus discus (HDD), H. gigantea (HG), and H. madaka (HM) and their hybrids [HDD × HM, HM × HG and HG × HM, mother first] by rearing individually marked abalones for 217 days at low (22 % of available surface area; LD), medium (53 %; MD), and high (126 %; HD) densities. Feeding rate (FR) and feed conversion rate were observed by measuring the amount of feed ingested at an interval of 2–3 days. Reduction of growth rate with the increment of density was found in all three species [Specific growth rate in weight (G _W ) HDD, LD: 0.121, MD: 0.093, HD: 0.069; HM: 0.12, 0.082, 0.061; HG: 0.254, 0.222, and 0.131] and the hybrids HDD × HM (0.18, 0.109, 0.108). The medium density produced the highest growth rates in HM × HG and HG × HM hybrids (0.284, 0.342, 0.28). A growth spurt was observed in all three species and hybrids in the last 44 days of rearing. FR varied from 0.72 to 7.97 % body weight and decreased with the increase in density in all species and hybrids. The results indicate differences in density thresholds for the three abalone species and their hybrids suggesting requirement of different aquaculture management strategies for them.  相似文献   

FOOD SAFETY STANDARDS AND REGULATORY MEASURES: IMPLICATIONS FOR SELECTED FISH EXPORTING ASIAN COUNTRIES     

Madan M. Dey  M. A. Rab  K. M. Jahan  A. Nisapa  A. Kumar  M. Ahmed 《Aquaculture Economics & Management (Blackwell Science)》2013,17(1-2):217-236

ABSTRACT

Developing Asian countries continue to record an impressive trade surplus in fish products. However, raising consumer concerns about a range of food safety matters and increasingly stringent regulatory standards related to fish product supply pose on-going challenges to the sustained international market access of many developing country suppliers. This paper provides an overview of emerging trade patterns in fish products and the trade regime in which this is occurring. It then reviews the implementation of various food safety standards on fish and seafood exports in the major fish-exporting countries in Asia, and analyzes the costs and benefits of compliance with these standards and regulations in these countries. Results show that, at the factory level, implementation of the standards has significantly increased the cost of processing, and the cost per unit of fish processed is higher for the smaller plants. These economies of scale could exclude small operators in developing countries. Continued competitiveness of small plants would seem to require government policies and support designed to minimize the cost of compliance with international standards.  相似文献   

Economics of fish farming in Saudi Arabia: Analysis of costs of tilapia production     

Ahmed M. Elhendy  Abdulaziz A. Alzoom 《Aquaculture Economics & Management (Blackwell Science)》2013,17(3-4):229-238

Abstract

Because Saudi Arabia is a substantial importer of fish and its capture fishery is operating beyond maximum sustainable limits, it has a special interest in developing fish farming. It has been encouraging tilapia production. This study examines the costs of tilapia farming in the Central Region of Saudi Arabia using cross sectional data from 23 intensive fish farms. It provides information about the relative importance of different cost items such as variable costs and feed costs in total costs. Also, cost functions are estimated by ordinary least squares and a cubic cost function is found to provide the best fit to the available data. Minimum average cost of production occurs for 201 tonnes of tilapia per year per farm and profit is maximised for a production of 300 tonnes annually per farm. All farms operate at less than profit‐maximising scale and most operate at less than minimum efficient scale. The reasons could be low quality fry, low levels of management expertise in culturing tilapia and the secondary nature of tilapia farming. Lack of water is likely to limit future expansion of tilapia farming in Saudi Arabia.  相似文献   

THE SUSTAINABLE LIVELIHOODS APPROACH TO THE DEVELOPMENT OF FRESHWATER PRAWN MARKETING SYSTEMS IN SOUTHWEST BANGLADESH     

Nesar Ahmed  Catherine Lecouffe  Edward H. Allison  James F. Muir 《Aquaculture Economics & Management (Blackwell Science)》2013,17(3):246-269

A conceptual framework, drawn from an approach to poverty reduction known as the Sustainable Livelihoods Approach (SLA), is applied to understanding the role of freshwater prawn (Macrobrachium rosenbergii) marketing systems in southwest Bangladesh. Freshwater prawn marketing potentially provides economic returns and social benefits to the rural poor. Although the potential benefits are great, a number of constraints were identified for the long-term sustainability of prawn marketing systems. The study used the SLA framework as an analytical tool to identify ways to strengthen livelihoods of prawn traders and associated groups.  相似文献   

Color and Antioxidant Characteristics of Some Fresh Fig (Ficus carica L.) Genotypes from Northeastern Turkey     

Ercisli S  Tosun M  Karlidag H  Dzubur A  Hadziabulic S  Aliman Y 《Plant foods for human nutrition (Dordrecht, Netherlands)》2012,67(3):271-276

Fruit skin color, total phenolics, total anthocyanins, soluble solids content, titratable acidity and total antioxidant capacity in fresh fruits of a number of local and well-known fig (Ficus carica L.) genotypes and cultivars grown in northeastern Turkey were determined. TEAC (Trolox equivalent antioxidant capacity) and FRAP (ferric reducing antioxidant power) assays were used to determine total antioxidant capacity. Fruit skin color of genotypes were found to be very diverse, i.e., light green, light purple, purple, dark purple and black. The content of total phenolics, soluble solids content (SSC) and titratable acidity greatly varied in the range from 24 to 237?mg of gallic acid equivalent per 100?g fresh weight, 18.60 to 26.30?% and 0.16 to 0.47?% in local genotypes and studied cultivars. In general, total antioxidant capacities determined by two methods expressed higher values in the local fig genotypes compared with the cultivars. The results suggested that genotype is the main factor that determines difference in the composition of bioactive compounds in figs and provide information on putative health benefits locally grown genotypes.  相似文献   

Influence of Growth Stage and Season on the Antioxidant Constituents of Cosmos caudatus     

Ahmed Mediani  Faridah Abas  Tan Chin Ping  Alfi Khatib  Nordin H. Lajis 《Plant foods for human nutrition (Dordrecht, Netherlands)》2012,67(4):344-350

The impact of tropical seasons (dry and wet) and growth stages (8, 10 and 12 weeks) of Cosmos caudatus on the antioxidant activity (AA), total phenolic content (TPC) as well as the level of bioactive compounds were evaluated using high performance liquid chromatography (HPLC). The plant morphology (plant height) also showed variation between the two seasons. Samples planted from June to August (during the dry season) exhibited a remarkably higher bioactivity and height than those planted from October to December (during the wet season). The samples that were harvested at eight weeks of age during the dry season showed the highest bioactivity with values of 26.04 g GAE/100 g and 22.1 μg/ml for TPC and IC_50, respectively. Identification of phytochemical constituents in the C. caudatus extract was carried out by liquid chromatography coupled with diode array detection and electrospray tandem mass (LC-DAD-ESIMS/MS) technique and the confirmation of constituents was achieved by comparison with literature data and/or co-chromatography with authentic standards. Six compounds were indentified including quercetin 3-O-rhamnoside, quercetin 3-O-glucoside, rutin, quercetin 3-O-arabinofuranoside, quercetin 3-O-galactoside and chlorogenic acid. Their concentrations showed significant variance among the 8, 10 and 12-week-old herbs during both seasons.  相似文献   

Multiple response optimization of rotor yarn for strength,unevenness, hairiness and imperfections     

Farooq Ahmed Arain  Anwaruddin Tanwari  Tanveer Hussain  Zulfiqar Ali Malik 《Fibers and Polymers》2012,13(1):118-122

In this study, a multiple response optimization model based on response surface methodology was developed to determine the best rotor speed and yarn twist level for optimum rotor yarn strength and unevenness, and minimum yarn hairiness and imperfections. Cotton yarn of 30 tex, was produced on rotor spinning machine with different twist levels (i.e. 500, 550, 600 and 700 tpm) at different rotor speeds (i.e. 70000, 80000, 90000 and 100000 rpm). Yarn quality characteristics were determined for all the experiments. Based on the results, multiple response optimization model was developed using response surface regression on MINITAB® 16 statistical tool. Optimization results indicate that with the quality of raw material selected for this study, top 50 % quality level, according to USTER® yarn quality benchmarks, can be achieved with 100 % desirability satisfaction for all the selected yarn quality parameters at rotor speed of 77,800 rpm and yarn twist of 700 twists per meter.  相似文献   

ZnO-mediated photocatalytic degradation of Benzopurpurine BP4B in aqueous solution     

Laouedj?Nadjia  Elaziouti?AbdelkaderEmail author  Bekka?Ahmed 《Fibers and Polymers》2012,13(3):303-312

The photocatalytic degradation of a commercial azo dye Benzopurpurine 4B (BP4B) in aqueous solution was investigated under UV-A light at different operating conditions, including irradiation time, pH solution, initial dye concentration, amount of catalyst, light intensity as well as band gap of other semiconductor groups by UV-spectrophotometric monitoring. The highest decomposition efficiency was obtained at pH 8 as a result of 97.24 % degradation of BP4B for 80 min of irradiation time. Photodecomposition reaction of BP4B dye was correlated with pseudo-first-order kinetic model. The degradation data of BP4B dye were satisfactory described by Langmuir-Hinshelwood (L-H) mechanism.  相似文献