Hue University Journal of Science: Agriculture and Rural Development

Study for enhacing the in vitro shoot multiplication rate of Melaleuca quinquenervia

Nguyen Thi Nguyen Man — 2024-09-30

Melaleuca quinquenervia (Cav) S.T. Blake, 1958) is an imported species that is commonly grown for wood and essential oil production. The micropropagation method produces seedlings with fast growth and high oil yield characteristics similar to the selected original plants. Stem segments were collected from natural sources were washed and disinfected with 0.1% HgCl₂ for 16 minutes. After three weeks of culture, the survival rate without contamination reached 83.33%. Additionally, the MS medium supplemented with 30 g/L sucrose, 8.0 g/L agar, and 1.5 mg/L BAP proved to be the most suitable for culturing stem segments, yielding 2.13 shoots per segment with an average shoot height of 1.49 cm. The optimal medium for shoot proliferation was MS supplemented with 2.5 mg/L BAP + 1.0 mg/L KIN + 0.5 mg/L NAA + 0.2 mg/L GA3 + 0.2 mg/L vitamin B2, resulting in 15.93 shoots per segment with an average cluster height of 2.53 cm. Root formation and development thrive best on ½ MS medium supplemented with 1.5 mg/L IBA, yielding of 3.03 roots per shoot with an average length of 3.47 cm.

Biochemical and immunogenic characteristics of the Erysipelothrix Rhusiopathiae isolated in Khanh Hoa province

K. M. Duong Vu — 2024-09-30

In this study, we determined some biochemical and immunogenic characteristics of the E. rhusiopathiae strain IVER1, which was isolated in Khanh Hoa in 2017. The result showed that the colony morphology and biochemical characteristics were similar to previous reports on E. rhusiopathiae in Vietnam and other countries. 16S rRNA nucleotide sequence analysis indicated the strain IVER1 was 100% similar to the E. rhusiopathiae strain ZZ12.3 isolated in China in 2012 (NCBI accession number: KC660995.1). Virulence of the strain IVER1 in pigs was equivalent to the national strain E.47. Immunogenicity of the strain IVER1 was identical to the immunogenic requirements for the inactivated swine erysipelas vaccine. Further research using the strain IVER1 for vaccine production is necessary to enhance disease prevention against the current E. rhusiopathiae strains.

Study on some soil chemical properties in pennywort growing soil at Quang Dien district, Thua Thien Hue province

Nguyen Tan Trong — 2024-09-30

Pennywort (Centella asiatica) plays an important role in cropping systems. Currently, the quality of agricultural production land and pennywort soil is at risk of degradation. Therefore, it is necessary to evaluate the quality of pennywort soil. The study was conducted in Quang Dien district, Thua Thien Hue province in 2024 to survey some pennywort soil chemical properties as a basis for evaluating soil quality and proposing some practices in improving the pennywort productivity and soil properties. 20 composed soil samples were collected from pennywwort soil at the 0-20 cm layer. The analytical parameters included pH_KCl, OM (Organic matter), total N, P₂O₅, K₂O, available P₂O₅ and CEC according to standard methods. The analysis results showed that the soil for growing pennywort contained pH_KCl (4.15 – 4.30), OM (2.41 – 2.78%), total N (0.066 – 0.085%), total P₂O₅ (0.045 – 0.080%), total K₂O (0.18 – 0.33%), available P₂O₅ (3.5 – 7.2 mg/100 g) and CEC (6.10 – 7.95 cmolc/kg). The general fertility of the soil for growing pennywort was from poor to medium level, with potassium content at poor level. Some practices for improving the soil quality by liming and using fertilizers appropriately for pennywort were proposed.

Evaluation of Trichoderma asperellum HL6 against Aspergillus niger Van Tieghem causing collar rot in groundnut

Nguyen Xuan Hieu — 2024-09-30

Collar rot disease, caused by the fungus Aspergillus niger Van Tieghem, significantly impacts peanut production. The long-term survival of fungal pathogens in soil can decrease the effectiveness of chemical fungicides. The use of antagonistic microorganisms can help control the fungal pathogen A. niger. A fungus strain HL6 which has been isoolated from the soil around the root zone of peanut plants grown in Hai Lang district, Quang Tri province, exhibited the inhibitory against A. niger of 77.41% efficiency under in vitro conditions. Molecular identification revealed that the strain HL6 belonged to the Trichoderma asperellum species based on nucleotide sequence comparison of the ITS1-4 region. The test results showed that the T. asperellum HL6 did not affect the germination rate of the peanut seeds. In net-house experiments, the addition of T. asperellum HL6 significantly reduced the occurrence of collar rot disease in peanut plants, with a disease prevention effectiveness reaching 99.55%. These results propose the field trials to evaluate the effectiveness of the T. asperellum HL6 in preventing collar rot diseases for production of bio-inoculants against A. niger.

Efficiency of cassava cultivation in industrial cassava areas of Dak Lak province

Nguyen Hac Hien — 2024-09-30

The study analyzes factors affecting the efficiency of cassava cultivation in industrial cassava areas of Dak Lak province, using data from in-depth interviews with 12 key informants and a survey of 364 farming households in Ea Kar and Krong Bong districts. Descriptive statistical analysis and multivariate regression were employed to analyze data. Results show that nearly 90% of the studied households rarely invest adequately in cassava production as they perceive cassava to be a crop for the poor and an easy crop to grow. Despite this, cassava yield in the studied area is almost equal to the national average, at approximately 20tons/ha. The profit margin from growing cassava is relatively high. With a return of about 2.79 times (in Ea Kar) and 4.27 times (in Krong Bong). Within the scope of this study, the more households invest in growing cassava, the lower profit margin they gain. Varieties of cassava, geography, soil fertility and climate conditions are factors that greatly affect household’s income from cassava. Besides, farm size, level of investment, connections with middlemen, geography and soil fertility are deciding factors of profit margins from cassava farming.

Application of the Universal Soil Loss Equation (USLE) and GIS to simulate and analyze soil erosion changes in Nam Dong District, Thua Thien Hue Province, during the period from 2013 to 2023

Pham Gia Tung — 2024-09-30

This research was conducted in Nam Dong district explore the changes in soil erosion in agricultural land areas from 2013 to 2023 using the Universal Soil Loss Equation and GIS techniques. There are three soil erosion maps for the years 2013, 2018, and 2023 were created based on the USLE formular and the available spatial database. The highest soil erosion rate was found in 2023, while the lowest soil erosion rate was occurred in 2018. Differences in rainfall and coverage coefficients between the years are causes of these variations. Additionally, the result showed that production forest land has the highest soil erosion rate due to the topographical factors because almost this land use type is located in the areas where the slope is over 15°, followed by land for perennial crops, unused land, and land for annual crops.

Effects of some technology factors on the quality of straw mushroom floss (Volvariella volvacea)

Phan Do Da Thao — 2024-09-30

This study aimed to determine the appropriate blanching method and drying temperature for the processing of straw mushroom floss. The study included an investigation of the effect of 3 factors: (i) blanching method (hot water, steam); (ii) blanching time (3–9 minutes); and (iii) drying temperature (50–80 °C) on the quality of raw materials and straw mushroom floss. The results showed that blanching with steam (90 ± 2 °C) for 5 minutes can inhibit the loss of nutrients (protein and sugar) of straw mushrooms to the blanching environment, and the product has good sensory qualities, especially flavor and texture. Moreover, the straw mushroom floss product, dried at 70 °C for 2 hours, has high nutritional content (21,6% protein and 7,2% sugar), ensuring microbiological safety and getting high evaluation sensory of customers (color, flavor and texture). These results provided the theoretical basis for the comprehensive processing of the straw mushroom floss procedure.

Determining factors affected by expanding urban space in Hue city

Nguyen Hoang Khanh Linh — 2024-09-30

This research was conducted to identify factors influenced by the expansion of urban space in Hue city. The study used principal component analysis (PCA -Principal Component Analysis), cluster analysis (CA - Clustering Analysis) and survey methods interviewing 420 households in the expanding urban space. The research results have identified 5 main groups of factors with 11 factors that are influenced by the expansion of urban space on land users in Hue city. In particular, indicators on address, land price, infrastructure and public services are most affected. Identifying the prominence of the urban development model and related impacts will help localities have new options suitable to actual conditions, contributing to promoting the urbanization process over time.

The Isolation and selection of potential Lactobacillus probiotic strains against Gram–negative bacteria causing diarrhea in chickens

Hoang Thi Anh Phuong — 2024-09-30

This study aimed to isolate and select Lactobacillus strains from indigenous chicken feces, which were collected from rural areas surrounding Hue City, capable of counteracting Escherichia coli FG31-1 and Salmonella typhimurium FC13827, which cause diarrhea in chickens. Among the 67 isolated Lactobacillus spp., 7 strains were selected based on their high antibacterial activity against both pathogens. After confirming their safety (no hemolytic activity and no potential for antibiotic resistance gene transfer), 5 strains were identified using 16S rRNA sequencing to confirm their belonging to the Lactobacillus genus. The result showed that the identified strains include LA8 (L. plantarum 1582), LA3 (L. plantarum JDM1), LA18 (L. acidophilus NCFM), LA5 (L. agilis DSM 20509), and LA36 (L. agilis La3). Among them, L. plantarum 1582 was selected as the most promising strain based on its superior probiotic characteristics, such as extracellular enzyme production (amylase and protease), adhesion to intestinal mucosa (hydrophobicity, auto/co-aggregation ability), and tolerance to acidic and bile salt conditions of the chicken gastrointestinal tract. In conclusion, this finding provides a scientific basis for using Lactobacillus-based probiotics as a potential alternative to antibiotics in combating gastrointestinal pathogens in poultry farming.