Red soils and Yellow soils in Okinawa Island have the problem of severe hardening in dry conditions. It is important for the improvement and management of these soils to make the factors and mechanisms that affect the soil hardening clear. For this purpose, the properties and the degree of hardening of 43 topsoil samples in upland fields in the central area of Okinawa Island were determined. The results showed that the clay content and pH values were positively related to the degree of hardening. It is well known that clayey soils become very hard by air-drying because of the remarkable shrinkage, however, the pH-dependency of soil hardening has not been reported. Some investigations on the cause of the pH-dependency suggested that some physico-chemical conditions such as charge on the surface of soil particles in high-pH conditions, and the remarkable shrinkage of alkaline soils due to a large amount of calcium ions, enhance the hardening of these soils. The pH-dependency of hardening was also observed in the Red soils and Yellow soils in Kyushu Island, and this phenomenon probably occurs in soils with properties similar to the Red soils and Yellow soils in Okinawa, such as some Ultisols, Alfisols or Inceptisols in tropical, subtropical or temperate regions in the world.

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Fungicides have greatly contributed to sustaining quality food production through protecting a variety of crops from fungal diseases. However, such production is often threatened by the occurrence of pathogen strains resistant to fungicides. In this paper, the resistance to QoI and MBI-D fungicides in the pathogens of horticultural crops and rice blast fungus, respectively, are introduced as representative cases of resistance which have been experienced recently. Implications for integrated disease control that reduces the risk of fungicide resistance are discussed, then strategies to cope with resistance are overviewed. Application of PCR-based molecular techniques has become a powerful tool in the diagnosis of pathogens and/or fungicide resistance. Rapid and quantitative detection of resistant strains in fungal populations will make it easier to precisely predict the resistance risk without control failure by fungicides. The approach will also match the direction demanded by the society to reduce pesticide inputs to the agricultural environment.

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We screened snap bean (Phaseolus vulgaris L.) germplasm for heat and drought tolerance during the reproductive stage under extremely hot conditions as well as in the winter seasons in closed net houses to raise the temperatures under field conditions, a practice usually followed by vegetable growers. Substantial genotypic differences were found in morpho-physiological characteristics like phenology, plant water relations, photosynthetic parameters and shoot growth, which were related to the reproductive responses. The associations of days to podding and leaf water content with the number of pods per plant and seed yield were consistent across the different environments and experiments. The leaf water content was maintained by reductions in leaf water potential and shoot extension in response to heat and drought stress. Therefore, these traits can be used as a marker to screen germplasm for heat and drought tolerance. In this paper, we briefly reviewed the results of our studies carried out on heat and drought tolerance in snap bean at Okinawa Subtropical Station, Ishigaki.

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Agriculture in developing countries usually depends on rainfall. However, erratic rainfall makes agricultural production unstable. It is necessary to harvest water resources and to use them efficiently in order to stabilize crop yields. Methods of harvesting water resources are subject to topography. In lowlands, it is easy to collect water, because water f lows in, but this is difficult in uplands, because water f lows out. This article reviews methods of harvesting water resources and using them effectively in developing countries by reviewing papers from the last 20 years.

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Time Domain Reflectometry (TDR) has recently become popular as a method to measure soil water content. An empirical Topp′s equation and some dielectric mixing functions are often used as calibration curves of TDR. This review describes the Topp′s equation and dielectric mixing models. In addition, applicability of Topp′s equation and some dielectric mixing models for the θ-ε relationships for typical upland soils (two types of Ando soils, Red-yellow soils, two types of Brown forest soils, and Toyoura sand) are discussed. Following are several remarks that are stressed on TDR: (1) The empirical Topp′s equation underestimates soil water content for mineral soils of low bulk density. (2) Since dielectric mixing models described the effect of bulk density on the calibration curve, they could be more suitable than the Topp′s equation for the experimented soils. (3) Judging from the fitness of the whole curve, the third-order polynomial regressions and α model were superior to the Maxwell-De Loor model, which has no parameter to be identified. (4) The Maxwell-De Loor model was found to be so flexible that it reasonably fitted with measured data for different types of soil.

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This is a self review about the development of a roll baler for chopped material that can form chopped maize into a roll bale and a bale wrapper that can load and wrap fragile roll bales. These machines were developed for family managed dairy farms in Honshu district to reduce heavy labor and to minimize the work force in maize harvesting. Through the development and examination of the test machines, we found some points that need improvement for practical use. A practical baler and wrapper were developed based on the test machines. Practical tests evaluated the machines at 10 different fields throughout Japan. In these tests, 2 or 3 workers could manage almost all work from harvesting to wrapping, and the silage had good fermentation qualities and could be stored satisfactorily for a long time. These machines have been on the market since 2004. Subsequently, the technology obtained through the development of these machines could be applied for large-scale dairy farmers or contractors.

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Brittle rachis is an important trait to study the domestication process in barley. Ancient farmers preferred to have non-brittle barley for cultivation, and domesticated barley lost the brittle rachis after a process of human selection. In this study, partial linkage maps in the region of non-brittle rachis genes btr1 and btr2 were constructed using two wild × cultivar F₂ populations. STS markers derived from AFLP markers e09m25-08, e30m07-09 and e50m21-01, which showed no recombination with the btr1 and btr2 loci in recombinant inbred lines (RILs), showed recombination with the btr1 and btr2 loci in the two F₂ populations. Though there were few differences in map distances, orders of the markers were highly conserved. OUH602 (wild) × Kanto Nakate Gold (cultivar) was suitable for highresolution mapping of the btr1 locus due to unambiguous phenotypes in segregating F₂ plants.

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Near-isogenic lines (NILs) were applied for the first time to microarray analysis of 8,987 randomly selected expressed sequence tags (ESTs) aiming at screening rice genes associated with seed callus proliferation. Callus proliferation of the variety Koshihikari is poor, since its callus tends to become brown with time. We developed ten NILs that each had a chromosomal segment of the variety Kasalath on chromosome 1 in a Koshihikari background, to cover a region that contains two QTLs for subcultured callus color, qSc1-1 and qSc1-2. The existence of QTLs was verified through tissue culture of the seed calli of these NILs. mRNAs from the calli of three NILs that had the Kasalath allele in qSc1-1 and/or qSc1-2 were applied to microarray analysis. A comparison of expression profiles between Koshihikari and each NIL followed by Northern hybridization showed that 22 unique genes were induced and 15 unique genes were repressed in the calli of these Kasalath allele-containing NILs on chromosome 1. The results of a cis-element search using 500 bp of genomic sequence upstream of each gene suggested that the expression profiles of GA- and/or sugar-responsive genes were different between each NIL and Koshihikari, and that defense-related genes and genes that act negatively in metabolism were repressed in the NILs compared with Koshihikari.

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The agro-climatic environments in subtropical islands around Japan were analyzed by using meteorological data (average for 1971-2000). This study found that the horizontal distribution of monthly mean temperatures in both the subtropical islands and Japan′s main islands can be expressed accurately as a function of latitude for all seasons. These relationships cannot be applied to the monthly mean temperatures in the eastern areas of the Asian continent except for summer. On the other hand, the annual mean diurnal ranges of temperature in the subtropical islands are around 5°C, which are about only half of those in the inland areas of Japan′s main islands. The ocean has the effect of reducing the temporal and spatial variations in temperature due to its large heat capacity. The strength of this effect depends on the temporal and spatial scale of temperature variations. That is, although the thermal effect of the ocean to the diurnal temperature variations is restricted to the subtropical islands and the coastal areas of Japan′s main islands, the seasonal temperature variations in all areas of Japan are under the influence of the thermal environment of the Pacific Ocean. The ocean also contributes to supplying water vapor into the atmosphere, resulting in more precipitation over all areas of Japan. Water balances between precipitation and potential evaporation at several sites were estimated in order to elucidate the hydrological properties in the subtropical islands.

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Cut rose (Rosa hybrida L.) cv. Rote Rose was treated with glucose, fructose or sucrose at 10 g L^-1 in combination with a commercial preparation of isothiazolinonic germicide (a mixture of 5-chloro-2- methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one; CMI/MI; Legend MK) at 0.25, 0.5 or 1 mL L^-1. To stabilize germicidal activity, the solution was acidified by the addition of citric acid to a final concentration at 30 mg L^-1. Of the sugars, glucose was the most effective in extending the vase life, followed by fructose. CMI/MI was most optimal at 0.5 mL L^-1. The addition of aluminum sulphate at 50 mg L^-1 to glucose plus CMI/MI considerably extended the vase life of cut roses more than glucose plus CMI/MI. Based on these results, a formulation comprising 10 g L^-1 glucose, 0.5 mL L^-1 CMI/MI, 30 mg L^-1 citric acid and 50 mg L^-1 aluminum sulphate was designated as GLCA and the effect of GLCA on the vase life of 8 cultivars was compared against 10 g L^-1 glucose plus 200 mg L^-1 8-hydroxyquinoline sulphate (HQS). Treatment with GLCA extended the vase life of all the tested cultivars more than glucose plus HQS. Hydraulic conductance of stem segments in the control ‘Rote Rose’ roses decreased rapidly after harvest, but those for GLCA and glucose plus HQS were maintained at near their initial levels. The extension of vase life in cut roses by the addition of GLCA is attributed to the supply of sugars and the suppression of vascular occlusion without toxicity to cut flowers.

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African swine fever (ASF) is one of the most important infectious diseases of wild and domestic pigs. To develop safe and efficient diagnostic tools for ASF, we amplified the CP204L and E183L genes, which encode the major antigenic proteins p32 and p54, respectively, of the ASF virus Lisbon′60BM89BC1 strain by polymerase chain reaction and expressed them in recombinant baculoviruses. Each recombinant protein was recognized as a single band in baculovirus-infected insect cells by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Specific reaction was observed between these recombinant proteins and test sera from pigs infected with several strains of ASF virus in Western blot analysis and indirect enzyme-linked immunosorbent assay (ELISA). In Western blot analyses, p54 showed relatively higher sensitivity than p32 in antibody detection in the early stage of infection. On the other hand, p32 exhibited better reactivity in indirect ELISA to discriminate between positive and negative reactions. These data indicate that the recombinant p32 and p54 are useful as diagnostic reagents for serological tests of ASF. In order to diagnose ASF accurately, both recombinant proteins should be used in Western blot analysis and indirect ELISA.

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After the 1998 forest fire in East Kalimantan, Indonesia, biomass recovery of naturally regenerated vegetation was estimated in order to evaluate the initial secondary succession patterns of the burned land. We established research plots in naturally regenerated vegetation that included pioneer tree species, and the dominant pioneer species were Homalanthus populneus, Macaranga gigantea and M. hypoleuca, Mallotus paniculatus, Melastoma malabathricum, Piper aduncum, or Trema cannabina and T. orietalis. Annual tree censuses over 4 years (from 2000 to 2003) showed that on plots where the initially dominant tree species were M. malabathricum and T. cannabina and T. orietalis, they tended to disappear, and were replaced with M. gigantea and M. hypoleuca. In contrast, on plots where the initially dominant species were M. gigantea and M. hypoleuca, M. paniculatus, or P. aduncum, they continued to dominate 5 years after the fire. We classified tree species that were initially dominant but disappeared within 5 years after the fire as extremely short-lived tree species. The aboveground biomass of trees (AGB) averaged 12.3 Mg ha^-1 (ranging from 9.2 to 17.0 Mg ha^-1) in 2000 and 15.9 Mg ha^-1 (ranging from 7.4 to 25.0 Mg ha^-1) in 2003. Between 2000 and 2003, some plots exhibited an increase in AGB and some a decrease in AGB. In the plots dominated by M. gigantea and M. hypoleuca, the AGB increased to over 20 Mg ha^-1, but other plots accumulated significantly less AGB in the 5 years following the fire. These results suggest that the pattern of AGB accumulation in secondary forests is strongly dependent on the dominant pioneer tree species.

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The effect of the hydraulic turnover rate on dominance of the cyanobacterium Microcystis was examined using field data from the summer of 2001 for the Minami-shio Reservoir, a shallow eutrophic regulating reservoir in Japan, where the water outflow and storage volumes are measured hourly. A Microcystis bloom occurred in late summer when the daily hydraulic turnover rate decreased to 15%. The hydraulic turnover rate provided an index of nutrient supply rate, because the nutrient load was input mostly in the inflowing water and because the water body was well mixed. Field measurement results indicate that the low hydraulic turnover rate led to the Microcystis bloom.

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