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Study of Fruit Diversity and Selection of Elite Acid Lime (Citrus aurantifolia Swingle) Genotypes in Nepal

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American Journal of Plant Sciences 2012年第8期3卷 1098-1104页

作者： ram lal shrestha Durga Datta Dhakal Durga Mani Gautum Krishna Prasad Paudyal Sangita shrestha Agricultural Research Station (ARS) Dhankuta Nepal Horticulture Research Division (HRD) Lalitpur Nepal Institute of Agriculture and Animal Science (IAAS) Rampur Chitwan Nepal Nepal Academy of Science and Technology (NAST) Lalitpur Nepal

Acid lime (Citrus aurantifolia) fruits are cultivated in terai, mid hill and high hill districts of Nepal. It is cross-pollinated crop and has a high variation in fruit characters within the species. Fruit character is the main basis of genotype selection. Study of fruit diversity is of utmost importance to select the elite genotypes for breeding and variety development program. Therefore, total of 620 fruit samples were collected and evaluated in the main production season of the year 2010 and 2011, from 62 bearing trees. Samples were collected from three agro-ecological domains, representing terai, mid hill and high hill areas of eastern Nepal. Elite landraces were selected on the basis of scoring fruit characters. High variation in vitamin C was observed between the terai (57.4 mg) and high hill (72.5 mg) samples. Amount of juice was 36.8% in mid hill and 44.1% in terai samples. Higher percent of juice and total soluble solids (TSS) observed in terai samples but tritable acidity (TA) and vitamin C was low as compare to high hills. There was significantly negative correlation found in fruit weight, fruit diameter, juice percent and seed number, whereas significantly positive correlation was in pulp and vitamin C, with altitude range. Total landraces were separated in five major cluster group. Variation in the level of similarity was observed among the cluster groups. The variability distance of fruit characters was highest in cluster group II (–17.45%) and lowest in cluster group V (58.5%). On the basis of scoring number of fruit characters, total four elite genotypes i.e. LD-49 from mid hills, LD-23 and LT-17 from higher hills and LM-44 from terai were selected for conservation, breeding and variety development purpose.

关键词： Vitamin C TSS TA Correlation Elite Genotypes Conservation

Variation of Physiochemical Components of Acid Lime (Citrus aurantifoliaSwingle) Fruits at Different Sides of the Tree in Nepal

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American Journal of Plant Sciences 2012年第12期3卷 1688-1692页

作者： ram lal shrestha Durga Datta Dhakal Durga Mani Gautum Krishna Prasad Paudyal Sangita shrestha Agricultural Research Station (ARS) Dhankuta Nepal Horticulture Research Division (HRD) Khumaltar Lalitpur Institute of Agriculture and Animal Science (IAAS) Chitwan Nepal Nepal Academy of Science and Technology (NAST) Lalitpur Nepal

Acid Lime (Citrus aurantifolia Swingle) is one of the important commercial fruits cultivated from terai to high hill of Nepal. It is an important source of vitamin “C” (ascorbic acid) for human nutrition. Amount of juice, TSS (Total soluble solids), TA (Titrable acid) and vitamin C are the determining factors of quality of acid lime fruits which may vary according to bearing sides of the trees. The main objective of this study is, to determine the variation of fruit quality at different sides of the tree. Total of 15 bearing trees were selected randomly (5 trees per site) from three different agro ecological domain representing terai (1200 m asl) and samples were collected from the selected trees. Randomly ten fruits (from east, west, centre, north and south sides) were collected from each tree and analyzed for amount of vitamin C, TSS, TA and juice. Highest ascorbic acid 79.6 mg and 69.9 mg was observed in south side fruits whereas lowest 62.8 mg and 55.1 mg was observed in centre fruits in the high and mid hills zone respectively, but in terai, highest ascorbic acid 58.7 mg was observed in north side and lowest 41.8 mg was observed in centre. Highest amount of juice 43.9% was observed in south side fruits and lowest 36.6% in centre fruits, but amount of TSS 8.2% and TA 7.2% was observed in south side fruits and lowest 7.3% TSS and 7.0% TA was observed in centre fruits in high hills. In terai highest TSS 8.3% and TA 7.4% was observed in north side fruits and lowest TSS 7.3% and TA 6.7% was observed in centre fruits. Variation of TSS, TA percent and ascorbic acids was observed according to the agro ecological zone.

关键词： Ascorbic Acid Agro-Ecological Zone TSS TA Juice

High-resolution modeling and evaluation of ozone air quality of Osaka using MM5-CMAQ system

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Journal of Environmental Sciences 2009年第6期21卷 782-789页

作者： shrestha Kundan lal KONDO Akira KAGA Akikazu INOUE Yoshio Division of Sustainable Energy and Environmental Engineering School of EngineeringOsaka University

High-resolution modeling approach is increasingly being considered as a necessary step for improving the monitoring and predictions of regional air quality. This is especially true for highly urbanized region with complex terrain and land-use. This study uses Community Multiscale Air Quality （CMAQ） model coupled with MM5 mesoscale model for a comprehensive analysis to assess the suitability of such high-resolution modeling system in predicting ozone air quality in the complex terrains of Osaka, Japan. The 1-km and 3-kin grid domains were nested inside a 9-km domain and the domain with 1-km grid covered the Osaka region. High-resolution Grid Point Value-Mesoscale Model （GPV-MSM） data were used after suitable validation. The simulated ozone concentrations were validated and evaluated using statistical metrics using performance criteria set for ozone. Daily maxima of ozone were found better simulated by the 1-krn grid domain than the coarser 9-km and 3-km domains, with the maximum improvement in the mean absolute gross error about 3 ppbv. In addition, 1-km grid results fared better than other grids at most of the observation stations that showed noticeable differences in gross error as well as correlation. These results amply justify the use of the integrated high-resolution MM5-CMAQ modeling system in the highly urbanized region, such as the Osaka region, which has complex terrain and land-use.

关键词： air quality model evaluation ozone Community Multiscale Air Quality MM5 statistical analysis

Fog simulation using a mesoscale model in and around the Yodo River Basin,Japan

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Journal of Environmental Sciences 2008年第7期20卷 838-845页

作者： HIKARI Shimadera KUNDAN lal shrestha AKIRA Kondo AKIKAZU Kaga YOSHIO Inoue Graduate School of Engineering Osaka UniversityYamada-oka 2-1SuitaOsaka 565-0871Japan.

In this study,fog simulations were conducted using the Fifth-Generation NCAR/Penn State Mesoscale Model (MM5) in and around the Yodo River Basin,*** purpose is to investigate the MM5 performance of fog simulation for long-term *** simulations were performed for January,February,March,and July,2005 with a coarse 3-kin and a nested fine 1-km grid domains. Results of the simulations were compared with data from ten meteorological observatories,fog sampling site in ***,and visibility measurem...

关键词： fog simulation the Fifth-Generation NCAR/Penn State Mesoscale Model (MM5) model evaluation occurrence of fog liquid water content

Potential cotton aphid, Aphis gossypii, population suppression by arthropod predators in upland cotton

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Insect Science 2013年第6期20卷 778-788页

作者： ram B. shrestha Megha N. Parajulee Texas A&M University AgriLife Research and Extension Center 1102 E. FM 1294 Lubbock TX 79403 United States

The cotton aphid, Aphis gossypii Glover, predation rate of convergent lady beetle, Hippodamia convergens Guerin-Meneville, was determined by assigning a single predator randomly to each of four prey density treatments in the laboratory. Prey densities included 25, 50, 100, and 200 aphids per Petri dish arena. Predation response was recorded at 1, 4, 8, 16, 24, and 48 h after assigning predators to their prey treatments. Rate of consumption increased through time, with all 25 aphids consumed during the first 4 h of the experiment. At the highest density, adult lady beetle consumed on average 49, 99, 131, 163, 183, and 200 aphids within 1, 4, 8, 16, 24 and 48 h, respectively. Predators showed a curvilinear feeding response in relation to total available time, indicating that convergent lady beetles have the potential to suppress larger populations of aphids through continuous feeding by regulating their predation efficiency during feeding. The analysis of age-specific mortality in absence of prey revealed that lady beetles could survive for an extended period of time （more than 2 weeks） without prey. The ability of a predator to survive without prey delays or prevents the rebound of pest populations that is a significant factor in natural biological control. A two-year field sampling of 10 cotton arthropod predator species showed that spiders （27%） were the most dominant foliage dwelling predators in the Texas High Plains cotton followed by convergent lady beetles （23.5%）, hooded beetles （13.5%）, minute pirate bugs （11%）, green lacewings （9.5%）, bigeyed bugs （7.5%）, scymnus beetles （3%）, soft-winged flower beetles （2%）, damsel bugs （1.5%）, and assassin bugs （1.5%）. A field cage study showed that one H. convergens adult per plant released at prey density of one aphid per leaf kept the aphid population below economic threshold for the entire growing season.

关键词： Aphis gossypii biological control cotton IPM functional response Hippo-damia convergens natural suppression

Metapopulation approach for landscape level management of western tarnished plant bug,Lygus hesperus,in Texas( Hemiptera,Miridae)

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植物保护学报 2014年第6期41卷 761-768页

作者： Parajulee Megha N shrestha ram B Texas A & M University System AgriLife Research and Extension Center

Insect source-sink dynamics are vital to ecologically intensive pest management. Maintaining sink plant hosts,or "trap crops",and destroying alternate hosts or breeding places adjacent to the field crop are effective pest management strategies for some arthropods. However,determining whether a host acts as a source or a sink is challenging, especially when the pest species is highly mobile and polyphagous. The western tarnished plant bug,Lygus hesperus,is highly polyphagous,and can utilize >300 hosts. Its presence has been documented in 26 roadside weed hosts in the Texas High *** studies demonstrated that L. hesperus prefer alfalfa over cotton and several alternate weed hosts.A four-year project involved surveying and sampling for L. hesperus in the agricultural landscapes of several sub-regions of the southwestern United States,including the Texas High Plains. In Texas,geographic information of the landscape vegetation complex was compiled from a 150 km radius in the Texas High Plains. In one study,fifty irrigated cotton fields representing the crop diversity within this region were sampled via sweep-net for 10 weeks. This effort also included sampling of up to six noncotton insect habitats within a 3 km radius of each field. Seasonal average L. hesperus abundance data were regressed with 27 field characteristics( variables),including habitat-specific land cover,distance between focal cotton fields and non-cotton habitats,longitude,latitude,elevation,habitat heterogeneity index,and several environmental / ecological variables. Significant variables were selected using a stepwise regression at 15% probability rate. A 10-parameter linear model explained 93% of the variation in the data. Major parameters contributing significantly to variation in L. hesperus abundance in cotton were corn and sunflower acreages,focal cotton field distances from several non-cotton hosts,and habitat heterogeneity index. In addition,field marking-and-capture studies were cond

关键词： western tarnished plant bug cotton IPM ecological pest management alternate host management

Long-Term Effects of Different Passages of Vehicular Traffic on Soil Properties and Carbon Storage of a Crosby Silt Loam in USA

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Pedosphere 2019年第2期29卷 150-160页

作者： Gulab Singh YADAV Rattan lal ram Swaroop MEENA Basant RIMAL Carbon Management and Sequestration Centre the Ohio State University

The passage of vehicles with heavy axle loads causes soil compaction, and this adversely affects soil properties and crop *** adverse effects can persist for several years due to significant changes in key soil properties. However, the mechanisms of the aforementioned effects are not well understood for conservation agriculture(CA)(e.g., no-till(NT)) wherein the use of heavy machinery is considerably common. Therefore, known compaction forces(0 Mg load for compaction(NT-0, control), two passages of 2.5 Mg water wagon axle load(NT-2), and four passages of 2.5 Mg water wagon axle load(NT-4)) were applied to all the plots annually for 20 consecutive years. The experiment was established in 1997 at the Waterman Agricultural and Natural Resources Laboratory(WANRL), Ohio State University, Columbus, Ohio. Each treatment was replicated thrice. Soil samples were obtained in November2016 to determine the effects of variations in the axle load and vehicular passages on carbon(C) and nitrogen(N) storage and selected soil properties of a Crosby silt loam soil under NT-based corn-soybean rotation with residue retention in Central Ohio, USA. Three locations were also randomly selected in an adjoining natural woodlot(WL) soil plot and sampled(30 m away from the compaction field) to compare the effects of vehicular traffic on soil under NT with WL soil. Results revealed that soil bulk density(ρb) and total porosity at 0–10 and 10–20 cm depths were not affected by the passages of vehicular traffic for 20 years under the NT *** penetration resistance(PR)(1.86 and 2.03 MPa at 0–10 and 10–20 cm soil depths, respectively) was significantly higher under NT-4 compared with that under other treatments. Saturated hydraulic conductivity at 0–10 and 10–20 cm soil depths ranged from19.7 to 31.4 and 18.5 to 29.5 mm d^(-1), respectively, across all the treatments. The proportion of macroaggregates(> 0.25 mm) and microaggregates(< 0.25 mm), mean weight diameter and geometric mean diam

关键词： carbon stock heavy machinery no-till residue retention soil aggregates soil compaction soil quality well-drained soil

Investigation of air pollution concentration in Kathmandu valley during winter season

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Journal of Environmental Sciences 2005年第6期17卷 1008-1013页

作者： KONDO Akira KAGA Akikazu IMAMURA Kiyoshi INOUE Yoshio SUGISAWA Masahiko shrestha Manohar lal SAPKOTA Balkrishan Graduate School of Engineering Department of Environmental Engineering Osaka University JapanGraduate School of Engineering Department of Environmental Engineering Osaka University JapanEnvironmental Pollution Control Center Osaka Prefecture JapanGraduate School of Engineering Department of Environmental Engineering Osaka University JapanGraduate School of Engineering Department of Environmental Engineering Osaka University JapanGraduate School of Engineering Department of Environmental Engineering Osaka University JapanInstitute of Engineering Pulchok Tribhuvan University Nepal

The monthly concentrations of NO2, NOx, SO2 and O3 measured by a passive sampler from February 2003 to January 2004 showed that the air pollution during the winter season in Kathmandu valley was higher than the summer season. The O3 level was found the highest during April, May and June due to strong radiation. The hourly concentrations of NO2, NOx, O3 and suspended particulate matter（SPM） were also measured by automatic instruments on December 2003. Temperature at the height of 60 m and 400 m at Raniban Mountain in the northwest of Kathmandu valley was measured on February 2001 in the winter season and the average potential temperature gradient was estimated from observed temperature. Wind speed was also measured at the department of hydrology, airport section, from 18 February to 6 March 2001. It was found that the stable layer and the calm condition in the atmosphere strongly affected the appearance of the maximum concentrations of NO2 and SPM in the morning, and that the unstable layer and the windy condition in the atmosphere was considerably relevant to the decrease of air pollution concentrations at daytime. The emission amounts of NOx, HCs and total suspended particle（TSP） from transport sector in 2003 were estimated from the increasing rate of vehicles on the basis of the emission amounts in 1993 to be 3751 t/a, 30570 t/a and 1317 t/a, respectively. The diurnal concentrations in 2003 calculated by the two-layers box model reproduced the characteristics of air pollution in Kathmandu valley such as the maximum value of O3 and its time, the maximum value of NO in the morning, and the decrease of NO and NO2 at daytime. The comparison with the concentrations in 1993 calculated suggested that the main cause of air pollution was the emission from transport sector.

关键词： air pollution concentration Kathmandu vallay box model

Perception, Determinants and Barriers for the Adoption of Climate Change Adaptation Options among Nepalese Rice Farmers

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Agricultural Sciences 2018年第3期9卷 272-298页

作者： Niranjan Devkota ram Kumar Phuyal Durga lal shrestha Tribhuvan University Kathmandu Nepal Center for Economic Development and Administration Tribhuvan University Kathmandu Nepal

This paper estimates the perceptions, determinants and barriers regarding the adoption of climate change adaptation options among Nepalese rice farmers. A multi-stage sampling technique was used to source respondents for the study, and structured questionnaire techniques were used to collect data from 773 households across seven districts (3 from Terai and 4 from the hilly region of Nepal). A binomial logistic regression model was used to detangle the determinants for the adoption of climate change adaptation options among farmers. The results revealed that approximately 80.7% of the farmers perceived change in temperature, and 90% believed that there was a decrease in rainfall in the 30-year period. In total, 77% of farming households responded that rice production and yield has decreased due to such changes, which has forced them to adopt available adaptation options. This study found that 12 adaptation options have been mainly used by rice farmers, and among them, there has been an increasing use of chemical fertilizer, climate-smart rice verities, and changes in nursery date, which are the first three adoption options. Overall, 71% of farmers adopt such adaptation options to protect themselves from perceived risk. However, farmers are facing several barriers, such as capital inadequacy, high cost of agricultural inputs, poor adaptation information provided to farmers, inadequate access to credit facilities and inadequate awareness about adaptation regarding the adoption of such options. Binomial regression results revealed that several factors influence a farmer’s choice in adaptation measures. Our findings suggest the need for greater investment to remove these barriers and institutional shortcomings and help to improve a rice farmer’s wellbeing.

关键词： Climate Change Barrier to Adopt Rural Rice Farmers Logit Model Nepal