Vol. 14 No. 5 (2016)

A study was conducted to isolate parasitic fungi on mealybugs and cicadas attacking coffee roots, making materials available for research and selection of entomopathogenic fungi with high activity to produce biopesticides for controlling mealybugs and cicadas damaging on coffee roots. In 2013, 421 samples of coffee root-ìnfested mealybugs and cicadas parasitized by fungi were collected from coffee plantations in Dak Lak province. A toatl of 156 isolates of entomopathogenic fungi belogning to 4 genera were isolated, including Beauveria, Cordyceps, Metarhizium and Paecilomyces. Based on morphological identification, 18 samples were selected for DNA sequencing and 7 species were genetically identified, i.e. Beauveria bassiana, Cordyceps bassiana, Cordyceps cicadae, Cordyceps takaomontana, Metarhizium cylindrosporae, Paecilomyces lilacinus and Paecilomyces hepiali. These are new species parasitized on coffee root mealybugs and cicadas and are identified for the first time in Viet Nam by DNA sequencing.

Drought is one among the major abiotic stress factors severely limits maize grain yield production. Improving drought tolerance in maize has become one of the top priorities in maize breeding programs. Thirty two maize inbred lines and two check varieties were evaluated under field conditions and screened for drought tolerance under water stress conditions in the greenhouse. For drought evaluation, the first experiment was carried out using plastic pots exposed to drouhgt stress conditions. In the second experimen, thirty two inbred lines were planted at four planting dates startng from 2 March and successive planting after very ten days, in soil bed conditions and drought was imposed when plants of the first planting were at dough stage and the plants of other plantingss were at tassel and silking stage, at 12 collars stage and at 6 collars stage. Eleven and 14 inbred lines were identified as drought tolerant in pots experiment and in greenhouse soil bed, respectively. With the use of molecular marker, 20 inbred lines containing QTL related to drought tolerance were identified. Combining phenotypic evaluation and molecular markers, 11 inbred lines possessed desirable characters and drought tolerance, i.e. H4, H6, H14, H15, H17, H20, H23, H24, H28, H29 and H30. Drought tolerant inbred lines identified in this study can be utilized for future breeding programme.

A total of 150 nasal swab specimens collected from H3N2 canine influenza -suspected cases in Hanoi from May 2015 to February 2016werediagnosed by the RT-PCR method. The diagnostic results showed that6% of swab samples were positive for H3N2 canine influenza.Dogs infected with canine influenzavirus(CIV)showed typical clinical signs such as coughing, sneezing, difficulty to breath and fever. However, some cases occasionally developedsecondarycomplications, such as severe pneumonia. The rate of infected dogs was highest at 2-6 monthsold. The proportion of infected dogs with H3N2 in winter-spring was higher than in summer-autumn.

Acute hepatopancreatic necrosis disease (AHPND), also known as Early Mortality Syndrome (EMS), has become one of the most harmful threats to the shrimp aquaculture industry in Southeast Asia, including Vietnam. It occurs on both tiger and white leg shrimps at 20 - 45 days of age with a mortality rate up to 100%. AHPND pathogens were identified as bacteria containing plasmid carrying toxin genes that cause acute hepatopancreatic necrosis. Observation of biochemical characteristics, the use of PCR technique using specific primers to detect the toxin genes and sequence analysis of 16S-rRNA gene confirmed that there were at least three strains of AHPND pathogenic bacteria on brackish shrimp cultured in Vietnam, of which two strains belong to Vibrio parahaemolyticus species, including V. parahaemolyticus KC13.14.2 and V. parahaemolyticus KC12.020; and the other strain of Vibrio sp. KC13.17.5. Vibrio sp. KC13.17.5 was confirmed as V. harveyi KC13.17.5, a non V. parahaemolyticus species. The detection of non - V. parahaemolyticus that caused AHPND is a new finding not only in Vietnam but also worldwide.

This study was conducted to assess reproductive performanceof Ho breed of chicken byartificial insemination. Semen qualities of Ho chicken were surveyed on 30mature chickens (30 weeks of ageand4.0 - 5.5 kgin weight)and45 mature hens (30 weeks old, weighing 3.0 - 3.5 kg)were chosen. All experimental Ho chickens were characterized by appearance-characteristic features.The cocks of Ho breedwere trained to exploit semen by hand massageandafter each extraction the semen wereassessed for quality (color, pH, volume - V; motility - A; sperm concentration - C; VAC; and the percentage of abnormality sperm). Hens were artificially inseminated by direct delivery of semen into the Hen’s vagina/oviduct. The study results showed that the cocksgainedejaculatory reflexrightafter the first time, 3 days and 7 days of training and the cocks without ejaculatory reflex were73.33%, 6.67%, 3.33%and 16.67%, respectively. Semen color was mostly milky white. Total straight moving sperms and the proportionof abnormal sperms in an ejaculationwas 1.59 billion and 12.06%, respectively. Highest percentages of fertilized eggs (92.51%) with class I chicks were achieved with semen collection frequencyof three daysintervaland insemination with0.05mlsemen.

The aims of the present study were to investigate the prevalence of postpartum metritis in sows and to evaluatetheeffects of some risk factors on the prevalence of thedisease. The data monitored and collected from309 sows ofthreepig farms in threeprovinces,i.e.Bac Giang, Nam Dinh, and Hoa Binh wereanalyzed using logistic regression. Followingthe univariate logistic regression analysis, the factors associated with postpartum metritis (P < 0.2) were retained and used to construct a multivariate logistic regression model. Results showed that the prevalence of postpartum metritis in sows was 76.38%. Multivariate logistic regression analysis demonstrated that midwifery (OR = 8.86, P <0.001) and farrowing duration (OR = 1.36, P < 0.01) significantly affected the postpartum metritis status in sows. The present study substantiated that the prevalence of postpartum metritis in sows at studied farms was very high. Avoiding midwifery and reducing the farrowing duration may help reduce the risk of affliction of postpartum metritis.

Piscicolasp.causinglesions on soft skin tissues wasfirstly detectedon the turtles Heosemys annandaliiin Vietnam.The present research was conducted to investigate leech infection on fourdifferent kinds of turtlesand todetermine some biological features of the species and efficiency of CuSO4 and Ca(OH)2 treatment. The result showed that Piscicolasp. only parasitizeson the turtle Heosemys annandalii with high density (67.7 ± 3.9 leechs/turtle). The leech hasalength between 11.4-25.5 mm on averageandcylindrical shape with twosuction heads. The maturation time of the eggs from being laid was 5.8 ± 0.3 days with hatching percentage 81.5 ± 9.3% at26-27°C condition.Immersion in lime Ca(OH)2at 75ppt and copper sulfate CuSO4at 10-15ppm cancompletelykill theleeches on turtles. However, CuSO4showedthe highest efficiency due to no negative influence on turtle health.

The objective of this study was to determine the magnitude of enteric methane emission and to develop scenarios to reduce methane emission per unit product from a semi-intensive cattle production system. Methane emission was estimated according to the tier 3 of IPCC (2006) method. Results showed that average enteric methane emission was estimated at 33.4 kg/animal/year and enteric methane efficiency was 11.23 kg CO2eq/kg daily weight gain (DWG). Results of scenarios indicated that increasing dietary concentrate levels from 30-40% for cows and 35-45% for cattle > 1 year old resulted in increased DWG from 50 to 83% with reduced enteric methane efficiency from 24 to 31% compared to the current cattle keeping practice (20% for cows and 25% for cattle > 1 year old). The use of forage mixture of elephant grass, rice straw and ruzzi grass or elephant grass, maize foliage and rice straw resulted in increased DWG and reduced enteric methan efficiency compared to elephant grass and rice straw mixture.

Agricultural land use plays the vital role in supplying agricultural products for people, increasing the income of land users, and contributes significally to protection of environment, landscape in rural area. Recently, agricultural land use in Duy Tien District has actually been a significal change to produce more goods with high value to contribute vitally to improvement of the people’ income and their livelihood. The research objective is to assess the actual agricultural land use towards commodity production in the district. The results show that there were 5 Land Use Types (LUT) with 26 sub-LUTs. For economic efficiency, vegetable, other annual crops, fruit trees were the highest, these LUTs are able to expand in the future. Specifically, 3 LUT and 14 sub-LUTs have been planted and developed towards commodity production to increase the gross output and added value of local land users, such as: vegetable, other annual crops with the percentage for sale of >80%, for fruit trees of >90%, and so the consumption level is very low. Therefore, actual agricultural land use towards commodity prodcution is astimated as suitable to zone the agricultural commodity production area, to decrease the labour force in agriculture sector and to be a significant background to reorganize the sector of agriculture towards to increasing gross output and added value.

A total land areas of 39.139 hectaresincludingagricultural land, productive forest land and unused land of Ngeun District were evaluatedfor the suitability ofland use by FAO guideline for land evaluation. The principal crops of concerns werelowland rice, upland rice, maize, groundnuts, tobacco, garlic, vegetable, pineaple, citrus, litchi, mango and rubber. Based on land use requirements of the selected crops and the natural characteristics of the district, the following factors were chosen for Land mapping Unit (LMU): soil type, slope, depth of fine soil layer, soil texture, rock fragment content, irrigation ability and fertility of the top soil. The land evaluation results showed that due to complex topographic features and soil/land characteristics, 80 LMU were identified in the area of agriculture land. Highly suitable (S1) area for lowland rice, upland rice, maize, groundnuts, tobacco, garlic, vegetable, pineaple, citrus, litchi, mango and rubber in the Ngeun district were 867.83; 15,303.74; 5,316.80; 5,138.45; 3,669.53; 3,669.53; 14,789.86;22,517.95; 15,473.94; 18,777.39; 7,521.76; 10,823.63 hectares, respectively. These results serve as an important basis for agricultural land use planning in Ngeun district.

In the world as well as in Vietnam, multi-objective optimal model has been used in various fields. This article reports the research results of multi-objective optimal model in forecasting the demand of land use for new rural construction in Yen Dung district, Bac Giang province. Among four land use groups identified, land use of group IV was analyzed by multi-objective optimal model with two objective functions -maximizing economic benefits and maximizing the number of jobs from the distribution of land use - and otherconstraints, i.e. natural area limit, labor resource, food security, average income, environmental sustainability insurance, rural landscape and the conformity to strategic development and local land resource potential. Test model results for Huong Gian commune apparently showed more advantages over the land-use plans being applied.

Management of natural resources in accordance with river basin is an indispensable trend towards sustainable resource management and use. However, in Vietnam, the resources are managed based on administrative boundaries. Therefore, the information and data are scattered in many places with different quality and not willing to be shared, making them unavailable for scientific research. In the present study, remote sensing combined with GIS was used for building the land cover map to correct the input data with regard to Srepok watershed. The process of analysis and classification for Landsat 8 OLI in Srepok watershed in 2015 yielded reliable results with the Kappa coefficient over 0.69 and overall accuracy of 73.53%. As a result, land cover map was produced in Srepok watershed with seven different classes including evergreen forest, deciduous forest, mixed forest, perennial trees, annual crops and specialized land and water surface.

The aim of this study is to identify the optimum mode of postharvest treatment with 1-methylcyclopropene (1-MCP) forgreen onion (Allium fistulosum) in order to remain quality and prolong storage life at ambient condition. The two factors, concentration of 1-MCP and time exposed to 1-MCP, were taken into account. Singer factor experiment on concentration of 1-MCP was carried out first (with 6 concentrations of 0; 100; 200; 300; 400; 500ppm) along with 8 hours exposed to the chemical. Then the singer factor experiment on time exposed to 1-MCP was conducted (with 5 levels of 2; 5; 8; 11; and 14hours) along with the best 1-MCP concentration selected from previous experiment. Analyzed parameters include yellowingrates, chlorophyll, vitaminC content and their changes during storage period. The best green onion was obtained from the treatment with 200ppmfor8 hours exposed to 1-MCP. Also, two factors experiment was made in order to see interactions between them and look for the most optimal modeof 1-MCP postharvest treatmentforgeen onion. The results showed that the treatment laid on 208,9 ppm 1-MCP for 7 hours 44 minutes gave highest quality green onion in atmospheric condition.

This study was conducted to investigate the operational mechanism of the insurance model for dairy cow farming in Moc Chau Dairy Cattle Breeding Joint Stock Company. In addition to the secondary data, 96 dairy cow farm households who participated the insurance model of the company were selected for direct interviews. The study results show that the insurance model for dairy cows in the company attracted the participation of more than 500 dairy cow farming households with a total of 9411 cows. The success of this insurance model was derived from its relevant mechanism based on the consulative opinions of dairy farmers, close requirements for becoming insured, technical and financial supports by the company, flexible compensation schemes, and transparent and corect risk assessment. These are the valuable lessons for designing agriculural insurance progarm, especially animal insurance program in Vietnam in the coming time.

King Oyster Mushroom (Pleurotus eryngii (DC.:Fr.Quél) is a delicious, edible fungus, high nutritional and medicinal values. King oyster mushroom’s fruiting bodies are of large size, pretty shape, so for these advantages, this mushroom is called "King Oyster mushroom” . From the assessment results on indicators of growth and development of 6 spawns of King Oyster mushrooms (P. eryngii) in cutivating period, King oyster mushroom strain E1 have been selected.With these results, some agricultural wastes abundant such as: rice straw, sawdust, corn cob, rice bran… were comparatively evaluated as substrate ingredient for the cultivation of King oyster mushroom strain E1. Formula for substrate mixture: 40% rice straw + 20% corn cob + 19% sawdust + 20% rice bran + 1% CaCO3 was the best formula giving the highest mycelium growth rate and the fruit body yield as well. The farming of E1 King oyster mushroom achieve the highest efficiency on the formula 5 (59,4%).

In Viet Nam, the swine industry is ranked as leading position in animal husbandry. Due to disease problems, the swine industry often faces with a lot of difficulties and suffers great loss every year. Hence, the diagnosis of the diseases for treatment and prevention in time is extremely necessary. This paper proposes a model for diagnosis of swine diseases using image feature extraction methods and automatic classification. In this model, we also used some image feature extraction methods to evaluate the classification effectiveness of each method on test dataset. The experimental results of an image feature extraction method that we used with classification accuracy over 84% showed that our model can be employed effectively in practice.

Solar energy is clean, endless and does not pollute the environment. Solar energy system research plays a very important role to fully exploit the natural energy resources while traditional energy sources become scare. Maximum Power Point Tracker (MPPT) control for Solar panels considered as an indispensable part of the solar power system is applied in order to improve the efficiency of solar panels. This paper described and proposed a modifier of Incremental Conductance (INC) algorithms with Constant Voltage tracking (CVT) that were used to implement for Maximum Power Point control of Solar panels. Simulation results showed that modifier of INC algorithm had a better effect.

An investigation was conducted to determine the chemical composition and inhibitory effect against Staphylococcus aureus of Mahonia nepalensis DC. (M. nepalensis) extract. Chemical analysis showed that the extract contained alkaloids, tannins, flavonoids, saponins and terpenoids. The growth of Staphylococcus aureus strain was inhibited by the different extract concentrations. The diameter of inhibition zones varied from 10 to 15 mm for the extract concentrations from 20-40 mg/ml. The MIC, IC50 and MBC values were 0.05; 4.17 and 21.67 mg/ml, respectively. It is, therefore, suggested that the extract from M. nepalensis could be used as an anti-Staphylococcus agent in particular and a promising antibacterial agent in general.

Plants interact closely with microorganisms, especially endophytic bacteria. Many researches showed that endophytic bacteria have positive effect on plant growth and render plants resistance against phytopathogens. Bacterial endophytes have been isolated from different plants, including agricultural crops and wild plants. In this study, 14 bacterial isolates from roots of Aloe vera collected from three different areas in Vietnam were isolated on NA medium. Among them, two isolates, designated as TB2 and TQ5 showed high activity against pathogenic soft rot, Erwinia carotovora. Especially, TQ5 isolate showed resistance against both Burkholderia glumae and Erwinia carotovora, which are two serious plant pathogenic bacteria. The other two isolates, PT11 and TQ3 exhibited phosphate solubilizing capability and IAA producing activity. The optimum temperature and pH for IAA production of these isolates were 35oC and 6.0, respectively.