Vol. 10 No. 6 (2012)

Five types of sex pheromone lures: Standard DJ- 2 mg (Z11-16Ald:Z9-16Ald) 3:1 ratio; Combined 1mg DJC - Z11-16Ac: Z13-18Ac 1:10 ratio and 1mg Z9-16ald: Z11-16Ald with 1:3 ratiol; DJZ1 - Z9-16:Ald (25 µg), Z11-16:Ald (75 µg) and Z9-18:Ald (12.5 µg); DJZ2- Z9-16:Ald (250 µg), Z11-16:Ald (750 µg) and Z9-18:Ald (125 µg) and DL - Z11-16:Ald: Z9-16:Ald with 2:1 ratio were tested in bottle trap design experiments conducted at Hanoi and Hai Phong. The experiment was arranged in a randomized complete block design with 5 replications. The distance between traps was 30m. The results showed that the average number of adult males caught in a trap per night was highest at the combined lure (DJC), followed by the standard lure (DJ) and the least was DJZ1 and DJZ2. Integrated effect of 4 components of the combined lure (DJC) showed the highest effect. Additional components (Z9-18L: Ald) compared with standard (DJ) has reduced the number of of adult males.

The experiment aimed to define suitable fertilizer dose for vegetative growth and tuberous root yield of mondo grass on Ferralic Acrisols at Phu Tho province. Amongsix different fertilizer doses of fertilizer applied, 10 tons organic fertilizer +20kg N + 30kgP2O5+ 30kgK2O/ha appeared to be most suitable to obtainmaximum tuberous root yield and economic efficiency.

“Bach Chi” is a medicinal plant and an essential constituent in traditional medicine. The plant has abundant flowers and fruits distributed on the different umbels. Time of flowering, number of umbels, umbel size, seed size and seed yields are different on each umbel position. Seed yield is highest on the secondary umbels (149.5 gr), but lowest on the central umbels. The aims of this paper are to determine whether the seed quality varies with umbel position and any effect of umbel position on growth, development and yield of Angelica dahurica Benth. Et Hook. F (Apiaceae) exists. Seeds were collected at five umbel types (center, primary, secondary, teriary and posterior umbels uppermost). Characteristics of individual umbels (duration of flowering, size) and plants (reproductivity, age, height, basal diameter) were recorded. The results showed that plants obtained from fruits on primary and secondary umbels grew much better (i.e. plant height, root diameter and yield) than those in collected from other umbels. The highest of root yield (3.16 ton/ha) and grade I percentage of roots (94.32%) were obtained from plants derived from seeds harvested on secondary umbels. The fruits on the primary, secondary and tertiary umbels are recommended for high quality of seeds to produce high quality of Bach Chi roots.

The use of irrigation mat made from textile materials is a new research trend for hi-tech agriculture. This technology has been using in developed countries such as Germany and the Netherlands. This paper summarized the study results on the effects of irrigation mat KT2 and three types of substrates on the watering cycle, the required amount of water, the growth and quality of dwarf marigold. The study composed of three experiments. The experiments were conducted with six treatments using the random complete block (RCB) design in the nethouse from January to June 2011. The experimental results indicated the following advantages of using irrigation mats: limitation of water loss, an appropriate water amount based on the demand of plant, long moisture retention of the substrates, extended watering cycle, and reduced water requirement and labor as compared with control treatment (no irrigation mats). Growing the plants using the substrate No.3 (alluvial soil, cattle manure, sooked rice husk and coconut fiber with the ratio 1.5:1:1:0.5) in combination with irrigation mat and normal irrigation methods gave better results than the substrate number 1 (alluvial soil) and 2 (alluvial soil, cattle manure and burning rice husk with the ratio 3:1:1).

The application of aeroponic system for propagation of Dendrobium nobile Lindl. in the nursery phase has opened a new way for the development of the model in culturing this species in the northern provinces. The results showed that Dendrobium nobile Lindl. grown in the aeroponic system had the maximum adaptability, attaining survival rate of 100% after one month of planting in the spring, spring-summer and summer seasons. The aeroponic system can be applied for propagation in all cropping seasons around the year, while the hydroponic system or planting on the substrate cannot be done in the summer period. The plants grow better in the aeroponic nutrient solution III (improved from Knoop solution) with pH = 6.0 - 6.5; EC = 400 - 500 µs/cm; the spraying time of 2 minutes in 4 hours interval.

A new chemical control method has been applied on Mimosa pigra L., one of the most dangerous weeds in the world, to control this species in a safer way with less environmental pollution. NaCl at different concentrations were applied directly on the leaves or secondary leaflets of this plant. The results showed that NaCl caused the browning on Mimosa pigra L. leaves, starting from the tip of the secondary leaflet, spreading to the base. Browning area increased over time after treatment and with the increase of NaCl concentration. The leaflets browning appeared after 24 hours and completely damaged after 2 days of NaCl 30 g/l treatment. NaCl 30 g/l caused the loss of chlorophyll, primary parenchymal cells plasmolysis, stomatal closing, and death after 24 hours. The loss of chlorophyll in chloroplasts appeared firstly at palisade parenchyma tissue and spread to other parenchyma tissue below. This was the original browning caused by NaCl on Mimosa pigra L. leaf.

Nowadays, agricultural practices cause serious problem for soil environment, especially in the long-term intensive agriculture system. Soil quality assessment using physicochemical method has many disadvantages. On the other hand, soil quality assessment using biological method offers several advantages, i.e. it provides accurate results at the sampling time and can predict long-term effects of pollution on the growth of living organisms in the soil. This study used nematodes as bioindicator to assess the quality of pepper cultivation area in Loc Hung commune at six sampling points, sampling notations were LH1, LH2, LH3, LH4, LH5 and LH6. A total of 35 genera belonging to 21 families and 8 orders were recorded. By analysing the community structure and calculating the biological diversity index (the Margalef index (d), the maturity index (MI), cp value and establishing ecological triangle model), our study showed that the soil quality in this studied area is relatively stable and does not suffer any significant contamination.

The present experiment was conducted to assess bio-agronomical characteristics and genetic diversity of forty-one rice asseccions. Results showed that these rice assessions possess short growing period and several of them are of short stature suitable for intensive farming. The number of panicles/hill, length of panicles, length and width of flag leaves, and 1000 grain weight are genetically diverse. Most of the accessions have long grain and serve as genetic resources for breeding of quality rice. Based on 14 phenotypic traits, forty-one rice accessions were classified into 10 groups of genetic diversity with coefficient of 0.08. The diversity of the morphological characters of rice accessions can be used in breeding pure-line rice for higher yield and quality.

The local cucumber (Cucumis sativus L.) variety cultivated by H’Mong people from long time ago is one of valuable indigenous crops of Son La that need to be efficiently exploited, conserved and developed. Our research was carried out at Moc Chau, Son La with the aim at determining the optimal plant spacing in combination with proper branch removal for suitable growth, development, yield and quality of H’Mong cucumber. The experiment was arranged in a triplicate split-plot design with two factors, plant spacing and branch removal. Three different plant spacings were 30cm, 40cm and 50cm correcsponding to three plant densities 4,6 pl were left on the main stem, 2) pruning with 3 lower lateral branches were left on the main stem, and 3) no pruning as control treatment. Evaluation parameters included growth and development characteristics, insect and disease incidence, yield, fruit traits (length, diameter, flesh thickness and hardiness of fruit) and fruit quality (0Brix). The results showed that 40cm spacing between plants in combination with second pruning method were most suitable for the growth and development of cucumber plant. This treatment combination resulted in highest harvested yield (105.3 tons/ha), more than doubled as compared with the control (30cm plant spacing, no pruning). Planting H’Mong cucmber in wider spacing (50cm) showed the best growth, flowering and fruiting but reduced the yield due to reduced plant population.

The effect of fertilizer dose on growth, development and yield of two groundnut varieties L14 and TB25 in Autumn growing season was studied in Hoang Hoa, Thanh Hoa. The experiment was replicated three times in a split plot design. The results showed that fertilizer influences on growth, development and yield. Fertilizer influences on duration, branch, leaf area index, dry matter accumulation, number of nodes, number of pods and grain yield. Optimum fertilizer dose for both two groudnut varieties L14 and TB25 at Hoang Hoa-Thanh Hoa is 30kgN+90kgP2O5+ 60kgK2O/1ha.

A study was carried out from 01/2010 to 06/2012 on 510 specimens of Scatophagus arguscollected in the canal of Can Gio District, Hochiminh City to identify some biological characteristics of this species. The biological characteristics observed included weight and length (120 specimens); age (30 specimens); male to female ration (120 specimens) reproductive characteristics (180 specimens), food composition in the intestine (60 specimens).. The results showed that the mean ofexploitable size was 88.71 ± 4.36 mm; absolute fecundity power was 289,797 ± 23,297eggs;relative fecundity was 2,772 ± 442 egg/g per female. This species is well known because of high exploitation, valuable food supply and economic value in this area. Beside economic value, it is also used asr ornamental fish. The study showed that this species can live in many kind of environment withfood diversity, etc.

The paper presents a mathematical model depicting heat and humidity exchange process in propagation nursery of forest planting materials under of heat control by ventilation or misting hot, cool water onto nursery seed beds covered with polyethylene in the net house. The model permits observation on the effect of the net house structure and the control regimes on the transition of temperature and humidity change in nursery environment. The results of this research further contribute to scientific foundation for designing control device system and selecting optimal heat and humidity regime regulation in the net house nursery for forestry planting materials in Vietnam.

Fingerling fish quality in aquaculture was concerned by the Fisheries Sector, specifically the Common carp, a traditional species raised in fresh water and more likely infected with zoonotic metacercaria. To investigate the epidemiological situation 1536 fingerling samples of common carp at size of 10.55 ± 1.51 g/fish from 54 waterbodies (ponds, canals, rivers, rice-fields) in 6 aquaculture systems (integrated fish-pig; fish-duck, rice-fish, biogas slurry, intensive culture and natural systems) was collected to test metacercaria by tissue digestion method. The result showed that the averaged prevalence was 23.89% and the intensity was 6.9 metacercaria/fish. High intensity occurred in natural and integrated systems, but low prevalence & intensity were found in biogas slurry and intensive culture systems. Three metacercaria species of small intestine flukes (Centrocestus formosanus, Haplorchis pumilio, H.taichui) and one metacercaria species of liver fluke (Clonorchis sinensis) were found in fingerlings of Common carp. Metacercaria of C. formosanus caused opened gill disease in fry and fingerling fish. Two metacercaria species of C. formosanus and H. pumilio were found with high prevalence and intensity (19.47-19.53%; 3.82-3.93 metacercaria/fish).

To evaluate effects of A639G of the IGFBB2 gene on meat yield traits in Tau Vang chicken, 152 commercial broilers from two different lines (CTU-BT01 and CTU-LA01) were slaughtered at 13 weeks old. Broilers were genotyped using PCR-RFLP/Bsh1236I and carcass traits of interest were measured. Studied polymorphism exhibited a insignificant effect on all meat yield traits. However, a significant effect on breast length (P=0.043), leg weight (P=0.007), shank length (P=0.001) and breast muscle weight (P=0.046) was found in interaction between genotype and two male lines. The CTU-LA01 males with heterozygous genotype AG showed the highest value for these traits. The study shows that the A639G polymorphism has no strong effect on the meat yield traits in Tau Vang chicken.

Litopenaeus vannamei) cultured in biosecurity system. Three groups of experimental shrimp (initial weigh 20.1±1.9 g/male and 21.4±2.2 g/female) were stocked at densityof10, 20 and 30 heads/m3in4m3indoor tank system. Each treatment was run in triplicate and fed with about 4% shrimp weight daily with pellet diets of CP 7704S and 7704P (38% crude protein), feeding four times a day. The water temperature ranged from 20.0 - 28.5oC and salinity ranged from 20-28‰. Water was renewed 80% volume weekly. The highest growth rate in weight was recorded in broodstock candidates cultured at 10 heads/m3(1.03 g/week/male; 1.11 g/week/female), followedby 20 heads/m3(0.89 g/week/male; 0.98g/week/female) and the least for 30 heads/m3(0.53 g/week/male; 0.62 g/week/female). Similarly, survival rate of shrimp at 10 heads/m3(71.7 ± 2.7%) ranked highest and the lowest rate for the 30 heads/m3 (60.1 ± 2.8%; P<0.05). Nevertheless, there is no significant difference in the survival rate between shrimp cultured at 10 heads/m3(71.7% ± 2.7%) and 20 heads/m3(71.5 ±3.0%; P>0.05). Size variation (CV%) and FCR recorded on 10 heads/m3 (CV%: 6.34 ± 1.12%; FCR: 2.78 ± 0.5) and 20 heads/m3(CV%: 6.68 ± 1.20%; FCR: 2.86 ± 0.3) were found remarkably lower than that for 30 heads/m3(CV%: 10.56 ±2.24%; FCR: 3.42 ± 0.8; P<0.05). The percentage ofshrimp harvested thatmet the criteria of broodstock was 67.1 ±2.6% and 66.7 ± 3.2% for the 10 and 20 heads/m3, respectively, whereasonly 23.1 ± 5.4% for the 30 heads/m3. All shrimp sample tissues were found negative for WSSV, YHV, TSV, MBVandIHHNV.

Moringa oleiferaLam. is a plant with high nutritional value for humans and livestock. Several studies also showed that the extract of the seeds is antibacterial. The experiments were executed to evaluate the antibacterial activity of Moringa oleiferaseed extracts against E.coli, Salmonella, Staphylococcus, aerobic bacteria and direct wastewater samples, wastewater samples from biogas of pig farms. The results showed thatMoringa oleifera seed extract has strong inhibitory effect ongrowth of gram-positive Staphylococcus, reducesthe number of aerobic bacteria, killsbacteria in aerobic and anaerobic of direct wastewater,and killsaerobic bacteria from the wastewater discharged frombiogas.

The experiment was carried out using a completely randomized design on 12 Lai Sind young bulls with twenty months of age, weighting 186 - 194kg to examine the effects of supplementing ensilaged casava leafy tops at different levels, i.e. 0% (control); 20% (treatment 1) and 30% (treatment 2) DM in fattening ration on their performance. Daily DM and CP intake increased with increasing levels of ensilaged casava tops. Daily weight gain was highest in treatment 2 (779.30 g/day), followed by treatment 1 (646g/day), and lowest in control group (563g/day). Feed consumption ration varied from 9.48 to 11.35 kgDM/kg weight gain. It was concluded that ensilaged cassava leafy tops are a suitable source of green feed with high protein in fattening ration of cattle.