Showing papers in "Jarq-japan Agricultural Research Quarterly in 2019"

Comparing Rates of Rock Weathering and Soil Formation between Two Temperate Forest Watersheds Differing in Parent Rock and Vegetation Type

Abstract: In the present study, the multiple regression analysis of mass balance equations of seven major geochemical elements (Al, Fe, Ca, Mg, K, Na, Si), among rock, soil, stream water, and precipitation in a watershed was used to simultaneously estimate the rates of rock weathering (RWR) and soil formation (SFR) in two template forest watersheds of Central Japan that had different types of vegetation and bedrock. Our results revealed that Mt. Kasuga watershed (MKW) with a primary evergreen broadleaf forest and gneissic bedrock had lower RWR (1.51 t ha−1 yr−1) and SFR (1.37 t ha−1 yr−1) than those in Yata Hill watershed (YHW) with a semi-deciduous mixed forest and granitic bedrock (RWR = 1.83 t ha−1 yr−1; SFR = 1.79 t ha−1 yr−1). Based on the hypothesis that the vegetation effect on the watershed scale mass balance is negligible in a steady state ecosystem, we concluded that the bedrock type can be a main factor causing the difference in RWR and SFR, as gneiss in MKW had smaller amounts of mica and feldspars and is supposed to have the higher resistance than granite in YHW to chemical weathering. Disciplines: Soils, Fertilizers and plant nutrition Additional key words: geochemical mass balance, multiple regression analysis, watershed management *Corresponding author: e-mail ishi5ro@hotmail.com Received 5 February 2018; accepted 22 October 2018.

Suppressive Effects of Vermicomposted-Bamboo Powder on Cucumber Damping-Off

Abstract: The suppressive effect of vermicomposted-bamboo powder (VB) derived from waste bamboo shoots on cucumber damping-off when VB is used as a nursery medium was characterized. A greenhouse inoculation experiment showed that the damping-off caused by each strain of Pythium aphanidermatum, P. ultimum var. ultimum, and Rhizoctonia solani AG1-IB was significantly reduced by VB compared to an autoclaved vermicomposted-bamboo powder (aVB) and a commercial-nursery medium (CNM). Due to the fact that the disease suppressiveness of VB was nulled by autoclaving, the soil biological factors were characterized with respect to those of the CNM by fluorescein diacetate (FDA) hydrolysis reactions, plate count techniques, and next-generation sequencing (NGS) analysis using prokaryotic universal primers. The FDA hydrolysis reaction and the plate count techniques showed that VB has a higher microbial activity and population density of fungi and bacteria than aVB and CNM. The NGS analysis revealed that the bacterial diversity was higher in VB than in aVB and CNM. In addition, the higher concentrations of NH4 in VB may be related to the Pythium damping-off suppression. This is the first report on the suppressive effect of VB on the damping-off disease, which is at least partially due to its rich microbial activity and diversity. Disciplines: Plant protection, Watershed and regional resources management Additional key words: bacterial diversity, microbial activity, microbial population, waste bamboo *Corresponding author: e-mail xiaodongyou@hotmail.com Received 13 March 2018; accepted 29 June 2018.

The tendency of expanding forest certification in Vietnam: Case analysis of certification holders in Quang Tri Province

Abstract: Forest management certification has been widely promulgated throughout the world, and the growth rate of forest management under the Forest Stewardship Council is especially high in Southeast Asia. In Vietnam, where the growth rate is the highest in all of Southeast Asia, timber processing and chip industries are developing dramatically. Here we clarify factors surrounding the expansion of forest management certification and the merits of attaining certification for corporations and farmers. We targeted two certified corporations and a group of farmers in Quang Tri Province in Central Vietnam where the movement for attaining certification occurred earlier than in other areas. The reasons of the two interviewed corporations to apply for certification were the helm of the government, a higher selling price for timber, and access to international markets. The farmers’ group was also motivated by the higher timber-selling price. Thus, higher timber selling points and access to international markets were the main motivations for applying for certification. Even though prices are increasing, income will decrease because of the long timber harvesting cycle; therefore, for expanding forest management certification can be said to correspond with the demand for certified timber from international markets and domestic timber demand from corporate channels. Discipline: Forestry and forest products Additional key words: acacia, company forest certification, farmer group certification, FSC (Forest Stewardship Council), timber processing company *Corresponding author: e-mail iwanagasage@ffpri.affrc.go.jp Received 6 February 2017; accepted 1 March 2018.

Retrospective and Histopathological Studies of Entamoeba spp. and Other Pathogens Associated with Diarrhea and Wasting in Pigs in Aichi Prefecture, Japan

Abstract: Postweaning diarrhea and wasting are a major concern in pig farms’ management. Although hemolytic enterotoxigenic Escherichia coli, porcine epidemic diarrhea virus, porcine circovirus type 2, and Salmonella spp. are the most frequent etiological agents of these diseases, Entamoeba suis and E. polecki were recently reported to be associated with diarrhea in pigs. Since the infection rate of Entamoeba in pigs and its relationship with other pathogens are unknown, we examined 206 pigs exhibiting diarrhea and/or wasting in Aichi Prefecture, Japan to determine the prevalence of porcine Entamoeba spp. E. suisand E. polecki-like trophozoites were detected by histopathology in 53 pigs, mainly in the lumen of the large intestine. Ulcerative colitis with infiltrating trophozoites was observed in 16 pigs, and most of these trophozoites were identified as E. polecki subtype 3 by PCR and sequence analysis. Tissue-invasive Entamoeba spp. were prevalent in pigs exhibiting diarrhea and wasting, and most samples were also positive for either Salmonella spp. or Lawsonia intracellularis by immunohistochemistry. These results suggested that Entamoeba was widespread in farms in Aichi Prefecture, and in most cases, enteritis was caused by coinfection by Entamoeba with Salmonella spp. or L. intracellularis, which causes wasting by exacerbating the original mucosal lesions. Discipline: Animal health Additional key words: Entamoeba polecki, Entamoeba suis, pig, diarrhea, wasting * Corresponding author: e-mail tshiba@affrc.go.jp # These authors contributed equally to this work. Received 21 November 2017; accepted 11 June 2018.

Does Soil Fertility Decline under Smallholder Rubber Farming? The Case of a West Sumatran Lowland in Indonesia

Abstract: In Indonesia, plantations of rubber tree (Hevea brasiliensis), which have been expanding rapidly in lowland areas of the Sumatra Island, are predominantly managed by smallholder farmers using a limited amount of fertilizers. The rapid growth of the rubber tree and the intensive collection of latex during an economic lifetime (ca. 25 years) of the rubber tree poses a risk of soil fertility decline in the rubber gardens, but changes in soil fertility under smallholder rubber farming have not been well assessed in this region. In the present study, we aimed to examine if the soil fertility declines under smallholder rubber farming through the assessment of the changes in the general soil fertility parameters along a chronosequence of rubber tree stands (n = 24; stand age, 3-27 years old) in a West Sumatran lowland. Our results revealed that all the parameters assessed in this study such as organic carbon, total nitrogen, available phosphorus, and exchangeable bases were found independent on the tree stand age and did not show any clear trends of decrease/increase during rubber cultivation period. These findings indicate that soil fertility decline under smallholder rubber farming system is unlikely in the study region. Discipline: Agricultural Environment Additional key words: chronosequence, Hevea brasiliensis, rubber garden, soil fertility replenishment

Neutrophilic Granulocytic Sarcoma and Acute Basophilic Leukemia in Cattle

Abstract: A case of neutrophilic granulocytic sarcoma and a case of acute basophilic leukemia are described. The former was diagnosed in an 8-year-old Holstein cow with a large intrathoracic tumor mass (case 1), and the latter in a 14-month-old Holstein heifer with a rapid increase in white blood cell count (case 2). In case 1, the tumor mass was composed of agranular cells and more mature cells with eosinophilic granules staining positive for naphthol AS-D chloroacetate esterase (CAE) and macrophage, myeloid/ histiocyte antigen (clone MAC387). In case 2, the tumor tissues consisted chiefly of myeloblastoid cells. However, differentiation to myelocytoid or metamyelocytoid cells was observed, and their intracytoplasmic eosinophilic granules were positive for tryptase (a marker for basophils and mast cells), but not for CAE (a marker for neutrophils and mast cells). Although reports of myeloid neoplasms are rare in cattle, as documented here, it is not difficult to diagnose them on the basis of histology, histochemistry and immunohistochemistry. Discipline: Animal health Additional key words: esterase staining, immunohistochemistry, myeloid leukemia, myeloid sarcoma * Corresponding author: e-mail tshiba@affrc.go.jp Received 9 November 2017; accepted 14 May 2018.

Influence of Daily Temperature Range on Seedling Emergence and Establishment and Estimation of Early Sowing Limits in Directly Seeded Rice Under Submerged Conditions in a Cold-Climate Area (Hokuriku Region, Japan)

Abstract: Although direct seeding in rice cultivation has potential for laborand cost-saving benefits in comparison with transplanting, the latter remains the predominant method in Japan because the former shows some weaknesses in seedling emergence and establishment, and in lodging resistance. We therefore set out to compare seedling emergence and establishment in direct seeding culture under different daily temperature ranges. We compared a windbreak-shielded and control plot using pot-grown plants under outdoor conditions. In the windbreak plot, which was subject to a high maximum temperature and wide daily temperature range, seedling emergence and establishment rates were higher than in the control plot. Additionally, detailed laboratory tests revealed that the influence of post-seeding daily temperature ranges on seedling emergence was greater under low-temperature than high-temperature conditions. Moreover, changes with time in the measured values for seedling emergence rates and those estimated using the Arrhenius equation were approximately the same. We also used maximum and minimum temperatures to calculate early sowing limits for direct seeding of paddy rice at different locations in the Hokuriku region; previously, daily mean temperature has been used as the basis of early sowing limit calculations. The two calculation methods showed different early sowing limits. Moreover, early sowing limits based on daily temperature ranges were observed to occur earlier in the inland and later in the coastal area when compared with early sowing limits based on daily mean temperature. Discipline: Crop Science Additional key words: AMeDAS weather data, Arrhenius equation, wind

Detection Frequency of Porcine Noroviruses in Healthy Pigs in Japan

Abstract: Porcine noroviruses have been previously reported by some Japanese research groups. However, there is limited information regarding their epidemiology and pathogenicity in pigs. Here, we attempted to determine the frequency of norovirus infection in pigs in Japan. Fecal samples were collected from 190 healthy pigs in the Tokai region of Japan and checked for noroviruses by reverse transcriptionPCR. Noroviruses were present in 11 of the 190 fecal samples (5.8%) and were genetically related to the porcine noroviruses previously detected in other regions of Japan. Our data suggest that porcine noroviruses are circulating among populations of healthy pigs without clinical signs in Japan. Discipline: Animal Science Additional key words: nested PCR, phylogenetic tree, swine

Dry Matter Yield Response to Seeding Rate and Row Spacing in Direct-seeded and Double-harvested Forage Rice

Abstract: Forage rice (Oryza sativa L.) must be cost competitive with other fodders, and thus an important goal is increasing its dry matter (DM) and total digestible nutrient (TDN) yields, while reducing labor and costs. Although the direct seeding of rice does not have higher yield stability than transplanting, it has the potential to reduce labor and costs. The objective of this study was to determine the effects of seeding rate (2, 4, or 6 g m–2) and row spacing (10 or 30 cm) on DM and TDN yields in direct-seeded and double-harvested forage rice in a well-drained paddy field. The seeding rate did not affect the total DM and TDN yields of the first and second crops, although those total yields were higher at 10 cm row spacing than at 30 cm row spacing. The DM yield and tiller number of the first crop increased with increasing seeding rate. Both were higher at 10 cm row spacing than at 30 cm row spacing. The seeding rate did not affect the DM and TDN yields of the second crop harvested at heading, although those yields were higher at 10 cm row spacing than at 30 cm row spacing. Neither seeding rate nor row spacing affected the DM and TDN yields of the second crop harvested at dough ripe. Thus, increasing the seeding rate is effective for increasing the DM and TDN yields of the first crop and reducing row spacing is effective for increasing total DM and TDN yields of the first and second crops. This cultivation method is expected to facilitate forage rice production by reducing labor and costs in temperate regions. Discipline: Crop Science Additional key words: ratooning, Ruriaoba, total digestible nutrient

Management of Huanglongbing (HLB) by an Intensive Vector and Disease Control in the Surroundings of the Orchard, in Addition to Planting HLB-Free Trees in Okinawa, Japan

Abstract: Citrus greening disease, huanglongbing (HLB), is one of the most destructive citrus diseases worldwide. The causal agent, Candidatus Liberibacter asiaticus (Las), is transmitted by the Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae). In Okinawa, in the beginning of 2000, HLB was widespread. Local control and planting of HLB-free trees were considered necessary measures to manage HLB. In 2006, 25 HLB-free trees were planted at an experimental field in Okinawa. Then, insecticides were sprayed in the experimental field according to the spray calendar (during the experimental period: imidacloprid 20%, thiamethoxam 10%, dinotefuran 20%, and clothianidin 16%; each application rate was 0.1 L/m2). In addition, “local control,” that is, insecticide spraying [fenitrothion 50% twice a year from 2006 to 2008, mineral oil 97% once, and methidathion 40% (June-July) once after 2008; each application rate was 0.1 L/m2] and removal of HLB-positive trees in the residential area, were continued. Until 2010, psyllids were very few, and none of the 25 planted trees were infected with HLB in the experimental field. Even in 2011, only 3 of the 25 trees were infected, indicating that the HLB infection rate was low when greening-free trees were initially planted and local control (pest control and removal of infected trees in the residential area) was effective at an early stage of cultivation. This result suggests that even in Japan, local control and planting HLB-free trees are effective in managing HLB. Discipline: Plant protection Additional key words: Asian citrus psyllid, Citrus depressa, Diaphorina citri, citrus greening disease, Candidatus Liberibacter asiaticus (Las) Present addresses: 4 Center for Bioscience Research and Education, Utsunomiya University (Utsunomiya, Tochigi 321-8505, Japan). 5 Division of Apple Research, Institute of Fruit Tree and Tea Science, NARO (Morioka, Iwate 020-0123, Japan). 6 Central Region Agricultural Research Center, NARO (Tsukuba, Ibaraki 305-8666, Japan). 7 Okinawa Prefectural Agricultural Research Center (Itoman, Okinawa 901-0336, Japan). *Corresponding author: e-mail uechinmi@affrc.go.jp Received 30 March 2018; accepted 10 September 2018.

Impact of Agricultural Investments on World Wheat Market under Climate Change: Effects of Agricultural Knowledge and Innovation System, and Development and Maintenance of Infrastructure

Abstract: The role of agricultural investment growth in alleviating climate risks for wheat production systems and markets was examined using a partial equilibrium model, the Wheat Economy Climate Change (WECC) model, which covers the wheat markets of 10 countries and two regions. This study examines how future agricultural investments will affect the world wheat market. The volatility of international wheat prices at baseline is expected to increase in 2014-2016 and until 2040 because of climate change. However, a constant increase in agricultural investments in major producing countries will contribute to international wheat price stability. In particular, agricultural investments in Russia are crucial for stabilizing international wheat prices in mid-long term under future climate change conditions. Discipline: Agricultural economics Additional key words: partial equilibrium model, wheat price, price stability in mid-long term, Russia and Ukraine *Corresponding author: e-mail koizu@affrc.go.jp Received 26 February 2018; accepted 18 July 2018. JARQ 53 (2), 109-125 (2019) https://www.jircas.go.jp

Viability of Bacillus subtilis (natto) Bacteriophages after Freezing and Thawing

Abstract: Bacillus subtilis (natto) phage ONPA suspended in an SM buffer without a cryoprotectant is sensitive to freezing at −20°C to −40°C. Freezing with a cryoprotectant and/or at low temperatures (−80°C and −165°C) can dramatically improve the viability of ONPA. B. subtilis (natto) phage JNDMP, the other principal type of B. subtilis (natto) phage used in this study, was stable even without a cryoprotectant at −20°C. The observation of ONPA using electron microscopy, after freezing at −20°C and subsequent thawing, suggested that the phage tails contracted and the phage genome DNA remained in the heads. The contraction of the phage tails may have caused the inactivation of ONPA phage particles. Discipline: Genetic resources Additional key words: cryopreservation, cryoprotectant, lyophilization, skim milk

Spatial Variability and Geostatistical Mapping of Selected Soil Properties in Mt. Wakakusa Grassland of Japan

Abstract: Mt. Wakakusa in Central Japan is a semi-natural grassland which has been maintained by repeated application of prescribed burnings of vegetation for more than 500 years. We assessed the spatial variability of selected soil properties and constructed their distribution maps using a geostatistical method to provide spatial information on soil resource for sustainable land management in this grassland. All the examined soil properties showed intermediate (coefficient of variation [CV] = 10%-90%) or high (CV > 90%) variability, except for the soil pH (CV < 10%), suggesting that the precision soil management approach is recommendable in the study site. The variogram analysis revealed that all of the soil properties, except for the electrical conductivity with a very weak spatial dependency (nugget-to-sill [N/S] ratio > 0.75), showed a very strong or moderately strong spatial dependency (N/S ratio ≤ 0.50), which might occur under the strong influence of intrinsic factors such as the inherent soil quality. The soil maps constructed by the ordinary kriging method helped in understanding the distribution patterns of the examined soil properties and identifying specific locations with signs of degradation and pollution. These spatial distribution patterns should be considered when developing a sustainable soil management strategy in Mt. Wakakusa grassland. Discipline: Agricultural Environment Additional key words: ordinary kriging, prescribed burning, semivariogram, spatial dependency

Spatial Variations in the Stable Isotopic Compositions of Surface and Groundwaters across Central Sri Lanka

Abstract: We present the spatial variations and isotopic fractionations of the stable isotopic compositions of waters across central Sri Lanka and discuss their applicability as tracers in hydrological studies of the island. The stable isotopic compositions of lake waters in the dry zone of the island were affected by evaporative isotopic enrichment and therefore can be used to estimate the evaporative loss from these lakes. The stable isotopic compositions of stream waters in the wet zone indicate a clear equilibrium isotopic fractionation with altitude (the altitude effect), which is useful in tracing water sources. The isotopic compositions of stream waters in the dry and intermediate zones are higher than expected from their altitude, likely stemming from the outflow of water from upstream tanks or reservoirs that are affected by evaporative isotopic enrichment and are unsuitable for estimating the altitude effect in those areas. The stable isotopic compositions of groundwater and tap and bottled waters plot along the local meteoric water line, suggesting that these waters preserve information on the isotopic compositions of rainwater in their recharge areas. Results indicate that the stable isotopic compositions of surface waters can be an effective tool in the hydrological and hydrogeological studies of the island. Discipline: Agricultural engineering Additional key words: isotopic fractionation, evaporation, altitude effect Present address: 3 Kanto Regional Agricultural Administration Office, Imbanuma Phase II Agricultural Irrigation Project Office (Sakura, Chiba 2850016, Japan). *Corresponding author: e-mail takeo428@affrc.go.jp Received 19 March 2018; accepted 6 June 2018.

Development of Small Automatic Guided Vehicle by Contact Detection to Hydroponics Cultivation System

Abstract: A small autonomous vehicle is required for automatic spraying, carrying, harvesting etc in greenhouse production areas and small open vegetable fields. This study uses simple structural guidance using horticultural cultivating materials to develop an automatic guided vehicle. The developed vehicle has four wheels: two front steering wheels and two rear driven wheels. The vehicle has a detection unit, a steering unit and a control unit. The detection unit has two extension rollers and a potentiometer, whose function is to detect the distance from the vehicle to the guided material. The control method is used for adjusting the ON/OFF control of the front wheel steer by detecting the distance between the object material and the vehicle. The driving tests were conducted on a plastic film covered soil surface of a greenhouse isle, the concrete surface of a greenhouse central road, and in the open field. The results of the straight driving control displayed absolute maximum errors of 35 mm, 23 mm, and 29 mm on the covered soil path, concrete path, and in the open field, respectively. The test results proved that the straight driving control of the developed system was sufficiently accurate to be used for spraying and carrying operations. Discipline: Agricultural machinery Additional key words: greenhouse, horticulture, orchard, tomato, vegetable *Corresponding author: e-mail toota@affrc.go.jp Received 7 November 2017; accepted 11 April 2018.

An overview of recent genomic research on biocontrol pseudomonad strains isolated from the field in Japan

Abstract: Many root-colonizing Pseudomonas spp. exhibiting biocontrol activities produce a wide variety of secondary metabolites with antibiotic activity against plant pathogens in the rhizosphere. Among these metabolites, 2,4-diacetylphloroglucinol (DAPG) is one of the most typical antibiotics in model biocontrol strains of Pseudomonas protegens. We screened DAPG-producing strains among 2,800 fluorescent pseudomonads isolated from the field in Japan. In addition to P. protegens, several other strains close to, but different from, P. protegens have been identified and found to exhibit biocontrol activity. Recent advances in genomic research on these strains revealed that they build up strain-specific genomic repertoires for the biosynthesis of secondary metabolites and niche adaptation. In this minireview, we introduced our recent genome-based characterization of P. protegens and related strains. Comparative genome analyses in combination with different bioassays have become a powerful tool for the identification of novel biocontrol factors of potentially beneficial strains. Discipline: Plant protection Additional key words: biocontrol, genome analysis, pseudomonads, rhizosphere, secondary metabolites *Corresponding author: e-mail kasumit@affrc.go.jp Received 23 March 2018; accepted 10 September 2018.

Effect of Feeding a Low Crude Protein Diet on Growth Performance of Finishing Pigs at a High Ambient Temperature

Abstract: The effects of reducing dietary crude protein (CP) in a high temperature environment (32oC) on growth performance and back fat deposition were investigated in finishing pigs. Twelve barrows (80.9 ± 7.6 kg) were allotted randomly to two dietary regimens (13.9% CP vs 11.8% CP) and were fed the diets for 4 weeks. The low-CP diet (11.8% CP) was supplemented with amino acids to meet the nutritional requirements. At the end of the experiment, back fat thickness, plasma urea nitrogen, and amino acid concentration were measured for all the barrows. The dietary CP level did not have any effect on growth performance, back fat thickness, or the plasma urea nitrogen concentration of the finishing pigs. Plasma free lysine, threonine, and methionine concentrations were higher in pigs that were fed the lowCP diet. These results indicate that reducing dietary CP by two percentage points does not alleviate the negative effect of heat stress and may not affect fat deposition. Discipline: Animal industry Additional key words: amino acids, fat deposition Present address: 2 Institute of Livestock and Grassland Science, NARO (Tsukuba, Ibaraki, 305-0901, Japan). * Corresponding author: e-mail yamazaki@affrc.go.jp Received 20 November 2017; accepted 30 March 2018.

Citrus Breeding 2.0: A Novel Approach Integrating Deciphered Parentage and Genomics-assisted Selection

Abstract: 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. Discipline: Plant breeding Additional key words: genome-wide association study (GWAS), genome-wide genotyping, genomic selection, parentage estimation, pedigree analysis *Corresponding author: e-mail tshimizu@affrc.go.jp Received 2 May 2018; accepted 4 October 2018.

The Panicle Blast Resistance Mechanism of qPbm11 in the Rice Cultivar Miyazaki-mochi is Independent from that of Pb1.

Abstract: Understanding the mechanism of disease resistance is critical for combating rice blast disease that causes the most deleterious effects on rice yield, and for evolving successful blast tolerance breeding programs using blast resistance (R) genes. The qPbm11 locus in the blast resistant cultivar Miyazakimochi exerts panicle resistance similar to the well-known quantitative panicle resistance gene Pb1. qPbm11 and Pb1 show similarity in panicle blast resistance, quantitative resistance, and proximity of loci on the rice genome. Pb1 resistance is dependent on the expression of transcription factor WRKY45. To identify the resistance mechanism of the qPbm11 locus, we downregulated WRKY45 in the cultivar Miyazaki-mochi through an Agrobacterium-mediated transformation and surveyed its panicle resistance. WRKY45 RNAi transgenic Miyazaki-mochi plants exhibited similar levels of panicle resistance compared to WT, indicating that the qPbm11 locus is independent of the Pb1 resistance pathway. Our results suggested that cloning the genes responsible for qPbm11-mediated resistance along with Pb1 using pyramiding technology could enhance panicle resistance in rice. Discipline: Agricultural Environment Additional key words: Oryza sativa, Pyricularia oryzae, panicle blast, QTL, salicylic acid, resistance gene

Identification of an Antigen Specific to a Protective Salmonella Monoclonal Antibody

Abstract: Previously, we developed the monoclonal antibody (mAb) 449 after immunizing BALB/c mice with a live attenuated mutant of Salmonella enterica serovar Typhimurium (S. Typhimurium), and it helped protect against S. Typhimurium infection. Although the immunogen specific for mAb449 has been found to be localized in the lipopolysaccharide (LPS) region, it is not clear which part of LPS is involved in the defense against Salmonella infection. The present study aimed to identify sites recognized by mAb449. Electron microscopy analysis showed that mAb449 binds to the surface of Salmonella serotypes that express the O4 antigen, such as serovar Abortusequi and Paratyphi B. In addition, mAb449 enhanced the uptake of only O4-positive Salmonella serotypes within mouse macrophage-like cells. The results demonstrated that mAb449 is specific for the O4 antigen. We further verified the protective potential of mAb449 against O4-positive Salmonella serotypes in mice infection model, and found that mAb449 exhibited protective effect against the O4-positive Salmonella serotypes such as Abortusequi and Paratyphi B. Discipline: Animal health Additional key words: infection, mAb449, O4 antigen, Salmonella *Corresponding author: e-mail egumaro@affrc.go.jp Received 31 May 2018; accepted 29 November 2018.

Time-course Changes in the Relationship between Serum and Milk β-carotene Concentrations in Mid-lactation Dairy Cows following a Shift from Drylot Feeding to Time-limited Grazing

Abstract: Grazing cows ingest large quantities of β-carotene (BC) from fresh pasture. The absorbed BC is carried to the mammary glands by the bloodstream and is subsequently transferred to the milk. This study was undertaken to assess the time-course changes in the relationship between serum and milk BC concentrations by calculating the rate of serum and milk BC concentration increase and estimating the mammary transfer of BC efficiency rate in mid-lactation dairy cows following a shift from drylot to time-limited grazing. For the first experiment, dairy cows were allocated to two treatment groups (each n = 3). The experimental grazing durations were 4 h (4hG) or 7 h (7hG) daily for 3 weeks. The serum BC concentration in the 7hG group was higher than that in the 4hG group. Nevertheless, no difference in milk BC concentration was found between the 4hG and 7hG groups. To investigate whether a difference exists in the rate of serum and milk BC increase in cows with time-limited grazing of more than 7 h daily, we conducted a second experiment for which the designated grazing time was 8 h daily for 4 weeks (n = 8). The rate of serum BC increase was greater than that of milk BC during days 14 to 28 of grazing. During the first 3 weeks of grazing, the estimated mammary extraction rate of BC significantly decreased, and the values at days 14 and 21 were significantly lower than those in drylot-feeding cows. These results suggest that the serum BC concentration strongly reflects the daily grazing time; however, the change in milk BC concentration is apparently delayed compared with that in the serum in cows grazing more than 7 h daily, and the relationship between the serum and milk BC concentrations changes following a shift from drylot feeding to time-limited grazing. Disciplines: Animal industry, Grassland Additional key words: carotenoid, extraction rate, mammary gland transfer, rate of increase

A Simple Variance Estimation of Herbage Mass Based on Two Assessments Per Pasture

Abstract: Grassland managers should consider the mean and variance of herbage mass for appropriate pasture management. Herein, a time and labor saving method to estimate variance in herbage mass was developed through extending an existing simple estimation method for mean mass. Herein, the difference between the highest and lowest masses in a given paddock and the quotient of pasture size by plot size were substituted for the range and sample size in an existing equation relating range to standard deviation (SD). The applicability of the method was evaluated using Monte Carlo simulations representing virtual pastures with a variety of conditions, and field experiments were conducted to confirm the simulation results. There was a clear relation between the ratio of the range to the SD and volume of generated random numbers in the simulation study, and the curve of the existing equation passed very close to the data points. Thus, the SD of herbage mass could be estimated using this equation. Although the accuracy of the estimate, which was expressed as a ratio of the actual variance of the random numbers, varied widely among simulated datasets, the average accuracy of the estimate was high; a similar result was produced under the field experiments that compares the new estimation method to the random sampling method. Discipline: Grassland Additional key words: gamma distribution, grassland management, labor saving method, Monte Carlo simulation, rising plate meter *Corresponding author: e-mail nakagami@affrc.go.jp Received 7 September 2018; accepted 11 December 2018.