Published: 2020-10-30

Value chain analysis of Mokara orchids cut flowers in Cu Chi district, Ho Chi Minh City

Tien T. M. Duong, & Quan V. Nguyen
Electronic version: 30 Oct 2020 | DOI: 10.52997/jad.1.05.2020
Abstract | PDF (298.8K)


The study was conducted to determine the value chain of Mokara orchids cut flowers in Cu Chi district, Ho Chi Minh City. Research data were collected by surveying 98 Mokara orchid farmers, 8 traders collecting flower branches, 8 Mokara orchid shop owners in Ho Thi Ky flower market. The study used descriptive statistics to assess the state of production and SWOT analysis to find out solutions for enhancing the Mokara orchid value. The results of the study showed that the average area for growing Mokara orchids was 0.33 ha per household. The average profit per 0.33 ha was VND 231 million per year. The value chain had 5 basic functions such as input function, production, collection, trade and consumption. There were 5 Mokara orchid value chains, corresponding to the value chain with 4 main trading channels. In particular, the trading channel for traders accounted for a high proportion (76.5%). The main source of selling price information came from traders (73.5%). Up to 55.1% of farmers believed that traders decided the purchase price. The compromise between farmers and traders on purchase price accounted for 32.7% and the rest of households (12.2%) set their own prices. Based on the results of value chain analysis, SWOT analysis was conducted to find out the strengths, weaknesses, opportunities and threats of partners participating in the value chain, thereby proposing some solutions to improve the production efficiency of Mokara orchid cut flowers in Cu Chi district, Ho Chi Minh City.

Effect of low-frequency tapping systems (d5; d6) on latex yield, labor productivity and latex physiological parameters on RRIV 106 clone

Hai V. Truong, Nang Nguyen, & Minh H. A. Bui
Electronic version: 30 Oct 2020 | DOI: 10.52997/jad.3.05.2020
Abstract | PDF (273.1K)


The tapping labor shortage has been identified as a major issue for natural rubber companies in Vietnam. This study aimed to determine a suitable tapping system to adapt to the labor shortage. The experiment was conducted on RRIV 106 clone at Dong Phu rubber company, Binh Phuoc province, Vietnam in two the tapping years 2018 and 2019. The results showed that the treatments of low-frequency tapping systems (d5, d6) increased individual yield per tree per tapping (g/t/t) compared with that of d4. The g/t/t of treatments d5 and d6 with latex stimulant (ET 2.5%) applied by 6 to 10 times per year (d5, ET.6/y; d5, ET.8/y; d6, ET.8/y; d6, ET.10/y) was 23; 27; 45 and 47% higher than that of the control (d4, ET.4/y), respectively. Labor productivity (kg/task/day) of low-frequency tapping systems increased similarly to g/t/t. The tapper requirements of low tapping frequency (d5 and d6) were 20% and 33% lower than that of d4, respectively. Land productivity per year (kg/ha/year) of low-frequency tapping systems (d5 and d6) was equivalent (98 to 101%) as compared with that of the control. The effects of tapping systems on latex physiological parameters, tapping panel dryness rate (TPD), and dry rubber content (DRC, %) were not significantly different.

Effects of Brassinosteroid on growth, development, yield and activities of some antioxidant enzymes of Jasmine 85 rice cultivar under salinity conditions

Tri M. Bui, Van H. Phan, & Sanh D. Nguyen
Electronic version: 30 Oct 2020 | DOI: 10.52997/jad.4.05.2020
Abstract | PDF (522.8K)


The objective of the experiment was to determine effects of Brassinosteroid (BRs) concentrations on growth, development and yield of Jasmine 85 rice cultivar under salinity conditions at panicle initiation stage. The experiment was laid out in a completely randomized design with three replications and consisted of two factors. The first factor comprised three salinity concentrations: 0%₀ (control), 2%₀ and 4%₀ and the second factor had three concentrations of BRs: 0 ppm (control), 2 ppm and 4 ppm. The results showed that under non-saline conditions, the control rice plants sprayed with BRs at a concentration of 2 ppm had the highest values of root length (33.39 cm), leaf area (42.41 cm2), proportion of firm seeds (72.20%), weight of 1000 seeds (28.14 g) and yield (725.55 g/barrel). At the salinity level of 4%₀, rice plants sprayed with BRs at a concentration of 2 ppm demonstrated the highest levels of APX and CAT enzymes. Briefly, rice plants grown under higher salinity levels had decreased growth and yield. Spraying BRs helped improve growth and yield parameters of rice under high salinity conditions.

Effects of temperature and time of thermal modification on density and colour of Pinus insularis and Dacrycarpus imbricatus wood

Boi D. Dang, Hoa V. Hoang, & Dung T. T. Ho
Electronic version: 30 Oct 2020 | DOI: 10.52997/jad.5.05.2020
Abstract | PDF (551.5K)


The Pinus kesiya and Podocarp (Dacrycarpus imbricatus) woods were obtained from the plantations of the Southeast region of Vietnam, with the initial humidity of 80 - 85%. The wood was cut into boards with dimensions of 40 x 80 mm to 120 x 500 mm. In this study, the Pinus kesiya and Podocarp woods were thermally treated at with high temperatures ranging from 161oC to 218oC and the duration from 7.5 h to 13 h. The experiment results showed that the oven-dry density of pine and Podocarp tended to decrease when it was treated at high temperatures during long periods of time. In particular, the density of Pinus kesiya and Podocarp woods decreased about 3.17 - 17.3% and 3.45 - 20.73%, respectively, compared with the control samples. In the thermal modification process, under the effects of high temperature Pinus kesiya and Podocarp woods became darker than the modified wood.

Using SSR markers for evaluation of genetic variation among sesame (Sesamum indicum L.) accessions

Tuyen C. Bui, Toan D. Pham, & Biet V. Huynh
Electronic version: 30 Oct 2020 | DOI: 10.52997/jad.2.05.2020
Abstract | PDF (420.7K)


Sesame (Sesamum indicum L.) is an annual plant belonging to the Pedaliaceae family which is considered to be the oldest of the oilseed plants. Sesame is known as the king of oilseeds because its seeds contain high oil content (50-60%). The objective of the study was to evaluate the genetic variation of sesame accessions based on ten SSR markers. The results showed that all sesame accessions showed high genetic similarity among individuals in each accession. Polymorphism information content ranged from 0.24 (TNB17) to 0.37 (MT20). HO varied from 0.04 (MT30) to 0.25 (GENE1). The highest HE was 0.37 (MT20) and the lowest HE was 0.28 (TNB17). The results also displayed the high genetic diversity among 7 sesame accessions. The genetic diversity distance varied from 0.0 to 1.0. Dendrogram analysis divided 7 sesame accessions into 5 clear groups at an average genetic distance of 0.25. The results achieved would be useful information for genetic evaluation and sesame breeding development in the future.

Evaluation of dietary supplementation of organic minerals on survivability and feed efficiency in larval rearing of striped catfish (Pangasianodon hypophthalmus)

Binh T. T. Vo, Hung T. Le, & Duy K. Ho
Electronic version: 30 Oct 2020 | DOI: 10.52997/jad.7.05.2020
Abstract | PDF (339.2K)


Microminerals of Zn, Se, Cu, Fe, Mn and Cr were supplemented in the feed either in inorganic minerals (sulfate salt) or organic minerals (Methionine-mineral) at various concentrations over an 8-week period. Catfish fry (15-day old) were fed the experimental diets for 8 weeks. At the end of the feeding trial, fish were challenged by immersion in a solution of Edwardsiella ictaluri bacteria. The mortality was monitored for 14 days. The results showed that the survival rates of fish fed the organic mineral-supplemented diets were higher than those fed the inorganic mineral-supplemented diets. Treatment 7 supplemented with organic minerals of 60.0 mg/kg Zn, 0.40 mg/kg Se and 0.40 mg/kg Cr had the highest weight gain and survival rates and the lowest FCR, there were significant differences in those parameters between treatment 7 and the control diet supplemented with inorganic minerals. The variation in fish weight and length of treatment 7 was also lowest and significantly different (P < 0.05) from that of the control treatment. After 14 days of bacteria challenge, the cumulative mortality of fish in the control treatment was highest (67.86%) and the cumulative mortality of fish in treatment 7 was lowest (34.82%), and the cumulative mortality rates of fish in these two treatments were significantly different (P < 0.05) from those of the others. The cumulative mortalities of fish in organic minerals treatments were lower than those of fish in inorganic mineral treatments. The study indicated that the dietary supplementation of organic minerals of zinc (Zn), selenium (Se) and chromium (Cr) would improve growth, survival rate and disease resistance to E.ictaluri bacteria in Pangasius catfish nursing (from 15 to 75 days old).

Assessment of heavy metals content and consumer health risk to Siganus fuscescens (Houttuyn, 1782) from Quang Binh province

Thiep V. Vo, Yen T. Tran, & Vu A. Hoang
Electronic version: 30 Oct 2020 | DOI: 10.52997/jad.6.05.2020
Abstract | PDF (413.7K)


Siganus fuscescens Houttuyn, 1782 is one of the common fish species in Quang Binh province and consumers are favored by its high nutritional value. However, the consumption of Siganus fuscescens may pose potential risks to human health since they can accumulate significant amounts of heavy metals in their tissues. From July to October 2019, a total of 50 individuals of Siganus fuscescens were randomly collected through fishermen at local markets in Quang Binh province. Liver, gills, and muscles were dissected and analyzed for cadmium lead, copper, zinc, and iron contents by the flame atomic absorption spectrometer, and the cold vapor atomic absorption spectrometer for mercury content. The metal content in all tested samples was lower than the threshold limit value by the Vietnamese Ministry of Health (MoH). The risk to human health by the intake of metal contaminated Siganus fuscescens was evaluated by estimated daily intake (EDI), target hazard quotient (THQ), and hazard index (HI). All of the EDI values were below the provisional tolerable daily intake (PTDI) set by the MoH, and all of THQ and HI values for male and female consumers did not exceed 1, indicating that there was no potential human healthrisk in consuming Siganus fuscescens from coastal areas of Quang Binh province.

Effects of stocking density on growth performance, survival rate and economic efficiency of Asian seabass (Lates calcarifer) cultured in earthen pond

Nhan T. Dinh
Electronic version: 30 Oct 2020 | DOI: 10.52997/jad.8.05.2020
Abstract | PDF (413.8K)


This trial aimed to evaluate effects of stocking densities of 1-5 fish/m2 on growth performance, survival rate and economic efficiency of Asian seabass (Lates calcarifer) in earthen ponds. Fish with an initial length of 90.7 ± 0.1 mm and weight of 20.8 ± 0.1 g/fish and ponds with 600 m2 each and 1.5 m depth were used for this study. Experiment was designed with three treatments, including different stocking densities of 1, 3 and 5 fish/m2. The fish was fed with pellets feed containing 43 – 44% crude protein. Water quality parameters including temperature, dissolved oxygen, pH, salinity, transparency and ammonia concentration were measured once a week. Fish were sampled every 30-day intervals for length and weight measurement then for their growth estimation. Costs were recorded for economic efficiency estimation. Results showed that the water quality parameters were in suitable ranges for growth and development of Asian seabass. The final average length and weight of density 1 fish/m2 was significantly higher than those at 3 and 5 fish/m2 (P < 0.05). However, there was no significant difference on the fish growth in terms of daily length and weight gain, as well as survival rate and feed conversion ratio between different stocking densities. Asian seabass culture at 3 and 5 fish/m2 resulted in a higher profit compared to at 1 fish/m2. The highest economic efficiency in terms of area pond was showed at 5 fish/m2 treatment.

Selection of glufosinate-resistant cotton lines (Gossypium hirsutum L.) among bar transgenic lines

Tri M. Bui, Nha T. Nguyen, & Kiem T. Phan
Electronic version: 30 Oct 2020 | DOI: 10.52997/jad.9.05.2020
Abstract | PDF (461.9K)


Basta-herbicide was tested at a concentration of 0.6 kg ai./ha for confirming resistance of 116 bar transgenic T1 lines; many lines with tolerance were obtained. Evaluation of selected lines using PCR, the integration and expression of transgenes in genome of transgenic plants was determined by southern blot and northern blot techniques. The combination of molecular and biological assessments resulted in the selection of 5 lines, i.e., B1, B6, B9, B18, and BF17 contained 01 target-gene copy which expressed transcription activities and showed uniform growth and best tolerance to glufosinate. Two T2 transgenic cotton lines, i.e., B9 and BF17, carried one copy of the gene which transmitted to the next generation according to the Mendel’s rules of inheritance. These transgenic lines were highly resistant to Basta-herbicide at a concentration of 0.6 kg ai./ha and had no difference in botanical characteristics and disease resistance in comparison with original non-transgenic Coker310 cotton plant.

Surveying decorative lights of garden cafe in Thu Duc district and proposing some new light patterns for the garden cafe

Tien T. M. Duong, Thuy T. Vuong, Thao V. Nguyen, Nam P. Cam, Hang T. Nguyen, & Thao N. Le
Electronic version: 30 Oct 2020 | DOI: 10.52997/jad.10.05.2020
Abstract | PDF (1.8M)


This study was carried out from September 2018 to May 2019 at some garden cafes in Thu Duc district. The objective of the study was to survey different types of lights used for decoration of cafe gardens. The study used questionnaires of light characteristics for data collection and then the information collected was analyzed and evaluated for creating lighting designs. The district selected for investigation was divided by wards, routes and cafe areas. The results showed that the majority of 40 garden cafes investigated had LEDs with yellow or white color. Due to the space of cafes, drop lights were preferred and light installation was focused on walkways using lights without lampshades. Five lighting models were designed using concentrated lighting with natural images such as bamboo, sunshine, water surface and folk items like bamboo fish trap. Briefly, the findings of this study would contribute to the improvement of decorative lights for existing garden cafes in Thu Duc district.