Vol. 4 No. 1 (2021): Vietnam Journal of Agricultural Sciences

This study aimed to determine the optimum nitrogen application rate for quinoa in saline soils. Two experiments were conducted: (i) the first experiment was under artificial saline conditions with the two factors of saline regime (stressed and non-stressed) and nitrogen application level (0, 30, 60, 90 and 150 kg N ha-1) in net-houses located in Gia Lam, Hanoi; and (ii) the second experiment was under natural field saline conditions with the two factors of quinoa cultivar (Atlas and Moradas) and nitrogen application level (0, 30, 60, 90, and 150 kg N ha-1) in the coastal areas of Hai Hau, Nam Dinh province. Data were collected for growth duration, insect and disease infestations during the growth period, and various growth parameters and yield components at harvest. The results showed that saline stress reduced the growth and yield parameters, but did not affect the quinoa growth duration of the investigated quinoa cultivars. In both experiments, the growth parameters and yield components increased according to the increase of the nitrogen application rates from 0 to 90 kg N ha-1, then decreased when the nitrogen rates were higher. The results suggested that 90 kg N ha-1 was the optimum nitrogen application dose for quinoa growth and development under saline soil conditions.

The aim of the present study was to evaluate the relationships between environmental temperatures and life-history traits of whitefly Bemisia tabaci on cassava in the Northern part of Vietnam. The influence of temperature on the biological characteristics of whitefly B. tabaci fed on cassava was evaluated at 20ºC, 25ºC, 27.5ºC, and 30ºC using individual insect rearing methodology. Results of the study showed that the development time from egg to adult of B. tabaci was influenced by temperatures. The data indicated that under different temperatures (20ºC, 25ºC, 27.5ºC, and 30ºC), the life cycle of B. tabaci were 41.46, 28.64, 24.29, and 20.25 days, respectively. The determination of lower developmental threshold and degree days for whitefly development were 11.2ºC and 344.8 degree-days. There were 14.31 whitefly generations within 1 year on cassava suggesting this plant is a suitable host plant for the development and reproduction of B. tabaci. Female longevity ranged from 4.92 to 10.23 days. The fecundity ranged from 49.3 to 74.0 eggs/female. The mortality rate reached its highest rate of 36.27% at 30ºC. Our results suggested that B. tabaci had high reproduction rates and demonstrated their positive fitness traits on cassava in a wide range of temperatures, being a potential important pest of cassava cultivars.

Cassava is Africa’s most important food security crop and sustains about 700 million people globally. Survey interviews of 320 farmers in three regions of Tanzania to identify their production characteristics, and interviews with 20 international whitefly/virus experts were conductedto identify adaptation strategies to lessen the impacts of cassava whiteflies and viruses due to climate change in Tanzania. Structured and pre-tested interview schedules were conducted using a multistage sampling technique. Most of the farmers (66.8%) produced cassava primarily for food, and relied mainly on their friends (43.8%) and their farms (41.9%) for cassava planting materials. Farmers significantly differed in their socio-economic and production characteristics except for gender and access to extension support (P < 0.01). A significant association was found between extension support, sources of planting materials, and reasons for growing cassava with both the control of cassava viruses and the control of whiteflies by the farmers. A significantly higher number of farmers controlled cassava viruses (38.1%) than cassava whiteflies (19.7%). The adaptation strategies most recommended by experts were: integrating pest and disease management programs, phytosanitation, and applying novel vector management techniques.The experts also recommended capacity building through the training of stakeholders, establishing monitoring networks to get updates on cassava pests and disease statuses, incorporating pest and disease adaptation planning into the general agricultural management plans, and developing climate change-pest/disease models for accessing the local and national level impacts that can facilitate more specific adaptation planning in order to enhance the farmers’ adaptive capacities.

The study was conducted to evaluate the germination, physiological responses, yield-related traits, and seed yield of three mungbean varieties, viz. DXVN7, DXVN5, and DX11, under waterlogging coditions in the 2019 Summer. In experiment 1, the seeds of the three mungbean varieties were immersed in distilled water in Petri dishes for 12, 24, 36, 48, and 72h. Afterwards, water was removed and the percentage of germinated seeds was calculated at 84h after sowing. In experiment 2, plants were waterlogged at the seedling stage (25 days after germination) for 3, 6, and 9 days. Waterlogging depth was maintained at 3cm above the soil surface. Physiological traits were determined at the recovery period after termination of waterlogging (45 days after germination). The results showed that waterlogging significantly decreased germination percentages, plant height, root dry weight, leaf relative water content (RWC), SPAD value, Fv/Fm index, leaf photosynthesis, total dry weight, and seed yield of all varieties. Germination percentages at 12 and 24h of waterlogging were not significantly affected, whereas germination was significantly reduced at up to 36h of waterlogging. Seventy-two hours of waterlogging caused failure in germination. Nine days of waterlogging at the seedling stage adversely affected the physiological traits and seed yield of the mungbean varieties with 31% of yield reduction. Meanwhile, plants grew better at 3 days of waterlogging. Among the three varieties, DXVN7 showed the best adaptability under waterlogging conditions, attaining the highest seed germination and yield.

Spotted sea bass (Lateolabrax maculatus, McClelland, 1844) is a species belonging to the genus Lateolabrax (Lateolabracidae), and is characterized by the many distinct black spots on the bodies of mature fish. For the first time, six specimens have been recorded in Quang Ninh province. The specimens were collected from Luon Cave in Bai Tu Long National Park in May-June 2019. The new specimens collected from Quang Ninh, Vietnam are different from the recorded specimens from Japan, Korea, Taiwan, and China in terms of lateral line scales (LLS) as the samples collected in Quang Ninh, Vietnam have 94-97 scales and the samples collected from the other countries have 66-82 scales. Phylogenetic analysis of the 16S rDNA sequence confirmed that all of the samples collected in Quang Ninh, Vietnam belonged to the species of spotted sea bass.

This study examined the effectiveness of different antioxidative compounds, namely 0.2% BHA (Butylated hydroxyanisole) + BHT (butylated hydroxytoluene), 0.03% α – tocopherol, and 3% and 6% tea seed oil (TSO) on the oxidative stability of vegetable oils. Four commonly used oils, viz. rapeseed oil (RSO), peanut oil (PNO), sunflower oil (SFO),  and soybean oil (SBO), were assessed by the Schall Oven test method and monitored during the 12-day preservation period under 60°C. The total oxidation values (TOTOX) of the samples treated with 6% TSO were lower than those treated with 0.2% BHA+BHT. The results indicated the potential of TSO as a novel natural antioxidant for dietary vegetable oils. Our study also suggested that TSO could serve as an effective substitution for currently used synthetic antioxidants such as BHA and BHT.

The goal of this paper was to identify major challenges in rebuilding the swine industry in Vietnam, using the Chuong My district, Hanoi as a case study. Primary data was gathered in 2020 mainly through a survey of 97 swine producers in the district. Analysis tools were descriptive and comparative statistics. Results show that after the ASF outbreak, the recovery of the swine industry in Vietnam faced several challenges, including the issues of piglet quantity and quality, changing consumer preferences which were worsened by the current Covid-19 pandemic, relatively cost disadvantage of domestic production under the context of new free trade agreements, disease risk (ASF under the condition of no effective and safe vaccine), insufficient resources of farms to restock, and environmental issues caused by swine production in rural areas. The paper proposed several recommendations to rebuilding the swine herd in order to address the issues and overcome the challenges, mainly focus on improving sow quality, market information and linkages, good practices in production, training for labor, and address environmental issues.

The integrated agriculture-aquaculture (IAA) farming system has been considered a form of diversified agriculture applied in Asia. In this paper, several IAA farming systems practiced in Vietnam are described, and their impacts are also reviewed. It is speculated that in developing countries like Vietnam, the IAA farming system should be targeted for support as a sustainable food safety model and a form of ecosystem-based technology to reduce environmental impacts, adapt to climate change, help avoid risks from market fluctuation, and increase incomes in comparison with monoculture farming.

Bone fracture is a common health problem in humans and animals, and the healing of the bone fracture is a complicated process. Several drugs may be used concurrently with the treatment of fractures, but they may interfere with the healing process of the bone. The present research reviewed previously published studies with the objective to enhance the understandings of the effects of different drugs on bone healing. There is clear evidence that antibiotics, corticosteroids, non-steroidal inflammatory drugs, and chemotherapeutic drugs all affect bone healing. By contrast, the effect of anticoagulants on bone healing is controversial, so more research is needed to determine its efficacy. In addition, there is no direct evidence to approve the effect of anesthetics on bone healing, so this is another area in need of further research.