Japan Agricultural Research Quarterly

Print ISSN: 0021-3551
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The World Rice Model (WRCM) was developed based on partial equilibrium approach in this paper. An impact of Renminbi (RMB or Chinese Yuan) appreciation scenarios on the world rice market was projected to 2020 by WRCM. The result indicates that RMB appreciation in the short term will lead to a dramatic change in the international rice price index. When RMB appreciation rate is greater than 4%, the international rice price index will continue to rise, and when it is greater than 8%, China will become the largest rice importer in the world.
 
Effects of social capital (SC hereinafter) on household welfare (rice yield, income, health) were examined in rice granary area of south peninsula Malaysia. SC is categorized into eight types by its form (structural and cognitive) and function (birding, linking, and bracing). OLS is used for estimation on randomly selected 60 household data. As for self-rated health status, those attending more community activity (bonding structural SC) appear less healthy, seemingly that old farmers normally have more time to spend on community activities and they are more loyal to their organization. Those who highly evaluate bureaucratic organization (linking cognitive SC) are relatively healthier. Frequency of attending community activities (bonding structural SC) and duration of involvement in organization (birding structural SC)) contribute to higher rice yield. Farmers who have wider and longer relationships with organizations seem to perform better farming. Wile official status in formal organization (linking structural SC) and involvement in bureaucratic organization (bracing structural SC) cause a decline in ric e productivity. The finding of bonding/bridging structural social capital has positive effect on productivity suggests that to further improve farming performance, more spontaneous and horizontal farmer-to-farmer connections became increasingly important. At the same time, to alleviate p overty, bracing structural social capital which strengthens both vertical and horizontal human network appears important. The efficacy of networking is also reflected by the positive sign of cognitive linking social capital for income and health.
 
It is important to adopt a common international understanding and perspective in the agreement on the environmental impact of agricultural water-use in the regions of the world. This paper investigates water-use sustainability as a measure of the impact on the environment and natural resources of irrigated paddy farming in 31 countries and regions of the world. A quantification theory was used to analyze the main simplified factors in water-use sustainability. A methodology and overall indicators for the evaluation on a national scale are proposed from an international comparison on water-use sustainability. The study provides a valuable insight into the international agreements on the relationship between agriculture and water resources.
 
Indole-3-acetic acid (IAA) endogenous levels were determined by liquid chromatography-mass spectrometry, diffusible levels were determined by fluorometric detection and polar transport activity was determined by radioactive IAA in tomato plants. IAA concentration in the apoplast (AP) solution was higher than those in the symplast (SP) solution in both upper and lower parts of stems. It is suggested that the amount of polar IAA transport might be only 19% of the amount of endogenous IAA in stems. In fruits, concentrations of abscisic acid (ABA) were high in the pericarp, axis and the locule tissue in the early growth stages. In seedless fruits of parthenocarpic tomato, the levels of IAA, gibberellic acid1 (GA1), trans-zeatin (Z) and trans-zeatin riboside (ZR) were analyzed. IAA concentrations of the pericarps and partitions were higher in fruits of 8cm in diameter (8-cm-fruit) than in 6-cm-fruit. In the partitions, IAA concentrations of SP were higher than those of AP solution. The SP of the partitions in 6-cm-fruit had the highest concentration of Z and was 2.7 times greater than the AP. The ZR concen-tration in locule tissues in 6-cm-fruit was the highest. These results suggest that the sites of synthesis may be the SP of partitions for IAA and Z, and locules for ZR.
 
The correlation between antioxidant activity of methanol extracts from Malaysian timbers and total phenol content in methanol extracts. Antioxidant activity is expressed as antiradical power (1/EC50) 5 . 
Yield (%), antioxidant activity (EC50) and total phenols (%) of methanol extracts from bark, heartwood, and sapwood of commercial Malaysian timber species 
Antioxidant activity [1,1-diphenyl-2-picrylhydrazyl (DPPH) assay], antifungal activity against Gloeophyllum trabeum (brown-rot) and Pycnoporus sanguineus (white-rot), and total phenol content (Folin-Ciocalteu method) of 11 selected commercial Malaysian timbers were investigated. The extracts from Neem bark showed the highest yield, 25.59%. Kelat gelam bark showed the highest antioxidant activity, followed by Kelat jambu air bark. The extracts that showed the four highest antioxidant activities were all taken from bark samples. These extracts also showed high yields of methanol extracts and high total phenol content, suggesting that they have great potential as a source of antioxidant material. The highest total phenol content was found in Neem bark, while the lowest was in Ramin melawis bark. The methanol extracts from the heartwood of Neem showed the highest antifungal activity against G. trabeum. The methanol extracts from the sapwood and the heartwood of Neem, and the heartwood of Kulim showed the highest antifungal activity against P. sanguineus. The antifungal activities of these methanol extracts were higher than those of the positive control, glycyrrhizic acid dipotassium salt. Almost all wood species showed antifungal activity against either brown-or white-rot fungus. However, methanol extracts from the heartwood of Neem showed strong antifungal activity against brown and white-rot fungi, G. trabeum and P. sanguineus, suggesting that they have great potential as a source of fungistats.
 
Ninety fungal strains with falcate conidia belonging to Colletotrichum spp. classified into the ribosomal groups 9-13 (the RG 9-13 spp.) and preserved at the NIAS Genebank, Japan were re-identified based on molecular phylogenetic analysis of the internal transcribed spacer (ITS) region of the rRNA gene, sequences of the glyceraldehyde 3-phosphate dehydrogenase, chitin synthase 1, histone3, and actin genes, and partial sequences of beta-tubulin-2 (TUB2) genes, or by BLASTN searches with TUB2 gene sequences. Seventy strains were reclassified into nine recently revised species, C. chlorophyti, C. circinans, C. dematium sensu stricto, C. lineola, C. liriopes, C. spaethianum, C. tofieldiae, C. trichellum and C. truncatum, whereas 20 strains were grouped into four unidentified species. RG 9, 10 and 12 corresponded to the C. spaethianum, C. dematium and C. truncatum species complex, respectively, while RG 11 and 13 agreed with C. chlorophyti and C. trichellum, respectively. Phylograms derived from a six-locus analysis and from TUB2 single-locus analysis were very similar to one another with the exception of the association between C. dematium s. str. and C. lineola. Thus, TUB2 partial gene sequences are proposed as an effective genetic marker to differentiate species of RG 9-13 in Japan except for C. dematium s. str. and C. lineola. Thirty-two plant species were identified as new hosts for seven of the species found in this study except for C. circinans and C. trichellum; and two unidentified species. Colletotrichum chlorophyti, C. lineola, C. liriopes, C. spaethianum, and C. truncatum were regarded as polyphagous, whereas C. trichellum and Colletotrichum sp. (Ra), designated tentatively in this study, appeared to have specific pathogenicity to single hosts, Hedera rhombea and Raphanus sativus var. hortensis, respectively. Conidial curvature properties, "outer curvature," "inner curvature" and "height/width ratio" successfully represented conidial shape parameters. Conidial curvature properties of the species in RG 9, 10 and 12 were found to correlate with the species complexes.
 
The natural ¹⁵N abundance (δ¹⁵N value) of organic rice tends to be higher than that of conventional rice. However, as δ¹⁵N values vary in both organic and conventional rice, it might be difficult to use a particular δ¹⁵N value as an indicator of organic growth conditions. This review describes an approach that was developed at the Tohoku Agricultural Research Center, National Agriculture and Food Research Organization. The relationship between the δ¹⁵N values of rice and those of soil under organic or conventional farming conditions has been investigated. Regardless of the farming method, the δ¹⁵N values of rice reflect those of the soil. The δ¹⁵N values of organically grown rice tend to be higher than the regression line obtained from the δ¹⁵N values of rice and soil without the application of an N fertilizer. The δ¹⁵N values of conventionally grown rice tend to be lower than the regression line. Thus, the relationship between the δ¹⁵N values of rice and soil without an applied N source could be used to differentiate between organic and conventional rice. However, the existence of regional variation in the relationship between the δ¹⁵N values of rice and those of unamended soil can confound the use of this discriminant method. Such variation may occur due to the differences in δ¹⁵N of natural N inputs, and also through ammonia nitrification and subsequent denitrification. Temporal variation can also occur, though the reason for such variation is unknown. When the relationship between the δ¹⁵N values of rice and those of unamended soil is employed to distinguish between organic and conventional rice, regional and temporal variations in that relationship should be taken into account. © 2018, Japan International Research Center for Agricultural Sciences.
 
Effective utilization of the biological nitrogen fixation (BNF) activity is important for enhancing the N fertility of paddy soils and for developing sustainable rice cultivation systems. To analyze the soil factors that affect BNF in paddy soils, in this study, the effects of the temperature, water regime, and long-term soil management on 15N2 fixation were examined in relation to the decomposition of organic matter in incubation experiments. Within the range of 15-30°C, heterotrophic 15N 2 fixation under dark conditions changed almost proportionally to the formation of CO2+CH4 with glucose and straw as C sources by increasing the temperature, while the C use efficiency (N 2 fixed/(CO2+CH4)) was relatively higher at low temperatures in the presence of cellulose. The examination of the effect of the water regime on heterotrophic 15N2 fixation indicated that flooding after aerobic conditions promoted heterotrophic 15N2 fixation as well as the decomposition of cellulose. Among the soils with different types of management, the soils amended with manure and rice straw showed the largest photodependent 15N 2 fixation. On the other hand, the soils with a lower content of mineralizable-N tended to depend more on heterotrophic 15N 2 fixation. Soils from paddy fields converted into upland fields (hereafter referred to as "converted upland soils"), particularly showed a high heterotrophic 15N2 fixation. Overall, it appeared that the management of organic matter application and the water regime may result in significant variations in BNF in paddy soils. The results obtained suggested that further studies should be conducted on the C and N metabolism involved in BNF during the decomposition processes of organic matter along with the changes in the soil redox status to identify methods for efficient soil management to promote BNF.
 
Hokuriku 193 is an indica rice cultivar released in Japan in 2007. It is characterized by a long panicle, a small number of panicles, a stiff culm, and a grain length typical of general indica rice cultivars. The mean brown rice yield of Hokuriku 193 was very high (7.65 t/ha) under experimental conditions during the period 1998 to 2005. The mean total air-dry weight was also very high at 20 t/ha. Hokuriku 193 is resistant to leaf and panicle blast and stripe virus and moderately resistant to bacterial leaf blast. It is expected to be useful worldwide not only as a staple food but also as a raw material for whole-crop silage and bioethanol production.
 
Ten novel microsatellite markers were developed for the western sand lance, Ammodytes japonicus, which has decreased significantly in many fishing grounds because of overexploitation and deterioration of its habitat. The 10 markers were successfully amplified in two sets of multiplex polymerase chain reactions (PCR). A total of 63 individuals collected in two successive years from a single population were used to assess the characteristics of the 10 markers. The number of alleles per locus ranged from seven to 24 with the observed heterozygosity ranging from 0.397 to 0.921. None of the loci deviated significantly from the Hardy-Weinberg equilibrium, and there was no evidence of linkage disequilibrium between any loci-pairs. Almost all of these novel microsatellite markers were also confirmed to be successfully amplified, not only for the other regional A. japonicus, but also for the closely-related Ammodytes heian and Ammodytes hexapterus. These polymorphic microsatellite markers for multiplex PCR will largely improve the throughput of microsatellite DNA analysis, and contribute to the effective genetic monitoring of A. japonicus and other sand lances around Japan.
 
The impact of forest fire in 1997 and 1998 on the mycorrhzae was studied at the dipterocarp forest in East Kalimantan, Indonesia. In unaffected forest more than half of total ectomycorrhizae distributed in the organic layer but in the fire-affected forest one and a half years after the fire, total amount of mycorrhizae was smaller and they were found in deeper soil. The number of morphotypes of mycorrhizae was also smaller in fire-affected forest. An artificial plantation established after clear cut and prescribed burn had the largest amount of ectomycorrhizae, but the diversity was smaller than the unaffected forest. After four years, mycorrhizae had not yet recovered in fire-affected forest although the organic layer had recovered. Pioneer species of mycorrhizal fungi (early-stage fungi) developed sporocarps around the surviving hosts in severely affected forest and this suggests the start of secondary succession of mycorrhizae. In moderately affected forest, the species composition of mycorrhizal fungi which fruited during the study was similar to those of unaffected forest. This fact suggests that such sites may be the refugia of symbionts and be important in reforestation.
 
In order to prevent aflatoxin contamination in the production of kecap, an Indonesian soy sauce, the starter culture was prepared using the white-spored mutant K-1A strain induced from the aflatoxin-negative koji mold, Aspergills sp. K-1 and applied to koji making process of kecap. The number of spores developed on the cooked rice inoculated with K-1A was not so different from that of K-1. The germination ability of K-1A after storing at 30ºC and 75% RH for 3 weeks was also not so different from that of K-1. While kecap koji making process took 9 days by conventional method (without inoc-ulum), the use of the starter culture shortened the process to 3 days at room temperature. Since the inoculated strain K-1A developed white conidia (spores) during incubation, the mutant could be distin-guished from contaminated aspergilli by their appearances on agar plates. The number (cfu/g) of con-taminated aspergilli in the kecap koji from the environment decreased to 1/10 by using the starter culture. The kecap mash prepared with the kecap koji inoculated with the starter contained higher for-mol nitrogen and water-soluble nitrogen than those prepared with the koji without any starter. These results demonstrate that the use of the white-spored mutant as a starter not only contributes to the pre-vention of aflatoxin contamination but also improves the conventional kecap fermentation process.
 
Current citrus breeding programs have three objectives: developing diverse varieties that satisfy assorted commercial needs; improving overall fruit quality; and releasing varieties quickly. However, these objectives may conflict with each other owing to the limited available orchard space, and conventional breeding systems have not progressed rapidly enough to resolve this problem. “Citrus Breeding 2.0” is a novel approach to overcome the trilemma of citrus breeding. “Citrus Breeding 2.0” will increase diversity by referring to parentage, improve the overall fruit quality through composite selection, and minimize the breeding time through genomics-assisted selection. Extended applications of “Citrus Breeding 2.0” are also possible for purposes of rebreeding or improving an existing variety.
 
Legislation represented by the Livestock Waste Disposal Law and Compost Quality Control Law were enacted in order to reduce the excessive use of chemical fertilizer and disposal of untreated livestock waste. These laws encourage the replacement of chemical fertilizer use with livestock waste compost. The potential supply of nitrogen (N), phosphorus (P2O5) and potassium (K2O) from compost was estimated using computer software and prefectural and municipal data from the 2000 Census of Agriculture in Japan. Use of N, P2O5 and K2O as chemical fertilizer in Japan was also estimated by the questionnaire data by the Ministry of Agriculture Forestry and Fisheries and the 2000 Census of Agriculture. The percent of chemical fertilizer replaceable with livestock waste compost was calculated by dividing the supply from compost by the use of chemical fertilizer on the basis of N, P2O5 and K2O. Average and range of replaceable percent was 20.4% (106.9-7.1%), 21.8% (105.3-7.0%) and 31.5% (124.1-7.6%) in N, P2O5 and K2O, respectively, among the 47 prefectures. The range in about 3,300 municipalities fluctuated between 2,047-0%, 3,762-0%, and 3,207-0% in N, P2O5, and K2O, respectively. The significance of the data is discussed in the text.
 
This paper reviewed the delineation of a new 1:200,000 national soil map and a 1:50,000 cultivated soil map in Japan based on the Comprehensive Soil Classification System of Japan - First Approximation (CSCJ) and the World Reference Base for Soil Resources 2006 (WRB2006). These new CSCJ soil maps were compared with the 1:200,000 National Land Survey (NLS) soil map and the 1:50,000 cultivated soil map classified by the Classification System for Cultivated Soils revised 2nd Approximation (2nd CSCS) previously published. The distribution area of Andosols, Brown Forest soils, and Red Yellow soils great groups in the NLS soil map, and that of the Andosols, Lowland soils, and Yellow soils groups in the 2nd CSCS cultivated soil map were changed. These new soil maps easily identified the soil profiles and characteristics from the soil name because the CSCJ adopted precise diagnostic criteria, keying rules, and new soil groups that introduced new knowledge on soil pedogenesis into the NLS soil map and the 2nd CSCS cultivated soil map. Then, the national soil map classified by WRB2006 was delineated from the CSCJ national soil map, and Cambisols were mostly distributed in this map. By using numerous soil data from previously conducted studies in Japan, this soil map could accurately represent the distribution of Japanese soils compared with SoilGrid250m that was published recently and is one of the digital world soil maps. In conclusion, these new soil maps will be useful for the management of agricultural land and for environmental analyses at national and regional scales, and they are consistent with international classification systems, making them suitable for global soil information-sharing through schemes such as the FAO's Global Soil Partnership.
 
The aim of this study was to provide data on the prevalence of serovars of 48 strains of Actinobacillus pleuropneumoniae isolated in Japan from 2006 to 2011, and their antimicrobial resistance profiles (ARPs) by using the disc diffusion method. Of the 48 strains, 10.4% were serovar 1, 60.4% were serovar 2, 14.6% were serovar 5, and 2.1%, 2.1%, 2.1%, and 8.3% were serovars 6, 7, 12, and 15,respectively. We found that 25.0%, 12.5%, 39.6%, 37.5%, 18.8%, and 0% of the strains were resistant to penicillin G, ampicillin, oxytetracycline (OTC), sulfisoxazole, chloramphenicol, and norfloxacin,respectively. The ARPs of each serovar differed, with serovar 1 strains exhibiting multi-antimicrobial resistance to more than three antimicrobials. In contrast, 44.8% of the serovar 2 strains exhibited no resistance, and 34.5% were resistant to only one antimicrobial. All serovar 1, 5, and 15 strains were resistant to OTC, whereas serovar 2 exhibited lower resistance to OTC (6.9%). No significant increase in the prevalence of resistance to these antimicrobials was observed during the last half decade in Japan when compared with published data on the prevalence of resistant strains of A. pleuropneumoniae collected from 1989 to 2005. Regarding the prevalence of serovars, there has been a recent increase in the isolated cases of serovar 15.
 
In autumn 2009, the first outbreak of the shellfish-killing dinoflagellate Heterocapsa circularisquama bloom was recorded in a small lagoon, Lake Kamo, located on Sado Isl., Niigata Prefecture, Japan. At the time, the fisheries damage on the oyster culture due to the bloom was estimated at about JPY 190 million. Also in summer 2010, H. circularisquama formed a bloom in Lake Kamo, but in this case, no oyster kill was recorded. In the present study, we measured the temporal change in the abundance of viruses causing lysis of H. circularisquama and compared it with the host dynamics. We checked the host specificity and virus sensitivity of the isolated virus clones and host clones, respectively. Different types of host and virus clone dominantly coexisted in this lake, and the intraspecies host specificity of each HcRNAV clone isolated in Lake Kamo, 2010, agreed well with the host range predicted based on thededuced amino acid sequence of the major capsid protein (MCP). Considering the contemporary appearance of the host and virus, viralinfection was assumed to be one of the factors affecting the dynamics of H. circularisquama population in this lake.
 
Correlations of the 44 Argentinean, 58 Brazilian, and 43 Paraguayan soybean rust populations based on pathogenicity to the differentials. The numbers at the nodes indicate AU p-values (> 65%) generated by 10,000 multiscale bootstrap resamplings. Rust populations from Argentina, Brazil, and Paraguay are indicated by blue, green, and red letters, respectively. Sampling seasons are denoted by different font styles: the 2007/2008-2009/2010 seasons in italics; the 2010/2011-2014/2015 seasons in regular font.
Frequency of infection types produced in 13 differentials by inoculation with South American P. pachyrhizi populations during the 2010/11-2014/2015 seasons. The number of samples tested (N) is shown at the top of the plot. The Rpp genes that each differential has are shown at the bottom.
Frequency of the resistant responses produced in 13 differentials by inoculation with South American P. pachyrhizi populations during the 2007/20082014/2015 seasons. A: Rpp1-carrying differentials of PI 200492, PI 368039, and PI 587886; and Rpp2-carrying differentials of PI 230970 and PI 417125. B: Rpp1-b-carrying differentials of PI 587855, PI 587880A, PI 587905, and PI 594767A. C: PI 462312 (Rpp3), PI 416764 (Rpp3-?), PI 459025 (Rpp4), and Shiranui (Rpp5). 
Infection types of 24 Phakopsora pachyrhizi samples from Paraguay and seven isolates from Japan on 16 differentials a 
Soybean rust caused by Phakopsora pachyrhizi is one of the most serious economic threats to soybean production in South America. A previous study using South American P. pachyrhizi populations collected between 2007/2008 and 2009/2010 revealed the pathogenic diversity in Argentinean, Brazilian, and Paraguayan rust populations. Because such pathogenic diversity has been a major constraint to the breeding program for soybean rust resistance, pathogen populations were continuously monitored throughout the 2010/2011 to 2014/2015 seasons using the same method of evaluating pathogenicity as used in the previous study. None of the 83 P. pachyrhizi samples collected from the three countries from 2010/2011 to 2014/2015 yielded identical pathogenicity patterns in the 16 differentials, thus demonstrating the pathogenic diversity of more recent South American rust populations. Cluster analysis using a total of 145 rust populations from 2007 to 2015 demonstrated that the Argentinean, Brazilian, and Paraguayan populations were not assigned to three distinct country-based groups. The analysis indicated that a majority of South American populations differed in pathogenicity compared with Japanese rust races. The rates of resistance to the rust populations varied among the 13 differentials carrying Rpp genes; the most effective resistance gene was Rpp1-b followed by Rpp5, and the least effective was Rpp1.
 
It is essential to analyze the interaction between surface water and groundwater in order to use water effectively and predict water quality. The conventional method of analysis, however, measures only the flow of a stream and can not determine groundwater seepage accurately. Since the concentration of Radon-222 (222Rn) in groundwater is much higher than in surface water, the use of 222Rn was examined as an indicator for the analysis of the interaction between surface water and groundwater. Measurement of the 222Rn concentration in surface water was conducted to detect groundwater seepage into a stream. Furthermore, the simultaneous movement of water both into and out of a stream from the underlying strata was quantified by solving the 222Rn and water balance equations.
 
Percolation of water from a pond may cause a landslide in a hilled rural area. Before measures to prevent such landslides can be planned, it is essential to identify reservoir-water influent from the pond. We describe an analytical method that uses 222Rn- and water-balance equations to quantify groundwater effluent and reservoir-water influent simultaneously, which is impossible using the conventional method that measures only surface-water inflow and outflow. We selected F pond, Nagano Prefecture, as the study site. We estimated the rate of 222Rn dispersion to the atmosphere by assuming a stagnant film between water and air with thickness inversely proportional to the rate of dispersion. By a laboratory experiment, we estimated the film to be about 830 μm thick and found that the film thickness was not influenced by wind velocities less than 1.5 m s-1. A preliminary investigation suggested that reservoir-water was mixed very well. The groundwater effluent and the reservoir-water influent during the investigation were calculated to be 0.67 × 10-3 m3 s-1 and 0.41 × 10-3 m3 s-1 respectively, by making 222Rn- and water-balance equations and solving them. This analytical method is expected to be useful for not only prevention of a landslide but also for effective use of water and prediction of water quality.
 
Radon-222 ( 222Rn) concentration in surface water is a useful indicator for groundwater seepage. However, the natural concentration of 222Rn in surface water is too low to measure. It is therefore necessary to concentrate 222Rn content in water samples before analysis. This is a difficult operation requiring specialized equipment. We developed a method of measurement of 222Rn concentration in surface water (a method to concentrate radon by air-circulation) and applied it to detect groundwater seepage in the Ban Phai subwatershed, northeast Thailand. We also measured electric conductivity to determine whether dissolved ions in water were brought by groundwater. In areas of high-elevation (>180 m above sea level), 222Rn concentration in surface water was low, indicating that the velocity of subsurface water flow was slow even in the rainy season. This result supported a flow velocity previously calculated from the permeability of surface soil and the hydraulic gradient. Our measurements of 222Rn concentrations revealed that groundwater can be obtained by digging to a depth of about 1 m in the river bed in some areas. In areas of low-elevation (<160 m above sea level), electric conductivity increased markedly in the dry season. This was attributed to evaporation, rather than the effect of groundwater seepage, because the 222Rn concentration was low, suggesting little influence of groundwater.
 
Although Shaanxi province is the largest in China, both in terms of apple production and cultivated areas, with local farmers’ income mainly sourced from apples, the per-capita net income of farmers in Shaanxi province remains behind the national average. Since the market channel choice of farmers could be perceived as one of the available income strategies, this paper provides empirical evidence to measure the impacts of market channel choice on farmers’ income using a Heckman sample selection model and an OLS model based on a farm household survey of 243 apple farmers in Baishui and Luochuan counties of Shaanxi province, China. Moreover, this paper discusses the different impacts of market channel choice on household income among farmers who are cooperative members and those who are not.
 
A tilling robot capable of unmanned rotary tilling with the XNAV navigation system was examined to improve and expand the adaptability of the robot operation. Firstly, as an effective and safe method of using the robot, we proposed a method whereby one operator manually operated a conventional tractor while engaged in the unmanned operation of a robot tractor. As a result of the rotary tilling test, to which the use method was applied, the robot operation was performed without trouble, and one operator could perform the operation with efficiency about 1.8 times superiorto manned operation. Secondly, as an application to farm work other than rotary tilling, operation software for seeding and soil paddling was created based on operation software for rotary tilling. From the results of robot wheat seeding field tests, it was proved that the operation could be successfully performed without trouble and that the conventional two-person work could be done by one operator. The robot soil paddling was also successfully performed with efficient operation paths compared to manned operation.
 
Potato scab is a serious disease affecting cultivated potato. Combinations of an inoculant application (Streptomyces sp. strain WoRs-501) and other control methods were tested for their ability to suppress potato common scab. The use of a moderately resistant variety of potato in combination with the soil application of WoRs-501 decreased an inoculant population of this strain required for suppressing scab disease as compared to a susceptible variety. When a susceptible variety of potato grown in paper pots was planted in a scab-infested field, the application of a small volume of WoRs-501 inoculum to soil in paper pots tended to increase the scab control effect. The incorporation of lopsided oat seedlings derived from seeds coated with a mycelial suspension of WoRs-501 into scab-infested soil as green manure prior to planting a susceptible variety of potato in pots tended to increase the disease-suppressive effect of lopsided oat, and would be a practical method of providing a significant disease-suppressive effect. Furthermore, when tubers of a susceptible potato variety coated with WoRs-501 suspension in 0.1% sodium carboxy methyl cellulose (CMC) were planted in pots, the disease incidence score was significantly reduced to almost the same level as that of NEBIJIN powder. The treatment of CMC alone at a concentration of 0.1% also tended to decrease the disease incidence score, suggesting that it could be a new candidate agent for practical disease control.
 
By successfully sequencing the entire genome of common wheat (Triticum aestivum L.) in 2018, the International Wheat Genome Sequencing Consortium (IWGSC) achieved its goal of publishing the first reference genome sequence of this important crop. During this period, various technological innovations have dramatically evolved genome sequencing technology; these advances have made it possible to rapidly decode large and complex genomes, including that of polyploid wheat. IWGSC completed reference genome sequence by exploiting these latest technologies via two primary approaches, “whole-genome sequencing” and “sequencing by chromosome.” As collaborators in the IWGSC project, a Japanese research team led by the National Agriculture and Food Research Organization was responsible for sequencing chromosome 6B, one of the 21 wheat chromosomes, and contributed to constructing the reference genome sequence. This article presents an outline of reference genome sequence construction and provides an overview of the common wheat genome information obtained. Moreover, it describes the methods used to sequence chromosome 6B, together with the associated analytical data and novel knowledge, including the structural analyses of Nor-B2 and Gli-B2 obtained during this work. Furthermore, it describes the recently undertaken sequencing of the genomes of diploid and tetraploid wheat and reviews the overall development of wheat genomic resources.
 
Experimental design of chronic social defeat stress (CSDS) using the resident intruder paradigm. Fig. 2. (A) A test mouse (intruder) was allowed to physically interact with an ICR mouse (resident) for 10 min. After the interaction, the mice were housed in the same cage, separated by a plastic perforated divider that enabled the transmission of visual and olfactory cues for 24 h. (B) A schematic diagram of open field for social interaction test. The social target was represented as a white mouse (ICR). The experimental animal (C57BL/6J or BALB/c mouse) was defined as a black mouse. (C) An elevated plus maze apparatus consists of two opposite open arms without wall, crossed with two closed arms surrounded by walls.
Effects of chronic social defeat stress (CSDS) on social interaction and anxiety-like behaviors. (A) Social interaction score of BALB/c and C57BL/6J mice that underwent CSDS (n = 6 per group). Social interaction scores (%) were estimated as 100 × (duration of time spent in interaction zone with the ICR mouse present / duration of time spent in interaction zone with the ICR mouse absent). (B) Effects of CSDS on anxietylike behavior in the elevated plus-maze in C57BL/6J and BALB/c mice (n = 6 per group). All values are means ± SD (n = 6 per group), *p < 0.05 vs. the control, n.s.: not significant.
Chronic social defeat stress (CSDS), which subjects a male mouse to repeated social subordination by an aggressor male mouse, results in the onset of depression-like behaviors. CSDS in rodents is a useful model for studying the mechanisms that underlie anxiety and depression. We investigated the effect of CSDS on expression of tight junction (TJ) components in colon in C57BL/6J and BALB/c mice to address the correlation of CSDS and the development of inflammatory intestinal disease associated with epithelial barrier dysfunction. After 10 consecutive days of CSDS, BALB/c mice displayed highly social aversive behavior compared to C57BL/6J mice, which was accompanied by the suppression of intestinal Claudin-1 expression. These observations suggest that increased susceptibility to CSDS in BALB/c mice was caused by the downregulation of Claudin-1. The CSDS model with BALB/c mice is a potentially useful system for evaluating food components for psychological stress control.
 
Quantitative trait locus (QTL) analysis was performed to identify the chromosomal region controlling rice stripe virus (RSV) resistance in Japanese upland rice, Kanto 72. As a result, two QTLs were detected on chromosomes 2 and 11. Using near-isogenic lines possessing a single QTL (QTL-NILs) on chromosomes 2 and 11, the effects of two QTLs were evaluated. The target QTL regions were introduced in the genetic background of Koshihikari with marker-assisted selection. A combined QTL-NIL, possessing two QTLs, was developed from the cross between two QTL-NILs. Investigation of RSV resistance using three QTL-NILs revealed that the effects of the two QTLs clearly differed in the reaction to RSV. The QTL on chromosome 11 provided a major effect on reducing the infection rate of RSV. The QTL on chromosome 2 did not affect the infection rate, but made symptoms of diseased plants milder. The combined QTL-NIL showed high and stable resistance to RSV equivalent to upland rice, Kanto 72. From these results, RSV resistance in upland rice, Kanto 72, was controlled by the complementary effect of two QTLs. Major agricultural traits of the three QTL-NILs were not significantly different to those of Koshihikari, therefore, these QTL-NILs were thought to be useful in RSV-resistant rice breeding.
 
To elucidate the molecular mechanism underlying the toxicity of nivalenol, we investigated the involvement of heat shock protein 90 (Hsp90), a molecular chaperone, in nivalenol-induced cytotoxicity in human promyelocytic leukemia HL60 cells using an Hsp90-specific inhibitor geldanamycin. Cytokine levels and cell proliferation were investigated after 24-h treatment. Nivalenol significantly elicited interleukin-8 (IL-8) secretion, conversely, geldanamycin faintly altered. IL-8 secretion in cells co-treated with these chemicals was much lower than that with nivalenol alone, indicating the importance of Hsp90 for nivalenol-induced IL-8 secretion. Both nivalenol and geldanamycin alone reduced monocyte chemotactic protein-1 (MCP-1) secretion. Regardless of geldanamycin, the values in the nivalenol-treated samples were almost the same. If Hsp90 is indifferent to the nivalenol signal transduction, the effects of these chemicals should be additive. However, statistical analysis shows that these effects are not additive, indicating that geldanamycin mitigates nivalenol’s effect on MCP-1 secretion. While nivalenol markedly hindered proliferation, geldanamycin retarded it moderately. The value of cells co-treated with these chemicals was lower than that with nivalenol alone, meaning that geldanamycin does not protect against nivalenol-caused retardation of proliferation. In this study, we showed that Hsp90 is involved in nivalenol-associated changes in cytokine secretion, however, it is unclear whether Hsp90 is involved in the nivalenol-caused retardation of proliferation.
 
This review provides information about the levels of abscisic acid (ABA), indole-3-acetic acid (IAA) and gibberellins (GAs) in reproductive organs and the effects of uniconazole-P application on those hormones in citrus to analyze their possible relationships with fruit set and growth. Endogenous phytohormone levels in flowers and fruitlets were studied in 'Hyuganatsu' (Citrus tamurana [Hort.] Ex. Tanaka), which had no parthenocarpic ability, and Satsuma mandarin (Citrus unshiu Marc. cv. Ozaki). ABA concentration in the style of Satsuma increased 6-fold from the bud to the anthesis stage. Stamens in Hyuganatsu contained higher concentrations of IAA and GAs than in Satsuma. Immediately after pollination, Hyuganatsu showed peaks of ABA and IAA concentrations in fruitlets and parthenocarpic Satsuma also showed smaller peaks of ABA and IAA concentrations. Parthenocarpic fruitlets contained higher concentrations of GAs than pollinated fruitlets after fruit-set. 'Sepals' which included floral disks, sepals and receptacles in both setting types contained higher concentrations of ABA than in the nonsetting type, suggesting that ABA in 'sepals' plays a positive role. 'Sepals' in both setting types contained higher concentrations of IAA after fruit-set, suggesting that IAA from 'sepals' may hinder fruitlet abscission. Uniconazole-P, a GA biosynthesis inhibitor, markedly stimulated fruitlet abscission in Satsuma and increased 4-fold the concentration of endogenous ABA in fruitlets.
 
Hatcheries in Japan’s Tohoku region induce the gonadal maturation of Haliotis discus hannai by controlling the water temperature. However, the cost of heating the water places financial pressure on the hatcheries. This study showed that the heating cost in rearing abalone broodstock can be reduced using a simple closed recirculating system that was constructed using common commercial products.During our experiment, the water quality parameters including ammonia-, nitrite- and nitratenitrogen were kept under recommended safety levels. pH did not show a significant decrease during the breeding period. Although the calcium ion concentration and salinity value were less stable in the closed recirculating system than in the flow-through system, both were within adequate levels for rearing abalone over long periods. Moreover, the gonadal maturation of H. discus hannai was not inhibited by rearing in a closed recirculation system. And the electric power consumption in the closed recirculating system was reduced to about one-seventh of that in the flow-through system.
 
Studies on the reproduction and early life ecology of an abalone, Haliotis diversicolor, are reviewed, especially focusing on the results of our recent field and laboratory studies in Sagami Bay, Japan. Our four-year monitoring of the occurrence of newly settled post-larvae and changes in adult gonads clearly indicates that the spawning of H. diversicolor in Sagami Bay was triggered by typhoon events with large-scale storms. The abalone could spawn at least twice in a single spawning season, but required an interval of at least 1 month between spawning events. The proportion of adults releasing gametes and the amount of released eggs/sperms from each individual tended to increase on the spawning events occurring later in a spawning season. Higher mortality rates of post-larvae and early juveniles were detected at places which had greater water turbulences and more frequent stone overturning caused by storms. A storm event caused by a typhoon appears to be a necessary cue triggering the synchronous spawning of H. diversicolor, but the violent water turbulence and overturning of stones caused by storms negatively affect the post-settlement survival. Cohorts experiencing lower seawater temperatures due to the later settlement in the spawning season tended to have a slower growth rate than those experiencing higher temperatures, suggesting the temperature-dependent growth of post-larval H. diversicolor. The timing of typhoon-triggered spawning in H. diversicolor was suggested to be an important factor affecting the growth and survival and eventual recruitment of the abalone.
 
The feeding habits of the Ezo abalone, Haliotis discus hannai, changed with growth. Three major changes in the feeding of H. discus hannai were identified by reviewing recent studies on the feeding habits of this species. The first change occurred at the time of the metamorphosis, namely a shift from lecithotrophy to particle feeding. In the second change, when the shell length (SL) reached values of about 0.6–0.8 mm, post-larvae were able to digest diatom diets and they grew more rapidly on efficiently digested strains. The final change consisted of a shift from a biofilm-dominated diet to a macroalgal-dominated diet. Post-larval abalone (> 1.8 mm SL) were able to utilize juvenile macroalgae efficiently. These changes in the feeding habits were closely related to ontogenetic changes in the digestive enzyme activities and the development of the radula morphology.
 
Knowledge of throughfall at abandoned skid trails in tropical forests is extremely scarce. Thus, throughfall was measured using 120 storage rain gauges set on a skid trail left abandoned 41 years after forest harvesting in the Bukit Tarek Experimental Watershed (BTEW) in Peninsular Malaysia. All trees of ≥ 1 m height in the plot were identified to the species level, and their diameter at breast height (DBH) and height were measured. Vegetation along the skid trail comprises trees with smaller DBH (0.2-31.0 cm, with a mean of 2.0 cm) and shorter height (1.0-20.0 m, with a mean of 2.8 m) than those in the regenerated secondary forests of BTEW. The diversity (i.e. 43 families, 131 species) at the skid trail was similar to that in an old tropical forest at BTEW. The ratio of throughfall to gross rainfall (Th/Rg) for 84 rain events ranged from 27.4% to 204.7% with a mean and standard deviation of 98.1% and 33.2%, respectively. We found that a considerable amount of rainwater dropped under bertam (i.e. Eugeissona tristis) and rattan (i.e. Daemonorops callicarpa, Calamus insignis) vegetation. The Th/Rg ratio weakly correlated with canopy openness. The mean Th/Rg ratio is the largest mean ratio ever reported for forests in Malaysia.
 
A field experiment was carried out from October 1999 to September 2001 to establish a cropping system with Italian ryegrass (Lolium multiflorum) and natural-reseeded barnyardgrass (Echinochloa crus-galli) in an abandoned paddy field. Ryegrass was sown in October 1999 and 2000, and barnyardgrass was sown only in October 1999. A split-split plot arrangement was applied with the ryegrass varieties (an early-maturing type (EM) and a mid- to late-maturing type (LM)) as the main plot factors. The subplot factor was barnyardgrass at various sowing rates (100, 200, and 300 g/a). EM and LM were harvested twice and once, respectively, the following spring, and barnyardgrass was harvested twice: once in the summer and once in the autumn in both the EM and LM plots. In both years, the ryegrass yields depended significantly on the variety: the yield of EM was greater than that of LM. The first crop yields of barnyardgrass were affected by the preceding ryegrass varieties: greater yields of barnyardgrass were obtained when EM was the preceding crop than when LM was. The barnyardgrass sowing rate had no significant effect on either the first or the second crop yields. A sufficient number of seeds were produced to naturally establish a sward of barnyardgrass the following year in both the EM and LM plots. To verify the feasibility of this cropping system with ryegrass and barnyardgrass,we applied the system to a small field owned by a cattle farmer. The productivity cost of using this cropping system for grass production, excluding the cost depreciation for farm equipment, was comparable to the price of imported hay.
 
Soil erosion from fields located in the hilly lands of Shikoku was investigated. These are the areas where agricultural practices are quite limited and fields are often left idle and unutilized. Based on the results of the investigation, the calculated soil loss in terraced paddy fields and upland fields was about 3 t ha -1y -1 and 8 t ha -1y -1, respectively. Large soil loss (about 90 t ha -1y -1) was calculated to occur within several years immediately after abandoning cultivation of fields. Though soil loss did not largely increase in fields which changed to mowed grass fields (about 12 t ha -1y -1), there was a significant increase in mowed grass fields which changed to wild fields (about 40 t ha -1y -1). Soil loss in wild fields which were not cultivated for more than 6 years, decreased and became relatively stable (about 10 t ha -1y -1). To estimate the potential soil erosion of abandoned fields which are no longer cultivated, the Universal Soil Loss Equation (USLE) was revised to create the Hilly-land Soil Loss Equation (HSLE) by the addition of a term related to the erosion caused by intrusive surface and shallow-underground water runoff.
 
Lymphoid neoplasms of abdominal cavity origin were found in two cows infected with bovine leukemia virus (BLV). Case 1 was a 3-year-old Japanese Black cow affected with a B-1 B cell lymphoma. Case 2 was a 14-year-old Japanese Black cow that developed a γδ T cell lymphoma. Immunohistochemically, CD79a-positive lymphoma cells were observed in case 1, whereas CD3-, WC1- or perforin-positive ones were seen in case 2. Despite the expression of CD5 in both lymphomas, the reactivity was surface or cytoplasmic in case 1 and surface membrane in case 2. Erythrophagia by tumor cells of both cases was considered to be due to the fact that their normal counterparts were more primitive forms than conventional lymphocytes.
 
To obtain basic information for the production of healthy and vigorous larvae and juveniles, a comparative study on meristic variations and bone abnormalities between wild and laboratory-reared red sea bream, Pagrus major, was undertaken. Although 95% of the specimens of wild juveniles had a definite number of dorsal fin rays, reared juveniles exhibited extensive variations, and the latter had fewer pectoral fin rays than the former. Bone abnormalities included the transformation of spines to soft rays, shrinkage of lower jaw, pug-headness, shrinkage of anterior centra, fusion of vertebrae, abnormal pterygiophores, etc. Detailed observations of cleared and double-stained specimens revealed that wild juveniles had an average of 0.2 abnormal bones per specimen, whereas, the reared ones had an average of 2.04-21.4 abnormal bones per specimen, depending on the groups. Therefore, reared fishes showed many abnormalities, although they appeared to be normal based on external observation. The causes of these abnormalities have not been elucidated, except for the lordosis. Abnormalities of reared fishes seemed to affect bones and cartilage as well as other tissues, such as the deformity of the inter-nostril epidermis in one case. It is likely that various defects associated with rearing conditions induce a variety of abnormalities. Aquaculturists should attempt to produce larvae and juveniles which are similar in morphological, behavioral, physiological and biochemical characteristcs to wild ones.
 
To analyze the sustainability and carrying capacity of a mangrove forest, we studied the profiles of species composition and biomass from the riverside to inland. A belt transect (25×180 m) divided into 9 plots was established in compartment 46, in the Matang Mangrove Forest Reserve, Perak, Peninsular Malaysia. Five tree species were distributed in the transect. Rhizophora apiculata showed the highest density, followed by Bruguiera parviflora, B. sexangula, R. mucronata and Avicenia alba. From the riverside to inland, the structure changed from pure R. apiculata stands to mixed Rhizophora - Bruguiera stands. The mean aboveground biomass of all the plots was 316 Mg ha -1. The largest and smallest volumes for biomass were 558 Mg ha -1 on the riverside and 144 Mg ha 1 inland , respectively. The values tended to be higher in R. apiculata-dominant stands. If a larger productive area could be set up where R. apiculata would predominate, i.e. an area at a lower ground level, a larger sustainable amount of biomass for firewood and charcoal use could be produced. The annual dead biomass, which is supplied to the forest floor as nutrients for aquatic life, was 5.1 Mg ha -1. While stocked biomass is more valuable to a local economy than the dead biomass, the contribution of the fallen trees (dead biomass) to habitats and nutrients for aquatic life must be evaluated exactly in the future.
 
The effect of a commercial inoculant on the fermentation quality of silage made from agricultural by-products (ABP silage) prepared in Thailand was examined. By adding an inoculant, the pH of silage became low and the counts of yeast and clostridia in silage decreased in comparison with the silage without inoculant. The effect of temperature against the inoculant was also examined by using a modified pouch method. The addition of inoculant provided good quality silage at 30°C. However at 45°C, the addition of the inoculant resulted in a remarkable decrease in the amount of lactic acid produced and an increase in pH about 0.6-0.8 with no good quality silage produced. From these results, it was suggested that the inoculant used in this study was effective for improving the fermentation quality of ABP silage in Thailand at temperatures less than 37°C, but was not effective at 45°C.
 
A 7-month-old Duroc boar exhibited anorexia and dark-bloody diarrhea. Despite antimicrobial therapy including enrofloxacin (fluoroquinolones) and tylosin (macrolides), the boar died. Gross examination showed hepatic abscesses. Histological examination showed chronic multifocal necrotizing and suppurative hepatitis with colonies of Gram-positive cocci. Necrosis was observed in the center of affected areas. The lesions were composed of numerous neutrophils, macrophages, a few lymphocytes, and fibroblasts. Dense fibrous connective tissue surrounded these necrotizing and suppurative lesions. Several cocci were also detected in the multifocal necrotic foci in the liver. The bacteria isolated from the hepatic abscesses were confirmed to be Streptococcus suis serotype 4 based on the results of 16S rRNA gene sequencing and agglutination tests with antisera. Immunohistochemically, the cocci observed in the hematoxylin and eosin and Gram-stained sections of the liver abscess were strongly positive for S. suisserotype 4. Antimicrobial susceptibility testing showed that the isolate was resistant to third generation cephalosporins. Thus, a diagnosis of unique streptococcosis caused by S. suis serotype 4 was made. The typical clinical manifestation of S. suis infection involves meninges, endocardium, joints, and the lungs. The present boar is the first natural case of porcine liver abscess caused by S. suisserotype 4.
 
Carotenoid mutants are useful for elucidating carotenoid metabolism. ‘Kusaie’ is a yellow-fruited form of ‘Rangpur’ (Citrus limonia Osbeck). Hyuganatsu (C. tamurana hort. ex Tanaka) is a mediumsized, light yellow fruit. Its bud mutation, wherein the fruit rind color becomes orange, is named ‘Orange-hyuga.’ To elucidate the mechanism underlying this alteration, their carotenoid composition and abscisic acid content were analyzed. In the flavedo of ‘Kusaie,’ significant phytoene accumulation, decreased xanthophyll, and ABA contents were observed, suggesting that phytoene desaturase was suppressed. Moreover, the total carotenoids in the juice sac of ‘Kusaie’ was significantly lesser than those in that of ‘Rangpur,’ suggesting that the production of carotenoids is suppressed in ‘Kusaie.’ In ‘Orange-hyuga,’ the total carotenoids was approximately 6-fold that of Hyuganatsu, and a significant xanthophyll accumulation, especially violaxanthin, was observed. Furthermore, ABA content was significantly lower. Accordingly, those might be associated with an altered gene expression balance upstream and downstream of biosynthesis. Difference in biosynthesis regulation in these color-altered cultivars might cause a change in the carotenoid contents and composition in fruits, which seemed to result in color changes from reddish-orange in ‘Rangpur’ to yellow in ‘Kusaie’ and from a light yellow color in Hyuganatsu to an orange color in ‘Orange-hyuga.’ In this study, these color-changing citrus mutants were observed to accumulate carotenoids differently from the original type, and we speculated that different changes occurred in carotenoid biosynthesis regulation.
 
We examined in this paper the interaction between carnation growth and air and soil temperatures to clarify the effect of the combination of reflective film mulching (RFM) and shading treatments on carnation growth. Dry weight and nutrient absorption of carnation were influenced more strongly by the air temperature than by the soil temperature, although favorable effect of cooler soil was noticed when the air temperature increased. RFM effect on the lowering of the soil temperature may contribute to higher nutrient absorption. Combination of RFM and shading treatments reduced the leaf temperature by 5.3°C compared with the untreated plot. The response was enhanced by the increase of the air temperature. The treatments also reduced the soil temperature in the daytime although the response was less evident than that to the increase of the air temperature. As shown above, since RFM and the shading treatments reduced the air and soil temperature, they alleviated high temperature stress in carnation plants and activated nutrient uptake, resulting in a larger plant size.
 
Various carotenoids with diverse structures are present in foods and have been reported to have beneficial effects on human health. Owing to their hydrophobicity, however, poor solubilization in the aqueous milieu of the digestive tract restricts their intestinal absorption. Fats and oils were found to increase the solubilization of carotenoids into mixed-micelles, which would therefore enhance their bioavailability. The uptake of carotenoids solubilized in the micelles by intestinal cells are thought to be mediated by simple diffusion and/or facilitated diffusion through scavenger receptors. Lipids that constituted the mixed-micelles affected the uptake of carotenoids. In particular, lysophosphatidylcholine significantly enhanced uptake. Highly polar carotenoids, meanwhile accumulated in mice but not in humans, suggesting discriminate absorption and metabolism in the latter. The metabolism of provitamin A carotenoids is well known to be mediated by the central cleavage enzyme. Recently, another cleavage enzyme was found to cleave various carotenoids asymmetrically into apocarotenoids. Xanthophylls were found to be oxidized to unstable keto-carotenoids in mice. These metabolic conversions are thought to affect the levels of bioavailable carotenoids in tissues. In this article, the solubilization into mixed-micelles, intestinal absorption and oxidative metabolism of carotenoids are reviewed to understand the factors that determine the bioavailability of carotenoids ingested from fruit and vegetables.
 
Top-cited authors
Sadanori Sase
  • Nihon University
Yoshimichi Fukuta
  • Japan International Research Center for Agricultural Sciences
Hisatoshi Kaku
Yasuhiro Inoue
  • National Agriculture and Food Research Organization
Aeni Sasaki
  • National Institute of Agrobiological Sciences