Vol. 22 No. 11 (2024)

The research was conducted to evaluate the morphological characteristics, growth, yield and quality of mulberry leaves of four new hybrid mulberry combinations in 2023 spring and autumn season. The field experiment was arranged in a Randomized Complete Block Design (RCBD) and included four newly hybrid mulberry combinations (THL1, THL2, THL3, THL4) and a control variety (GQ12) with three replications. The monitored indicators for mulberry included leaf morphology, leaf size, pest and disease status, and leaf yield. The quality of mulberry leaves was evaluated by rearing silkworms (Bombyx mori L.) in the laboratory. The laboratory experiment was arranged in a Completely Randomized Design (CRD), in which the leaves of each mulberry variety were equivalent to a silkworm rearing treatment. The silkworm evaluation parameters included the cocoon formation rate, single cocoon weight, cocoon shell weight, and cocoon yield per 300 silkworms. The results showed that THL1 had early germination time, and the level of damage caused by stem borers and powdery mildew disease of THL1 was equivalent to the control variety GQ12, but the leaf yield was 27.9% higher than that of the control variety in the autumn season. Silkworms fed mulberry leaves of THL1 had higher cocoon shell weight and cocoon yield from 3.3-13.8 % than those feeding mulberry leaves of GQ12. The results provide a basis for continuing to evaluate and develop THL1 to diversify sources of quality mulberry varieties to serve the sustainable and effective development of the mulberry industry.

This study aimed to investigate the effect of different temperature levels on the life cycle and population growth of the predatory mite Amblyseius largoensis reared on the citrus red mite Panonychus citri. The predatory mites were individually reared at 20°C, 22.5°C, 25°C, 27.5°C, 30°C, and 32.5°C, with 75% RH and a photoperiod of 12:12 hours light: dark. The results demonstrated that as temperature increased, the developmental time of A. largoensis decreased markedly. The longest life cycle was observed at 20°C (11.33 days), while at 30°C, the life cycle was reduced to 6.35 days. The total number of eggs laid increasing from 11.83 eggs per female at 20°C to a peak of 17.48 eggs per female at 27.5°C. However, when the temperature rose to 30°C, the egg production decreased to 11.83 eggs per female. As the temperature increased, the generation time (T) and population doubling time (DT) decreased, with DT reducing from 6.15 days at 20°C to 4.51 days at 30°C. The net reproductive rate (R0) was highest at 27.5°C (10.06) and lowest at 30°C (6.27). The intrinsic rate of increase (rm) was highest at 27.5°C (0.178), followed by 30°C and 25°C (0.154 and 0.162, respectively), lower at 22.5°C (0.137), and lowest at 20°C (0.113). This study confirms that the optimal temperature for the development, reproduction, and population growth of the predatory mite A. largoensis was 27.5°C.

Asparagus cochinchinensis (Lour.) Merr.) is a special plant with the characteristics of a dioecious plant. This study contributes to building a database for Asparagus breeding. 20-month-old plants of two types of A. cochinchinensis plants, (non-fruiting (TMĐ01) and fruiting (TMĐ02), were propagated by separating buds in Quang La, Ha Long, Quang Ninh. The treatments wes arranged in a sequential experiment with 3 repetitions with plot size of 50m2, from 2022-2023. The flowers of the non-fruiting (TMĐ01) showed a reduced ovary and the stamens had a full set of 6 anthers attached to the tip of the filament and filled with pollen. The fruiting flower had a developed ovary with 3 carpels and reduced stamen. There were 353.07 flowers/branch (TMĐ01 type) to 395.26 flowers/branch (TMĐ02 type), fruit diameter reached 8.57mm. There were 110.7 fruits/branch and 278.4g seeds/clump, weight of 1000 seeds reached 34g. At 30 months after planting, the fruitting plant grew better, with a height of 201 cm and 39.90 branches/clump, root diameter (36.19cm) and root length (44.07cm). The number of roots/clump (323.6 roots) in TMĐ01 plant was higher than of TMĐ02. The individual yield of the 2 plant types wasnot significant different, fluctuating from 1.72 kg/clump to 1.81 kg/clump at 30 months after planting.

Black double petunia (Petunia hybrida Hort. ex Vilm.-Andr. cv. ‘Midnight Gold’), belonging to the Solanacea family, is a high - value and popular potted ornamental plant on the flower market. This study aimed to establish an efficient in vitro regeneration system for Petunia hybrida “Midnight Gold”. A one-factor experiment was arranged in a completely randomized design with three replications. Leaf explants were cultured on Murashige and Skoog (MS) medium supplemented with various growth regulators and additives. The results showed that the optimal medium for shoot regeneration and multiplication was MS medium containing 1 mg/l benzyl adenine (BA) and 6.5 g/l agarose. For shoot development, MS medium with 30 g/l sucrose, 5% coconut water, and 6.5 g/l agarose was most effective for shoot tips, while 10% coconut water was preferred for nodal explants. Rooting was successfully induced on MS medium supplemented with 30 g/l sucrose, 0.1 g/l activated charcoal, and 6.5 g/l agarose. Acclimatized plantlets exhibited a 75% survival rate, reaching an average height of 7.83cm and producing 16.55 leaves per plant within four weeks. These findings provide a valuable protocol for Petunia hybrida “Midnight Gold” in vitro mass propagation, meeting the increasing market demand for this popular ornamental species.

The production of rice is significantly affected by adverse environmental conditions such as drought and heat. Heat shock proteins (HSPs) play a crucial role in mitigating stress tolerance responses associated with temperature and oxidation, thereby safeguarding cells and macromolecules from detrimental effects. The regulatory mechanism of HSP activity in some plant species involves the involvement of Heat Shock Factor Binding Protein (HSBP). This study aimed to investigate the functional activities and elucidate the stress response regulation mechanism of OsHSBP1 in rice. The expression pattern of this gene was analyzed under drought and heat stress conditions in two rice varieties, BC15 and OM54541. The OsHSBP1 expression increased at various time points during artificial heat and drought stress. The coding sequences of OsHSBP1 from these rice varieties were isolated and fully sequenced, revealing a gene segment of 237 base pairs in length. This segment encodes a polypeptide chain comprising 78 amino acids, including an α helix, exhibiting a similarity ranging from 59.8% to 97.4% homologous to HSBP proteins studied previously. These findings provide a foundation for exploring the functional role of OsHSBP1 to improve the drought and heat stress resistance of the major rice varieties such as BC15 and OM5451 through genetic engineering..

A field study was conducted in 2023 Spring and Summer-Autumn cropping seaons in Quang Huy commune, Phu Yen district, Son La province to determine the most suitable combination ratio of organic fertilizers for organic rice cultivation. The experiment was laid out in a randomized complete block design with 3 replications, including 9 treatments of combining of compost (PCU), industrial organic fertilizer (HCCN) and green manure (PX), in which the control applied 100% HCCN. The N content conversion in the treatments was equivalent to the control. Green manure was soybeans sown from the Winter season in 2022. The results showed that PX increased soil organic matter content from 0.4 to 1.9% after the Spring cropping season and increased from 0.4 to 0.6% after Summer-Autumn cropping seasons compared to the control. Green manure increased the total nitrogen, available phosphorus and available potassium contents after the Spring cropping season from 0.04 to 0.07%, from 1.32 to 2.16 mg/100g and from 0.51 to 0.71 mg/100g, respectively, compared to the control. Winter PX + 50% PCU + 25% HCCN was the best combination treatment for organic rice cultivation in Son La with grain yield of 58.4 quintals/ha in Spring cropping season (5.9 quintals/ha higher compared to the control) and 51.2 quintals/ha in the Summer-Autumn cropping season (3.7 quintals/ha higher compared to the control), with additional profit of 17.2 million VND/ha/year.

The study was conducted to determine the species composition and abundance of the polychaetes in the improved extensive-shrimp ponds in Duyen Hai district, Tra Vinh province. Samples of polychaetes were collected from 6 ponds from two sites: (1) not covered by mangrove (no mangrove) and (2) covered partly by mangrove (with mangrove). Samples were collected monthly from January to December 2023. The results revealed that 12 species of polychaetes belonging to 12 genera, 7 families and 3 orders of the class Polychaeta were recorded. Number of polychates species collected by site and time in the ponds ranged from 3 to 10 species, corresponding to a total density of 8 to 141 ind./m2 and biomass of 0.39 to 8.78 g/m2. The results also showed that the species composition, density and biomass of the polychaetes in the no mangrove shrimp ponds was higher than in the ponds with mangrove. The same trend was noticed for density and biomass of each polychaete species. Three species with highest density and biomass were Dendronereis chipolini, Hediste diversicolor and Nephthys sp.

This study aimed to evaluate the effect of different cold holding times on the reproductive efficiency of the black apple snails (Pila polita). The experiment was conducted in 1m3 tanks (1 × 1 × 1m) with a density of 15 pairs of broodstock snail/tank and the height of water column at the beginning was 40cm. The experiment was arranged with 5 cold holding times, each cold holding time was repeated 3 times: Control (No.C); 15 minutes (C-15); 30 minutes(C-30); 45 minutes (C-45) and 60 minutes (C-60). The broodstock snails in treatment from C-30 to C-45 released highest egg clutches, reproductive efficiency reproductive participation rate (88.9-90.6%; 13.3-13.6 clutch/m2; 4,44-4,53 clutch/day/m2) was higher and different (P <0.05) compared with treatment No.C, C-15 or C-60. The results showed that the weight of egg nest and egg seeds in the eggs of snails in the treatment from C-15 to C-45 (10,05-10,26 g/clutch; 199-203 egg seeds/clutch) was higher and different (P <0.05) compared to No.C (9,48 g/clutch; 189 egg seeds/clutch) and C-60 (9,57 g/clutch; 188 egg seeds/clutch). The quality of snail eggs and juverniles of black apple snail wá influenced by the different reproductive stimulation methods.

Antibiotic-resistant bacteria and the circulation of drug-resistant genes are a threat to public health globally. Research results show that the rate of detected of colistin ressitant E. coli from pigs in small- scale pig farm in Soc Son - Hanoi was 72% (36/50 farms) and from farm-workers was 16% (8/50 farms). Of these, 10 E. coli strains from 05 farms were selected for analyzing their genomic sequences by Oxford Nanopore Technologies (ONT) systerm (one strain from pig and one strain from farm-worker each of five farms). The studied results showed that 38 resistance genes (14 genes located on chromosome và 31 genes located on plasmids) with 9 antibiotic group. 10 strains were determined to carry to 7-22 resistance genes simultaneously. E. coli strains carried resistance genes of β-lactams, colistin, tetracycline, sulfonamide, quinolon, phenicol, aminoglycoside, marcolide, trimethoprim. The mcr-1 and/or mcr-3 were found in 10 E. coli strains carrying colistin-resistance phenotype. One strain isolated from farmer and 3 strains isolated from pigs carried 2 mcr-1 and mcr-3 simultaneously. One E. coli strain (barcode 60 - PCE 20.1) was detected from pigs and another (barcode 67- PCE 31.1) was isolated from farm-workers were of the same resistance gen characteristic eventhought they were detected from two diffirent farms.

This study aims to explore the current state of goat consumption and identify barriers to cosumption process of ethnic minority households. The study was conducted through the collection of primary data using semi-structured interviews with 30 ethnic minority households engaged in goat farming, in-depth interviews with two key informants, and two local goat buyers. The findings indicated that goat farming presents opportunities to improve the income of ethnic minority households. However, the scale of goat farming remains small, and the goat market faces several challenges. Although farmers are able to sell their goats, they encounter multiple obstacles such as lack of buyers, unstable prices, and price pressures. The power in purchasing and selling decisions mostly lies with the buyers, while the goat-rearing households are often passive and dependent on buyers. Establishing and developing horizontal and vertical linkages in goat farming and consumption is necessary to create stability in production and output market.

The study was conducted to assess the current situation and propose solutions to improve the quality of training specialized courses using English language at the Vietnam National University of Agriculture. Purposive sampling of 30 lecturers and 169 students of English-taught training programs showed that teaching staff, training program and classroom organization, learning materials and resources, assessment methods, learning support were advantageous factors in training implementation. There should be policies to support lecturers and students, organize training courses and seminars to share experiences on teaching methods for lecturers, improve the quality of basic English training, provide electronic documents, bilingual documents and English learning software for students and diversify classroom activities to improve the quality of teaching specialized courses using English.

Studies worldwide and in Vietnam have highlighted the critical role of internal control, including risk assessment activities in economic organization, helping risk management units achieve their goals. This study aimed to evaluate the current state of risk assessment practices in agricultural cooperatives in Vietnam, applying the internal control framework based on the COSO model. Descriptive statistics reveal that the overall state of risk assessment in agricultural cooperatives was at a moderate level. However, activities related to risk analysis and assessment, as well as identifying strategies and methods for risk response, were rated as weak. Based on an analysis of the existing risk assessment practices and control activities in the cooperatives, the study offers several recommendations. These include raising awareness among cooperative management boards and members about the importance of risk assessment, integrating risk assessment into core cooperative activities, and implementing appropriate control measures tailored to specific risk groups.

With increasing pressure from population growth and resource consumption demands, the transition to a circular economy model in agriculture has become an urgent requirement for effective waste management and sustainable resource utilization. This study synthesized models for managing agricultural by-products from advanced countries such as China, EU, USA, Japan, and Thailand, focusing on policies and techniques aimed at optimizing the use of agricultural by-products. By analyzing literature from international sources, the research provides lessons on legal frameworks and technologies to promote the recycling and reuse of agricultural by-products in Vietnam. The findings indicate that the adoption of a circular economy not only reduces greenhouse gas emissions but also enhances the economic value of agricultural by-products, thereby improving the competitiveness of Vietnamese agricultural products. This contributes to building a sustainable agricultural sector that meets development goals and Vietnam's commitment to achieving net-zero emissions by 2050.

Human resources have emerged as a critical driving force as the tourism market integrates and transitions towards a digital economy. Previous research has highlighted the challenges faced by the tourism human resources in the Viet Bac Interzone for enhancing living standards and preserving unique historical and cultural values. Based on the secondary sources, this study evaluates the current state of human resources for tourism and outlines strategic solutions for the development within the region. The proposed framework includes several key initiatives: refining mechanisms and policies for tourism development and high-quality human resources, enhancing the effectiveness of forecasting and planning, ensuring a balance between the supply and demand of tourism human resources, boosting investment, and enhancing the capabilities of institutions training tourism human resources, fostering early and far-reaching development of tourism human resources, strengthening regional collaborations in training and development to elevate the quality of tourism human resources, and implementing advanced technology to enhance the productivity of tourism human resources.