Vol. 20 No. 6 (2022)

This study evaluated the correlation, heterosis, and combining ability of ten melon lines using top cross mating design. Ten parental lines, two testers and twenty top cross hybrids with a check variety were evaluated in 2021 Autumn season in the nethouse at Vietnam National University of Agriculture. The result showed that marketable yield had a very strong positive correlation (P ≤0.001) with mean fruit weight (r = 0.998), fruit length (r = 0.772), fruit diameter (r = 0.957), and fruit flesh thickness (r = 0.845). Mid-parent heterosis and heterobeltiosis were observed in yield and yield-related traits while these values ​​were negative for harvesting time. The highest general combining ability (GCA) in yield and mean fruit weight were observed in D17 and D26 lines, and the tester DT16. D20 has the highest GCA value on total soluble solid content. The crosses DT16×D17, DT16×D01, and DT16×D26 had the highest marketable yield. The additive effect plays a larger genetic role in the control of yield traits while the dominant effect plays a larger genetic role in the control of quality traits in melon.

This study was conducted to evaluate morphological characteristics and growth performance of Hac Phong chicken. A total of 100 birds(50males and 50females)at 1 day of age were raised at the experimental station of the Faculty of Animal Science,Vietnam National University of Agriculture. Animals were fed and taken care following the standards for colored chicken. The results showed that Hac Phong chicken is a small chicken breed.Adult chickens (at 20 weeks of age) have black color of feather, skin, meat, and bone and the foot has five toes. All most animals have bud comb with purple-black color and all hens (100%) have head feather. The survival rate until 20 weeks of age was high at 96%. The body length of the cock at 8, 12 and 16 weeks of age was 13.00cm; 16.30cmand 18.14cm, respectively, and was higher (P <0.05) than the hens with the value of 10.76cm; 15.57cm; 16.20cm, respectively. At 20 weeks of age, the average body weight of the males and females was 1,381.90g and 1,150.49g, respectively. Feed conversion ratio was 4.58kg feed/kg weight gain during 1-20 weeks of age.

This study was conducted to identify the pathogen F. columnarefrom diseased grass carp cultured in northern Vietnam and to examine the susceptibility of this bacterium to various common antibiotics used in aquaculture. A total of 103 grass carp samples suspected to be infected with F. columnare were collected and screened from 25 grass carp farms in Ha Noi, Hai Duong and Bac Ninh provinces. The grass carps infected with F. columnareexhibited the symptoms of decayed, white-grey gill filaments, rotten fins, and skin discoloration. From 67 yellow and rhizoid isolates recovered from the collected samples, 25 representative isolates (one per farm) were identified by the phenotypic tests and PCR assays. Grass carps (20-25g) challenged with F. columnareat the dose of 2 ×106 CFU/ml by immersion in 2h resulted in 100% mortality within 48-72 hpi. Theantibiotic test showed that high proportion of F. columnareisolates were susceptible to doxycycline, amoxicillin, florfenicol, and oxytetracycline (92-96%), but resistant to sulfamethoxazole/trimethoprim (44%) and trythromycin (16%). The present study provided necessary information for diagnosing and controlling F. columnarein grass carp.

This study aimed at evaluating the characteristics andperformance of pig production in the Central Highlands.83 pig farms in 5 provinces in the Central Highlands were surveyed from June 2018 to December 2019.The research results show that the pig breeding was mostly small-scale, accounting for 84.34% of total farms surveyed. The small-scale breeding groups raised average 18.71 piglets/household whilelarge-scale breeding groups kept 173.15 piglets/household on average. The breeding techniques and disease prevention practices for pigs and livestock productivity in large-scale breeding groups werebetter than those in small-scale breeding groups. The survival rate to weaning was 93.17% in large-scale breeding groups and 89.35% in small-scale breeding groups. The weaning age and weight in large-scale groups were 25.64 days and 7.82 kg/piglet, and in small-scale group were 30.21 days and 7.39 kg/piglet, respectively. The fattening pig reached 105.91 kg/piglet after 5.05 months (large-scale breeding groups) and 88.89 kg/piglet in 6.01 months of raising (small-scale breeding groups).

The study was condcuted to evaluate the effects of phages on the phenotype and density of Vibriospp. The Vibriospp. strains were isolated from An Thanh 2 and An Thanh Dong commune, Cu Lao Dung district, Soc Trang province, and 18 bacteriophage strains were obtained from the Molecular Biology Laboratory, Biotechnology Research and Development Institute, Can Tho University. The spread counting method was employed to observe the number and changes in colony morphology of Vibriospp. after treatment with bacteriophages. The results showed that there were changes in the number and phenotype of colonies of the tested bacteria with different phage strains. Specifically, seven bacteriophage strains 2, 3, 4, 5, 7, 8, and 22 significantly reduced the number of colonies of Vibriosp. strain B1.1 while four bacteriophages 1, 19, 21, and 23 increased the number of bacterial colonies. In addition, remarkable morphological changes were observed in color, size and cover of Vibriosp. strain B1.1 after treating with phage 21, 22, and 23. The findings indicated that bacteriophages exerted the ability to change the number and phenotype of Vibriospp. colonies.

Bài báo này đề xuất một mô hình thu năng lượng động học được lắp đặt dưới gờ giảm tốc để thu năng lượng bị lãng phí do các phương tiện đi qua gờ giảm tốc. Mô hình bao gồm ba phần chính: hệ thống truyền động - bơm - hệ thống lưu trữ, mô-đun máy phát điện, mô-đun điều khiển. Hoạt động như một đầu vào năng lượng, hệ thống truyền động - bơm thu năng lượng động năng để tạo ra khí nén. Sau đó, hệ thống lưu trữ sẽ lưu trữ lượng không khí này để nó sẵn sàng xả khí tới hệ thống máy phát điện. Khi khí nén được xả vào mô-đun máy phát điện, mô-đun này sẽ tạo ra năng lượng điện có thể được sạc cho ắcquy. Mô-đun điều khiển có thể tự động giám sát và điều chỉnh lượng khí nén cũng như năng lượng trong ắcquy. Các thử nghiệm được đưa ra cho thấy hệ thống có khả năng tích trữ một lượng khí nén dưới 50psi. Năng lượng này cho phép tạo ra điện năng một chiều 14,8VDC để nạp vào ắcquy 12VDC. Kết quả ban đầu cho phép tiến hành những nghiên cứu sâu hơn về một nguồn năng lượng mới trong tương lai.

Passion fruits after harvest were treated with hot water atdifferent temperatures (44C, 48C and 52C) for 5 minutes and soaked in 1-Methylcyclopropene solution (440ppb, 490ppb and 540ppb) during 80 seconds. After drying, the fruits were placed in styrofoam trays inside carton boxes and stored at 5 ± 1C, 80-90% r.h. The treatments withouthot water and 1-MCP treatments were used as the control. Results showed that the treatments with hot water treatment at 48C for 5 minutes combining with 1-MCP at 490ppb for 80 seconds gained the climacteric respiration peak and had ethylene production later than control treatment. The study also identified the quality indicators of passion fruit after 39 storage days under the above conditions, i.e. soluble dry matter content 17.803%, vitamin C content 34.967 mg/100g; and total phenolic content 55.044 ml/100l.

This study aimed to build a monitoring and control system of some pollutant parameters (pH, COD, BOD) in the balancing tank during the livestock wastewater treatment process by using PLC.TIA Portal 15.1 sofware allows simple monitoring and control interface design, easy for users. The assay process is carried out in the laboratory, showed that the monitoring interface enables us to visually monitor the system's operation, in which the pH, COD and BOD parameters are displayed numerically or graphically in real time, device operation is shown by changing color state.

The present research work was undertaken to study effects of 1-MCP and exogenous ethylene on changes in fruit quality of heat tolerant tomato culivar during postharvest ripening. ‘Savior’ tomato fruits were harvested at mature green stage and treated with 3 treatments: air exposure (control), treated with 1-MCP at 5ppm, and treated with ethylene at 100 µl/l for 24h at 18C, and stored at 18C and 80% RH. 1-MCP remarkably retarded the changes in color and fruit softening. The acidity of 1-MCP treated fruits was significantly higher than that of the control fruits. On the orther hand, there was no significant difference in color, firmness, total soluble solid content, acidity, and respiration rate between ethylene treated fruits and control ones during postharvest ripening. Application of 1-MCP inhibited the respiration rate of the treated fruits. In summary, this study indicated that 1-MCP delayed fruit ripening process of the ‘Savior’ tomato. Nevertheless, exogenous ethylene of 100 µl/l did not fasten fruit ripening.

This paper presents a new solution for building a supervisory control and data acquisition (SCADA) system for a product sorting line based on color by using PLC S7-1200 integrated with IoT technology. Users can access the system anywhere using different devices, such as PC, tablets and smart - phones with internet connection. It is easy and simple to build the monitoring and control interface, and it does not depend much on the configuration of PLC. In particular, the system enables us to write/edit and load programs for PLC via the internet, which is very suitable for engineers and experts who can work online. The test results show that the system works stably, reliably and accurately.

This study explores the factors influencing the poverty of indigenous ethnic minority households in Dak Nong province. The study used the Binary Logistic regression model with a sample of 178 indigenous ethnic minority households, including poor households, and non-poor households. The results showed that the poverty rate of indigenous ethnic minority households is still high, accounting for 22.8% compared to the general poverty rate of Dak Nong province of 6.98%. In addition, we found that the factors affecting poverty of indigenous ethnic minority households included family size, education level, total farmland area, access to loans, participation in social organizations, diversification of livelihoods, communication means and natural disaster. Therefore, it is necessary to strengthen the implementation of family planning programs, improve education levels, career transition support policy, build and upgrade information and communication systems, and improve capacity to respond to disaster risks for indigenous ethnic minority households.

Ecotourism is growing rapidly and actively contributes to the improvement ofthe livelihoods of local people, tourists' understanding of biodiversity and protectionof natural resources. The article aimedatpointingout the current status of ecotourism development activities and thereby proposing solutions to improve the efficiency of ecotourism activities in Xuan Thuy National Park. In addition to secondary information, primary data were collected from 110 tourists, 35 households participating in providing ecotourism services, 2 management staff of Xuan Thuy National Park, and 12 managers at district and commune level. The research results show that ecotourism development has had an unstable growth over the past time and was facing many difficulties and challenges such as poor infrastructure for ecotourism, low level of human resources, etc. The tourism expertise wasnot high as well as tourism products werelimited, and lackedcohesion with tour operators and routes in attracting visitors. The solutions to promote ecotourism in Xuan Thuy National Park are suggested as follows: organizing and promoting ecotourism development; improvingthe efficiency of management and protection of natural resources and the environment; investingin infrastructure for eco-tourism in Giao Thuy district.

Wood vinegar is produced fromagricultural and forestry byproducts pyrolysis such as waste from woodandbamboo, rice straw, husks, sugarcane bagasse and corn-cob. Wood vinegar consistsof more than 200 water-soluble chemicalcompounds, 80-90%water and 10-20% organic chemicalcompounds: organicacid, alkane, phenolic, alcohol and ester. Thus, wood vinegar has a powerful antioxidant and antimicrobial activity as well as anti-inflammatory agent, anti-fungal drug, pest control and natural plant growth promotion. This review article sums up the rolesof wood vinegar in crop cultivation such as promotingcropgrowth andyield, enhancing the use efficiency of chemical fertilizersand pesticides, stimulating germination, improvingsoil health and manure quality,and eradicating weed.Therefore, wood vinegar can be considered to be a potential material for sustainable agricultural development in Vietnam.

The goal of this article was to summarize some of the mechanisms of spawning induction in gastropoda in the marine and freshwater environment. Nutritional and environmental factors (lighting, temperature, and the tidal cycle-for marine species) affected the changes of the endocrine system in gastropoda. The changes in environmental conditions also affected the change of reproductive structure. Illumination cycle, temperature, change of water source, and hydrogen-peroxide solution (H2O2) affected the central nervous system, stimulating the egg-laying process of most gastropoda. For marine gastropods, using H2O2solution and ultraviolet or heat shock all gave good spawning efficiency. However, other methods such as changing the water depth or combined with rain spraying, pituitary glandinjections, and tentacle cutting were more effective in spawning induction for freshwater gastropoda.