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Application of CLUMondo Model in Forecasting Land use Changes in Van Yen district, Yen Bai Province

Pham Duy Khanh, Vu Thanh Bien, Dao Xuan Thu, Nguyen Luu Ly, Ngo Thanh Son, Bui Le Vinh

Received: 25-10-2022 / Accepted: 18-04-2023
This study applied the CLUMondo model to simulate land changes for land use planning in Van Yen district, Yen Bai province under two scenarios: Scenario 1- land use demand in the past and Scenario 2- based on local land use orientation. The simulation principle of the model was based on the interaction between the influencing factors and land use types through logistic regression. The simulation accuracy of the model for the 2020 overlay map was evaluated by the Kappa coefficient of 0.88. The simulation results show that by 2030, in scenario 1, construction land fluctuates the most (increase by 9.82%), while forest land and agricultural land decrease to 83.25% and 1.77%, respectively. In scenario 2, the forest and agricultural land also tend to decrease, but less than in scenario 1. The most obvious difference between the two scenarios is that the area of construction land increases sharply in scenario 1 compared to scenario 2, and the bare land with shrubs increases in scenario 1 but decreases in scenario 2.
Genetic Diversity of Hibiscus rosa-sinensisL. Accessions Collected in Hanoi and Hung Yen Province

Pham Thi Ngoc, Ngo Thi Hong Tuoi, Nguyen Thi Bich Hong, Doan Thu Thuy

Received: 05-12-2022 / Accepted: 18-04-2023
The study aims to evalute for morphological characteristics and genetic diversity of hibiscus. Twenty-four Hibiscus accessions collected in Hanoi and Hung Yen provinces (denoted as DB1 - DB24) were evaluated based on 12 morphological markers and 9 molecular markers (SSR and ISSR). The resutls showed that Hibiscus accessions exhibited significant variation in leaf morphology and flower colors, with 5 flower color groups, i.e white, pink, yellow, orange and red. The red color was predominant with 9 accessions. The genetic diversity analysis using 12 morphological characteristics grouped hibiscus accessions into 5 groups at similarity coefficient of 0.55 similarity, of which DB4 and DB20 were in each separate group. Nine molecular markers SSR and ISSR produced 33 allenswith average of 3.67 allens/markers and all were polymorphic. PIC values ranged from 0.05 to 0.47 in which HB15 marker had the highest PIC value. With the similarity coefficient at 0.64, 24 accessions were divided into 3 distinct clusters.
Cloning and Sequencing of Genes Encoding Malonyl-CoA Synthetase (matB) and Malonyl-CoA Decarboxylase (matC) from Rhizobium leguminosarumKTCC 2362

Pham Tran Quy Anh, Nguyen Quang Duc Tien, Nguyen Hoang Loc, Nguyen Huy Thuan

Received: 14-02-2023 / Accepted: 07-04-2023
matB(malonyl-CoA synthetase) and matC(malonyl CoA decarboxylase) are two enzymes involved in the malonyl-CoA metabolism, an essential precursor in metabolic processes in prokaryotes and eukaryotes such as nitrogen fixation, fatty acid synthesis, secondary metabolites, brain development, etc. Therefore, the study's objective was to clone the genes matBand matCthat can be used in the biosynthesis of the bioactive compound using malonyl-CoA as a precursor. matBandmatCwere isolated by PCR and ligated to cloning vector pGEM®-T Easy and sequenced. The obtained sequences were analyzed and compared to the reference sequence (AF117694.1) in the Genebank. In conclusion, Rhizobium leguminosarumKTCC 2362 - derived matBand matCgenes were cloned and sequenced successfully.
Livelihoods of Households in the Bufferzone of Xuan Thuy National Park

Pham Thi Thanh Thuy, Do Kim Chung

Received: 27-03-2024 / Accepted: 02-07-2024
The study analyzedlivelihood capital sources, livelihood activities and livelihood outcomes of households in the buffer zone of Xuan Thuy National Park, Nam Dinh, thenprovidedsome suggestions to improve their livelihoods and income. The research conducted interviews with 30 households whose livelihoods entirely depend on mangrove forest, 60 households whose livelihoods partly depend and 30 households whose livelihoods are not dependent on the National Park's mangrove forests in Giao An, Giao Thien, Giao Xuan communes and in-depth interviews with 14 managers of relevant agencies and units. The results showed that the sources of livelihood assests of people in the buffer zone were relatively complete. The main livelihood activities were agricultural production, aquaculture and exploitation of aquatic products, trade and service business with 100% of households participating in agricultural production and over 88% of households in aquaculture. The lowest average household income in group was VND 85.19 million/year and the group 3 had the highest of VND 96.91 million. In order to increase outcome for households in the buffer zone, it is necessary to increase and effectively use livelihood capital sources, improve traditional livelihood activities and expand effective livelihood activities.
Consumer Awareness of Low-Quality Chemical Fertilizers in Bao Thang District, Lao CaiProvince

Le Thi Thanh Loan, Nguyen Thanh Phong, Duong Thi Tan

Received: 15-04-2024 / Accepted: 24-06-2024
The research was conducted in Bao Thang district, Lao Cai province to assess consumer awareness of low-quality chemical fertilizers. The information was collected through group discussion, in-depth interviews with stakeholders in fertilizer management and business, as well as a survey with a questionnaire administered to 90 consumers across 3 communes with large agricultural areas in the district. The results showed that consumers faced the most difficulty in recognizing the visual characteristics of low-quality fertilizer packaging. Regarding the harmful effects of low-quality fertilizers, most people could relatively recognize them, but the awareness of how to handle low-quality fertilizers was limited. Some challenges to consumer awareness include the sophistication in the strategy of producing low quality fertilizers, the sources of information available to consumers, and consumer characteristics. The study proposes several solutions to enhance consumer awareness of low-quality fertilizers, focusing on solutions for consumers, solutions for the district authority, and solutions for reputable fertilizer suppliers.
The Current State of Production and Business Performance of Garment Firms in Nam Dinh Province

Nguyen Mau Dung, Phan Thi Minh Phuong

Received: 27-03-2024 / Accepted: 12-06-2024
This study was conducted to assess the current state of production and business activities of the garment firms in Nam Dinh province. Using the dataset from a survey of garment firms in Nam Dinh province in 2021, along with descriptive statistical methods, comparative analysis, and the bivariate regression model, the research results show that Nam Dinh province had over 200 active garment firms, primarily limited liability companies and joint-stock companies with foreign investment. During the period from 2015-2021, key indicators reflecting the results and efficiency of production and business activities of garment firms in the province showed impressive growth with the quantity of products increasing by 8%/year and net revenue increasing by 13% per year. However, there were still a considerable number of firms with poor business performance and at risk of having to shut down production. The study analyzed the factors influencing the results and efficiency of production and business activities and proposed key measures to improve the performance and efficiency of garment firms in Nam Dinh province in the future.
Study and Designing Remote Electrical Load Monitoring and Control System for Electricity Demand Management Programs

Dao Xuan Tien, Nguyen Thi Huyen Thanh, Nguyen Xuan Truong

Received: 19-12-2023 / Accepted: 12-06-2024
The study aimed to design and manufacture a data collection and electrical load monitoring system based on SCADA and IoT technology platforms. A system with remote measurement and monitoring of electrical load parameters and remotely control of on/off electrical loads by mobile phone was manufactured. In particular, the system can automatically calculate electricity consumption and electricity bills monthly based on the flexible selection of two basic electricity billing methods currently applied by Vietnam Electricity Group (EVN). These features of the system help the users always know their current electricity costs. On that basis, the users could control and reduce electricity consumption or optimize electricity costs.
Biological and Ecological Characteristics of the mealybug destroyer (Cryptolaemus montrouzieriMulsant, Coleoptera: Coccinellidae)fed on papaya mealybug (Paracoccus marginatus W. & G. de W.)

Nguyen Duc Tung, Tran Thi Thu Phuong, Dang Thi Tuyen, Doan Thai Son

Received: 26-02-2024 / Accepted: 28-05-2024
This study aimed to investigate the biological and ecological characteristics of the mealybug destroyer, Cryptolaemus montrouzieri, an important predator of the papaya mealybug, Paracoccus marginatus. The mealybug destroyers were reared at two different temperatures: 30Cand 33C,with 80% humidity, 14L:10D, feeding on papaya mealybugs, P. marginatus. The results showed that the life cycle of C. montrouzieriwhen reared at 30°C (28.00 days) was significantly longer than at 33C(23.91 days). The total pre-adult period of male C. montrouzieriat 30Cwas 22.00 days, longer than when reared at 33C(17.95 days). The total number of eggs laid by C. montrouzieriwhen reared at 30C(253.72 eggs) was significantly higher than when reared at 33C(206.65 eggs). However, the daily oviposition did not differ significantly between the two temperatures, with an average of 5.50 eggs/day. The intrinsic rate of increase (rm) of C. montrouzieriat 33C(0.134) was significantly higher than at 30C(0.121). The total consumption of the larval stages of C. montrouzierifeeding on P. marginatusat 30Cwas higher than at 33C, and the consumption increases with each successive larval stage, peaking at the fourth instar with consumption rates of 19.26 and 18.19 individuals/day at 30Cand 33C, respectively.
Effect of Composting Methods of Agricultural by-Products on Quality of Compost and Its Application in Cucumber Cultivation

Thieu Thi Phong Thu, Chu Thi Dieu Linh

Received: 03-01-2024 / Accepted: 28-05-2024
The experiment was conducted to determine suitable composting method to convert agricultural by-product into organic fertilizer and evaluate effect on the growth and yield of cucumber in 2023 spring season. The experiments were carried out at the field of the Faculty of Agronomy, Vietnam National University of Agriculture. The traditional aerobic composting and mix aerobic composting were tested to compost agricultural by-products consisting of rice straw, chicken manure and elephant grass. Research results showed that the mix aerobic composting method produced higher mass and quality of compost in comparison with traditional method. Combination treatment of mix aerobic compost with chemical nitrogen fertilizers had a positive effect on growth, development and yields of cucumber than other treatments.
Detection and Identification of Pinworm Syphacia obvelatain Experimental Mice

Nguyen Thi Hoang Yen, Nguyen Chi Hieu

Received: 13-12-2023 / Accepted: 23-05-2024
This study was conducted to identify the species of pinworms in experimental mice. Eggs of pinworms were examined from four white mice that were purchased from an animal facility before the conduct of experimental infection. The eggs were detected by the perianal tape test method, adult worms were collected by necropsy method, and then eggs and adult worms were identified based on their morphology. Besides, PCR and sequencing techniques were also applied to confirm the species identification. The results show that eggs were pointed oval (with one side flatted) in shape and approximately 129.2 x 39.17m in size. Adult worms were 3-5mm in length, having two subtle cervical alea, a bulb at the end of the esophagus, and a long and pointed tail. PCR and sequencing techniques revealed the species of pinworm to be Synphacia obvelata. Even though the scope of the study was still limited, the results of the study provided information on the presence of S. obvelatain experimental mice and gave a warning signal about monitoring and eradication of pinworms for experimental animal facilities.
Correlation between the Level of Amphibious Lifestyle and Moving Characteristics with the Pectoral During Water-to-Terrestrial Transitionof Mudskippers(Oxudercinea subfamily)

Nguyen Minh Tai, Nguyen Van Lam, Tran Xuan Loi

Received: 15-01-2024 / Accepted: 12-04-2024
Showing amphibious features, mudskippers have been used as model species to gain understanding of the water-to-land transition of vertebrates. This study aimed to elucidate the relationship between terrestrial degrees and the utilization of pectoral fin-based locomotion and their morphology as well. The locomotor behavior, the aspect ratio of the fin, and the muscle ratio of three mudskippers and one goby were investigated. Results show that terrestrialization gradually increased in mudskippers, from Oxuderces nexipinnisto Scartelaos histophorusand Periophthalmodonseptemradiatus. Oxuderces nexipinnisand S. histophorusused the pectoral fins for crutching in aquatic, semi-aquatic, and terrestrial environments. They also employed the pectoral fins for waterskiing which is first reported for mudskippers in this study. In Pn. septemradiatus, the pectoral fins were mainly used for crutching on land (57.73%) and moistening (30.08%). The time proportion of crutching in terrestrial environment was high in species with higher terrestrialization. The aspect ratio of the pectoral fin and muscle ratio was correlated with terrestrial degrees.
Assessment of IBDV Antibody Titer and Productivity of Commercial Broiler Chicken at Field Trial Post-Vaccination with Tabic MB and IBDV-Icx

Le Thi Kim Tuyen, Nguyen Thi Kieu Oanh, Nguyen Manh Ho, Nguyen Thi Van Anh, Quach Tuyet Anh

Received: 27-07-2023 / Accepted: 05-01-2024
The study was conducted to evaluate antibody titers against IBDV and the productivity of commercial broiler flocks at field trial vaccinated with live vaccine Tabic MB and immune complex vaccine (IBDV-Icx). A total of 240 blood samples were randomly collected from 2 farms to test antibody titers against IBDV by ELISA technique. Mean body weight, average daily weight gain, and FCR were monitored until slaughter. The results showed that the chickens had high level of maternally derived antibodies (MDA). At 3 days old, the mean MDA was 5,582 titer units. At 30 days old, the number of positive samples with anti-IBDV (> 396 titers) in the group using Tabic MB and IBDV-Icx vaccines was 20% and 5%, respectively (P <0.05). Especially at 35 days of age, the titer at farm using the Tabic MB vaccine was 2,671 , which was significantly higher than that of the farm using the IBD-Icx vaccine, with titer of 132 only (P <0.05). Chicken body weight and average daily weight gain of this survey were similar (P >0.05). However, the FCR of chickens using Tabic MB vaccine was lower than chickens using IBDV-Icx vaccine (P <0.05). Briefly, commercial broiler chickens using Tabic MB vaccine had higher antibody titer against IBDV and productivity parameters were not affected compared with vaccinated with IBDV-Icx .
Optimizationof Cultural Conditions for Rhizobacterium Bacillus subtilisRB.CJ41 Against Fusariumsp.

Trinh Thi Huyen Trang, Nguyen Minh Trung, Dinh Lan Trinh, Tran Thi Phuong Hanh

Received: 03-10-2023 / Accepted: 07-03-2024
Rhizobacterium Bacillus subtilisRB.CJ41 isolated from black pepper hasantifungal activity against Fusariumsp. under in vitroand ex vitroconditions. The objective of the study was to select the appropriate culture conditions of the strain B. subtilisRB.CJ41. The single effect of environmental factors including C/N source, carbon sources, (NH4)2SO4and MgSO4sourceswas investigated on the density and Fusariumsp antifungal activity of the strain RB.CJ41. The results showed that bean residue, mannitol and MgSO4had the greatest impact on density and antifungal activity of strain RB.CJ41. Using Response Surface Methodology (RSM) - Central Composite Design (CCD), a quadratic equation describing the dependence of Fusariumsp. antifungal activity with three survey variableswas determined in the form “Antifungal activity (%) = 11.66 – 0.9452A + 1.00B + 0.2713C – 0.5625AB – 0.5625AC – 0.0625BC – 2.28A2 – 2.73B2– 1.84C2.Analytical results showed theoptimal range forhigh antifungal activity of rhizobacteriumB. subtilisRB.CJ41 was7 g/lto 8 g/lfor bean residue, 6g/lto 7g/lfor mannitol and 4 g/lto 5 g/lfor MgSO4.
Microalgal Composition in Fish Ponds at the Vietnam National University of Agriculture

Doan Thanh Loan, Nguyen Khanh Linh, Hoang Thi Tam, Le Thi Hoang Hang, Nguyen Cong Thiet, Hoang Dang Dung, Pham Thi Lam Hong

Received: 01-03-2023 / Accepted: 07-03-2024
This study was carried out to build a database of microalgae in fish ponds at the Fisheries Faculty of the Vietnam National University of Agriculture. Water samples were collected to examine the frequency of occurrence and microalgal composition in five aquaculture ponds. A total of 30 microalgal samples (15 from winter and 15 from summer) were analyzed in this study. The results showed that there were 136 microalgae species from 8 classes, 11 orders, 26 families, 49 genera, and 6 phyla (Euglenophyta, Chlorophyta, Cyanobacteriophyta, Bacillariophyta, Pyrophyta, and Xanthophyta). The number of microalgal species was abundant in summer. There were 27 microalgae species that could be used as live food for zooplankton. The occurrence of 12 microalgae species is a bioindicator of organic compound enrichment in water. There were three microalgae species that could cause harmful algal “blooms”.
Optimizationof Cultural Conditions for Rhizobacterium Bacillus subtilisRB.CJ41 Against Fusariumsp.

Trinh Thi Huyen Trang, Nguyen Minh Trung, Dinh Lan Trinh, Tran Thi Phuong Hanh

Received: 03-10-2023 / Accepted: 07-03-2024
Rhizobacterium Bacillus subtilisRB.CJ41 isolated from black pepper hasantifungal activity against Fusariumsp. under in vitroand ex vitroconditions. The objective of the study was to select the appropriate culture conditions of the strain B. subtilisRB.CJ41. The single effect of environmental factors including C/N source, carbon sources, (NH4)2SO4and MgSO4sourceswas investigated on the density and Fusariumsp antifungal activity of the strain RB.CJ41. The results showed that bean residue, mannitol and MgSO4had the greatest impact on density and antifungal activity of strain RB.CJ41. Using Response Surface Methodology (RSM) - Central Composite Design (CCD), a quadratic equation describing the dependence of Fusariumsp. antifungal activity with three survey variableswas determined in the form “Antifungal activity (%) = 11.66 – 0.9452A + 1.00B + 0.2713C – 0.5625AB – 0.5625AC – 0.0625BC – 2.28A2 – 2.73B2– 1.84C2.Analytical results showed theoptimal range forhigh antifungal activity of rhizobacteriumB. subtilisRB.CJ41 was7 g/lto 8 g/lfor bean residue, 6g/lto 7g/lfor mannitol and 4 g/lto 5 g/lfor MgSO4.
Microalgal Composition in Fish Ponds at the Vietnam National University of Agriculture

Doan Thanh Loan, Nguyen Khanh Linh, Hoang Thi Tam, Le Thi Hoang Hang, Nguyen Cong Thiet, Hoang Dang Dung, Pham Thi Lam Hong

Received: 01-03-2023 / Accepted: 07-03-2024
This study was carried out to build a database of microalgae in fish ponds at the Fisheries Faculty of the Vietnam National University of Agriculture. Water samples were collected to examine the frequency of occurrence and microalgal composition in five aquaculture ponds. A total of 30 microalgal samples (15 from winter and 15 from summer) were analyzed in this study. The results showed that there were 136 microalgae species from 8 classes, 11 orders, 26 families, 49 genera, and 6 phyla (Euglenophyta, Chlorophyta, Cyanobacteriophyta, Bacillariophyta, Pyrophyta, and Xanthophyta). The number of microalgal species was abundant in summer. There were 27 microalgae species that could be used as live food for zooplankton. The occurrence of 12 microalgae species is a bioindicator of organic compound enrichment in water. There were three microalgae species that could cause harmful algal “blooms”.
Extraction of Lipids and Piceatannol from Passion Fruit Seeds

Lai Thi Ngoc Ha

Received: 29-06-2023 / Accepted: 05-01-2024
The objective of this study was to determine the optimal conditions for oil and piceatannol extraction from passion fruit seeds. Oil was extracted by dynamic extraction and piceatannol extraction was optimised by response surface methodology. The piceatannol content was analysed by high performance liquid chromatography. Results showed that the best oil extraction conditions were as follows: ethyl acetate used as extraction solvent, temperature of 30C, extraction time of 30 minutes and two times of extraction (with material/solvent ratio of 1/10 and 1/5 (w/v) for the first and the second times, respectively). At these conditions, the oil extraction yield was of 78.12 ± 0.31%. The crude oil had acid value of 1.61 ± 0.05mg KOH/g and peroxide value of 0.62 ± 0.03 meq O2/kg. These values were lower than the maximal legal levels specified in TCVN 7597:2018 Vietnamese standard for vegetable oils. Piceatannol content in defatted passion seeds corresponded to 68.94% of initial piceatannol quantity of passion fruit seeds. A second-order polynomial model with three important variables (ethanol concentration, temperature and extraction time) was successfully built to describe the piceatannol extraction (R2 = 0.9635). The optimised conditions were the followings: 68% ethanol (v/v), at 85C during 45 min. This research could serve as bases for full exploitation of passion fruit seeds, producing by-products utilised in cosmetic and food technologies.
Isolation and Characterization of Lasiodiplodia theobromaeStrain Causing Dieback Disease on Grape in Ha Noi and Hung Yen

Nguyen Thanh Huyen, Dang Thi Thanh Tam, Do Thuy Hien

Received: 30-08-2023 / Accepted: 25-12-2023
Dieback is one of the most common diseases on grape that is caused by fungi belonging to the Botryosphaeriaceae family. Among these fungi, Lasiodiplodia theobromaehas been identified as the most virulent species. Unfortunately, the current treatments for this disease are still challenging and not truly effective. This study was conducted to determine the causative agent and biological characteristics of the grape dieback-causing fungus in Hanoi and Hung Yen as a basis for guiding effective measures in the prevention and treatment of dieback. From grape samples showing dieback disease collected in Hanoi and Hung Yen, three fungal strains were isolated through culture on the PDA medium and these strains were subsequently re-infected onto leaves and stems of grapes. Among them, CK1 and DN1 strains showed similar mycelial characteristics and pathogenicity. Therefore, the CK1 strain was selected for further experiments. Through the molecular identification method with the ITS1/ITS4 primer pair, the CK1 strain was confirmed asLasiodiplodia theobromae and was named L. theobromae CK1. L. theobromae CK1 exhibited good growth on the PDA medium, and the optimal conditions for the strain were 35C and a pH in the range of 6-8. In addition, during its growth, this fungal strain was also capable of producing cellulase, xylanase, and pectinase.
Genetic Diversity Analysis of 10 Oyster Mushrooms (Pleurotusspp.) Accessions by RAPD and ISSR Markers

Dinh Truong Son, Nguyen Thi Ngoc Anh, Nguyen Thu Hang, Nguyen Thi Bich Thuy, Nong Thi Hue, Ngo Xuan Nghien

Received: 15-08-2023 / Accepted: 25-12-2023
Oyster mushrooms (Pleurotusspp.) are widely consumed in the world due to their delicious taste, high nutritional value and medicinal properties. For breeding program to develop new cultivars, besides phenotypic characteristics genetic characterization of the material is important since it helps breeders to choose suitable materials for hybridization. This study analyzed the genetic diversity of 10 oyster mushroom accessions using 20 RAPD markers and 17 ISSR markers to provide information for oyster mushroom breeding programs. The markers amplified a total of 560 loci with 552 polymorphic loci and 2,138 PCR product bands. When combining both RAPD and ISSR markers, the genetic similarity coefficient of 10 oyster accessions ranged from 0.459 to 0.755. At the average genetic similarity coefficient of 0.579, 10 oyster mushroom accessions were divided into 3 main groups. These results indicate that 10 collected oyster mushroom accessions had a high level of genetic diversity and can be used for new oyster mushrooms breeding program.
RAPD and ISSR Markers Assessment of Genetic Diversity of 12 Cordyceps Accessions collected in Vietnam

Nong Thi Hue, Tran Thi Thao, Le Phuong Linh, Ninh Thi Thao, Ngo Xuan Nghien, Dinh Truong Son

Received: 15-08-2023 / Accepted: 25-12-2023
Cordyceps spp. belong to the most valuable medicinal caterpillar fungi. However, consumers hardly know the origin and species of Cordycepsspp. commercialized on the market. This study aimed to identify 12 collected Cordyceps samples collected at various locations in Vietnam by ITS sequencing and evaluate the genetic diversity these sampless using RAPD and ISSR markers. 12 Cordyceps accessions were identified as Cordyceps militarisusingITS sequencing. 15 RAPD markers and 15 ISSR markers successfully detected 340 loci of which 291 were polymorphic and a total of 2092 scorable bands were obtained.The similarity coefficientof 12 Cordyceps spp. accessionsrangedfrom 0.568 to 0.841 when combined RAPD and ISSR markers, indicating high genetic diversity. At a genetic similarity of 0.7, the UPGMA dendrogram constructed based on RAPD and ISSR makers separated 12 Cordyceps accessions into three distinct clusters. The correlation analysis between the matrices of similarity coefficients using Mantel’s test revealed a strong correlation among matrices analyzed by RAPD, ISSR or pooled data. Our results could provide useful information for the exploitation and breeding of Cordyceps militarisaccessions.
Assessment and Prediction of Productivity of wild macrofungal species in the Central Highlands of Vietnam

Dang Thi Thu Huong, Nguyen Van Sinh, Nguyen Hung Manh, Bui Thi Tuyet Xuan, Nguyen Tien Dung

Received: 18-08-2023 / Accepted: 25-12-2023
The assessment of productivity of some important wild macrofungi helps us to predict the mushroom supply in different natural conditions and make recommendations on development of empirical models for achieving highest productivity. This study aimed to evaluate productivity of seven important macrofungi in the forest from 90 plots in 03 National Parks belongings to the Central Hiaghlands for nearly 3 years (from 2021 to 2023). The macrofungi included 6 edible species: Boletus edulisBull., Agaricus bisporus(J.E.Lange Imbach), Ramaria botrytoides(Pk.) Comb., Amanita caesarea(Scop.) Pers., Termitomyces eurrhizus(Berk.) R. Heim. and Auricularia nigricans(Sw.) Birkebak, Looney & Sánchez- García and 01 medicinal species: Ganoderma lucidum(Curtis) P. Karst. to build the predicted models for them. The method of collecting and determining the fresh weight of edible mushrooms in the field was carried out weekly from May to November every year. The average yield of Ganoderma lucidumwas the highest at 19.22 ± 2.95 kg-1ha-1year and the lowest of Ramaria botrytoides: 2.42 ± 0.54 kg-1ha-1year. Using the quadratic polynomial function to build predicting models, 07 prediction models were built for each mushroom species and 04 predicting models for each National Park and in the Central Highlands with sufficient reliability as shown by high determination coefficient (R2 = 0.7518-0.9909).
EnhancingTechnical Efficiency ofDairy Farmers Through Value Chain Financing: ACaseStudy in Duy Tien Town, Ha Nam Province

Bui Thi Lam, Le Thi Thanh Hao, Bui Thi Nga, Vu Ngoc Huyen

Received: 28-07-2021 / Accepted: 20-11-2023
This study was conducted to analyzethe determinants ofdairyfarmers’ technical efficiency in Duy Tien town, Ha Nam province by using Stochastic Frontier Analysis (SFA). Research results show that the technical efficiency of localdairy farmers reached 77.8%, ranging from 13.8% to 96.9%. To improve thetechnical efficiency, dairy farmers need to change in the input usage, such as: (i) reducing synthetic feedsand increasing green ones; (ii) paying more attention to disease prevention and treatment (i.e., veterinary cost); (iii) increasing breeding areas; (iv) moving dairy farming from residential areas to concentrated livestock areas; and, (v) scaling up the herd size to achieve the economies of scale. In addition, receiving technical support from purchasing enterprises (internal finance) and accessing banking credit (external finance) play important roles in improving technical efficiency and income of households. These are the two core activities in the agricultural value chain financing approach, howeverthis approach is still not popular in Vietnam.
Antibiotic Resistance and Production of Extended Spectrum β-lactamase (ESBL) of SalmonellaIsolated from Pork and Chicken Meat in Local Markets of Soc Son District, Ha Noi

Cam Thi Thu Ha, Hoang Minh Duc, Pham Hong Ngan

Received: 10-08-2023 / Accepted: 20-11-2023
This study was conducted to identify anti-biotic resistance profile and ESBL- encoding genes of the Salmonellaisolates from one hundred meat samples (50 chicken and 50 pork samples) randomly collected in local markets in Soc Son district, Ha Noi. The results showed that Salmonellawere detected in 41.0% samples, of which 42.0% of chicken samples and 40.0% of pork samples were positive for Salmonella. The isolates exhibited highly resistance to tetracycline (97.56%), flofenicol (78.05%) and ampicillin (63.41%), but low resistance to ceftazidime (7.32%), ciprofloxacin (7.32%). However, all isolates were susceptible to meropenem and colistin. Notably, 68.29% of Salmonellaisolates were multi-resitant strains. 6/41 (14.63%) Salmonellaisolates produced ESBL, in which, one isolate carried blaCTX-M-9gene, three isolatescarried blaTEMgene, one isolatecarried blaCTX-M-1and blaCTEM, and one isolatesimultaneously carried blaCTX-M-1, blaCTX-M-8/25, blaCTEMgens.
Evaluation of Growth and Development of Tisue Culture-derived Plants ofFour GerberaDaisy (Gerbera jamesonii) Cultivars

Pham Thi Huyen Trang, Phung Thi Thu Ha

Received: 21-03-2023 / Accepted: 05-10-2023
Gerbera, which is diverse in colors and types of flowers, is a high valuecut flower in both the domestic and international markets. This study aimed to evaluate the growth and development of tisue culture derived plants of four cultivars of Gerbera (Red, Pink, Orange, and Yellow). The experiment was designedin a randomized completeblock design. The study results showed that, in the nursery stage, tissue culture plantlets had 83.33-100% survival rate, with 6.9-8.3 leaves/plant, and plant height in the range of 6.44 to 7.28cm after 1.5 months of transplanting. In the production stage, the survival rate of all four Gebera cultivars reached 100%, with 9.4-11.4 leaves/plant, and 26.95-34.05cm in height after 3.5 months of transplanting. The flower stalk diameter of four Gebera cultivars ranged from 5.55 to 6.13mm, and the flower stalk height reached from 39.67 to 46.14cm. The maximum head diameter of four cultivars reached 8.65-9.41cm. The head longevity from bud to fade was29.20-31.70 days. The head inflorescence longevity from fullbloom to fade was8.80-12.40 days. All four studied Gerbera cultivars grewand developed well and wereless affected by pests and diseases, suitable for planting in Gia Lam, Hanoi.
Evaluation of the Pathogenicity of Streptococcus AgalactiaeSerotype Ia and III in Tilapia under Experimental Challenges

Doan Thi Nhinh, Nguyen Vu Son, Dang Thi Hoa, Nguyen Thi Thuy Hang, Ngo Phu Thoa, Nguyen Thi Huong Giang, Kim Van Van, Dang Thi Lua, Truong Dinh Hoai

Received: 20-06-2023 / Accepted: 05-10-2023
The study was conducted to evaluate the pathogenicity of Streptococcus agalactiaeserotypes Ia and III causing disease in tilapia. A total of 10 isolates of suspected S. agalactiaeretrieved from diseased tilapia in northern Vietnam in 2022 were used for identification by biochemical method and by PCR assays and serotyping by multiplex PCR. The results revealed that of 10 identified isolates of S. agalactiaeseven isolates belongedto serotype III (ST III) and three others belonged to serotype Ia (ST Ia). The experimental challenges on tilapia of the representative of each serotype showed that fish infected with the ST III isolates caused early and faster death than those of the ST Ia isolates. However, there existed no significant difference in the cumulative mortalities of 14 dpi between the two serotypes. The LD50of the ST Ia and ST III isolates were at 2.5 × 104and 1.9 × 104CFU/fish, respectively. The clinical signs and gross and histopathological lesions of experimentally infected fish between serotype Ia or III were also similar. The circulation of S. agalactiaeST Ia and ST III in Vietnam wasreported for the first time in this study and their pathogenicity was characterized inlaboratory scale.

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