Vol. 20 No. 5 (2022)

This study aimed to assess the combining ability for yield and quality of purple waxy corn and sweet corn. A full diallel cross of six corn inbred lines (three purple waxy lines and three yellow sweet corn lines) was employed in 2020 Autumn-Winter season. Six parental lines and thirty F1hybrids were evaluated in 2021 Spring season at Vietnam National University of Agriculture. The field experiments were arranged in a randomized complete block design, with three replicates. The ratio of GCA/SCA less than 0.5 in most traits suggested that the non-additive gene action was more significant than the additive gene action for these traits. SCA is more important than GCA in high quality hybrid corn breeding. Reciprocal effects (REC) were found that the cross between purple waxy corn × sweet corn was more effective than the cross between sweet corn × purple waxy corn in terms of yield and quality traits. Seven hybrids that had potential commercialization with high SCA on yield-related traits and quality were identified, viz, THL1, THL2 (purple waxy), THL4, THL5, THL13 (purple waxy sweet), and THL20, THL30 (yellow sweet).

Understanding host-pathogen interactions is key in breeding disease-resistant crops, including bacterial leaf blight. As a key virulence strategy to cause bacterial leaf blight, Xanthomonas oryzae pv.oryzae(Xoo) secretes transcription activator-like effectors (TALEs) to control the expression of host target genes through binding to the effector-binding elements (EBEs) located on the promoter regions. Precise mutagenesis at the TALE-interaction sites on the host genes by using gene editing tools such as clustered regularly interspaced short palindromic repeats/CRISPR-associated protein-9 nuclease (CRSIPR/Cas9) has been seen as a promising way to improve BLB resistance ofrice cultivars. In a previous study, we generated some transgenic TBR225 rice lines containing a single copy of CRISPR/Cas9 expression construct for editing AvrXa7/Tal5EBE on the promoter OsSWEET14. In this study, we continued to evaluate genotype and phenotype of T1edited TBR225 lines to determinethe genetic stability and phenotypic effective of the CRISPR/Cas9-induced OsSWEET14mutations. The genotypic analysis showed that 65%of transgenic TBR225 plants harbored the targeted OsSWEET14mutation, including nucleotide (Nu) insertion and deletion. The OsSWEET14mutations were stably inherited to the next generation with an expected segregation ratio consistent with Mendelian segregation (1:2:1). The preliminary phenotypic analysis suggested that the mutation of OsSWEET14promoter did not affect the growth and yield of gene-edited rice plants. Some T1TBR225 lines showed the resistance to Xoo isolate VXO_11 in the leaf-clipping experiment. The obtained results are a premise for development of the BLB-resistant TBR225 rice variety in the future.

The research was conducted to evaluate the effect of biochar on growth, physiological traits and yield of groundnut cv. L27 under saline conditions. The two-factor experiment was arranged in a split-plot design. Factor 1 consisted of 4 rates of biochar (0, 5, 10, and 15 tons ha-1); factor 2 consisted of salinity and non-salinity conditions. The saline stress was imposed every three days for 30 days with 200 ml of 100mM NaCl solution at the flowering stage. The results showed that salinity significantly reduced growth and physiological parameters. Besides, salinity significantly increased the relative ion leakage and the water saturation deficit in the leaves resulting in reduced yield components and individual yield. The application of biochar improved growth and physiological parameters, yield components, and individual productivity in both salinity and non-salinity conditions. Comparison among biochar rates showed that the highest values of growth, physiological parameters, yield components, and individual productivity were observed in 10 tons biochar ha-1.

Egg production is an important economic trait in poultry production in general and egg-laying hens in particular. Prediction of eggs performance at early stage could improve livestock efficiency by setting up a early production plan. This study was conducted to describe the egg production rate and determine the best models to estimate egg production at the peak of egg-laying of D310 chickens raised at experimental farm, Faculty of Animal Science of Vietnam National University of Agriculture from December 2020 to May 2021. Five functional nonlinear models (Logistic, Compartmental I, McNally, Compartmental II and Yang) were used to estimate egg production rate at the peak of egg-laying from 19 to 49 weeks of age. Egg production rate was collected from 360 hens from 19 weeks of age (fisrt egglaying week) to 49 weeks of age (26 weeks of egglaying period). The egg production rate at the peak of egg-laying (a) estimated by Logistic model was 0.839. The mean egg production week at egg production peak estimated by Logistic model was 5.265 eggs. The Logistic function appeared most appropriate to describe egg production rate of D310 chickens with the highest coefficient of determination (99.58 %) and the lowest values of AIC (-1862,53) and BIC (-1843,82).

The study focused on describing the otolith morphology of 14 fish species in the territorial sea areas of Cat Ba (Hai Phong) and Tho Chu (Kien Giang) islands. Using the descriptive method of the authors Harkonen, Campana, Svetocheva; Brodeur. The results showed that otoliths had various shapes and structures such as bow-shaped ellipse (Sargocentron rubrum…), leaf-shaped (Hemiramphus sp…), disc-shaped (Plotosus lineatus…); rostrum,antirostrum(Pentapodus setosus - long;Sargocentron rubrum - unclear), ostium, cauda - shallow, deep(Selaroides leptolepis -shallow; Crenimugil pedaraki- deep…). The otolith size measured using the software Olympus cellSens Standard 2.2 and the ShapeR package in the R programming language.The results indicated thatthere existed differences in otolith size between species (F >> 1; P<0,05).The average size OL, OW, P of Longfin mullet (Crenimugil pedaraki) was highest (OL = 8.03 ± 0.12; OW = 4.07 ± 0.08; P = 24.38 ± 0.15) and the size of Decorated ponyfish(Nuchequula gerreoides)wassmallest (OL = 0.75 ± 0.01; OW = 0.37 ± 0.02; P = 1.35 ± 0.112). The ratio OL/OW has the highest value for tropical sand goby (Acentrogobius caninus)(0,84) and the lowest value for shrimp scad (Alepes djedaba)(0.34).This ratio was different between species (F = 169.1; P <0.05).

Canine Parvovirus type 2 (CPV-2) is a virus that causes acute diarrheal enteritis in dogs. CPV-2 is a DNA virus and based on the VP2 gene sequence, CPV-2 is clasified into CPV-2a, CPV-2b and CPV-2c. Currently, CPV-2c is the most popular variant circulating in the world as well as in Vietnam. In this study, the genome sequences of eight canine Parvovirus strains isolated in some northern provinces of Vietnam during 2018-2020 were sequenced. The results of genome sequencing of the Parvovirus strains have obtained genetic sequences of 4269 nucleotides (nt) in length, in which the gene sequence coding for the open reading frame (ORF) corresponding to the non-structural proteins was 2007 nt and structural proteins was 2256 nt in length. The phylogenetic analysis based on the full genome sequences showed that all eight present canine Parvovirus strains belonged to CPV-2c and shared the same evolutionary brand with clade Asia-4. The whole genomic sequence data of canine Parvovirus obtained in this study will be an important source for any spatial and temporal genetic evolution studies of canine Parvovirus strains circulating in Vietnam.

This study was designed to estimate the additive genetic, heterotic, and maternal effects on harvest body weight and survivalof tilapia (Oreochromis niloticus) combinations in a 4x4 complete diallel cross involving four populations, i.e. NOVIT, GIFT, China, and the Philippines. Mass spawning method was applied to produce hybrid combinations (with 60 males and 60 females per cross) for testing on harvest body weight and survival at three locations, Quang Nam, Tien Giang and Bac Ninh. A total of 8,001 Nile tilapia was evaluated after a grow-out period of 6 months. A linear mixed model was used to estimate strain additive genetic, heterotic, and maternal effects for body weight and survival at harvest. Research results showed that the non-additive genetic (heterotic) effects were small and not significantly different from zero for the traits studied, whereas the additive genetic effects were statistically significant (P <0,001). Based on heterotic and additive genetic effects among crosses, pure crosses between Novit and Novit showed the highest additive genetics effects, while different strain cross between Novit and the Philippines indicated the best additive genetics effects.

This article presented the spatial vibration model of a Frontloader Tractor (FLT), which is formed based on a universal wheeled tractor combined with a frontloader when traveling on the road roughness profile. In the model, a method for determining the components of the moment of inertia of the wheel loader corresponding to different lifting positions was proposed. The results of solving the system of oscillating differential equations are an important premise to study the influence of the wheel loader on the motion stability, control features, and traction ability of the FLT, serving as a basis for perfecting the machine model.

Golden oyster mushroom (Pleurotus citrinopileatus) is a popular edible medicinal mushroom that contains diverse bioactive compounds. This study aimed to optimize culture conditions for spawn production and cultivation of golden oyster mushroom. In this study, golden oyster mushroom mycelial were incubated at some different temperature levels; besides, mycelial were incubated on the supplemented medium with different carbon and nitrogen sources.The results showed that the optimal temperature for mycelial growth was 25C±1. Fructose (20 g/l) and peptone (4 g/l) were considered the most suitable carbon and nitrogen source, respectively. The substrate containing 49.50% sawdust, 49.50% cotton, and 1% CaCO3 gave highest yield performance (31.45%) of the mushroom.

Bank credit activities for foreign direct investment (FDI) enterprises at the Joint Stock Commercial Bank for Foreign Trade of Vietnam - Bac Ninh branch (Vietcombank Bac Ninh) have been developed and contributed significantly to the development of Bac Ninh province on the way to the top provinces in terms of attracting foreign investment. However, its efficiency and market share is still limited. This article assessed the current situation and proposed some solutions to improve the credit quality of FDI enterprises at Vietcombank Bac Ninh through primary information collected from 80 FDI enterprises with outstanding loans on credit quality in 2021. Data were processed by SPSS 20 software, and analyzed by EFA factor analysis and regression analysis. Results showed that there were four groups of factors: credit policy, credit procedure, service quality, and credibility, of main interest to customers. The article proposed some solutions to improve credit quality for FDI enterprises for banks in the coming time, including: improving responsiveness, promoting service capacity, enhancing reliability and perfecting control and supervision activities.

The aim of the study was to identify the factors influencing the decision of using information technology for accounting work at small and medium-sized enterprises in Hanoi city. Applying the model of theory of planned behaviour (TPB) and technology acceptance model (TAM), the study developed the research framework for explanation of reason and scope in survey. The study used 186 small and medium-sized enterprises in Hanoi with 23 criteriawere analyzed by structural equation modelling (SEM).The research results showed 4 key groups of factors that affect the decision of using information technology for accounting work; among them, the most influential factor belonged to perceived behavioural control, followed by the groups of perceived usefulness, subjective norm and perceived ease of use.

This study attempted to assess the effect of rice farmers’ participation in linkage system on their farm performance. Data used for the study were collected through the househould survey with 113 rice farmers located in Vi Thuy district of Hau Giang province. The propensity score matching (PSM) method was employed to assess the impact of the linkage on rice farmers’ farm performance. Results showed that farmers’ participation in the linkagehad no impact on rice yield. However, participation in the linkage helped the farmers obtain higher selling price for rice and reduce production cost. Remarkably, the farmers engaging in the linkage system were not likely to gain higher net revenue as compared to non-participants.

This study used a dataset of 100 tea farming households surveyed in 2018 and 2019 in Yen Son district, Tuyen Quang province. Statistical analysis was used to analyze the current situation of tea production of the households while the binary logit model was used to analyze the factors affectingthe household’s decisionto participate in the association.In addition, the study also usedthe analysis of the impact of linkageson the income of households by using the propensity score matching. The results showedthat the decision to join the association of households was affected bygrowing area, number of household’s laborers, household’s assets (cellphones, tea harvester), and educationof the household head. Further policy implications were given such as continuing the land consolidation policyandstrengthening support policies such as training, input and output, promotion, and branding.

In the context of complicated developments of the Covid-19epidemic, Vietnam's livestock industry is suffering a lot from the sharp drop in output prices of products, while input materials increase, causing many difficultiesfor re-production. For sustainable stress reduction, insects or their larvae could be a promising alternative protein source. The results of synthesizing information and data from previous studies show that black soldier flylarvae have the ability to convert organic waste to create high-quality protein sources, control some harmful bacteria and insects, and provide healthy nutrients, providepotential chemical precursors to produce biodiesel and provide high-value nutrients for animal feed use. By desk researchmethod, a synthetic approachwasused in this review to provide an overview of the biology of the black soldier fly, its role inenvironmentally friendly management of waste, its potential for fish, poultry and animal feed industries of Vietnamas well as liquid fertiliser for crop production.