A small interfering RNA (siRNA) can be custom-produced in plant cells when a transgene comprising an inverted-repeat sequence is used to form the corresponding double-stranded (ds)RNA. This siRNA induces methylation of the homologous DNA through the RNA-directed DNA methylation (RdDM) pathway. As methylation of the promoter region causes transcriptional gene silencing (TGS), dsRNA for the promoter sequence of a gene can induce TGS of the gene, accompanied by modification of chromatin. Such epigenetic variation provides a novel technique to induce silencing of a target gene. Furthermore, once epigenetic variation has occurred, the siRNA need not be present to maintain the stable repression of transcription even in the subsequent generation. Thus, the induction of epigenetic changes is a potentially new plant-breeding technology to improve crops.

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Composting of livestock manure is a significant source of greenhouse gases such as nitrous oxide (N₂O), but the complexity of the N₂O generation pathway hinders efforts to develop effective countermeasures. In this paper, we present one mitigation option for N₂O emissions from composting. Nitrite (NO₂^-) has an important role in N₂O generation. It has been observed that significant N₂O emissions from composting are induced when NO₂^- is accumulated during nitrification. Accordingly, in our technique, nitrite-oxidizing bacteria (NOB), as nitrifying bacteria, are added in the middle of composting fermentation to prevent NO₂^- accumulation. Adding NOB prevents prolonged NO₂^- accumulation, which had resulted in low N₂O emissions. This technique is also cost-effective, because mature compost can be used as an NOB source. Mitigating N₂O emissions allows more nitrate nitrogen (NO₃^-), of high value as fertilizer, to be preserved in the compost product. Moreover, it was confirmed that this technique could be combined with that for NH₃ mitigation using chemical reagents. Before actual use, it is necessary to investigate the methods used to determine optimal timing to add NOB source and prevent N₂O from being generated from an NO₃^- reduction.

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Enzymatic peeling of fruit and vegetables is considered superior to conventional peeling methods in terms of minimizing product damage and indeed is expected to improve them. This technology was first proposed for the peeling of citrus fruit and numerous studies on its practical use have been conducted. However, its application to non-citrus fruit and vegetables remains limited. A novel process, including heat treatment prior to enzymatic treatment, is proposed to peel persimmon fruit. Heat treatment induces fine and even cracks on the fruit surface of certain persimmon cultivars, which act as channels via which enzyme solution can enter the peel tissue. Another function of the heat treatment is to inactivate polygalacturonase-inhibiting protein (PGIP), which is inherent in persimmon fruit. Inactivation of PGIP improves the efficiency of enzymatic peeling with exogenous polygalacturonase. Chemical pre-treatments with a food-grade emulsifier solution and a weak basic solution also enhance the permeability of enzyme solution into the peel tissue. These physical and chemical treatments are useful for applying enzymatic peeling to various persimmon cultivars. In future, enzymatic peeling technology is expected to be applied to various agricultural crops as the technology is further refined.

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Soil physicochemical properties were determined for soils under cropland and forest at the headquarters of the International Institute of Tropical Agriculture in Ibadan, Southwestern Nigeria to examine the 30-year effects of different land use on the fertility of five soil series toposequences underlain by a Basement Complex. The cropland had been under cultivation for 30 years, during which mainly maize and yams had been cultivated in rotation with application of chemical fertilizer and intermittent fallow, while the forest had secondary vegetation that had been regenerated during a 30-year period under protection. The findings for cropland indicated an accumulation of available phosphorus and exchangeable potassium, soil compaction and slight depletion of topsoil organic carbon content; and the findings for forest indicated soil acidification and accumulation of exchangeable Ca at the surface soil horizon. These findings suggest the possibility of maintaining soil fertility with a long-term intensive and continuous crop farming system in kaolinitic Alfisol soil over the inland valley toposequences of tropical Africa.

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The effect of rice bran on dry matter production of different rice cultivars, namely the Chinese panicle weight types and Japanese panicle number types, was evaluated in field conditions, with growth, canopy production structure and the root system determined over a period of 60 days. The treatments consisted of rice cultivars with 1000 kg ha^-1 rice bran without agrochemicals (RB), cultivars with chemical fertilizer and cultivars with herbicide, with the latter serving as a control. The crop growth rate (CGR) and mean leaf area index (mLAI) in RB treatment were lower than that of the control; however, the net assimilation rate (NAR) was higher for all growth stages in this treatment. It was noted that CGR in RB and the control treatment depended greatly on mLAI during the early and middle growth stages, whereas CGR was more dependent on NAR in the late growth stage. Correlation between CGR in middle stage and the extinction coefficient of the canopy (k) at heading was apparent (p < 0.05). NAR in middle stage was positively correlated with mean leaf color and specific leaf weight (SLW). The correlations between NAR in the late stage and bleeding rate per number of primary roots, and per leaf area at maturity was apparent (p < 0.01). Root vitality and NAR were higher in RB treatment. The photosynthesis-related traits after heading in RB treatment were better than the control. Reduction of ∆W in RB treatment as well as the spikelets number (SN) was unapparent. The panicle number type cultivars did not inhibit growth during the early and middle growth stages with the presence of rice bran. The difference between growth, panicle number and weight cultivars was insignificant in the late stage.

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Reed canarygrass (Phalaris arundinacea L.) is a cool-season perennial grass widely distributed throughout North America, Europe and Asia. P. arundinacea is currently considered a major invasive plant species in the USA. Despite recent concerns that P. arundinacea has become an invasive plant species in Japan, differences between invasive and native Japanese genotypes remain unclear. We used flow cytometry to clarify genome size differences among 14 populations of putative native Japanese P. arundinacea genotypes and three exotic cultivars. The average genome size of the 14 Japanese populations and the three exotic P. arundinacea differed significantly (P < 0.05) and ranged from 4963.90 to 5166.69 Mbp/C. These results implied that the sampled populations included native Japanese genotypes. These populations may be useful in discriminating between invasive and native Japanese P. arundinacea genotypes.

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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 β-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.

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We developed a water circulation model that incorporates paddy water management, including reservoir operation and water allocation schemes, which is applicable to extensive and well-developed irrigation areas. First, reservoir operation and water allocation and management models were introduced into the water circulation model previously developed by the NIRE. Subsequently, we applied the developed model to assess the impact on irrigation reservoirs of climate change in the Mun River basin of northeast Thailand. As a result, taking into consideration the fluctuation in rainfall, the developed model reproduced the seasonal changes in storage water and water release at two large reservoirs, and monthly diverted water at a major diversion weir. Moreover, introducing the operation of reservoirs and diversion weirs improved the simulation accuracy of river discharges, particularly in dry seasons. According to climate change projections, the impacts of climate change on reservoir operations differed in each reservoir, although the reservoirs are in the same basin. This means that the impacts of climate change on the operation of water-use facilities should be individually assessed. Since the developed model requires only basic information and assumes simple operation rules, this model is useful for assessing impacts on the operation of numerous water-use facilities simultaneously at the macro level.

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Classification maps are required for agricultural management and the estimation of agricultural disaster compensation. The extreme learning machine (ELM), a newly developed single hidden layer neural network is used as a supervised classifier for remote sensing classifications. In this study, the ELM was evaluated to examine its potential for multi-temporal ALOS/PALSAR images for the classification of crop type. In addition, the k-nearest neighbor algorithm (k-NN), one of the traditional classification methods, was also applied for comparison with the ELM. In the study area, beans, beets, grasses, maize, potato, and winter wheat were cultivated; and these crop types in each field were identified using a data set acquired in 2010. The result of ELM classification was superior to that of k-NN; and overall accuracy was 79.3%. This study highlights the advantages of ALOS/PALSAR images for agricultural field monitoring and indicates the usefulness of regular monitoring using the ALOS-2/PALSAR-2 system.

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According to rising social and environmental concerns, the number of small-scale oil mills growing and milling rapeseed has increased over the past decade. This study was undertaken to clarify small-scale rapeseed oil mill production, which is under pressure from mass-produced vegetable oil, and propose the application of this community-based system to developing nations. We analyzed all domestic rapeseed oil mills between 2009 and 2011, and discussed the transition from traditional mills to newly established town office-sponsored mills and its effect on the rural economy. We clarified that small-scale oil mills in rural areas have survived through strong self-sufficient production and have restructured into self-managing local communal businesses. This restructuring of local rapeseed production has had a positive effect on the local community and has revitalized the rural economy. Thus, we concluded that it may be suitable for microcredit in developing nations.

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We investigated the shoot growth and fruit production of ‘Masui Dauphine’ fig trees (Ficus carica L.) with a newly devised “renewal long pruning” method and compared the results with those of conventional short pruning under straight-line training with both normal and high limb styles. This novel pruning method combines long pruning and continuous renewal pruning such that a few dormant shoots remain long and serve both as long mother shoots and as replaceable limbs. In experiments in 2009 and 2010, the shoots sprouted earlier from the renewal long pruning trees than from the short pruning trees. The number of lateral shoots was less in the renewal long pruning trees, indicating the prevention of excess vigour in bearing shoots. Renewal long pruning did not affect total percentage of fruit set; however, it slightly increased fruit set failure in the basal portion of bearing shoots. It potentially induced early maturation and greater enlargement of the fruit. Renewal long pruning was especially useful in high-limb straight-line training because it effectively compensated for disadvantage of this training, such as increasing numbers of lateral shoots and inhibition of fruit enlargement.

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This study was conducted to determine the energy balance of beef cattle by indirect animal calorimetry utilizing a ventilated head box respiration system. Fifteen native Thai bulls were randomly allocated to one of three dietary metabolizable energy intake (MEI) levels (1.1 × maintenance, 1.5 × maintenance and 1.9 × maintenance) in a completely randomized design for a 116 day feeding trial. Animals were allocated to individual metabolic cages for the determination of digestibility and energy balance. Heat production was determined from oxygen consumption, carbon dioxide and methane production. The results showed that dry matter, organic matter and crude protein intake were increased (P < 0.01), but digestibility of all nutrients, except neutral detergent fiber, was not significantly affected (P > 0.05) by MEI levels. The energy loss in feces and urine (% of gross energy intake) were not different (P > 0.05); however, enteric methane conversion rate (% of methane energy loss per gross energy intake) and heat energy production loss (% gross energy intake) were linearly decreased (P < 0.01) with increasing MEI levels. Methane conversion rates ranged from 8.4 to 10.0% and appeared to have been underestimated by the Intergovernmental Panel on Climate Change 6.5% default values set for cattle fed low quality crop residues and by-products. The estimate of metabolizable energy requirements for maintenance was measured using linear regression analysis derived for native Thai cattle was 520 kilojoules per kilogram of metabolic body weight per day. Increased dietary intake levels reduced enteric methane emissions in beef cattle fed on tropical feedstuffs. The results of the present study indicated that greater dietary intake feeding strategy in cattle fed above the maintenance level resulted in improved energetic efficiency utilization, and thus improved energy retention because of the reduction of enteric methane energy emission and heat production.

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Although sweet sorghum is in focus as a promising multi-purpose crop in semi-arid tropical regions, information on optimum nitrogen (N) management remains rather limited. To determine and understand the N dynamics in sweet sorghum-soil ecosystem, we evaluated the N recovery of applied fertilizer in the Alfisol field during the 2009 and 2010 rainy seasons. Sweet sorghum was grown under six N rates (0, 30, 60, 90, 120 and 150 kg N ha^-1) with split application (at 0, 30 and 60 days after sowing) and N concentration and N recovery efficiency (NRE) were measured. In addition, to determine the fate of basal and topdressed N, ¹⁵N-labeled urea was applied at each application timing within main plots of 90 kg N ha^-1. There was no significant difference in NRE calculated by the difference method between six N rates and N uptake rose with increasing N rate. The total dry weight and sugar yield increased at rates up to 90 kg N ha^-1 and higher N rates did not significantly affect sorghum productivity. As a total of basal and topdressing applications, 33% of the applied ¹⁵N-labeled urea was absorbed by the sorghum plant, while 36 and 30% remained in the soil and unaccounted for, respectively. The NRE calculated by the isotopic method was about 39 and 37% for topdressings at 30 and 60 days after sowing, respectively. The distribution ratio of absorbed N in leaves was higher for basal applications and topdressing at 30 days after sowing, while that in grains was higher for topdressing at 60 days after sowing, compared to the other application timings. In contrast to topdressings, the NRE was very low (13%) for basal N application: about 70% of the basal applied N remained in the soil at the physiological maturity. The results imply that the NRE might be increased by improving the ways in which basal N is applied.

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