Neochetina eichhorniae (Coleoptera: Curculionidae) is a natural enemy of water hyacinth and its morphology as well as biology has been investigated previously. In this study, the host range of N. eichohorniae was examined using the following 7 groups of plants: Pontederiaceae (water hyacinth, Eichhornia crassipes; hastate-leaf pondweed, Monochoria hastata); food crops (rice, Oryza sativa; maize, Zea mays; sweet potato, Ipomoea batatas and cassava, Manihot esculenta); vegetables (cucumber, Cucumis sativus; mustard greens, Brassica juncea; turnip, Raphanus sativus; water spinach, Ipomoea aquatica; pepper elder, Peperomia pellucida; cabbage, Brassica oleracea var. capitata); herbaceous (boat lily, Tradescantia discolor, gotu kola, Centella asiatica, purple-heart, Tradescantia pallida); fruits (mango, Mangifera indica; longan, Dimocarpus longan; rambutan, Nephelium lappaceum); water plants (sacred lotus, Nelumbo nucifera; red water lily, Nymphaea rubra, yellow bur-head, Limnocharis flava) and industrial plants (sugarcane, Saccharum ssp.; peanut, Arachis hypogaea). The N. eichohorniae was found to be the only survivor that developed and completed its life cycle on water hyacinth. The N. eichohorniae caused only minimal damage to hastate-leaved pondweed and its life cycle was not completed on this weed. When fed with water hyacinth, N. eichohorniae female produced 358.9 eggs on average and the egg-laying period was 16 weeks. Forty three percent of eggs were laid from the 5th to the 8th weeks after females emerged from cocoons. The hatch-ability of N. eichohorniae eggs was 75.2% and 66.8% of the larvae could survive and became pupae. Approximately 79.1% of the pupae emerged as adults. Among the adults, the female ratio was 48.7%. These results indicated that N. eichohorniae could be considered as a natural enemy to be used for biological control of water hyacinth.

The study on General Combining ability (GCA) of 15 cucumber in-bred lines (I5) was carried out at the Research and Development Center for High-tech Agriculture, Ho Chi Minh City. The objective of the study was to identify the appropriate parental lines for producing F1 hybrid cucumber cultivars. Experimental materials included 15 cucumber inbred lines (I5) (L3, L9, L21, L22, L28, L32, L33, L36, L39, L61, L63, L69, L71, L74 and L78) and two test lines (T1 - TN 456 from Trang Nong Company, imported from Thailand and T2 - Cuct 1450 from Chia Tai - Thailand), forming 30 hybrid combinations by the method of topcross. The results showed that seven inbred lines including L3, L9, L21, L28, L33, L61 and L71 had high ability to combine with both T1 and T2 tester lines abby fruit yield with GCA index from + (0.8) to + (9.4). Evaluation of 30 cucumber hybrid was combinations on the growth and fruit yield characteristics showed that L28/T1 and L71/T2 hybrids were significantly different from other hybrids with high yields of 43.1 tons/ha and 41.3 tons/ha, respectively.

The objective of this study was to determine the bioaccumulation of heavy metals (HM) (Cu, Zn, Hg, Pb and Cd) in 15 tissues (brain, breast muscle, sternum, thigh muscle, femur, blood, heart, lung, gizzard, liver, intestine, spleen, pancreas, bile and kidney) of domestic ducks exposed to HM-contaminated water with levels equal to values specified in the column B of QCVN 40:2011/BTNMT. The experiment was a completely randomized design with two treatments: without exposure to HM (CT) and with exposure to HM (ET). Each treatment was replicated 3 times. Ducks were randomly allocated to the treatments with a stocking density of 10 ducks per cage and reared for 8 weeks. The results showed that concentrations of HM, particularly toxic metals such as Hg, Pb and Cd, in all tissues of duck in the CT were lower than those in the ET. The highest levels of HM in tissues were found in the liver and kidney. In the ET, Pb levels in kidney and bone and Cd levels in liver and kidney exceeded the permissible exposure limit according to the guidance of the Ministry of Health of Vietnam and the European Commission. This study demonstrated that the accumulation of HM in duck tissues could happen even though ducks were exposed to relatively low concentrations of HM in water. Thus, further investigation on the bioaccumulation of HM in farmed ducks as well as wild water-birds should be conducted in the near future.

The objective of this study was to evaluate the effects of dietary supplementation of vitamin E on reproductive performance of Japanese (JP) laying quails from 49 - 132 days of age. A total of 40 JP quails of 49 days of age were randomly assigned to 1 of 4 dietary treatments and there were 10 replicate cages per treatment with each JP quail per replicate. The experimental diets were as follows: (1) the control was a basal diet without vitamin E supplementation (KPCS); (2) E75 consisted of KPCS supplemented with 75 mg vitamin E per kg of feed; (3) E100 consisted of KPCS supplemented with 100 mg vitamin E per kg feed, and (4) E125 consisted of KPCS supplemented with 125 mg vitamin E per kg of feed. The experiment was carried out for 12 weeks from December 23th, 2019 to March 15th, 2020. The results showed that from 105-132 days of age, the laying rate and egg weight of the E100 (93.57% and 11.42 g), control (90% and 11.58 g) and E75 (89.29% and 11.39 g) were significantly higher (P < 0.05) than those of the E125 (79.44% and 10.04 g), respectively. There were no significant differences among treatments in feed consumption and feed conversion ratio (P > 0.05). Egg parameters such as eggshell weight and its percentage, albumin percentage and eggshell thickness were significantly different among treatments (P < 0.05). Briefly, it is suggested that either 75 mg or 100 mg of vitamin E should be added to the feed to improve the egg performance of JP quails.

This study was carried out to evaluate the effects of storage temperature (5 - 7oC, 29 - 31oC, and 50oC) and relative humidity (RH 10 - 84%) on the stability of antioxidant compounds such as betacyanin, polyphenols. The changes in color, moisture content, the water activity of spray-dried red  flesh  dragon fruit powder during storage were also observed. The results showed that after 40 days of storage at 5 - 7oC, the samples got betacyanin content of 3.76 mg/100 g dw and a total phenolic of 28.31 mg/100 g dw. These values were higher than those of samples stored at ambient temperature (29 - 31oC) and 50oC. Besides, this study also recorded that the low relative humidity of the environment at 10 - 23% maintained the product’s betacyanin (4.16 - 3.61 mg/100 g dw) and polyphenol content (27.29 - 25.66 mg/100 g dw) as well as a desirable water activity, which was better than the zone from 57% to 84% (0.28- 0.3).

Nowadays, building a land database and land use planning database is an indispensable requirement, especially for a seaport city as Vung Tau city (Ba Ria - Vung Tau province) where there are complex land fluctuations. Accordingly, a complete land use planning database with the participation of community will contribute to connecting planners, managers and people, and increase the publicity, transparency and feasibility of land use planning options. The study designed a database model of land use planning with the community consultation for Vung Tau city in accordance with the land data standards of Circular No. 75/2015/TT-BTNMT. Based on the designed model, a set of land use planning database with high accuracy was created and it was in line with the data standards of the Ministry of Natural Resources and Environment and the designed database model. This database structure contained 22 spatial data tables on ArcGIS and 8 attribute data tables (with the community consultation) on Microsoft SQL Server. Finally, we successfully used the VBDLIS software to build the land use planning database (period 2010 - 2020) for Vung Tau city with 6 data layers, including land use planning data layer (15.060 records), project layer (163 records), adjustment layer for land use planning (12.002 records), adjustment layer for project (570 records), and 2 attribute data layers of community consultation. The results of this study indicated that the correct model and complete database structure were the basis for successfully building and effectively exploiting the database of land use planning. The designed model could contribute to the planning of land management and improve the efficiency of land use.

The study was conducted from June to September 2020 in Ho Chi Minh City. This research aimed to identify the palm species and incorporate them into the garden design. To investigate the species, 85 ornamental plant stores and nurseries were surveyed in Go Vap district, District 7 and at Highway 22. Then, morphological comparison method was used for plant species classification. According to the analyses, this region had 25 species belonging to 22 genera in the Arecaceae family. Twenty two of the 25 species surveyed were imported and 03 being native to the area. The majority (68%) was solitary-stemmed palms, with the remaining 08 species having clustered trunks (32%). To incorporate palm trees into the garden design, Sketch-up, Lumion, and Photoshop software were used.

Ba river is the biggest river system in the South-Central Coast of Vietnam and plays a significant role in the socio-economic development of the region. Recently, land-use changes in Gia Lai province have been significantly transformed. Hence, to provide the information for land-use planning, there is an urgent need for land-use change assessment in the upstream Ba river basin. This study employed the Markov chain coupled with GIS to assess land-use changes between 2010 - 2015 and 2015 - 2020 periods. The results showed that during the period 2010 - 2015, there was no significant conversion of agricultural and reserve forest land. Meanwhile, a large proportion of unused (86%) and water and aquaculture land (57.5%) was converted into the other land-use types. Between 2020 and 2015, unused land decreased while the surface water and aquaculture land increased. The forest land accounted for a significant area (51.16%) during the 2015 - 2020 period. In addition, the driving forces leading to these changes were also analyzed, providing a more comprehensive of land-use change in the study area. In general, GIS and Markov were suitable for assessing land-use change. This study outcomes provide a general framework for land-use planning in Gia Lai province.