Vol. 3 No. 2 (2020): Vietnam Journal of Agricultural Sciences

The experiment was conducted to evaluate growth and nitrogen uptake of the twelve sugarcane varieties, viz. NiF3, NiF8, Ni9, Ni12, Ni15, Ni17, Ni21, Ni22, Ni25, Ni27, Ni28, and Ni29, under rain-fed conditions during the period from 70 to 160 days after transplanting (DAT) at the experimental field, Faculty of Agriculture, University of the Ryukyus, Okinawa, Japan. The results showed that water shortage from a rain-fed condition caused reductions, but not significant in plant height and SPAD of sugarcane varieties. The genetic variation in leaf area, yield components, partial and total biomass, and cane yield was found among the investigated varieties. The positive associations between total nitrogen uptake with total biomass production and cane yield suggested that higher nitrogen uptake supports better growth performance of sugarcane under rain-fed conditions. From this study, NiF3 and Ni27 could be introduced as the promising sugarcane varieties for better growth performance and high nitrogen uptake under rain-fed conditions.

The objectives of this study were to identify promising rice genotypes and evaluate the genetic variance and effectiveness of selection of the rice varieties for several yield attributing traits. A varietal trial of fifteen rice genotypes was laid out in a randomized complete block design (RCBD) with three replications in a farmer’s field in Sundarbazar, Lamjung, Nepal during the rainy season of 2018. Analysis of variance indicated that all the genotypes showed significant variation for all the traits considered. The phenotypic coefficient of variation (PCV) was higher than the genotypic coefficient of variation (GCV) for all the characteristics being studied indicating the presence of environmental influence on the traits. High heritability coupled with high genetic advance as a percent of the mean was found for days to physiological maturity, number of tillers per m2, plant height, leaf area, effective tillers per m2, flag leaf area, test weight, grains per panicle, filled grains per panicle, harvest index, grain yield, and straw yield indicating that additive gene interaction is present in their inheritance. Direct selection can be effective for yield improvement in the populations through selection of these traits. Cluster analysis based on eighteen traits grouped the fifteen rice genotypes into four clusters. Cluster I was the largest and consisted of five genotypes. Radha 11, NR 119, and Sukhadhan-5 were the top performing genotypes having yield potentials of 5.78, 5.49, and 4.89 tons per ha, respectively.

This study was conducted to detect Ascaris suum, Toxocara canis, and Toxocara cati in naturally infected chicken livers, and then to provide information related to ascarid infections in humans. Ninety-four chicken liver samples collected at a fresh market were used for this study. DNA was extracted from each minced liver sample (500 mg) by the alkaline lysis method using NaOH 50mM and Tris-HCl (pH 8.0). The nested multiplex PCR assay using ascarid universal primers was applied to amplify the ITS1 ribosomal RNA gene of A. suum, Toxocara canis, and Toxocara cati in all the liver samples. Then, species specific-primers were used to discriminate between A. suum and Toxocara spp. The results showed that 2 of the 94 chicken liver samples detected positive for the presence of A. suum DNA. This study provided useful information and evidence about A. suum infection in humans via exposure to contaminated soil or eating raw/undercooked chicken livers in Vietnam.

Histomoniasis, commonly known as blackhead disease, is a parasitic disease in poultry caused by the protozoan Histomonas meleagridis. The availability of various compounds for chemotherapy in the 1970s resulted in the successful control of blackhead disease. Since the ban of antihistomonal drugs in the European Union, the disease has re-emerged, resulting in up to 100% mortality in turkey flocks. This has renewed the interest of scientists with numerous publications focusing on prophylactic strategies. This review summarizes the literature on the preventive and curative options for the control and treatment of histomoniasis. Two main approaches to the prophylaxis of the disease were found, which included chemotherapies and plant substrate products. Histostat-50 and paromomycin were the only available drugs that showed antihistomonal activity despite some concern about their threat to human health and antibiotic resistance. None of the plant substrate products provided potential protection to birds against blackhead disease. The use of attenuated histomonads could be an alternative for the prevention of the disease, but the production of this vaccine prototype is still challenging due to advanced technique requirements.

White turmeric (Curcuma aromatica Salisb.) has been widely used as a traditional herbal drug both in Vietnam and other Asian countries. In this study, the essential oil of white turmeric rhizomes (collected from Dien Bien province) was extracted and evaluated for its chemical composition and antibacterial potential against E. coli and S. aureus. The raw material was 82.48% in moisture and was steam distilled within 3 days from collection at a 0.4 kg L-1 ratio of raw material/equipment volume for 180 minutes. Under these conditions, the essential oil accounted for about 0.3% of the raw material. The GC-MS analysis showed that the composition of the essential oil consisted of more than 46 substances including a-zingiberene, 17.85%; β-sesquiphellandrene, 13.28%; and ar-curcumene, 9.45%. The white turmeric essential oil exhibited antibacterial activity against gram-positive strains of S. aureus with an inhibition zone diameter of 8.0mm but did not inhibit gram-negative strains of E. coli. Importantly, white turmeric essential oil at a concentration of 0.25% could extend the shelf life of mangoes by at least 5 days more than the control samples.

The current aims to apply the Internet of Things technology (IoT) in designing an automatic system for measuring and monitoring important parameters of aquaculture ponds such as temperature, pH, and dissolved oxygen (DO). The system includes the Arduino Nano main microcontroller (the device that transmits and pushes data to the Raspberry Pi 3 Web server), the DS18B20 temperature sensor module, the pH sensor module V1.1, and the DO Sensor SKU SEN0237. The system is capable of continuously measuring the above parameters of aquaculture ponds. The measurement results are stored and transmitted wirelessly to smart devices such as computers and mobile phones. Farmers can continuously monitor water quality parameters of aquaculture ponds (pH, DO, temperature) through these smart devices. In addition, a warning message will be sent to the farmer's phone when the DO index of the aquaculture pond falls below the prescribed level. The results of the test evaluation also show the high accuracy of the system when compared with the sample measuring device. All  relative errors are satisfied less than the limit value of 5%.

This study aimed to determine the factors influencing Vietnamese tea export quantities, namely, the internal factors of national tea production, productivity, and cultivated areas, and the external factors of export price and world tea export quantity (excluding Vietnam). We employed a time-series linear model to estimate the magnitude as well as the sign of the aforementioned factors on Vietnam’s tea export quantity and two Box-Cox transformations called a simple back-transformed forecast and a bias-adjustment to forecast the growth rate of the Vietnamese tea export quantity until 2030. The results suggested that except for the total domestic tea production, all the proposed factors significantly affected the Vietnamese tea export quantity. The tea export quantity of other nations around the world had a significantly negative impact on Vietnamese tea that led to Vietnam’s tea exports dropping by 34 tons on average since the other countries exported 1,000 tons of tea. The forecasted outcome suggested an upward trend of Vietnamese tea exports up to 2030. In order to sustainably develop Vietnam’s tea industry, we recommend that the government should take supportive actions such as investing in in-depth tea processing to improve Vietnam’s tea export quality, focusing on post-harvest activities, investing in organic or high-value tea rather than conventional tea, continuing to  accumulate land to support the growth of cultivated tea areas, and maintaining high productivity by using hybrid seeds.

Since the time of Doi Moi, the Vietnamese government has implemented a variety of policies to foster more balanced economic growth and development between rural and urban sectors. Several government policies that have been enacted were in the fields of agricultural reform and rural development. However, uneven development between urban and rural areas still exists. Based on secondary data, this study shows the urban-rural gaps in terms of education, employment, and income. The paper points out that the higher the level of education a person attains, the more considerable the disparities between urban and rural inhabitants can be observed. This fact strongly influences the occupations and incomes of urban as well as rural workers. The recommended policies to reduce the gaps between urban and rural areas include enhancing credit access for rural people, particularly to the poor; improving access to education and job training opportunities for formal sector employment; and entrepreneurial support to start household businesses, which all serve to increase income opportunities for low-income groups in the rural sector.