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Evaluation Cultural Practices for Improving Multiplication Rate of Sedge by Division

Hoang Duc Hue, Ninh Thi Phip, Nguyen Tat Canh

Received: 10-03-2014 / Accepted: 15-07-2014
Sedgeor matgrass is mainly propagated by division. The present research aimed to evaluate the effects of granular fertilizer, foliar fertilizer, narrow-wide row arrangement and shoot cut on multiplication coefficient of two elite sedge varieties, MC005 and MC015, by division method.The results indicated that application of granularfertilizer(16:7:12)and foliar fertilizer Atomik 1.8,shootcuttwiceper season, and 15 -15 -30 cm row spacing appeared as appropriatecultural practicesfor increasing multiplication coefficient by division of sedge.
Growth and Survival Rate of SPF Vannamei Broodstock Candidate (Litopenaeus vannamei) Cultured in Indoor System at Different Stocking Density on Cat Ba Islands, Hai Phong

Vu Van Sang, Le Van Nhan, Nguyen Phuong Toan, Nguyen Huu Ninh, Tran The Muu, Vu Van In

Received: 03-08-2012 / Accepted: 25-09-2012
Litopenaeus vannamei) cultured in biosecurity system. Three groups of experimental shrimp (initial weigh 20.1±1.9 g/male and 21.4±2.2 g/female) were stocked at densityof10, 20 and 30 heads/m3in4m3indoor tank system. Each treatment was run in triplicate and fed with about 4% shrimp weight daily with pellet diets of CP 7704S and 7704P (38% crude protein), feeding four times a day. The water temperature ranged from 20.0 - 28.5oC and salinity ranged from 20-28‰. Water was renewed 80% volume weekly. The highest growth rate in weight was recorded in broodstock candidates cultured at 10 heads/m3(1.03 g/week/male; 1.11 g/week/female), followedby 20 heads/m3(0.89 g/week/male; 0.98g/week/female) and the least for 30 heads/m3(0.53 g/week/male; 0.62 g/week/female). Similarly, survival rate of shrimp at 10 heads/m3(71.7 ± 2.7%) ranked highest and the lowest rate for the 30 heads/m3 (60.1 ± 2.8%; P<0.05). Nevertheless, there is no significant difference in the survival rate between shrimp cultured at 10 heads/m3(71.7% ± 2.7%) and 20 heads/m3(71.5 ±3.0%; P>0.05). Size variation (CV%) and FCR recorded on 10 heads/m3 (CV%: 6.34 ± 1.12%; FCR: 2.78 ± 0.5) and 20 heads/m3(CV%: 6.68 ± 1.20%; FCR: 2.86 ± 0.3) were found remarkably lower than that for 30 heads/m3(CV%: 10.56 ±2.24%; FCR: 3.42 ± 0.8; P<0.05). The percentage ofshrimp harvested thatmet the criteria of broodstock was 67.1 ±2.6% and 66.7 ± 3.2% for the 10 and 20 heads/m3, respectively, whereasonly 23.1 ± 5.4% for the 30 heads/m3. All shrimp sample tissues were found negative for WSSV, YHV, TSV, MBVandIHHNV.
Pathological Characteristics inPhu Quoc Dog Infected with Canine Distemper and Application of Immunofluorescencefor Diagnosis

Nguyen Thi Lan, Khao KEONAM

Received: 12-05-2012 / Accepted: 29-10-2012
The clinical symptoms and pathological characteristics of Phu Quoc dogs infected with Canine Distemper Virus (CDV) were studied. The first clinical signs of infected dogs were high fever, loss of appetite or not eating, vomiting or coughing, sketchy notes in abdominal skin, diarrhea and neurologic signs - walking in a circle. The gross changes were mainly found in lung and intestine including congestion and hemorrhage in lung and intestine, congestion in brain. The other gross changes were enlarged spleen, lymph nodes, swollen gall bladder, and degenerated liver. The microscopic findings were mainly in lung, intestine and brain. There were lots of red blood cells in alveoli, inflammatory brain cells, alveoli and damaged villi of intestine. In the present research, the distribution of CDV in different organs of dogs was identified by using immunofluorescent test.
Theoretical Considerationsand Practical Issues of Low Carbon Rice Farming for Transferring Farming Practices to Reduce Greenhouse Gas Emmissions in SomeProvinces in The Mekong Delta

Tran Thu Ha, Do Kim Chung

Received: 18-06-2014 / Accepted: 01-09-2014
The low-carbon rice farming technique has proven to deliver the triple wins that include economic, social and environmental benefits from the reduction of inputs (seed, fertilizer, agro-chemical and water); increase of rice yield, increase the social linkages among rice farmers in their communities by the sharing the common farming practices; and at the same time reduce significantly the greenhouse gas emissions from rice cultivation, protection of the water resource from pollution and the overdose as well as the ecological system. The low carbon rice farming technique is therefore urged to scale-up through the transfer of technology to the intensive rice cultivation provinces. In order to understand thoroughly about this low carbon rice farming technique and its essentiality, this paper discusses the concepts, essentiality, characteristics and the key major factorsaffecting the effectiveness and efficiency of the process of technology transfer. At the same time, this paper also seeksto discuss and draw the experience and lesson learnt in applying and implementing the low carbon rice farming technique from both foreign countries and within Vietnam in order to consolidate the theoretical and practical issues of this contemporary advanced farming technique.
Vibration Analysis of Functionally Graded Plates Using Higher Order Shear Deformation Theories (HSDT)

Duong Thanh Huan, Duong Thanh Huan, Le Minh Lu

Received: 02-10-2014 / Accepted: 25-11-2014
A higher order shear deformation theory (HSDT) was presented for free vibration analysis of simply supported (diaphragm), elastic functionally graded (FG), rectangular, plates. Functionally graded materials (FGMs), although heterogeneous,are idealized as continua with their mechanical properties changing smoothly with respect to the spatial coordinates.. Poisson’s ratio was assumed to beconstant,buttheirYoung’smodulianddensitiesvarycontinuouslyinthethicknessdirectionaccording to the volume fraction of constituents, which is mathematically modelled as power law function. The equations of motion were obtained using Hamilton’s principle employing HSDT. Navier’ssolution was used to solve the equations ofmotion. The effect of variation of material properties in terms of gradation index,the effects of aspect ratios, thickness-to-side ratio on the natural frequencies of FG plates werestudied in this article. The numerical results were compared with results available in the literature to validate theoretical model of the paper.
Effects of Temperature on Embryonic Development and MalflormationEof Pompano,Trahinotus blochii

Tran Thi Mai Huong, Nguyen Thi Nien, Dam Thi My Chinh, Le Van Khoi, Nguyen Huu Ninh

Received: 27-07-2016 / Accepted: 28-12-2016
The experiment of the effect of temperatureeffecton embryonic development and malformation of pompano (Trachinotus blochii) was carried out at the Northen National Broodstock Center for Marine aquaculture oin Cat Ba, Hai Phong, Vietnam. Five temperature levels of 24oC, 26oC, 28oC, 30oC and 32oC were studied with 3 replicates each. The results showed that,there was a significant differencetbetween five treatments in terms of hatching, deformity and survival rates. The result indicated that the significant highest hatching rate was 47.7% at 24oC. The lowest deformity rate was observed at 24oC (3.3%) but no significant difference was found between 24oC, 26oC and 28oC. The survival rate was higher at 26oC (58,6%) and 28oC (58,2%) after five days of post-hatching than other. The results show that sSuitable temperatures for pompano incubation are ranged from 24oC to 28oC. At 26oC and 28oC, the lowest deformity rate (3,98 - 4,20%) and the highest survival rate (10.48% and 10.69%) after 40 days of post hatching were recorded. From this study, the temperature rangedfrom 26 - 28oC are recommended for pompano rearing.
Effect of Medium and Cutting Type on asexual Propagation of Butterfly Ginger lily (Hedychium coronarium Koenig) by Aerial Stem Cuttings

Nguyen Thi Thuy Hanh, Phung Thi Thu Ha, Pham Thi Huyen Trang, Trinh Mai Dung

Received: 05-09-2023 / Accepted: 26-01-2024
Butterfly ginger lily belongs to the Hedychium genus including 80 species, and is one of the important and popular genera of the Ginger family (Zingiberaceae). It has both medicinal and horticultural uses. The research aimed at studying the possibility of asexual propagation of butterfly ginger lily by aerial stem cuttings contributing a new propagation method for Butterfly ginger lily in particular as well as for other plants in generally. The experiment on propagation media and aerial stem cutting type of butterfly ginger lily were arranged in a randomized block design with three replications. The results showed that the medium containing smooked rice husk : sand (1: 1 in volume) and aerial stem cuttings with 2 nodes were the most suitable for asexual propagation of butterfly ginger lily by aerial stem with sprouting time of 10 days after planting and shoots reaching 20.2cm in length, 0.74cm in diameter, with7.8 leaves/shoot and 7.4 roots/shoot and roots of 7.0cm long.
Alternaria Leaf Spot Diseaseon Cabbage (Brassica oleraceaL. var. capitata) in Nghe An Province

Nguyen Xuan Canh, Nguyen Xuan Truong, Nguyen Thi Thu, Vo Thi Bich Thuy, Dang Thi Thanh Tam, Nong Thi Hue, Pham Hong Hien

Received: 30-08-2023 / Accepted: 05-01-2024
The study was conducted to isolate and identify the causal agent of leaf spot disease on cabbage (Brassica oleracea L. var. capitata) in Hung Tien, Nam Dan, Nghe An province. Ten symptomatic cabbage leaves were collected from three diseased fields. Morphological examination revealed that only one type of fungus (designated as BC01) was isolated from the cut surface of the diseased leaf pieces. The isolate BC01 had dark olive colonies, white margin, cottony mycelium, branched conidial chains, brown oval or ellipse conidia shape with a short cone-shaped beak at the head, 0-3 longitudinal septa and 1-5 transverse septa. The conidial size ranged from 10.17 to 40.06 × 4.16 to 13.09µm. Based on the ITS gene sequence analysis and morphological characteristics, the isolate BC01 was identified as Alternaria alternata. After 7 days of re-infection, the symptoms on the re-infection leaves were similar to those on the isolated leaves. At the site of infection, the fungal mycelium grew densely and invaded deep into the leaf tissue, while the control leaves showed no symptoms.
Evaluating Properties of Mycelial Growth and Effect of the Wheat Bran Ratio on Formation and Fruiting Body Development of Golden Lingzhi Mushroom Strain(Tomophagus cattenensis)

Nguyen Thi Huyen Trang, Ngo Xuan Nghien, Tran Dong Anh, Nguyen Thi Luyen, Nguyen Thi Bich Thuy

Received: 15-08-2023 / Accepted: 25-12-2023
The golden lingzhi strain Toc1 (Tomophagus cattienensis)is a new strain that was discovered in the Cat Tien National Park in Đong Nai provine and it was identified to be a precious mushroom species. In this study, mycelial of strain Toc1 were incubated in 4 temperature levels (20 ± 1C, 25 ± 1C, 30 ± 1Cand 35 ± 1C); culture medium supplemented 5 different carbon sources (glucose, fructose, saccharose, maltose and lactose), 5 different nitrogen sources (yeast extract, peptone, ammonium clorua, ammonium nitrate and ammonium sulfate), 6 mineral salt sources (kali cloride, kali nitrate, natri nitrate, dikali phosphat, kali dihydrophosphat and magie sulfate). Beside that, mycelial of this strain were cultivated in 4 substrates added different wheat bran ratio (0%, 5%, 10% and15%). This study aims to figue out the optimal temperature, the suitable carbon, nitrogen and mineral salt source for mycelial growth of golden lingzhi mushroom strain Toc1 and also evaluating effect of the wheat bran ratio, which was supplemented on substrate, on formation and fruiting body development of this strain. The results showed that the optimal temperature for mycelial growth is 25C±1. Glucose and yeast extract were considered the most suitable carbon and nitrogen sources for mycelial growth. This strain grew very well on culture supplemented K2HPO4. The substrate containing 89% sawdust, 5% corn powder, 1% CaCO3and 5% wheat bran performed the highest BE, reached 15,97%.
Application of the Law of Diminishing Returns in Sustainable Development of Livestock Production - an Integrated Review

Nguyen Xuan Trach

Received: 17-04-2023 / Accepted: 29-08-2023
The law of diminishing returns(LDR) has been applied in numerous fields, including livestock production, to determine the optimum level of a certain variable input. This integrated review tries to synthesize and discuss the appropriateness of LDR in describing profiles of livestock yields and grass regrowth after each cutting in response to to increased levels of a variable production input, as well as to analyse and generalize major applications of the law in determining the optimum levels for a number of important variables such as slaughtering age, feeding level, nutrient contents in the ration, grass cutting interval, herd size, stocking density, etc. in order to balance economic profit, social justice, environmental protection, and animal welfare, thus ensuring sustainable development of livestock production.
ComparativeAnesthesia Effectiveness ofInhalation Isoflurane andIntravenousZoletil 50 forHysterectomizein Cats

Dinh Phuong Nam, Nguyen Thi Giang, Pham Hong Trang, Nguyen Thi Ngoc, Nguyen Van Phuong, Tran Van Nen, Nguyen Van Hai, Le Van Hung, Ngo Thi Hanh, Nguyen Duc Truong, Nguyen Thi Huong, Nguyen Thi Thanh Huong, Vu Van Dung, Duong Thi Ha Ly

Received: 07-07-2021 / Accepted: 10-01-2022
A comparative study was conducted to evaluate the effectiveness of anesthetic methods in surgical surgery on catsat the Veterinary Hoaspital, Vietnam National University of Agriculture. A total of 20 selected experimental cats were devided into two groups, in which 10 cats were inhalative anesthetized using isoflurane (2-3% starting doseand maintain at 1-2% throughout surgery);and 10were anesthetized using intravenous injection with Zoletil 50 (13 mg/kg P). The results showed that inhalative anesthesia produced more stablize status of cats during surgery in term of body temperature, heart rate and blood pressure. In addition, the blood oxygen concentration of the inhalative group fluctuated between 93-95% and significantly higher than injection method. Moreover, cats in inhalative anesthesia group shows minor pain reflexes after surgery and 80% of cat have no hysterical reaction. On the other hand, disturbance were observed in 70% of cats in injection anesthesia group. Thus, inhalative anesthesia using Isoflurane is stable, safe and may become the prefered method for feline surgical anesthesia.
Distribution of Larvae and Juveniles of Beloniformes in the Ba Lat Estuary, Northern Vietnam

Ta Thi Thuy, Nguyen Thi Huyen Trang, Pham Thi Ngoc Diem, Nguyen Thi Nga, Tran Duc Hau

Received: 31-05-2021 / Accepted: 09-12-2021
Coastal fisheries play an important role for local residents. The Ba Lat estuary is a significant area for aquatic organism recruitment or serves as nurseries for many fish species. Beloniformes has 275 species of 6 families in the world and 30 species of 3 families in Vietnam. Many species occur in estuarine habitats, even inhabit freshwater, but little is known about their early stages. The present study aims to provide species composition of larvae and juveniles of this order, and examine their distribution in estuary and mangrove forests. From 431 collected specimens, primarily postflexion larvae and juveniles (5.0-174.6 mm body length)during surveys between 2018 and 2020 using a small seine net at 19 stations along the bank water of the Ba Lat estuary of the Red River, the study identified five species of this order (i.e.,Strongylura strongylura, Hyporhamphus limbatus, Hyporhamphus far, Zenarchopterus buffonisandZenarchopterus sp.). This is the first record of early stages of Beloniformes in the Ba Lat estuary, northern Vietnam. Larvae and juveniles of the Beloniformes appeared at all stations (many were distributed at stations with mudy-sand, sandy-mud bottoms and mangrove forests), mainly in the rainy season, at the mean temperature range of 23.1-31.6C and salinity 0.1-12.5‰. They showed different tendencies in distribution patterns indicating that bottom sediments, water temperature, salinity and mangrove forests were important factors related to the distribution of larvae and juveniles of the Beloniformes in the study site. Especially, occurrences of two abundant species, H. limbatus andZ. buffonis, would have been an evidence for the distribution pattern of early stages of the Beloniformes in the Ba Lat estuary.These findings are valuable for conservation, exploitation and culture of species of this order in Vietnam.
Ecological Characteristics of Seaweed Communities at Phu Quy Archipelago, Binh Thuan province

Dinh Thanh Dat, Do Anh Duy, Tran Van Huong

Received: 31-08-2020 / Accepted: 06-05-2021
This study aimed to obtain more knowledge about the ecological characteristics of the natural seaweed communities in the coastal areas of Phu Quy archipelago, Binh Thuan province. Usingthe line-intercept method and SCUBA diving, we conducted a study of24 survey stations in the coastal areas of Phu Quy archipelago from 2017 to 2018. The results showed that a total of 136 species belonging to 36families, 21 orders of 4 seaweed phyla was identified. Of the identified scpecies, the red seaweed (Rhodophyta) was the most abundant group with 67 species(44.85%). The seaweed species in Phu Quy archipelago were recorded in the tropical floras (P = 3.3). The seaweed species were mostly concentrated on hard bottomsfrom the tidal zone to the sub-tidal zone and a depth of 20m. The high biomass and density of seaweed were calculated at Hon Tranh Island. For example, the average coverage of seagrapes (Caulerpa) was 100% and the wet biomass weight from 500 to 10,880 g/m2in Hon Tranh Island; the coverage of brown seaweed (Sargassum) was from 35 to 60% and the wet biomass weight from 600 to 6.200 g/m2in the Mo Thay area, the East and Northwest of Phu Quy island. These research results are scientific bases for the conservation and development of seaweed communities in Phu Quy archipelago.
Variation in Morphometric Characteristics of Glossogobius aureusDistributed from Can Tho to Ca Mau

Phan Hoang Gieo, Dinh Minh Quang, Truong Trong Ngon, Nguyen Huu Duc Ton

Received: 19-02-2021 / Accepted: 12-03-2021
This study aimed to provide information on the morphometric variations of Glossogobius aureus, a commercial fish species in the Mekong Delta. A total of 742 individuals (282 males and 360 females) were collected during the dry and wet seasons (January 2020 to December 2020) at four studied sites (Cai Rang, Can Tho; Long Phu, Soc Trang; Hoa Binh, Bac Lieu; and Dam Doi, Ca Mau). The results showed that total length and body weight of this species varied along with seasons and studied sites, but not genders. There were no significant differences in all morphological characteristics were not significant difference except the body length and weight variations of the immature and mature fish. The studied site and season variables influenced the total length and body weight of this species. The results of the present study have provided useful information for this species identification and understanding of the ecological adaptation of the fish in the study locations.
Evaluation of Agronomical Characteristics of Ginger Lily (Hedychiumspp.) Accessionsin Gia Lam - Hanoi for Ornamental Purpose

Trinh Thi Mai Dung, Vu Van Liet, Nguyen Thanh Hai, Phung Thi Thu Ha

Received: 01-07-2020 / Accepted: 03-03-2021
Hedychium(ginger-lily)genus, belongs to Zingiberaceae familyand is not only known as medicinal plants but also ornamental materials. Our study focused on evaluating the characteristics of growth, development, and flower quality of five ginger-lily accessions, collected in some Northern provinces of Vietnam and planted in Gia Lam, Hanoi for ornamental purposes. The experiment was arranged in blocks of non-repeating sequence, each accession being as one block. The results showed that five ginger-lily accessions grew all-year-round, lacked the withering stage, flowered from July to November, had the height of plants from 90.5 to 168.8 cm, with slight pest damage. The flowers of all accessions were fragrance with the milky white perianth, except the NT3 had bright yellow perianth. Five ginger-lily accessions hadlongevity of spike from 15 to 27 days, a big spike with 8.5 to 29.2cm in length and 1.9 to 8.5cm in diameter, number of bracts on a spike from 8 to 30, number of flowers on the bract from 2 to 7 flowers/bract, number of the spike on a clump from 1 to 4 spike/clump. In conclusion, all five accessions were well suited to develop decorative landscaping and cut flowers purpose.
The Association of Insulin and Insulin Like Growth Factor Binding Protein 2 Gene Polymorphismswith Body Weight in Lien Minh Chicken

Tran Thi Binh Nguyen, Nguyen Thi Thanh Tra, Do Thi Thu Nguyet, Nguyen Huu Duc, Le Cong Toan, Nguyen Thi Dieu Thuy, Nguyen Manh Linh, Hoang Thi Yen, Vu Cong Quy, Vu Duc Quy, Pham Thu Giang

Received: 10-06-2020 / Accepted: 19-08-2020
Lien Minh chicken is an indigenous breed with several favorable propertiesand associated with the economic development of the people in the Lien Minh village, Cat HaiDistrict, Hai PhongCity. Chicken Insulin (INS) and Insulin-like growth factor binding protein 2 (IGFBP2) are physiological candidate genes involved in the growth traits. This study aimed to investigate the association of single nucleotide polymorphism (SNP) of INS and IGFBP2genes concerned with bodyweight inLien Minhchicken.The indexes for 100 Lien Minh chickens were observed individually about their body weights from 01 day to 20 weeks age.Blood samples were used for DNA extraction and then genotyping by PCR-RFLP method. Two SNPs of INSandIGFBP2genes were analyzed. Allele frequencies ofINSand IGFBP2were: A (0.65), G (0.35) and A (0.46), T (0.54), respectively. Genotype GG INSshowed the highest values of mean body weight at 14, 16weeks of age for hen, 18 weeks of age for cock (P <0.05), and genotype AAof IGFBP2 (IGFBP2)wasalsoshown thehighest values of mean body weight at 20 weeks of age. These results suggested that the beneficial alleles/genotypes could be used to support the improvement of the egg production capacity in the breeding of Lien Minh chicken.
Study on Induced Spawning Whitespotted Clarias (Clarias fuscuslacepède, 1803)

Luu Van Bien, Thai Thanh Binh, Nguyen Duc Khiem

Received: 12-06-2020 / Accepted: 14-09-2020
Whitespotted Clarias is an indigenous and economically valuable species in North Vietnam. However, seed resources have not meet farmers’ demands. The research to induce spawning of Whitespotted Clarias was conducted with 03 treatments: NT1 = 4,000IU HCG; NT2 = 100µg LRHa + 10mg Dom; NT3 = 2,000IU HCG + 50µg LRHa + 5mg Dom/kg female fish. The dose of drug was injected for male fish with 1/3 of that for the female fish. Each treatment used 35 females and 17 males. Water temperature ranged from 25-27C. The results showed that after 11-14h injection hormones fish spawning. The highest spawning rate, fertilization rate and hatching rate were 92.38 ± 8.73%; 72.86 ± 4.07%; 75.41 ± 1.23%, respectively obtained from NT1. There was no significant difference between treatment NT1 and treatment NT3 (P >0.05). The fry production ranged from 7.187 to 8.750 fish/kg female fish. The time to hatch Whitespotted Clarias eggs is about 31h 20m. The research results are the scientific basis for the development of the techniques producing seed Whitespotted Clarias in North Vietnam.
Influence of Nitrogen Fertilizer Rate on the Growth and Yield of Ly Son Garlic (Allium sativumL.) Plants in Sandy Soil at Quang Dien Commune, Thua Thien Hue Province

Phung Thi Bich Hoa, Pham Thanh

Received: 26-02-2020 / Accepted: 22-06-2020
Ly Son garlic (Allium sativumL.) is a high economic value crop. This is one of the first reports to evaluate the effect of nitrogen fertilizer application rate on the growth, development and yield of Ly Son garlic grown on the sandy soil inThua Thien Hue, Viet Nam. Four nitrogen fertilizer levelwere selected and tested in this study: 230kg N ha-1, 55kg N ha-1, 115kg N ha-1, 165kg N ha-1. Theresults showed that A. sativumwas suitable for growing and developing under the natural conditions of Thua Thien Hue. The growing duration of A. sativumranged from 120 to 145 days. Furthermore, the traditional fertilizer dosage (230kg N ha-1) gave the lowest yield;while, the nitrogen fertilizer level of 115kg N ha-1was the best treatment,which resulted inhigh yield and good growth in terms ofthe number of leaves per plant (6.1 leaves), pseudostem height (12.1cm), the weight of fresh bulb (5.73g), the weight of dry-bulb (0.45g) and the yield of A. sativum(6.03 t/ha), respectively. This result also demonstrated that the agro-biological characteristics, yield parameters such as bulb diameter and length, number of cloves per bulb of A. sativumplanted in that area have not been different comparing with the originally planted garlic grown in the areas of Ly Son, Quang Ngai province.
Correlation between Density of Vibriospp. and Salinity in Shrimp Pond

Truong Thi My Hanh, Kim Van Van, Huynh Thi My Le, Phan Thi Van

Received: 09-01-2017 / Accepted: 24-04-2017
This study investigated the relationship between the salinity and development of Vibriobacteria inthefield and laboratory conditions. A totalof 90 water samples were collected from 9 ponds at timescorresponding tof 10 different salinities. Three strains of bacteria.V. parahaemolyticus, V. vulnificus14.2 and V. vulnificuswere experimentally culured in different conditions of salinity (3, 15, 25, 35 and 40 ‰). V. choleraewas cultured in sterilized shrimp pond and distilled water. The densities of bacteria in shrimp pond water samples and cultured mediawere measured. Research results showed that there was a correlation between bacterial density and salinity inpond water environment as well as in experimental culture media. The correlation coefficient betweenVibriospp. and salinity in the pond was 0.75 (P <0.05); betweenV. vulnificus17.5 and the salinity was 0.69 (P <0.05). V. cholearedensity in sterile water pond was (7,5 x 106), significantly higher than that in distilled water (1.3 x 102colonies/ml). However, the growth of V. vulnificus14.2 and V. parahaemolyticuswas not significantly correlated withsalinity ( r =0.19 and 0.17), respectively. Research showedthat salinity can have an important role in disease outbreak caused by Vibrio.
The Effectof Potassium Chlorideon the Productivity and Quality of Allium fistusolumL.

Vo Minh Thu

Received: 25-07-2014 / Accepted: 04-06-2015
Allium fistusolumL.is a spicy vegatable containing variousnutrients beneficial to the human body, suchas vitamins and mineral elements. In addition, onionscaneliminatestinking/discomforttastes and excite apatite. There are several cultural practicesavailable to increase in the productivity and the quality of Allium fistusolumL, including the fertilization withmacronutrients.An experimental was carried out in Phu Cat district of Binh Dinh province to determine the effect of different KCl levels (160 kg K2O to 220 kg K2O hecta-1) on yield and quality of Allium fistusolum.The onion bulbs were planted in slight loam substrate.Theresults showed that applyingKCl at 190 kg K2O per hectare yielded in high bulb yield, larger bulbsizeand weight and higher dry matter content, reducing sugars, vitaminsCand PPand minerals in comparison with other KCl rates.
In vitro Propagation ofSalvia miltiorrhiza Bunge

Le Tien Vinh, Ninh Thi Thao, La Hoang Anh, Nguyen Thi Thuy, Nguyen Thi Phuong Thao

Received: 06-06-2014 / Accepted: 10-08-2014
Salvia miltiorrhiza Bunge, one of the high-valued medicinal plants, is mainly used for the treatment of cardiovascular and cerebrovascular diseases. This study was conducted to establish the procedure for in vitro propagation of Salvia miltiorrhiza Bunge with the aim of preservation and development this precious medicinal species. The highest seed germination of 40.43% was observed on MS medium supplemented with 1.0 mg/l GA3 within 2 weeks. The seedling nodal explants (approximately 2-3 cm in height and one axillary bud) were used as source of in vitro propagation. The multiplication rate was highest (5.05 shoots/explant) after 4 weeks of culture when MS with 0.5 mg/l BA was used. α-NAA, IAA or IBA had positive effect on in vitro rooting of shoot. The optimal medium for in vitro rooting was MS medium containing 0.75 mg/l IAA, on which 100% of shoots induced roots with a mean of 6.19 roots/plant within 4 weeks of culture. In vitro plantlets after 30-days period of rooting were the most appropriate for successful acclimatization in greenhouse. Survival percentage of planlets was 100% in the substrate containing 50% of coconut fiber and 50% of sand and acclimatized plantlets showed good growth and development.
Biological Characteristics of Cassava Witches’ Broom Disease Related to Phytoplasma in Dongnai Province

Nguyen Duc Thanh, Mai Van Quan, Ngo Gia Bon, Nguyen Huu Hy, Ha Viet Cuong, Trinh Xuan Hoat

Received: 04-04-2014 / Accepted: 09-06-2014
In Vietnam, cassava witches’ broom is an important disease in cassava production. Phytoplasma, 16SrI group-‘Candidatus Phytoplasma asteris’ is the causal agent associated with cassava witches’ broom disease. In this study, leafhopper species were collected by using light traps. Total DNA was extracted from the insect species and the symptomatic plants. Nested polymerase chain reaction assay was used to detect the presence of phytoplasma. Amplification of a fragment 1100 base pair 16S rDNA gene confirmed that insect bodies were infected by the phytoplasma. Restriction fragment length polymorphism analysis using EcoRI and HaeIII endonucleases revealed the insignificant difference between the test samples. Cassava witches’ broom disease is transmitted by cutting through vegetative propagation using diseased plants under screenhouse or field conditions. Whitefly (Aleurodicus dispersus), mealybug (Paracoccus marginatus) and red mite (Tetranychus urticae) do not transmit phytoplasma although they fed on cassava plant in the field.
Prevalence of Foot-and-Mouth Virus Infection and Risk Factors in Hotspots in Vietnam from October to December 2012

Nguyen Thu Thuy, Nguyen Van Long, Phan Quang Minh, Tran Thi Thu Phuong, Nguyen Quang Anh, Nguyen Ngoc Tien, Nguyen Dang Tho, Ngo Thanh Long, Nguyen Ba Hien

Received: 25-03-2014 / Accepted: 26-04-2014
A cross-sectional study together with a case-control study was carried to estimate the prevalence of foot-and-mouth (FMD) virus infection in animals in three provinces (Lang Son, Nghe An and Kon Tum) from October to December 2012. Serum and probang samples were taken from 884 cattles and buffaloes of 590 households. Information about risk factors were collected using a standardized questionnaire. Data analyses showed that FMD antibody was detected in all three provinces with a high level of 24.21% (95% CI 21.42-27.17) at the individual level and 29.83% (95% CI 26.16-33.70) at the household level; FMD virus belongs to serotype O and A. Cattles procured from unknown sources were a major risk factor, with the odds ratio (OR) of 5.27 (95% CI 2.22-12.52) times the OR for cattles kept by households. Control measures should be strictly taken at the household level. In addition, management of animal movement should be improved to stop spreading FMD virus.
Recovery of vitamin E from deodorzing destillate of soybean oil purification

Bui Thi Bich Ngoc, Ly Ngoc Tram, Vu Duc Chien, Bui Quang Thuat

Received: 24-10-2013 / Accepted: 26-12-2013
Deodorizing distillate - major by-product from purifying soybean oil, which contains three high value compounds like fatty acids, tocopherols (vitamin E), and phytosterols, is useful material for obtaining vitamin E. Firstly, deodorizing distillate was dehydrated by Na2SO4 and then free fatty acids in deodorizing distillate were converted to ethyl esters with concentrated H2SO4 catalyst and 20 ; 1 ethanol : deodorizing distillate ratio (mol/mol) at 700C for 80 minutes. Secondly, the product mixture of ethyl esterification reaction was evaporated, alcohol and acid removed by water washing. Ethyl esters of fatty acids were removed by vacuum distillation at 5mbar and at 198 - 2250C. Phytosterols were separated from distillation bottoms by crystallization method with etanol at 50C to obtain crude vitamin E. It was extracted with two times ethanol, then crystallized at -150C to remove remnant phytosterol and other undesired substances. Finally, natural vitamin E with 90.8% purity was extracted on silica gel (0.063 – 0.200 m) column with eluted solvents, n-hexan : ethanol: 9:1.
Effect of Biochar and Foliar Fertilizer on Growth and Yield of Tomato Grown on Sandy Soil

Vu Duy Hoang, Nguyen Tat Canh, Nguyen Van Bien, Nhu Thi Hong Linh

Received: 29-05-2013 / Accepted: 16-09-2013
The study was conducted in net house to investigate the interactive effects of sandy soil amendment with biochar and foliar fertilizer on growth and yield of tomato. The experiment arranged in a Completely Randomized Design- CRD included three biochar levels (amendment 1%, 3% or unamended) and four kinds of foliar fertilizer with three replications were used. The result showed that biochar had significant effect on plant hight and leaves of tomato whereas foliar fertilizer did not affect on those of tomato. The interaction of biochar and foliar fertilizer increased significantly the number of fruits, individual fruit weight and yield of tomato grown on sandy soil. The individual yield of tomato was climbed by biochar amendment and supplement foliar fertilizer from 23.6% to 39.8% and from 43.0% to 66.8% respectively.

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