A high-density genetic linkage map with PCR-based markers provides a simple and fast system for scanning genome. One hundred and six newly developed RAPD markers were assigned to a RFLP framework map previously constructed using the RI lines of a cross between rice varieties of Asominori and IR24. From a total of 306 RAPD primers screened, 119 reproducible RAPDs were detected. Of the 119 RAPDs, 95 showed a normal Mendelian segregation at a 1:1 ratio in the RI lines. One hundred and six out of the 119 RAPD markers were assigned to the 12 chromosomes and the rest (13 markers) did not show a significant linkage with the RFLP markers on the framework map. ‘The RAPD markers were distributed widely over the rice genome, but some of them were placed by clustering in particular chromosomal regions. This combined RFLP/RAPD genetic linkage map could be an important tool for marker-assisted selection in a breeding program. Furthermore, this map will greatly facilitate quantitative traits analysis and map-based cloning of agronomically important genes.

Effects of UV light elimination on the flavonoid content in the bulbs of Allium x wakegi and shallots (Allium cepa aggregatum group) were investigated. The mean anthocyanin content was about 16% less under UV cut-off films, eliminating < 360 and < 390 nm of the sunlight than under the film transmitting UV light (control). Changes in the anthocyanin content by the UV light elimination were accession dependent. Flavonols were relatively more stable than anthocyanins under the UV cut-off films and did not statistically show any difference between the treatments. The change of anthocyanin content under UV cut-off film did not definitely follow the change of flavonol content. It was clarified that UV light eliminating treatment given to the leaves decreased the anthocyanin content in the bulbs which were not directly exposed to the light.

Three varieties of groundnut (Dhaka-l, DG-2, ACC-12) were studied to observe the seed bone diseases and the extent of disease development in the field at two depths of plantation. There were significant differences among the varieties in case of germination and pre-emergent death in the laboratory. Highest pre-emergent death was found in Dhake-1, followed by DG-2 and ACC-12. Pre-sowing test in the laboratory revealed association of 8 fungal species with the seeds. Seeds of three varieties planted in the field showed that the two depths of plantation (4.0cm and 6.5cm) showed significant difference in case of pre-emergent mortality. The depth of plantation also showed significant differences on percentage of germination and post-emergent death for all the varieties. Varital differences had marked influences in disease development in all stages of groundnut seedling. Periodic uprooting of seedlings showed considerably higher percentage of disease symptoms in 6.5cm depth than that of 4.0cm depth. ‘The highest root rot was occurred in DG-2 followed by ACC-12 and Dhaka-1. Interactions between depth of sowing and variety were observed for germination, pre-emergent death, post emergent death and total disease development of groundnut and was found significant at 1% level.

The effect of Azospirillum lipoferum inoculation of seed and seedling of rice and different levels of nitrogen fertilization (0, 45 and 90 kg N/ha) were studied under two types of soil moisture regimes (80% and 100% field capacity) in pot under controlled conditions. Phosphorus, potassium and sulphur were applied at rates of 60 kg/ha, 40 kg/ha and 10 kg/ha respectively, as basal doses. Rice seed and later rice seedlings were inoculated with at least 10⁶ colony-forming units of Azospirillum lipoferum for the inoculated treatments. Colonization of roots by Azospirillum lipoferum was determined by Enzyme-Linked Immunosorbent Assay (ELISA) test. Azospirillum inoculation significantly (P=<0.001) increased the grain yield and nutrient content of rice, and an economic yield was found for the application of 45 kg N/ha with inoculum, but 80% and 100% of the field capacity values did not have any significant effect compared to the inoculation and nitrogen fertilization.

The purpose of this study is to identify the apoplastic pathway in the root systems of Euonymus japonicus in relation to their development. Tinopal CBS, a fluorescence dye staining the cell wall, was used as a tracer of the apoplastic pathway. The inflow of the dyeing agent to the vascular tissues from a branch separation point was not observed. Although the dyeing agent did not enter into the progressing young primary root system, which did not contain a dead root, it entered into the mature root system containing a dead root. It was inferred that the dead roots were more important than the branching points of the lateral roots as an entrance of an apoplastic flow.

Using a berberine-aniline blue dyeing procedure, the development of Casparian strips from the roots of four evergreen broadleaved tree species (Osmanthus fragrans, Cinnamomum camphora, Machilus thunbergii and Enonymus japonicus) was observed. This dyeing procedure was effective for observing the Casparian strips from the roots of the four species. ‘The Casparian strips of the exodermis were formed near the position where one of the endodermis was formed. The positions where these Casparian strips were formed did not relate to the salt tolerance of these species.

One hundred fifty four strains of X. oryzae pv. oryzae, the causal agent of bacterial blight, were isolated in the northern part of Vietnam and preserved. This work is conduct as a joint research between the HAU-JICA ERCB Project and Kyushu University Interdisciplinary Programs in Education and Projects in Research Development.

Cuc Phuong National Park is one of the oldest protected areas in North Vietnam and represents the typical lowland forest flora. The authors conducted surveys of ants for this area in 1998 and 2001. In total 160 species belonging to 50 genera in 8 subfamilies are recorded. At the genus level, Cladomyrma (Formicinae) is new to Indo-Chinese fauna. The following 20 species are omitted from the list compiled by Bui and Yamane in 2001: Platythyrea parallela, Diacamma rugosum, Leptogenys peuqueli, Odontomachus simillimus, Odontoponera nitens, Aenictus ceylonicus, A. sp. 4, Acanthomyrmex ferox, Myrmica sp. 1, Pheidologeton silenus, Crematogaster difformis, Prenolepis melanogaster, Camponotus sp. aff. saundersi, C. sp. aff. praerufus, Polyrhachis rastellata, P. bellicosa, P. ramellidens, P. bicolor, P. equina, P. inermis. Misidentifications of several species are also corrected.

Most of the investigations in compost application have concentrated on the physical and biological characteristics of vegetation; little has been known about the gas phase in soil. In this study, the levels of CO₂ and 0₂ contents were associated with the effect of recycled compost application to sandy, clay loam and clay soils, respectively. Since a large amount of organic matter is correlated with the rise in CO₂ level especially in clay soil during the early stage of the decomposition process, it is expected that the rise in CO₂ greatly affects the O₂ content where the normal gas exchange within the soil is inhibited. Perforated aeration tubes were installed to determine the rate of gas exchange in soils treated with recycled compost. CO₂ problems were monitored at various soil depths and distances from the aeration tube. The levels of CO₂ in each soil increased significantly at depths and distances with values that ranged from 3-12%, 8-18% and 10-19.5% for sandy, clay loam and clay soils during the early stage of the study. The relationship between CO₂ and O₂ contents at any depths and distances shows an inverse linear relationship. Rates of gas exchange have been improved particularly in clay soil as a result of the installation of aeration tubes.

For the purpose of studying the response of growth characteristics such as leaf water potential, leaf photosynthetic rate and yield of mungbean to soil water condition, a pot experiment was conducted under the different water conditions using two varieties, Mubarik and 880137. The significant differences were found among water treatments in all investigated items. However, the difference between the varieties showed several variations among the investigated items. There were significant differences of leaf water potential and leaf photosynthetic rate between varieties. However, the variety with higher leaf water potential did not coincide with the variety with higher leaf photosynthetic rate. Among the yield components, only pod number plant^-1 showed significant difference between varieties, and Mubarik's pod number plant^-1 was higher than that of 880137. However, seed number pod^-1 and 100 seed weight were higher in 880137 than Mubarik though these two components did not show the significant difference. Therefore, no significant difference of yield between varieties was found. The advantage of higher photosynthetic rate in Mubarik did not contribute to the yield and its components.