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Effectiveness Evaluation of Agricultural Land and Proposing Land Use Type for Commodity Oriented at Lucngan District, Bac Giang Province

Vu Thi Thuong, Cao Viet Ha

Received: 29-11-2012 / Accepted: 25-06-2013
Luc Ngan isanimportant agricultural district of BacGiang province. The district has five main land use types, i.e.paddyrice, paddy rice – upland crops, vegetables– upland crops, fruit crops and forest. The key commodity crops arelychee, persimmon and Acacia. Ofthe current land-use types, lychee and acacia bring maximum economic efficiency in terms oftotal revenueperha per annum, mixed income,workday value and cost-benefit ratio. The land use typesof rice-rice and rice-upland cropsdo notbring not high economic efficiency but play a vital role inensuring food security. By 2020, 4,000-4,200 hectaresare projected forrice and rice and non-rice crops andabout 18,500 ha forlychee cultivation, of which12,000-15,000 hectaresdevoted to high quality lychee. Forestareawill be expandedto 33,000ha,mainly with Acaciafor timber and paper pulp.
The Results of Breeding New Aromatic Thermosensitive Genic MaleSterile (TGMS) Line in Rice

Tran Van Quang, Tran Manh Cuong, Nguyen Thi Hao, VuQuoc Dai, Pham My Linh, Dam Van Hung

Received: 12-03-2013 / Accepted: 18-06-2013
The new E15Sline is thermosensitive genic male sterile line thatwas selected from 135S/Hoasuacrossingby pedigree method. The E15S has short growth duration, leaves numbers 14.1 and good phenotype such as: good tillering, stem and violet awn, long grain. The leaves and endosperm of E15S have aromatic smell mark 4. The critical sterility inducing point (CSIP) of E15S is 240C and high outcrossing ratio. The F1 was crossed between E15S and pollinators which have short growth duration, high yield, good quality and moderated resistance for disease and insects. The results of evaluation on F1 was selected E15S/Huongcom combination that has short growth duration (128 days), high yield (7.4 tons-1ha), milling rice 71.2%, head rice recovery 58.0%, long grain 7.1 mm and aromatic smell mark 3.8.
Some Fundamentals of Theories and Practices on Sustainable Development in Agriculture and Lessons for Agricultural Development in Cambodia

Serey Mardy, Nguyen Phuc Tho, Chu Thi Kim Loan

Received: 18-03-2012 / Accepted: 26-06-2013
This paper codifies theoretical and practical issues on sustainable development in agriculture. After discussing concepts, objectives and contents of sustainable agricultural development, the paper mentions to methodology for evaluation of sustainable agriculture. The paper also draws lessons learned from some of ASEAN countries for Cambodian agricultural development such as: Improving the socio-economic development policies, Improving the master plan and the detail plan for each region, Enhancing the quality of rural labor forces, Investing the rural infrastructure, Raising the farmers’ awareness in environmental protection.
Services of Agricultural Cooperatives for Farm Households Business in Thai Binh and Hoa Binh Provinces

Nguyen Trong Dac, Tran Manh Hai, Bach Van Thuy

Received: 18-06-2014 / Accepted: 01-09-2014
The studyinvestigatedservice activities of agricultural cooperatives and the role of services for farm households business through farmers’ assessment in Thai Binh and Hoa Binh provinces. The results showedthat most of farmers are aware of and use basic services from agricultural cooperatives such assupply of agricultural inputs, transfer of advanced technology, crop protection, irrigation,andfarm production management support. The quality of services after cooperative joint in MARD-JICA Project was rated by farmerswith good remarks. The proportionof farm households reported that their income improved by services of the cooperative varied but at a high level for all of the two provinces, indicating thatthe important role of cooperatives in providing services to farm households. Farm households also suggested that services of agricultural cooperatives should be diversified and expanded in scale in almost types of services in the future. Especially, some services such assupply of inputs, marketing support, transfer of advanced technology, mechanical cultivation, crop protection, andfarm production management support should be expanded and improved.
Production Development of Doan Hung Pomelo and Gia Thanh Persimmonin Phu Tho Province

Nguyen Thi Thu Huong, Do Thi Bac, Nguyen Ngoc Son Hai

Received: 18-06-2014 / Accepted: 01-09-2014
Production development of Doan Hung pomelo and Gia Thanh persimmon in Phu Tho province is a positive direction in order to exploit the potential advantages of agricultural products that have location-specific speciality. However, the implementation of development activities for Doan Hung pomelo and Gia Thanh persimmon has met many difficulties such as fragmented landconditions and scattered planting acreage primarily athousehold scale. The investment for cultivation, care, pest control, harvest and storage, processingof product is not paid attention. To partly solve these shortcomings,it is necessary to realize in harmony ofdevelopment and production solutions, constantly improve product quality of Doan Hung pomelo and Gia Thanh persimmon.
The Results of Purification of the Female Line and EstablishingProcedurefor Hybrid Seed Production of TheNew Two-Line Hybrid Rice Variety TH8-3

Vu Thi Bich Ngoc, Tran Thi Huyen, Pham Thi Ngoc Yen, Nguyen Van Muoi, Nguyen Thi Tram

Received: 26-11-2013 / Accepted: 03-02-2014
The new two-line hybrid rice variety TH8-3 (T7S-8/R3) has been recognizedastesting variety by Ministry of Agriculture and Rural Developmentin2010because it combines early maturity, high yield (6.0-8.0 tons/hectare), good lodging resistance and high grain quality. The yield of F1seed production is notyethigh becausethe parental linesare notcompletelypure and instable in terms of critical sterility temperature. Four successiveexperiments were conducted in growth chamber to screen/select female lines that havecritical sterility inducing temperature ≤ 240C,concurrently maintainheterosis of T7S-8/R3hybrid combination. Suitable planting dates and technical measures for F1seed production were also identified. These results can serve as basis to establish protocol for female line multiplication and procedure for hybrid seed production.
Rapeseed Variety trial on Karst Plateau of Ha Giang Province

Vu Duc Chien, Bui Quang Thuat, Le Binh Hoang, Nguyen Trung Hieu

Received: 24-10-2013 / Accepted: 24-02-2014
Twoexotic rapeseed varieties, Agamax from Germany, Hyola 432 from Australia and a local rapeseedvarietywere evaluated on field where rice was grownprevious season in Dongvan Karst Plateau during 2012-2013. The resultsindicated thattwo exotic rapeseed varieties were adapted to the local weather and soil conditions and gavehigh seed yield per hectare basis (1.820-1900kg/ha) and good seed quality. Theaverage oil content of Agamax and Hyola 432 attained43.6% and 41.3%, respectively. These varietiescan be adopted to integrate into winter cropping structure in Hagiang province.
Solition to the Management of Labor Export Activities of Labor Export Enterprises in Hanoi

Doan Thi Yen, Nguyen Thi Minh Hien

Received: 16-02-2013 / Accepted: 28-02-2014
The purpose of the study was to understand the current situation and to propose solutions for labor export management issues at labor export enterprises in Hanoi. The results showed that the management activities in those labor export enterprises strictly followed processes and achieved certain efficiency. However, the implementation processes has revealed many shortcomings, such as un-seriously in planning, mass recruitment and training... The main factors affecting these included unqualified staff involving in managing labor export activities and labor export supply and unapproapriate labor export policy. Eight groups of solution proposed included good planning, strengthening marketing and market development activities, improving recruit process, enhancing the quality of vocational education and training, strengthening the overseas labor management, enhancing control, evaluation and adjustment and improving the capacity of the labor managers.
OPTIMIZATION OF FACTORS AFFECTING SYRUP PRODUCTION FROM "SIM" FRUIT (Rhodomyrtus tomentosa) FOR HIGH ANTHOCYANIN CONCENTRATION AND GOOD QUALITY

NguyenMinh Thuy, Nhan Minh Tri, Pham Thi Kim Quyen

Received: 11-11-2013 / Accepted: 24-02-2013
Rhodomyrtus tomentosaor Rose Myrtleis a wild plant native to Southeast Asia. Itsberry orfruit is sweet, edible and medicinallyused as a folk remedy for various diseases. The fruitcontains high concentration of anthocyanin,a natural polyphenol withpowerful antioxidantactivity. In this study, Sim fruitsharvested from Mang-Den, a highland area in Komtum, were pretreated withpectinase to maximize yield, transmittance (clarify) and anthocyanin in the filtrate. After taste adjustmentwith sugar and citric acid, the juice was pasteurized for preservation. The extraction by pectinase enzymes was optimized using response surface methodology. The results showed that the extraction condition with 0.1% pectinase at 40oC in 60 min wasoptimal for maximum yield of fruit juice (62.93%), clarity (T=38.3%) and amount of anthocyanin (68.52 mg/L). Pasteurizationwith PU858,3 = 9.18 minutes at 85oC for 4 minutes yielded syrup withgood safety and high anthocyanin concentration.
EFFECT OF PROCESSING CONDITIONS AND GELLING AGENTS ON THE PHYSICO-CHEMICAL AND SENSORY CHARACTERISTICS OF JACKFRUIT JAM ADDING TO YOGURT

NguyenMinh Thuy, Ly‎NguyenBinh, NguyenAiThach, NhanMinh Tri, HoThanh Huong, Nguyen PhuCuong, DinhCongDinh, NguyenThiMyTuyen

Received: 21-10-2013 / Accepted: 16-01-2014
Jam is an effective and tasty way of preserving fruit. Most tropical fruits can be processed and preserved in order to reduce post harvest loss in small scale operations. The potential of the nutritious jackfruit (Artocarpus heterophyllus), has remained largely untapped. The study was conducted to investigate the effects of pectin concentration (0.7 to 0.9%) and gum arabic concentration (0.9 to 1.1%); vacuum pressure (450 to 650 mmHg) and holding time (2.5 to 4 minutes) on processing and jackfruit jam quality. Stirred and FOB-type fruit-flavored yogurt were made by adding jackfruit jam at different ratios (5 to 20%). In this work, vacuum technology was proven as adequate to obtain jam with the typical characteristics of water activity, degree Brix and viscosity of jam adding to yogurt. Proximate analysis showed vitamin C in jam 0.45 mg%, pH from 3.9 to 4 and oBrix from 53-54. The sensory evaluation showed that samples submitted to more intense vacuum pressure heating had significantly higher scores in color saturation, brightness, good texture and taste. These indicated that high vacuum pressure treatment prevents jackfruit jam color change and increases the consistency of the jam. In this way, jam was preferred by assessors mainly due to its higher consistency and suitability for adding to yogurt processing. The samples obtained by this procedure were stable during storage. Addition of 15% of Jackfruit jam into stirred yogurt and layered type of yogurt (FOB) provided products with strong aroma, good taste (sour and sweet harmony) and texture without water release.
Effect of Resources on Incomes of Agricultural Households in Thanh Hoa Province: A Case Study at Tho Xuan and Ha Trung Districts

Chu Thi Kim Loan, Nguyen Van Huong

Received: 13-03-2015 / Accepted: 08-09-2015
The overall objective of the paper was to describe the existing situation of resources and their effects onincomes of agricultural households in Thanh Hoa province through a casestudy at Ha Trung and Tho Xuan districts. The primary data were collected throughthe survey of 80 agricultural households and analyzed using descriptive statistics and multiple regression. The survey results showedthat labor quality, productive land and capital of the households were quite low. Average income of the households wasabout VND 72 millionper year, especially the income from salary and wages contributes a significant share in the household income. Land size, quantity and educational level of labor, and value of production means werepositively correlated withthe household income, wherebythe land size exerted highest impact. In addition, the accessibilityto credit, gender of household head and geographical location also significantly affected the household income.
Comparison of Spectral Clustering Algorithms for Gene Expression Data

Hoang Thi Thanh Giang, Nguyen Thi Thuy Hanh, Nguyen Hoang Huy

Received: 22-07-2015 / Accepted: 03-09-2015
Spectral clustering algorithms have been the most effective algorithms to divide genes into groups accordingto the degree of their expression similarity. Such a grouping may suggestthat the respective genes are correlated and/or co-regulated, and subsequently indicatesthat the genes could possibly share a common biological role. In this paper,three spectral clustering algorithms were investigated: unnormalized spectral clustering, normalized spectral clustering according to Shi and Malik (2000), and normalized spectral clustering according to Ng, Jordan and Weiss (2002). The algorithms were benchmarked against each other.The performance of the three clustering algorithms wasstudied on time series expressiondata using Dynamic TimeWarping (DTW) distance in order to measure similarity betweengene expression profiles. Four different cluster validation measures were usedto evaluate the clustering algorithms: Connectivity and Silhouette Index for estimatingthe quality of clusters, Jaccard Index for evaluating the stability of a clustermethod and Rand Index for assessing the accuracy. The results were analyzedby Friedman’s test. The performance of normalized spectral clustering according to Ng, Jordan and Weiss (2002)wasdemonstratedto be the best under the Silhouetteand Rand validation indices.
Building Image Database and Retrieval System for Rice Seed Identification

Tran Thi Thu Huyen, Nguyen Thi Thao, Nguyen Thi Thuy, Hoang Thanh Tam, Vu Thi Luu

Received: 22-07-2015 / Accepted: 03-09-2015
This paper presents a database of rice seeds properties to aid users in the assessment and recognition of seed characteristics of rice varieties based on their apprearance. Inspired by practical demands in quality control and rice seed purity assessment in seed production, we collected rice seeds of different varieties, acquired their images and consulted with experts about the visual properties for rice variety identification. As a result, we built a database of rice seed properties accompanied with their images and the description of the visual features. The database included popular rice varieties in the northern delta of Viet Nam. A database management system (DBMS) was built for managing and searching for rice seeds in the database. A web-based version of the DBMS was also developed. The system can be used to search for different rice varieties based on name and/or the description of the seed appearance. It can help users to learn about rice seed varieties, their visual features for discrimination and recognition. The system is easy to use, especially for non-IT users such as technicians, agronomy students or rice experts of rice seed production companies. This is also the first web-based database of rice varieties in Viet Nam with rice seed images to support rice seed searching and recognition.
Selection Source Circuit Structure of Position Hydraulic Control System Used in Agriculture

Nguyen TrongMinh, Bui Hai Trieu, Nguyen Cong Thuat

Received: 14-10-2014 / Accepted: 25-11-2014
The exact control of machanism position in agricutural machines is an important taskto improve the capacity and quality of the machines. According to resultsof the survey on imitative models of source circuitsin hydraulic system, the article provided soluttionsfor source circuit structure in position control used in agricuture to improve controlling propertysuitable forproduction conditions in Vietnam.
Research and Apply Automatic Submerged Arc Welding Technology to Weld Q345B High-Strength Low-Alloy Steel

Nguyen Huu Huong, Tong Ngoc Tuan

Received: 04-07-2016 / Accepted: 25-12-2016
Based oOn the currentavailableequipments, constructing an experimental model combining with equipment system, attachment and automatic submerged arc welding machine to weld Q345B high-strength low-alloy (HSLA) steel with T-letter shapedjointwith,a thickness of plates isof5 mm and 8 mm,respectively. Based on theoretic research into on automatic submerged arc welding technology, experimental welding,using design ofexperimental designsand,data processing were performed to find out parameters of for welding conditions to serve welding process of Q345B steel. Through the initial survey,fix somewith constantparameters and experimental welding with about input parameterintervals and evaluating output parameters, determining the followingparameters of welding conditionswere determined: welding current Ih≈ 440 Aand,welding speed Vh≈ 19,.6 m/h. With parameters of welding conditions that were determined,combining with technological elementsand specific structure, T-letterjoint that was weldinged toensureproducedgood form, dimension and quality.
WATER USE MANAGEMENT IN NAM ROM IRRIGATION SYSTEM OF MUONG THANH VALLEY, NORTHWEST VIETNAM

Ngo Thanh Son, Do Thi Thanh Duong

Received: 05-04-2016 / Accepted: 20-10-2016
The research aim was to analyse the main aspects of water use management and stakeholder conflicts within Nam Rom irrigation system, Dien Bien valley, Dien Bien province in the northwest region of Vietnam. The study identified the key stakeholder groups relating to water distribution, viz. Dien Bien provincial People’s Committee (DBPC), Dien Bien Irrigation Management Co. Ltd.(DBIMC),Dien Bien Phu city People’s Committee, and Dien Bien district People’s Committee. The results of this study indicated that the conflicts over water use for irrigation relate to quantity and quality of water supply, decentralized management and water fee exemption policies. The outputs of the study are important for improving water allocation and management in irrigation sector in Dien Bien province.
EFFECTOF TRICHODERMA sp. TC1 AND ITS EXTRACT ON GROWTH INHIBITION AND AFLATOXIN PRODUCTION OF Aspergillus flavusAND Aspergillus parasiticus

Nguyen Thi Thanh Thuy, Luu Thi Phuong Thao, Vu Quynh Huong, Nguyen Van Giang

Received: 20-04-2016 / Accepted: 10-08-2016
Aflatoxins are toxic carcinogenic secondary metabolites produced predominantly by two fungi: Aspergillus flavusand Aspergillus parasiticus. These fungi are a health risk and are responsible for losses and contamination of processed foods and feeds. It is very important to find methods to inhibit the growth of A. flavus andA. parasiticus,and degrade aflatoxin. In laboratory conditions, the Percentages of Inhibition of Radial Growth (PIRG %) of Trichodermasp. TC1 against A. flavusLA21 and A. parasiticusNG10 after 7 days’ dual culture were 63.51% and 60.22%, respectively. However, the use of Trichodermasp.TC1mycelium has restrictions in agricultural products due to the risks of consuming the substrate and degrading the products’ quality. Therefore, its extracts are more preferred in application. In the PD media, when up to 4% Trichodermasp. TC1 extract was added, the biomass rate for A. flavusLA21 and A. parasiticusNG10 reduced to 74.00% and 60.30%, respectively, after 5 days of incubation. The toxin levels of corn samples deliberately infected by aflatoxin producing fungi were negatively correlated with sprayed on Trichoderma sp. TC1 extract. Seven days after spraying the extract 4%, the aflatoxin in samples from more than 60 ppb at the initial time reduced down to 16 ppb for A. flavusLA21 and 21.33 ppb for A. parasiticus NG10.
THE EFFECTS OF A POTENTIAL RETARDANT ON THE STEM’S HARDNESS, GROWTH AND YIELD OF IR50404 RICE

Le Vinh Thuc, Mai Vu Duy, Nguyen ThanhHoi, Mai ThiNhung

Received: 11-06-2016 / Accepted: 18-08-2016
Lodging is one of the important factors that limitsrice yield and reducesgrain quality. Lodging obstructs the process of transporting carbohydrates fromtheleaves and stem to grains, and causes the panicles to sink into water and decompose, which causes many difficulties for harvesting. This study was conducted with the aimof determining the optimal paclobutrazol concentration with respect to the growth and hardness of rice to help limit lodging and increase the yield. The experiment was conducted in the field on the autumn-winter crop inVi Thuy District, Hau Giang province. The experiment was carried out in a randomized complete block design (RCBD) with five paclobutrazol treatments (control (spraying water without paclobutrazol), 25 mg.l-1, 50 mg.l-1, 75 mg.l-1, 100 mg.l-1) and four replications per treatment. The results showed that the treatment of paclobutrazolat a concentration of 50 mg.l-1induced the rice to increase the number of tillers, the stems’ hardness index (the lodging index was reduced),the filled grain ratio,andthe yield (6.98 tons/ha, increasing 12.1% compared to the control).
Breeding Results of Rice Variety TBR225

Tran Manh Bao, Tran Thi Hop, Tran Thi Tiec, Nguyen Thi Nhung, Nguyen Van Hoan

Received: 15-01-2016 / Accepted: 10-09-2016
TBR225 rice variety wasselected from K2/TBR27 cross since 2006 Autumn cropping season. The parentalvarieties K2 and TBR27 were selected from working collection of Thaibinh Seed introducedfrom China. Pedigree selection was made continuously from F2 to F5 and perspective uniform line was named NC7. NC7 line possessedvarious valuable characters such as short growing duration, good plant type, high disease resistance, high yielding potential, long grainwith whiteness and translucence, low amylose content, andgood taste quality. After a series of replicated yield trials at thebreeding nursery of Thaibinh Seed, NC7 proved to be promising line and was named TBR225. TBR225 was evaluated/tested forDUS and VCU test by National Center for Plant Products and Fertilizers inorthern and central regions of Vietnam since 2012 Autumn season. The average grain yield of TBR225 ranged from 6.5 to 7.5 tons/ha, 3.76 - 11.44% higher than the check variety,KD18 and 4.87 - 15.67% higher than Huong thom1.TBR225 was prelimarily approved for production trial according to the DecisionNo.458/QĐ-TT-CLT datedNovember 08, 2013 and officially recognized as ntional variety according to the Decision No.202/QĐ-TT-CLT dated June 09, 2015.
Application of RT-PCRfor Detection of InfectiousbronchitisDisease in Laying Hens in Some Northern Provinces of Vietnam

Le Van Phan, Nguyen ThiLoan, Le Dinh Quyen, Duong Hong Quan, Le Huynh Thanh Phuong, Nguyen Ba Hien

Received: 23-03-2016 / Accepted: 20-09-2016
Infectious bronchitis (IB) is one of the severe infectious disease causing tremendous economic losses in the poultry industry. In order to have an effective strategy for disease prevention and control, a method for rapid and accurate dectection of infectious bronchitis virus (IBV) is urgently needed. In this study, the tissue samples oflung, trachea and kidney collected from IB-suspected laying hens in three hen farms in Hanoi (Ba Vi District), Thai Nguyen and Bac Ninh have been diagnosed by the RT-PCR method. The diagnostic results showed that 34/71 (47,88%) samples were positive with the IBV.The common clinical signs ofIBV-infected hens included fever, depression, loss ofappetite,dyspnea, coughing, sneezing, tracheal rales, nasal discharge, diarrhea, fluid retention in the abdomen, facial swelling and conjunctivitis. The pathological signs in IBV-infected hensincluded kidney swelling (90%), tracheal hemorrhagea (77.5%), pulmonary hemorrhage and congestion(63,7%), inflammation of airsacculitis (60%) and upper respiratory tract (57,5%). Egg production and quality in IBV-infected laying hensdecreased by 20,7to 43%.
Effects of Nitrogen, Phosphorus and Potassium Levelson Tomato Grown on Organic Substrate

Nguyen Van Thao, Nguyen Thu Ha, Do Nguyen Hai

Received: 21-04-2016 / Accepted: 15-07-2016
Nutrient supply to plants grown on substrate is necessary to obtain high product quality and yield. The objective of the present study was to determine the suitable amount of N, P, K fertilizers for tomato grown on organic substrate. The experiment consisted of 28 pots that were applied with different fertilizer levels. Study results show that pHKCl of organic substrate was neutral (7.28), total nitrogen, phosphorus and potassium were high and equivalent to some popular organic substrates. Different levels of phosphate, potassium fertilizer application (with the same level of nitrogen fertilizer) did not affect tomato yield. Combination of 6.0 g N, 4.5 g P2O5 and 6.0 g K2O per pot improved average fruit weight (78.32 g/fruit) and actual fruit yield (2.38 kg fruit/pot). Potassium fertilizer application significantly affected sugar content of tomatoes (> 5.0%) in pots applied with 4.0 - 6.0 g K2O. After 15 days of fertilization, NO3- content of the tomatoes fluctuated between from 29.7 to 110.3 mg/kg fruit which was lower than VietGap standard.
Growth and Grain Yield of Newly Developed Rice Lines with Very Short Growth Duration in Summer - Autumn Cropping Season in Nghe An Province

Le Van Khanh, Tang Thi Hanh, Vo Thi Nhung, Pham Van Cuong

Received: 20-05-2016 / Accepted: 15-08-2016
The field experiments were laid out in a randomized complete block design (RCBD) with three replications in 2014 and 2015 summer- autumn cropping season in Yen Thanh and Quy Hop district of Nghe An province to assess the growth and grain yield of fivenewextremely early maturing rice lines (D1, D2, D3, D4,andD5) with twocheck varieties,Khang Dan 18 (KD18)andVat tu- NA2 (NA2). The results showed that the growth duration of therice lines ranged from 88to96 days,shorter than that of the check varieties. Dry matter accumulation rate oftherice lines before heading stage wassignificantly higher than that of the check varietieswhilepest and disease infestationof thelines was lowerat all growth stages.Grain yield accumulation (kg/ha/day) oftherice lines (except D3) wascomparable to orhigher than that of the check varieties. Grain yield oftherice lines was similar to or significantly higher than the check varieties, withD5 showing highest yield in both growing seasons. Amylose content of the rice lines wasbelow 23%, much lower than that of KD18 (above 28%). Cooking quality ofD5 was higher than that of KD18 but similar toNA2.
Apparent Digestibility of Some Commercial Feeds for Short Fin Pompano (Trachinotus ovatus)

Tran Thi Nang Thu, Nguyen Huu Ninh, Tran The Muu, TranThi Thap Hieu, Nguyen Tuan Dat

Received: 20-10-2016 / Accepted: 17-07-2016
The study was carried out from March to June 2015 at National Broodstock Center for Mariculture Species in Northern Vietnam (Center), Cat Ba, Hai Phong province, to evaluate digestibility of protein (ADP), lipid (ADL) and gross energy (ADE) of some available commercial feeds for pompano,Trachinotus ovatus, using indirect method with chromic oxidize (Cr2O3) 1% as inert marker. Pompano of 400g/fish were held in marine cage- culture system (3 x 3 x 3 m, six of each cage) at density of 10fish/m³. Three commercial aquafeed brands with different protein content,46, 50 and 51% were determined for their digestibility inpompano (abbreviated as D46, D50 and D51) with three replicates. The feaces were collected each day by stripping method before feeding the fish. Fish were fed by hand to apparent satiety, once daily at 9h. Feaces werethen pooled in sealed bottles and stored at- 200C until use. The results showed that ADP of D50 (71.34%) was lowest among experimental diets (P< 0.05), while that of D46 (76.42%) and D51 (77.52%) did not significantly differ (P> 0.05). ADL value of D51 was lower than that of D46 and D50 (P< 0.05). Result of ADE indicated that ability of pompano to digest energy from three commercial diets was similar (P> 0.05). The digestibility of protein and energy of three pellet feedsusedto test in pompano culture wasnot so highandthe quality of these feedsshould be further improved.
Mapping Land Units and Evaluating Land Suitability for Agricultural Production in Ha Tinh CitySuburbs

Tran Quoc Vinh, Ho Huy Thanh, Dao Chau Thu

Received: 04-02-2016 / Accepted: 20-03-2016
The study area included3 communes (Thach Quy, Thach Mon and Thach Ha) in the suburbs of Ha Tinh city: The total area is 760.62 ha. Sixclassification criteria were identifiedincluding soil type, terrain, top soil depth, texture, soil fertility and irrigation regime. Consequently, sixcorresponding thematic maps were constructed using GIS functions in ArcGIS software. Those maps were overlaid in order to construct a land unit map. The results showedthat there were 31 land mapping units(LMU), among which LMU number 16 had the smallest area (9.64 ha)whileLMU number 31 had the largest area (113.6 ha). Both of them are Thionic Pluvisols in FAO classification. By assessing the land quality of the LMUs, 456.05 ha were identified assuitable for paddy rice, 490.49 ha suitable for paddy rice and vegetable cultivation,alternately and 526.62 ha suitable for vegetable cultivation.
Effect of Colchicine Concentration and Duration of Treatment on Polyploidy Induction in Shallot (Allium cepaL., Aggregatum Group)

Tran Thi Minh Hang, Pham Thi Minh Phuong, Nguyen Thanh Tuan, Phan Thi Ngan

Received: 09-11-2015 / Accepted: 11-03-2016
Local shallot (Allium cepaL. ), Aggregatum group) variety grown inKinh Mon, Hai Duong was treated with colchicine in order to produce polyploid materials for high-quality shallot breeding in Viet Nam. The research was carried out at Faculty of Agronomy, Vietnam National University of Agriculture. The shallot bulbs were immersedincolchicine solution with different concentrations (0,2%; 0,4%; 0,6%; 0,8%; 1,0%; 1,2%; 1,4%; 1.6%; 1,8%; 2,0%)for oneto tendays. The results revealed that colchicine treatment at concentration 1,0% for 6 days was most suitable for inducing tetraploid shallot plants with survival rate of 80%. Thepercentage of tetraploids was20% in total treated bulbs. Treatment at higher concentration and longer duration increased the percentage of dead plants up to 100%. Thirty six tetraploid plants of shallot were produced.

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