Vol. 18 No. 2 (2020)

The study aimed at evaluatingthe growth, development, yield and quality of 3 potential cucumber hybrids THL2, THL6 and THL9 in the Red River Delta (Hanoi, Ha Nam and Hung Yen provinces) in fall-winter season 2017. The experiment fields were arranged in randomized complete block design with 3 replications and the control cultivar was GL1-2. The results showed that the growing duration time of these hybrids was approximately the same as the control cultivar in a total average of growing time (85-88 days after planting), vigorous growth, early appearing of female flowers (30-32 days after planting), early harvest (35-38 days after planting) and long harvest period, respectively. Although there was no significant difference among three hybrids and the control, THL9 had the significantly highest individual yield due to attaining more fruit per plant and higher fruit weight. Furthermore, THL9 was not damaged by powdery mildew and downy mildew diseases, infected very lightly by viruses so that these hybrids have been given the highest harvested yield, reached by 48 tons/ha in all three different experiment sites.The study initially indicated that THL9 showed adaptability to the ecological conditions in the Red River Delta.

This study was conducted to assess the soil properties and soil nutrient contents in Kham Muon Province, Lao PDR,as a basis to propose improvements and variable crops for cultivation purposes. The results showed that the soil had light soil texture (sandy soil), very acidic soil, no saline, high organic matter (OM: 2.6), high N content (N: 0.4%), high total P (TP: 0.1%), total dissolved P (TDP: 5.9mg/100g soil) was relatively high, total sulfur and total dissolved sulfur were high. However, total potassium, total dissolved potassium, calcium and magnesium exchange, micronutrient contents were low, microorganism in underdeveloped soil and high-density population of nematodes. In order to improve the soil quality, lime should be applied to improve the pH, increase the use of organic fertilizers and mulching to prevent soil erosion. Base on the soil analysis results, the variable grasses and crops use as animal feed or vegetable crops, tuber crops, mangos, dragon fruit, pineapples etc. on this soilare proposed to apply.

This study was conducted to determine the pathological characteristics and to apply PCR method to diagnose the disease caused by Edwardsiella ictalurifor Channel catfish (Ictalurus punctatus) in Northern provinces of Vietnam. The infected Channel catfish was collected and determined the clinical symptoms,gross features and microscopic lesionsusing through clinical observation and histopathologicalmethods. Subsequently, PCR method was applied to confirmed the pathogen. The results revealedthat the diseased fish exhibited the symptoms of lethargy swimming, mucusin the gills, haemorrhage of gill operculum, fins, anus. The liver and kidneys contained white spots, intestinal walls and epithelial cells were severe haemorrhage. Theevaluation byPCR showed that all affected fish was infected with E.ictaluri. Histopathological examination revealedthat the gill tissue, liver, kidney, and intestines were the most severely damaged organs. Gills exhibited the hyperplasia and hemorrhage, while liver and kidneys are necrosis and loose structure, decreasing cells and severed haemorrhage.

The study was conducted to detect the presence of Porcine Cytomegalovirus (PCMV) in northern Vietnam pig farms.Total122 samples of pigs with respiratory pathological signs were screening by PCR and identified 59 positive samples with PCMV, accounting for 48.36%. Results of analyzing the nucleotide (nt) and amino acid (aa) of 3 PCMV virus strains collected in Thai Binh and Ha Noi showed that these strains were closely related to one other, sharing 99.22-100% at nt and 99.17-100% at aa, respectively. Phylogenetic tree analysis indicated that the PCMV strains belonged to two different branches, PCMV1.HN.2018 and PCMV3.HN.2019 strains were in the same branch as HN0601 strain isolated in China (accession number HQ686081), the 489 strain of Germany (AF268042), the OF-1 strain of Japan (AF268041) and the 55b strain of Spain (AF268040). Meanwhile, the PCMV2.TB.2019 strain was located in the same branch as the FJ01 strain isolated in China (MG696113). Thus, it can be concludedthat PCMV had circulated among pigs raised in northern Vietnam and had the same origin as the PCMV strains from China.

Objectives of research is to determine Greenhouse Gas (GHG) emission on rice field. Research was carried out on 3 soil types and 2 land use type: rice-rice and rice-rice-winter crop in 2018. Gas samples were taken 4 replications at each site, at 8 growing states and 2 rice season with total of 1024 sample by close chamber method and were analyzed by Gas Chromatograph. Research results showed that, CH4 emission in spring season increases from deriving new roots to tillering periods, then fluctuated depending on water level in the field. With acid sulphate soil, emission higher and in longer time. In summer, emission increase immediately after transplanting, get pick at periods of tillering - particle initiation (28mg CH4/m2/hr),then decrease gradually. N2O emission in spring season largely range in growing states and N fertilizer scheme and get pick at flowering time (0,4mg N2O/m2/hr). Total emission in terms of Global Warming Potential (GWP - ton CO2e /ha/year) ascending are the fluvisols of double cultivating rice season < saline soils < fluvisols cultivated 3 crops of double rice and upland crop <acid sulphate soils. Emission intensity (kgCO2e/kg rice grain) in the spring season in ascending are saline soils <double rice on fluvisols <3 crops of double rice and upland crop on fluvisols <acid sulphate soil.In summer season, double rice on fluvisols <saline soils <acid sulphate soils <3 crops of double rice and upland crop on fluvisols. 

The study aimed to evaluate the effect of cow breed, lactation cycle, lactation stage and protein beta-casein (β-CN) variant on milk composition (protein, fat and solid non-fat). A total of 81 milk samples were collected from 81 dairy cows, including Holstein Friesian (HF) and crossbred cattle (¾ HF and ⅞ HF) and the details of lactation cycle number and lactation stage were provided by the dairy farmers. Protein β-CN variants were identified using ultra-high-performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS). Protein, fat and total solid content were determined using Kjedahl, Gerber and the drying method. Cow breed and lactation stage significantly influenced protein and fat contents but insignificantly impacted on solid, not fat. Lactation cycle and protein β-CN phenotype were not significantly associated with milk composition.

Basil is widely cultivated in Vietnam and mostly used for spice and medicinal purposes. In this study, in vitrobasil plants were cultivated under three blue LED light conditions (440, 450, and 460nm,respectively)byusing fluorescent lamps asthecontrol. After four weeks, the morphology, biomass, gas exchange in photosynthesis, chlorophyll, total sucrose, starch, phenol compounds and total flavonoid content of the plants were determined. Under the fluorescent light or blue LED of 450nm, the stem height was lower, but the number of leaves was greater, and the total leaf area was higher than those of plants grown under blue LEDs (440 and 460nm). Root dry mass percentage of the plants under blue LEDs decreased compared to that of the control. Blue LED at 440 and 460nmincreased the percentage of stem dry mass, whereas blue LED light (450nm) increased the percentage of leaves dry mass. Monochromatic blue light reduced photosynthetic rate, chlorophyll a, sucrose, starch, and phenol compounds content of leaves. However, blue LED light (450nm) maintained the carotenoid and flavonoid contents, chlorophyll a/b ratio in leaveswhich were rather highin comparison with the fluorescentlightof the control.

This study aimed to estimate the effects of participation in agricultural cooperatives on households’ rice crop performances through a case study in Co Do district, Can Tho city. Data used for this study were collected from 106 rice-farming households, including 40 members and 66 non-members of the cooperatives located in Co Do district. Propensity score matching (PSM) approach was employed to estimate the impacts of cooperative memberships on rice-cultivating performance. Results showed that characteristics of farms and households between participant and non-participants in agricultural cooperatives were relatively similar. Evidence of the study indicated that participation in the cooperatives helps rice households increase remarkably selling price for rice and net return but almost had no effect on production cost and rice yield.

This study aims to analyze the development of irrigation systems in service of agricultural production in My Loc district, Nam Dinh province. Data were collected through interviews with households and irrigation managers in the district. Statistical methods of description, comparison, SWOT analysis were used. The results revealed that the yield and crop productivity were increased, the rate of meeting the agricultural production demands of the irrigation system has not been high, the ability of staff has been limited.Therefore, the main solutions need to do in coming time should be: improving the quality of maintenance of irrigation works; strengthening management capacity; determining the price of irrigation products or the services according to the willingness to pay of the users.

The purpose of this research was to identify the factors affecting customer purchase intentions toward organic food in Long Bien district, Hanoi. The study used the factors (Subjective Norm (SN), Perceived Behavioral Control) in the model Theory of Planned Behavior (TPB) and use some other factors, based on the previous studies on the same subjects. Responses were collected from 296 consumers on Long Bien area. Data were analyzed using Structural Equation Modeling (SEM) to evaluate the strength of the relationship between the constructs. The findings showed that there were 4 factors affecting customer purchase intentions toward organic food:SN, health consciousness, consumer knowledge, sensation about price (SPr) positively. Importantly, the SPr factor was the negative affecting purchase intentions. The study has supported the inclusion of new constructs in the TPB as it has improved the predictive power of the proposed framework in determining consumer's intention to purchase organic food.