The genes required for the pathogenicity of plant pathogens can be divided into two groups: those for eliciting virulence and those for establishing host-parasite interactions. Basically, the former genes are required for efficient production of the virulence factor(s) leading to the development of symptoms, while the latter genes are needed for well-balanced production of the factors required at each step of the parasitism. To understand the overall picture of plant pathogenicity, we need to understand not only the list of both genes but also how their expressions are regulated. We chose the major virulence genes of soft rot causing Enterobacteriaceae (represented by Pectobacterium carotovorum subsp. carotovorum and Dickeya dadantii) as a model system for dynamic study of the former genes. For the dynamic study of the latter genes, we chose the hrp genes, many of which are responsible for the Type III secretion system (T3SS) and the genes for the T3SS-dependent effectors of xanthomonads. Particularly since the major effector of xanthomonads, the AvrBs3 group or TAL (transcription activator-like) effectors contain NLS (nuclear localization signal) and an acidic activation domain, their studies are also expected to lead us to dynamic analyses of plant genes too.

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This paper reviews new methods of evaluating the quality of vegetables, which included physical methods, ion-selective electrode (ISE), liquid chromatography (LC) (high-performance liquid chromatography (HPLC), ultra-performance liquid chromatography (UPLC)), gas chromatography (GC), visible (Vis) spectroscopy, near-infrared (NIR) spectroscopy and VIS-NIR spectroscopy. Moreover, penetrability, juiciness, nitrate ions, lycopene, glucosinolate (GSL), isothiocyanate (ITC) determination, rapid total dietary fiber (TDF) determination and non-destructive determination were also described.

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We examined the fruit productivity of vertically trained watermelon plants, focusing on leaf area, light reception, and field photosynthesis characteristics. We also examined the source–sink relationships of photosynthates during fruit development to characterize fruit productivity in vertical training. Furthermore, the fruit productivities of both the plant and unit land area were compared between vertical training systems and conventional, horizontal training systems. The fruit weight of both types of watermelon plants could be determined by the total leaf area, total solar radiation received, and photosynthetic production per plant. Regardless of the leaf position, most photosynthates of vertically trained watermelon plants during fruit development were distributed to the fruit, meaning the fruit weight could be determined by the above-mentioned factors. Photosynthates for roots were characteristically distributed from leaves on non-fruiting vines in plants with two vines and one fruit, and from limited lower leaves in plants with one vine and fruit respectively. Vertical training of watermelon plants increased the fruit yield per unit land area under higher planting density than horizontal training, with no loss of light-use efficiency.

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This paper reviews the impact of biodiesel called “fatty acid methyl ester” (hereinafter referred to as “FAME”), which was manufactured domestically using waste edible oil, on the performance and gas emissions of agricultural diesel engines. In terms of engine performance, one indicator showed output equivalent to diesel fuel. However, the resulting specific fuel consumption (hereinafter referred to as “SFC”) was high because the density of FAME, which exceeded that of diesel fuel, increased the mass flow rate of the fuel. Moreover, the nitrogen oxide (NO_X) emissions of FAME were comparable to those of diesel oil. However, emissions of particulate matter (hereinafter referred to as “PM”) discharged by FAME were smaller than from diesel fuel. Under a driving condition tending to generate a large amount of black smoke due to high engine load, PM emissions were halved compared to those of diesel fuel. This phenomenon is presumed attributable to the reduction in soot production achieved using FAME, which contains a relatively high amount of oxygen.

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This paper reviews the impact of using biodiesel fuel containing large amounts of raw material components on engine performance in an agricultural tractor. If a fuel containing abundant methanol, a raw material component, is used, the engine output decreases; presumably due to the drop in fuel injection. Accordingly, it emerged that the engine’s original fuel consumption could not be maintained as methanol vapor was generated from the fuel and accumulated in the fuel pipe. Moreover, the engine was operated for 700 hours using a fuel containing abundant triglyceride, which, in itself, is a raw material fat residue for a new tractor, regularly inspecting and servicing as specified by the tractor manufacturer and using the electrical dynamometer. Consequently, the power output from the power take-off shaft（hereinafter referred to as “PTO”） decreased by 0.4 to 1.2kW from the value before the start of the operation, the specific fuel consumption (hereinafter referred to as “SFC”) increased by 7 to 23g/kWh and the carbon monoxide (CO) and black smoke concentrations increased significantly. Based on the disassembly and adjustment of engine parts after the operation, this phenomenon is considered attributable to the reduction in exhaust valve clearance accompanying the wear of the valve seat, which may occur, even in the middle of the operation with diesel fuel.

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Soil aggregation by earthworms is important for sustainable agriculture because soil aggregates are highly permeable and retain water. Casts are a soil aggregate and indicator of earthworm activity. The effects of reduced tillage using a rotary tiller on earthworm cast productivity and yield of Chinese cabbage were investigated in volcanic-ash soil. Five tillage practices were investigated; conventional tillage (CT), no tillage (NT), and three reduced tillage practices: shallow tillage, row tillage, and shallow row tillage respectively. Cast production of Pheretima (Amynthas) carnosa, the species which dominated the study site, and yields of Chinese cabbages were measured during three crop seasons. Crop yield under the NT treatment was lower than that under the CT treatment (p<0.05) in fall 2004, while in spring 2005 Chinese cabbage under NT treatment did not head out. Yields under reduced tillage treatments tended to decrease in spring 2005, but were similar to those under CT treatment in the other two cropping seasons. Under CT treatment, the surface cast production was almost zero. Cast production under reduced tillage exceeded that under CT treatment, but was lower than that under NT treatment. Accordingly, reduced tillage can combine the ability to preserve aggregate formation by earthworms while also preventing any decline in Chinese cabbage production yield in the cropping system studied.

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The evaluation of a total of 122 blast (Pyricularia oryzae Cavara) isolates collected from the Tonle Sap and Mekong river regions of Cambodia revealed wide variation. Using a new designation system, the blast isolates were categorized into 92 races based on the reaction patterns of rice (Oryza sativa L.) differential varieties (DVs) harboring 23 resistance genes and of 1 susceptible cultivar, Lijiangxintuanheigu (LTH). Cluster analysis was used to classify the blast isolates into 3 groups — I, IIa, and IIb — using data from these reaction patterns of the DVs and LTH. We used the classifications established under the new designation system, alongside cluster analysis and the geographical distribution of blast isolates, to investigate the diversity and differentiation of blast races in the Tonle Sap and Mekong river regions. The distributions of the blast races differed between the 2 regions, although blast isolates of group IIa were distributed commonly in both regions and groups I and IIb occurred at higher frequencies in the Tonle Sap region rather than the Mekong region. The blast isolates in groups I and IIb were also less diverse than those in group IIa. Accordingly, Group II blast isolates overall were distributed in both regions with high diversity, but some modified blast isolates were additionally distributed in the Tonle Sap region. We also investigated the pathogenicities of blast isolates from wild rice (Oryza rufipogon Griff) weeds neighboring the cultivated rice, and discuss the relationship between these isolates and those from cultivated rice.

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This study aims to clarify the current status of rice plant damage caused by the brown planthopper (BPH) in Cambodia through semi-structured interviews with government officials and rice farmers from the main rice-producing province. BPH is known to cause serious damage to rice crops in many Southeast Asian countries. However, few studies exist on the damage caused by BPH in Cambodia and information on effective pest-control management remains limited. Interviews with provincial government officials revealed that BPH infestation had been recorded in 6 of 8 target provinces located near the border with the southern part of Vietnam. Of these, Takeo province was selected for a more detailed survey using semi-structured interviews with district government officials and workshop-style interviews with 416 farmers from 3 communes. These interviews indicated that damage by BPH in Cambodia was possibly attributable to BPH occurrence in the Mekong Delta of Vietnam.

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To gain a physiological understanding of the effect of drought stress on the cucumber (Cucumis sativus L.), we subjected ‘Jinchun No. 5’ seedlings to three treatments: control (C), moderate drought stress (MDS) and severe drought stress (SDS) during exposure to high temperature and strong light. We then investigated the metabolic properties of active oxygen species, nitrogen and photosynthesis in leaves from the 3rd to 15th days of treatment. The amounts of active oxygen species superoxide anion (O₂˙‾) and hydrogen peroxide (H₂O₂) increased with increasing drought stress in C, MDS and SDS. The malondialdehyde (MDA) content, which reflects the excess metabolism of active oxygen was increased on the 12th and 15th days of treatment with increasing drought stress. The nitrate-reductase (NR) activity of nitrogen metabolism indicators decreased on the 3rd to 15th days of treatment, while soluble protein content increased on the 9th to 15th days of treatment with increasing drought stress. With respect to the photosynthetic properties, stomatal conductance (g_s) decreased from the 6th to 15th days of treatment with increasing drought stress, no significant difference was seen in sub-stomatal CO₂ concentration (C_i) between all three treatment plots, transpiration rate (E) was lower in SDS than C, and the net photosynthesis rate (A) decreased with increasing drought stress. A significant correlation between g_s, H₂O₂ and E with A, and secondly between MDA and NR with A was observed. These findings suggest that drought stress during periods of high temperature and strong light results in the generation and accumulation of abundant active oxygen species, and inhibition of nitrogen and photosynthesis metabolism in cucumber ‘Jinchun No. 5’ seedlings.

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To provide relevant information on utilizing fodder-sugarcane for dairy cows, we investigated the chemical composition, and long-term effect of fodder-sugarcane feeding on physiological aspects in non-lactating cows and milk production in lactating cows. The CP content of fodder-sugarcane silage (KRFo93-1; harvested 4 months after regrowth) was at the lowest level, whereas NDFom content peaked in roughage fed to lactating cows on conventional dairy farms. When 6 non-lactating Holstein cows were fed fodder-sugarcane silage with soybean meal and steam-rolled corn or sudangrass hay for 106 days, there were few changes in BW, hematological parameters, and blood metabolites throughout the experimental period. Seven lactating Holstein cows were fed TMR (TDN, 69%DM; CP, 15%DM) containing 0, 3, 5, 10, 15, or 20% fodder-sugarcane silage along with commercial concentrate (1.8 kg DM/cow/day). Milk yield and milk composition were unaffected by the proportion of fodder-sugarcane silage in the TMR. Conversely, the percentage of large particles (>19 mm) in TMR and in orts rose with an increasing proportion of fodder-sugarcane silage in TMR. The BUN concentration increased when cows were fed TMR containing over 15% fodder-sugarcane silage. These results suggest that fodder-sugarcane can be fed to cows without adversely affecting their physiological condition. However, for practical feeding to lactating cows, it is necessary to observe sorting against fodder-sugarcane silage.

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Litter plays key roles in forest ecosystems, and forest degradation is likely to spur a further decline in leaf litterfall inputs to forest soils. However, the effects on physicochemical surface-soil properties remain largely unknown, especially in seasonal tropical forest ecosystems. We initiated a litterremoval manipulation experiment in a Cambodian lowland evergreen forest undergoing intensive selective logging. Litter removal performed for 2 and 4.4 years respectively triggered an increase in bulk density and decrease in surface-soil carbon (C) and nitrogen (N) contents to 67 and 73% of the original levels, respectively. After only 2 years of treatment, bulk density rose to very high value (>1.40 Mg m^–3) likely preventing further soil compaction, while the C and N reduction effects lasted over 2 years. Greater soil compaction occurs in stands with a smaller initial bulk density. However, C (N)-rich soils did not necessarily lose a greater relative proportion of C (N) than C (N)-poor soils. Although N remained above C following the litter removal, conservative trends in the C:N ratio suggested a limited capacity for N retention. Together, our data suggest that shifts in leaf litter inputs in response to localized human disturbances may have rapid and lasting consequences on physicochemical surface-soil properties; possibly accelerated by a tropical climate. Moreover, a speedy recovery to an adequate litter supply, at least before reaching the upper soil compaction limit, is essential to conserve forest ecosystems.

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Allometric models to estimate the aboveground mass AGM, belowground mass BGM and total mass TM of juvenile trees (stem diameter at breast height DBH ≤ 5 cm, tree height H ≥ 30 cm) in open-canopy terra-firme forests after wind disturbance were developed in the Amazon. For comparison, the allometric models were also developed for a closed-canopy terra-firme forest. After six models had been compared in each forest type, the model with diameter at ground basis DGB and H was selected as the best for estimating AGM and TM, and the model with diameter at ground basis DGB as a single variable was selected as the best for estimating BGM considering the adjusted coefficient of determination and standard deviation of the mean. Models based on the diameter at breast height DBH showed poor correlation with each biomass component compared with those based on DGB for the open-canopy forest. The juvenile trees in the open-canopy forest showed higher AGM and H at a given DGB than in the closed-canopy forest, while the DGB – BGM relationships did not differ significantly between the open- and closed-canopy forests. It was concluded that the allometric models used to estimate AGM and TM were unique to each forest type. This would be because light-demanding species show higher allocation to AGM than BGM to be advantageous for competition for light by achieving rapid growth in height.

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It is necessary to understand the heterogeneity in necromass and carbon (C) and nitrogen (N) contents within a dead bamboo culm before estimating these parameters in dead culms. This study determines differences in necromass and C and N contents between node and internode material of decomposing bamboo culms. We collected dead culms of Phyllostachys bambusoides and P. pubescens from 11 bamboo stands in central and south-western Japan, and determined the necromass per culm cylindrical volume (culm volume density), the C and N stocks per culm cylindrical volume (C and N densities), and the C and N concentrations of node and internode material. In both species the culm volume density was greater in node than internode, which led to a greater C density in node than internode, whereas the C concentration scarcely differed between the two. The N density was greater in node than internode material in both species, due to the difference in culm volume density, while the N concentration was also greater in node than internode. These differences remained unchanged with the degree of decomposition, because the dynamics of necromass and C and N were similar for node and internode materials. The decomposition process in node and internode resembles that in dead wood although variation in N dynamics is observed for P. bambusoides. When the greater culm volume density and C and N densities in node than internode were not taken into account, the necromass and C and N stocks in a dead bamboo culm decreased by 4.46–4.50, 4.51–4.59 and 9.47–10.83% respectively. We must sample numerous dead culms to mitigate node and internode differences. However, it might be better to take into account these differences when the number of dead culm samples is limited.

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Fine roots are an important component of the carbon flow of forests. Soil properties in tropical forest (terra firme forest) of the Central Amazon differ substantially along topography, and the biomass and vertical distribution of fine roots may also differ accordingly. Information on the vertical distribution of fine roots is essential to obtain unbiased estimates of fine root biomass. Accordingly, we examined fine root biomass and its vertical pattern along the gradient of topography in a typical terra firme forest in this region. The regressions on the cumulative fine root biomass along soil depth (at 5 cm intervals from 0-40 cm in depth) revealed significantly different vertical distribution of fine root biomass among three topographic habitats (lower-slope valley called baixio, mid-slope, and upper-slope plateau). A shallower rooting pattern was observed in the plateau than the other habitats, while fine root biomass was larger in the baixio than the plateau – a difference likely attributable to the soil physical properties than the aboveground stand structures among the sites. More than 74 and 93% of the fine root biomass was estimated to be distributed within the upper 20- and 40-cm soil layers, respectively. Our results suggested that a shallow sampling depth, which is common in fine root research in the Amazon, would be reasonable, though we should examine the consistency of our results in different regions.

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The allowable biological catch (ABC) in Japanese fishery management is currently determined by applying harvest control rules, which are categorized into two types depending on whether or not stock-size information is available. We evaluate management procedures (MPs) in data-poor situations using an operating model (OM) based on a production model. The OM incorporates uncertainties regarding its assumptions and the process and observation errors of population dynamics and fishing processes, while the values of the MP parameters are determined to avoid stock collapses and low catches. We evaluated the MP formulation ABC = δ×C_t ×(1+k(b/I)), where δ is a coefficient dependent on the stock status level on the stock size, C_t is the catch in year t, k is the weight coefficient, b reflects the trend in stock abundance index over time, and I is the mean of the stock abundance index I. This study shows that smaller values of k reduce the frequency of substantially low catches, particularly when there is significant uncertainty surrounding the stock status.In addition, the value of δ affects both the frequency of fishery collapse as well as stock and catch sizes. We conclude that more reliable stock abundance indices are necessary if the stock size and catch are to stabilize and MPs become more robust to uncertainties.

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The species of the genus Decapterus are important for fisheries in western Japan, but few in number and reports on their biological characteristics remain limited. This is the first report on the growth and maturation of the roughear scad Decapterus tabl in the East China Sea. The growth model of the roughear scad was estimated as follows: FL_t = 390{1–exp [–0.56(t+0.36]} (1 < t < 8) using otolith annual rings that were formed once a year. The spawning period was from May to July, while the 50% maturation gonad somatic index GSI₅₀ was calculated as 3.80 for female using logistic regression. The minimum length over the GSI₅₀ was 274 mm, meaning a first spawning age of 2 years old in the East China Sea.

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