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Modeling and Investigating the Dynamical Turning Processof the Pneumatic Tire Tractorson the Field

Han Trung Dung, Bui Hai Trieu

Received: 04-09-2013 / Accepted: 10-11-2013
This paper presents a method for establishing a general model which enables to simulate tractor’s turning process and calculate its main characters in considering basic characteristics of engine, transmission system andinteraction between tyre wheels and flexible base pavement. The mathematical model which describes approximatively working characters of the farm tractor, can display general image for the ralation of kinetic and dynamic parameters when a farm tractor moves on the deformation ground. The boundary condition and the input parameters of the model can be defined from experimental studies.The built model has been applied in order to investigate qualitatively and quantitatively by digital computer the effects of some structure parameters and working condition on turning capacity of several popular farm tractors in Vietnam.
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.
Growth Performance and Feed Conversion Ratio of [BBB × F1(BBB × Lai Sind)] Crossbred Calvesfrom 6 to 12 Months of Age Raised in Hanoi

Tran Bich Phuong, Nguyen Thi Vinh, Nguyen Thi Nguyet

Received: 14-12-2020 / Accepted: 30-08-2021
The study was conducted to evaluate the growth performance and feed conversion ratio (FCR) of [BBB ×F1(BBB × Lai Sind)] crossbred calves raised in farm condition in Ba Vi district, Hanoi city, Vietnam. A total of 20 animals iconsisting of 10 male and 10 female calves from 6 to 12 months of age were used in this study. Calves were kept in individualy and fed a mixture of forage and concentrate. The results showed that [BBB ×F1(BBB ×Lai Sind)] crossbred calves grew well with good feed efficiency in farm conditions. Calves weighed 198.9 kg and 356.05 kg at 6 and 12 months, respectively. Average daily gain (ADG) in the period of 6-12 months of age was 873.05 g/head/day. Feed conversion ratio in the period of 6-12 months was 8.55 kg DM/kg. Gender affected body weight, ADG, and FCR (P<0.05). The male calves had higher body weight, ADG and lower FCR as compared to female calves.
Roles of Agricultural Production for Households in Peri-urban Areas: Case Study in Trau Quy Town, Gia Lam District, Hanoi

Nguyen Phuong Le, Le Van Tan

Received: 05-08-2013 / Accepted: 12-11-2013
Urbanization is an inevitable process in socio-economic development. In Vietnam, urbanization has been happening with bigger scale and higher speed. Urbanization has impacted on peri-urban livelihood strategies both positively and negatively. However, negative influences, particularly the reduction of farmland, unemployment and food insecurity, have been more concerned by researchers and policy-makers. According to several researchers, maintenance and development of peri-urban agriculture is one of the solutions to reduce negative impacts. Based on a combination of quantitative and qualitative research methods, this study shows that agriculture plays important roles in socio-economic lives of households in Trau Quy town. For economic aspect, agriculture contributes to households’ income, food security and safety, and generates job opportunities for family labours, especially for those who could not find new off-farm jobs in labour market. With regard to social roles, farmland property, livelihood security, and maintenance of traditional community relationship are considered as significant roles of suburb agriculture.
Design and manufacturing of automated greenhouse misting control system for vegetables during nursery stage

Ngo Tri Duong, Nguyen Thai Hoc

Received: 02-04-2013 / Accepted: 21-06-2013
Control system automatic spray irrigation is an important factor, determines the success of the whole system in greenhouse vegetable production covered. Especially the vegetables in the nursery phase has many favorable characteristics for development of the disease, so the problem of monitoring and care of seedlings in the nursery should be top priority . The design, manufacture spray irrigation control system is very important in maintaining moisture, control the rate of the nutrients as well as the concentrations of plant protection spray vegetables. This paper introduces the results of research, design and manufacture of control systems automatic spray irrigation over time and temperature. Operator when the system is working just install the desired temperature value then the system will automatically control ventilation, misting pump to continuously ensure the installation parameters. The system also allows the operator can choose the location of fresh vegetables need watering time depending on the needs of each vegetable for systems with a variety of vegetables are grown in the same greenhouse.
Effects of Packaging to Quality of Strawberry by Hyokan Technology

Nguyen Thi Hoang Lan, Ta Thu Hang, Doan Thi Bac, Nguyen Ngoc Cuong

Received: 02-03-2021 / Accepted: 26-04-2021
The study investigated suitable packaging materials for strawberry storage with Hyokan technology. Strawberries were harvested at 80% full-ripen when the fruit skin changed to red and stored using Hyokan technology at -2C, electric pressure 3.500V. Four packaging materials were investigated, including PE foam, PE clings film, filter paper and plastic box. The control sample was kept at 2-4C in a regular refrigerator. The control sample showed a significant decrease in sensory quality, nutritional quality and microorganisms. The fruit covered by PE cling film (CT5) had the best nutritional quality and sensory score, and microorganism. By using the Hyokan technology and PE cling film, after 21 days storage, the weight loss was 0.31%, waste 13.89%, TSS 7.83Bx, total axit1.15% and vitamin C 13.38 mg/g; the sensory score was a distinction; the total aerobic microorganism was within the standard 46/2007 QĐ-BYT.
Effects of Packaging to Quality of Strawberry by Hyokan Technology

Nguyen Thi Hoang Lan, Ta Thu Hang, Doan Thi Bac, Nguyen Ngoc Cuong

Received: 02-03-2021 / Accepted: 26-04-2021
The study investigated suitable packaging materials for strawberry storage with Hyokan technology. Strawberries were harvested at 80% full-ripen when the fruit skin changed to red and stored using Hyokan technology at -2C, electric pressure 3.500V. Four packaging materials were investigated, including PE foam, PE clings film, filter paper and plastic box. The control sample was kept at 2-4C in a regular refrigerator. The control sample showed a significant decrease in sensory quality, nutritional quality and microorganisms. The fruit covered by PE cling film (CT5) had the best nutritional quality and sensory score, and microorganism. By using the Hyokan technology and PE cling film, after 21 days storage, the weight loss was 0.31%, waste 13.89%, TSS 7.83Bx, total axit1.15% and vitamin C 13.38 mg/g; the sensory score was a distinction; the total aerobic microorganism was within the standard 46/2007 QĐ-BYT.
Effect of Stocking Density on Growth and Survival Rate of Mouse Grouper (Cromileptes altivelis) Larvae FromFry to Fingerling Stage

Vu Van Sang, Tran The Muu, Le Xan, Pham Thi Lam Hong, TranThi Nguyet Minh, Nguyen Van Phong, Vu Van In

Received: 15-12-2013 / Accepted: 26-02-2014
The study was carried out to identify the most suitable stocking density for mouse grouper larvae (Cromileptes altivelis)from fry to fingerling stage. The larvae were reared at the densities of 10,20 and 30 individuals/l. Lower stocking densities, at 10 and 20 individuals/l weremore favorable forspecific growth rate (0.063 and 0.0625%/day), final total length (34.45 and 33.33mm)and survival rate (6.45 and 6.30%)(P<0.05). Results showed that the most appropriate density for rearing the mouse grouper from fry to fingerling stage is 20 individuals/l to optimize the growth, survival rate and economic efficiency.
Characterization of Fungal Strains Isolated from AlcoholicFermentation Starters of Nga Son, Thanh HoaProvince

Nguyen Huy Thuan, Le Thi Hanh, Tran Dang Khanh, Nguyen Van Giang

Received: 18-05-2020 / Accepted: 10-08-2020
This experiment was conducted to find the fungal strains with high saccharification activity isolated from the alcohol fermentation starters collected in Nga Son, Hau Locdistrict, Thanh Hoa province and growing well under normal conditions to increase the alcohol yield and decrease fermentation time in alcohol production. The contents of the study include the isolation of mold strains from traditional alcoholic fermentation starters, evaluation of amylase production, and saccharification of the isolated fungal strains using methods described by Xu-Cong & cs., (2012); Scheherazed & cs., (2016); Samson & Hoekstra(2002). Besides, the effects of cultural conditions on the saccharification of selected fungal strains were surveyed. Seventeen strains of fungi isolated from alcoholic fermentation starter samples produced amylase with activitiesfrom 2.0 to 4.5 U/ml. Among them, two mold strains NS1.1 and HL2 exhibited the highest saccharification when they grew on the block of sticky rice. The sugar content in the solution obtained from the fermented rice block of the NS 1.1 strain reached 7.02µM, 6.18µM with the HL2 strain. The appropriate temperature for the selected strains exhibited amylase activity ranging from 25C-35C, optimum at 30C. The comparative result of the 18S rRNA nucleotide sequence showed that the strain NS 1.1 has 99% similarity to the one of Rhizopus oryzea strain 150138 and was named Rhizopus oryzaestrain NS1.1.
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.
Solanum nigrumL., A Plant Capable of Treating CadmiumContaminated Soil

Nguyen Thanh Hung

Received: 15-03-2016 / Accepted: 15-07-2016
A study of Cadmium (Cd) absorption by Solanum nigrumL.(S. nigrum) was conducted through using outdoor pot- culture experiments from March to June 2015. Results showed that S. nigrumbiomass compared with the controlwas not significantlydifferent(P<0.05) under the concentration of 10- 25mg/kg of Cd in soil. The ability to accumulate Cd in the above-ground parts was greater than 100mg/kg dry biomass; TF and BF coefficient was greater than 1. The results of this study demonstrated that S. nigrumis a Cd-hyperaccumulator. This is an important finding that may contribute to solve heavy metal pollution problems as well as to apply phytoremediation in specific situations.
Phân lập và tuyển chọn các chủng vi khuẩn sinh enzyme chitinase, đối kháng với nấm Fusarium oxysporumtừ đất vùng rễ cây hoa lily

Tran Thi Hong Hanh, Tran Thi Dao, Le Thi Ngoc An, Lam Thuong Thuong

Received: 03-07-2018 / Accepted: 25-06-2020
Enzyme chitinase có tiềm năng ứng dụng trong nhiều lĩnh vực như môi trường, nông nghiệp và y học. Vi khuẩn sinh enzyme chitinase được tìm thấy trong môi trường tự nhiên (đất vùng rễ, nước biển) được ứng dụng để đối kháng với nấm gây bệnh thực vật và sản xuất enzyme chitinase phân huỷ các chất thải chứa chitin. Nghiên cứu đã tiến hành phân lập và tuyển chọn các chủng vi khuẩn có khả năng sinh enzyme chitinase có hoạt tính cao bằng phương pháp khuyếch tán đĩa thạch và phương pháp so màu với thuốc thử DNS (3,5-dinitrosalicylic acid). Từ đất vùng rễ cây hoa lily, 32 chủng vi khuẩn có khả năng sinh enzyme chitinase đã được phân lập. Trong đó, 4 chủng HP02, VRQ9, HM03 và GL10 có hoạt tính chitinase là cao nhất, lần lượt là 1,47; 1,44; 1,29; 1,21 U/ml. Các chủng sinh chitinase được thử đối kháng với nấm Fusarium oxysporumgây bệnh thối củ và thân ở cây hoa lily. Kết quả cho thấy rằng 4 chủng HP02, VRQ9, HM03 và GL10 đều có khả năng đối kháng với nấm. Chủng HP02 có hoạt tính chitinase cao nhất và có khả năng đối kháng nấm Fusarium oxysporum, được xác định là Bacillus subtilisdựa vào đặc điểm hình thái, hoá sinh, so sánh trình tự 16S rRNA với các trình tự trong ngân hàng gen và xây dựng câyphân loại.
Comparison of Technical and Economic Efficiency of Specialized Artemia Culture Model and Artemia-Shrimp Rotation Model in Coastal Area of Soc Trang

Huynh Thanh Toi, Tran Thi Kim Muoi, Nguyen Thi Hong Van

Received: 19-02-2020 / Accepted: 04-08-2020
The study was conducted to compare the technical efficiency and economic efficiency of the two models of specialized Artemia culture and Artemia-shrimp rotation to make recommendations for a suitable farming model that brings high economic efficiency foraquaculture farmers in that area. Data of the study were collected by directly interviewing 60 Artemiafarmers with relevant information on Artemiaculture and other aquatic species in the 2018 coastal area of Soc Trang province. The results show that in the dry season, most of the households cultivate only Artemia, Artemiacyst production with an average return of 66 million VND/household/year, the rate of returns is 1.59. In contrast, while in the wet season, the land is used for alternately rearing other aquatic animals (about 55% of total area), the returns are quite high for the Artemia - shrimp alternative model reaching 194 million/crop/year, the rate of returns is 2.1. Based on the survey results, it is necessary to consider the investment and expansion of the Artemia- shrimp alternation model, encouraging households to uses 100% land for aquaculture which aims to stabilize the economy for households.
Growth Performance and Meat Quality of 3/4 Dong Taoand1/4 Luong PhuongCrossbred Chickens

Nguyen Van Duy, Nguyen Dinh Tien, Vu Dinh Ton

Received: 01-06-2020 / Accepted: 25-06-2020
This study was carried to determine the growth performance, meat productivity and quality of 3/4 Dong Tao (ĐT) and 1/4 Luong Phuong (LP) crossbred chickens raising. The growth performance was determined on the 180 chicks from one day of age to 24 weeks. We first randomly divided all the chicks into 3 cocks and 3 hens to determine the meat yield and meat quality at 16, 20 and 24 weeks of age. The survival rate of 3/4ĐT and 1/4LP from one day of age to 24 weeks was 98.33%. At 24 weeks, the alive weight was 3068.33 g for cocks and 2046.67 g for hens. The average daily gain of chickens gradually increased from 1 to 12 or 13 weeks for hens and cocks, respectively and then decreased. From 19 to 20 weeks of age, the growth rate was very low with ADG/day at 12.9 g (cocks) and 8.21 g (hens). The FCR of chickens in period 20 weeks was 4.47 and in period 24 weeks was 5.15. The 3/4ĐT and 1/4LP chickens had a high meat yield and good quality of meat. In conclusion, it is possible to use the 3/4 Dong Tao and 1/4 Luong Phuong in the production of broiler chickens.
Estrus Synchronization and Fixed Time Artificial Insemination in Dairy CowsinVinh Phuc Province

Su Thanh Long, Do Thi Khanh Linh, Phan Thi Hang, Nguyen Thi Suong, Nguyen Van Thanh

Received: 21-05-2020 / Accepted: 01-07-2020
The study was designed to determine the effects of estrus induction method combined fixed-time artificial insemination (FTAI) in dairy cows. This study was conducted on 17 sixteen-month-old prepubertal heifers and 34 repeat breeder cows in Vinh Phuc province between July and November 2019. Hormones therapy and progesterone device were used to induce estrus and performed artificial insemination during 14-18 hours after finish the treatment. Pregnancy diagnosis was performed from 60 days after FTAI date. The results have indicated that the insemination rate and the conception rate were 100% (51/51 cows) and 37.25% (19/51 cows), respectively. Regarding the non-pregnant group, the estrus resumption proportion was 96.87% (31/32 cows). In conclusion, the significant effects of estrus synchronization and fixed-time artificial insemination (FTAI) were proved to increase the insemination rate and to promote cow to return to the normal physiological estrus cycle, although the first service conception rate was not high after treatment.
Design and Manufacture of Data Collection System on Parameters Affecting Growth and Development of Gerbera Plants Grown in Greenhouse

Ngo Tri Duong, Nguyen Van Dieu

Received: 15-10-2015 / Accepted: 03-03-2016
One of the methods for increasing crop yield is to nurture plants in greenhouse.Important factorsdirectly affecting the growth stages of plants are temperature,air humidity, soil humidity and light intensity. Therefore, collecting data on these factors is of great concern to help growers observe closely and adjust accordingly. The manufacture of a data collection system will help growers approach new technologies. The system was designedand manufactured in order to collect and store the parameters such as temperature (20-60oC, step 0,1); humidity (40-100%, step 0,1); light intensity (10-14000 lux, step 0,1) with accuracy of 5% of measured value. The research provides preliminary solution to the collection andmanagement of the data for greenhousecrop production in Viet Nam.
Effects of Fruit Pruning and Wrapping Materials on Fruit Size and Quality of Jujube Fruit (Ziziphusmauritiana Lamk.)Variety 05

Nguyen Thi Phuong, Nguyen Hoang Viet, Vu Thanh Hai, Nguyen Thi Thu Huong, Nguyen Thi Hai Xuan

Received: 17-12-2019 / Accepted: 03-02-2020
The study aimed to evaluate the effects of fruit thinning and fruit wrapping materials on fruit size, fruit quality traits and fruit loss rate due to insects and diseases infecting jujube fruit variety 05. Two independent experiments were conducted on 3-year- old jujube plants, which was designed as a randomized complete block design with four treatments and three replications per treatment. Fruit thinning treatments included removing 10%, 20%, 30% and zero % (control) of the total number of fruits per plant. Fruit wrapping material treatments included nylon bag, sponge bag, oil bag and no-wrapping (control). The results showed that fruit thinning increased fruit size, fruit weight and total soluble solids content (TSS), and decreased total acid content (TA) of the fruit. Out of fruit thinning treatments, thinning 30% of the total fruit number per plant resulted in the highest fruit weight (99.36 g) and TSS (17.2oBrix), and the lowest TA (0.180%), at the same time, the treatment reduced actual fruit yield (37.8 kg/plant) and increased the net revenue (772.000 Vietnam dong/kg). Wrapping fruits by nylon bag and sponge bag increased fruit weight of 25.3% and 17.7% compared to the control treatment, respectively. The sponge bag returned the second rank of fruit yield (44.7 kg/plant) and net revenue (1,001,000 Vietnam dong/plant) and did not affect TSS value (17.02%). The nilon bag decreased TSS (15.69%) but returned the highest fruit yield (47.8 kg/plant) and net revenue (1.258.000 Vietnam dong/plant). Therefore, the application of the wrapping materials into commercial production of jujube, nilon and sponge bags, is potentially economical.
A New Method of Optimum Tuning for Cascade Control Systems

Nguyen Thi Hien, Nguyen Van Dat

Received: 13-11-2015 / Accepted: 08-03-2016
Cascade control systems are widely used in practice with one or more loops inside the primary loop and thecontrollers are in cascade. In this structure, the control signal calculated by the outer loop is the setpoint of the inner loop. This paper presents an algorithm that directly uses the experimental data to simultaneously tune parameters of the controllers in cascade control systems. The algorithm does not require a mathematical model of the plan but only one-shot experimental data collected from the closed loop system.
Screening Herbs and Determining Their Mixing Ratio to Create a Product for Preventing Diarrhea andImproving Weight Gain for Pigs and Chickens

Pham Hai Son, Nguyen Van Toan, Nguyen Thi Lieu, Bui Le Kha Tu, Nguyen Thi Dung

Received: 04-07-2023 / Accepted: 23-05-2024
The purpose of this study was to investigate the mixing ratio to create aherbal product from six types of extracts: Syzygium aromaticum, Glycyrrhiza uralensis, Andrographis paniculata, Zingiber officinale, Phyllanthus urinaria, andPsidium guajavato support weight gain and prevent diarrhea in pigs and chickens. The antibacterial activity was evaluated using the MIC method, screened by the Plackett-Burman matrix, and the efficacy of the herbal product on pigs and chickens was assessed.The mixing ratio of herbs was screened by Plackett-Burman matrix. The results showed that the mixture of three extracts Syzygium aromaticum, Glycyrrhiza uralensisand Andrographis paniculatamixed in a 1:1:1 ratio exhibited good antibacterial using MIC. The MIC was obtained at 2.083 mg/ml on E. colivàS. typhimurium. This herbal product formulation yielded better weight gain and disease prevention efficiency in both pigs and chickens. Results on disease preventive efficiency showd that the survival rate in pigs and chickens after 6 weeks was 100% and 98.44%, respectively. This indicates that the herbal product had significant effect on supporting the resistance of pigs and chickens and on improving weight gain for pigs and chickens due to the biologically active ingredients of herbs combined in the product.
Effect of Night Break Duration on Off-Season Flowering,Fruiting and Yield of Red Dragon Fruit Cultivar Tl5 in Gia Lam, Hanoi

Nguyen Thi Thu Huong, Nguyen Quoc Hung, Doan Van Lu

Received: 07-11-2019 / Accepted: 05-02-2020
The studywas aimed to establish atechnical protocol to extend the fruit harvest in Northern provincesfor off-season flowering of red-fleshed dragon fruit TL5 variety growingin Gia Lam, Hanoi. The study was conducted in 2 seasons of lighting, on October 20, 2016,and October 20, 2017. The lighting treatment used 60W incandescent light bulbs to supplement light from 10 pm to 3 am, in the 5 different lighting durations of 13, 16, 19, 22 and 25 nights. The experiment was arranged in RCBD, with 20 posts/treatmentforeach replication. The results showedthat in both seasons of lighting supplement, the treatments of lighting in 19, 22 and 25 nights were recorded with good flowering. The number of shoots per post-producing flower buds and number of stable flower buds per post in these lighting treatments reached 28.2-33.6 and 52.7-67.2 respectively, which were significantly different from those of the treatments with 13 and 16 nights of lighting. Actual yields in treatments of 19; 22 and 25 supplement nights reached 6.2 to 7.3 kg/post in both the 2 seasons, which were significantly different from those of treatments with fewer lighting days. Among the lighting treatments, the supplement in 22 nights was the most effective that the profits were increased to 150.8 million dong/ha in the first crop and 144.8 million dong/ha in the second crop.
Evaluation of Growth and Development of some Potted Chrysanthemum Cultivars (Chrysanthemumspp.) in Gia Lam, Hanoi

Phung Thi Thu Ha, Pham Thi Huyen Trang, Nguyen Thi Phuong Dung

Received: 04-04-2024 / Accepted: 23-05-2024
Chrysanthemum is an important floriculture crop in the international flower market because it has an attractive beauty and a high economic value. They are popularly grown as cut flowers and potted flowers world-wide due to their varied in flower color, size, and petal shape. The study aimed to evaluate the growth and development characteristics of five Chrysanthemum cultivars in Gia Lam, Hanoi. The single- factor experiment on five Chrysanthemum cultivars was arranged in a randomized completeblock design with three replications. The results showed that all five Chrysanthemum cultivars grew and developed well in Gia Lam,Hanoi. The plant height of five studied cultivars ranged from 32.50-58.12cm, with 0.53-0.55cm of stem diameter. The number of leaves varied from 17.6-33.0 leaves with 4.82-6.62cm in width and 8.50-12.36cm in length. The number of days to 30% inflorescence bud initiation varied from 40-58 days after transplanting. All cultivars had double head inflorescence form with 3-7 head inflorescences/plant. Head inflorescences bloomed after 23-32 days from the initiation of inflorescence buds. The diameter of head inflorescences ranged between 4.33 to 11.70cm. The head inflorescence longevity varied from 34 to 40 days.
Study on Biological Characteristics of Onychostoma laticepsGunther, 1896

Vo Van Binh, Nguyen Hai Son, Nguyen Quang Huy

Received: 13-05-2019 / Accepted: 17-07-2019
In order to maintain, protect and develop the gene source of Onychostoma laticeps, the study of biological characteristics of O. laticepswas carried out from January 2018 to December 2018 on 300 samples of O. laticepscollected in the Giang River, Mon Son commune, Con Cuong district, Nghe An province. Results showed that all collected fish samples were in the age of ranging from 1+-3+, corresponding to the weight of 22.5-98.8 g/fish. The O. laticepsis an omnivorous species (Li/Lo was 3.08 ± 0.57). The food composition in the fish intestines was diverse, including more than 28 species, representing for 5 different animal and plant sectors, of which the algae sector was dominated (65%) compared to other sectors. There were no much differences between the Fulton fat coefficient and Clark fat coefficient, this was reflected correctly the level of the nutrient that was accumulated in fish. In nature, O. laticepsstarted breeding in early February, the average absolute fertility was 3,113 eggs, the average relative fertility was 231 eggs/g of the female. The gonosomatic index (GSI) was high during the period from February to June (Male fish ranged from 1.81 to 2.12%; Females fish from 4.62-9.80%) and reached the highest value in March (Male fish: 2.64%; Female fish: 9.80%).
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.
Physiological Chacracters of Some Peanut Vatieties (Arachis hypogaeaL.) with Drought Tolerance at Seedling Stage

Pham Van Cuong, Dinh Mai Thuy Linh, Ha Thi Quynh, Tran Anh Tuan

Received: 03-01-2018 / Accepted: 18-04-2018
Seven genotypes of groundnut (DM1, DM2, DM3, DM4, HL11, HL22 and LDDL) provided by the Agricultural Genetics Institute were evaluated for growth and physiological characteristics under drought conditions at seedling stage. A pot-experiment in nethouse was arranged according to a completely randomized design. Drought stress was imposed on three true leaf seedlings (15 days after sowing) by withholdingt irrigation untill the soil osmotic pressure reached -80 KPa. Meanwhile, regular irrigation schedules were perfomed for maintaining the soil moisture at 70% saturation in the control and in non-drought periods. Drought stress inhibited growth and photosynthesis, transpiration and significantly reduced dry matter of groundnut at seedling stage and the inhibition varied with genotype. Three indexes showing close correlations with dry weight included drought susceptibility index (DSI); drought tolerance efficiency (DTE) and drought tolerant index (DTI) with correlation coefficients of r = -0.55 and -0.602, r = 0.55 and 0.83, and r = 0.53 and 0.98 at drought and recovery periods, respectively. The chlorophyll stability index (CSI) showed no correlation with dry weight and did not reflect drought tolerance. The results also showed that the genotypes HL22 and DM4 possessed higher drought tolerance comparing to the others.
Assessment of Semen Quality and Artificial Insemination for Dong Tao Chicken

Le Thi Tham, Do Van Thu, Tran Xuan Khoi, Le Thi Hue, Ngo Xuan Thai, Doan Viet Binh

Received: 28-03-2017 / Accepted: 10-07-2017
The research was conducted tocollect semen of Dong Tao cocks, evaluatesemen quality, preserveand artificiallyinseminateDong Tao hens. A total of 62 cocksand420 hens with typical characteristics of Dong Tao breedrearing at households in Dong Tao, Khoai Chau, Hung Yen were selected for the study. The results showedthat the cocks had relatively slow ejaculation reflex. The semen volume, sperm activity and concentration were 0.46 ml, 76.04% and 3.26 billion/ml, respectively. The semen quality in summer was relatively low. The best semen collection interval was once a day. It was possible to use both buffer 1 and 2 to dilute semen, but buffer 1 beingmore appropriate, because after 9 hours of conservation at5oC, the sperm activity remained over50%. With the interval of 3 days between two artificial inseminationsata dose of 150 millionsperms per insemination, the rate of fertilized eggs reached over 84%. Insemination in the evening wasbetter than in the morning. The results suggestedthe applicabilityof artificial insemination for Dong Tao chickens.

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