Japan Agricultural Research Quarterly: JARQ
Online ISSN : 2185-8896
Print ISSN : 0021-3551
ISSN-L : 0021-3551
Volume 51, Issue 2
Displaying 1-11 of 11 articles from this issue
REVIEWS
Biotechnology / Crop Science
  • Hiroshi YASUDA
    2017 Volume 51 Issue 2 Pages 99-105
    Published: April 01, 2017
    Released on J-STAGE: May 10, 2017
    JOURNAL FREE ACCESS

    Having originated in tropical regions, rice is more sensitive to cold stress than other grain crops, such as rye, wheat, and barley, which originated in temperate regions. Despite the limited knowledge about the exact mechanisms of cold tolerance, breeders have generated new rice cultivars that can grow in Hokkaido, Japan’s northern limit of rice cultivation, for more than a hundred years. However, greater cold tolerance in rice would enable more stable production and elevate productivity. Because cold tolerance is a complex quantitative trait, it is difficult to pyramid the genes that could improve plant tolerance to this abiotic stress. Therefore, it is important to develop effective strategies for improving cold tolerance in rice. In this review, the use of a ‘cross-tolerance’ strategy is proposed, and the current status of such strategy introduced.

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Crop Science
  • Masahiro CHIBA, Tomio TERAO, Hajime WATANABE, Osamu MATSUMURA, Yoshihi ...
    2017 Volume 51 Issue 2 Pages 107-116
    Published: April 01, 2017
    Released on J-STAGE: May 10, 2017
    JOURNAL FREE ACCESS

    The increased occurrence of chalky rice grains as a result of global warming is becoming a serious problem. The application of deep-flood irrigation (DFI) to a water depth of 18 cm from the active tillering stage to the maximum tillering stage suppresses the occurrence of chalky grains under both high and normal temperature conditions without decreasing yields. The mechanism by which DFI reduces chalky grains was analyzed relative to carbohydrate supply as carbohydrate deficiencies have been proposed as a cause of chalky grains. DFI suppresses the occurrence of chalky grains due to the increased supply of carbohydrates to the panicles. In paddy fields where a water depth of 18 cm is not possible, such as in paddy fields with low levees or low water supplies, the combined use of moderate DFI at a water depth of 10 cm with deep planting can be substituted to produce high-quality rice. DFI did not damage root activity at the ripening stage, even in soils with a low redox potential. Although the DFI treatment slightly decreased the penetration resistance of the soil, the bearing capacity was not affected at the time of combine harvest.

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Agricultural Engineering
  • Koji KAMEYAMA, Yukiyoshi IWATA, Teruhito MIYAMOTO
    2017 Volume 51 Issue 2 Pages 117-127
    Published: April 01, 2017
    Released on J-STAGE: May 10, 2017
    JOURNAL FREE ACCESS

    In this work, we reviewed the following: 1) the influences of feedstocks and pyrolysis temperature on the physicochemical properties of biochar as a soil amendment material in Japan; and 2) the effects of biochar application on the physicochemical properties of two Japanese soils. We analyzed the physicochemical properties of biochar produced from waste woodchips (Japanese cedar and Japanese cypress), waste moso bamboo chips, rice husk, sugarcane bagasse, poultry manure, and domestic wastewater sludge at pyrolysis temperatures of 400°C, 600°C, and 800°C. Biochar produced from both wood-based biomass and sugarcane bagasse are suitable as a soil amendment material for enhancing water retention in soil. Biochar produced from wood-based biomass at a low pyrolysis temperature (400°C) is suitable for enhancing the cation exchange capacity, whereas biochar produced from wood-based biomass at a high pyrolysis temperature (800°C) can enhance nitrate adsorption. Poultry manure-derived biochar can improve the soil pH and supply phosphate. Based on two case studies using sand dune soil and calcareous soil, we demonstrated that soils can be effectively improved by considering specific soil properties that require improvement/remediation, and by applying a suitable biochar to enhance these properties.

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ARTICLES
Crop Science
  • Seung Ho JEON, Young Son CHO, Byung Jin LEE, Takuya MINETA
    2017 Volume 51 Issue 2 Pages 129-136
    Published: April 01, 2017
    Released on J-STAGE: May 10, 2017
    JOURNAL FREE ACCESS

    Rice cropping areas have recently been restricted or reduced under the policy of the South Korean government. Therefore, the development of new crop or cropping systems is essential. Foxtail millet (Setaria italica.) is considered among the best candidate crops to substitute for rice, but there is limited information about maintaining or improving the grain yield without crop damage caused by excessive water content in sandy paddy fields. A two-year study from 2013 to 2014 was conducted in a trial field in the southern part of Korea (N 35˚ 05′ 16.8″, E 127˚ 56′ 34.6″). The three cultivars selected—Gyeongkwan 1, Samdachal, and Hwanggeumchal—are the most common varieties of foxtail millet in South Korea due to their highly functional nutrients and potential productivity. For the purpose of establishing the stable production of Foxtail millet in paddy-upland rotation fields, the effects of ridge width (60, 120 and 240 cm) on soil moisture in the ridge, and on the growth and yield of foxtail millet were investigated in a sandy paddy field. Soil water content increased in line with increasing ridge width. Therefore, the estimated retention time of excessive soil water during the cultivation period tended to increase in line with increasing ridge width. Foxtail millet plants reached the highest level of height in the 60-cm ridge width treatment in both years of the study. The grain yields in 2014 were 3.44, 3.77, and 3.28 tons˖ha-1 for Gyeongkwan 1, Samdachal, and Hwanggeumchal, respectively, grown in the 60-cm ridge width. The plant height and yield of foxtail millet had increased with a narrowed ridge width because soil-moisture conditions are remedied by ridge width. Therefore, we recommend that a ridge width of 60 cm be maintained to prevent excessive water damage to foxtail millet growth in a sandy paddy field.

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  • Shinichiro TAKAHASHI, Ayano MEGURO-MAOKA, Midori YOSHIDA
    2017 Volume 51 Issue 2 Pages 137-146
    Published: April 01, 2017
    Released on J-STAGE: May 10, 2017
    JOURNAL FREE ACCESS

    Changes in sucrose metabolism have been implicated in tissue damage found in rice plants exposed to cold. However, little is known about the effect of low temperature on sucrose transport in cold-sensitive plants such as rice. Here, we investigated the changes induced by a 12°C chilling treatment on the soluble sugar content relative to the expression of sucrose transporter genes (OsSUT1-5) in various tissues of young (6-week-old) and mature (booting stage) rice plants. Sucrose levels increased in source tissues but decreased in young panicles during the chilling treatment. Sucrose transporter genes also responded to the chilling treatment: OsSUT1 in leaf sheaths and OsSUT2 and OsSUT4 in panicles were down-regulated. Our results suggested that the sucrose translocation supported by OsSUTs in rice plants decreased during chilling treatment, assuming the involvement of OsSUT1 and OsSUT4 in phloem loading of sucrose. These changes may induce a sugar imbalance in anthers, resulting in impaired pollen development.

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  • Innabat SARTBAYEVA, Bakdaulet USENBEKOV, Aiman RYSBEKOVA, Dauren KAZKE ...
    2017 Volume 51 Issue 2 Pages 147-153
    Published: April 01, 2017
    Released on J-STAGE: May 10, 2017
    JOURNAL FREE ACCESS

    Although there is low precipitation in Kazakhstan, rice is grown in regions serviced by irrigation canals. And breeding has begun in order to reduce the cost of importing glutinous rice. To develop glutinous rice cultivars efficiently, we need information on the haplotypes of Wx and Alk genes that affect eating quality. We investigated the haplotypes and amylopectin chain-length distribution in the first glutinous rice breeding lines developed in Kazakhstan. Such information could be useful to other countries starting glutinous rice breeding using parents possessing variation in Wx and Alk haplotypes.

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Agricultural Environment
  • Motoko SHIMURA, Hidehiro TAKAHASHI, Chiharu ITO, Makoto SHIBUYA, Kiyot ...
    2017 Volume 51 Issue 2 Pages 155-164
    Published: April 01, 2017
    Released on J-STAGE: May 10, 2017
    JOURNAL FREE ACCESS

    This study conducted a life cycle assessment of new techniques and approaches in rice paddy cultivation. We evaluated reclaimed land in Hachirogata, located in Japan’s Akita Prefecture. Non-puddling cultivation is a technique of planting rice without the puddling. A rotary plow is used to plant the rice in finely crushed soil. Non-puddling allows a delay in irrigation. Thus, the soil is less likely to become deoxidized and a smaller amount of methane gas is released from the disturbed soil. Sparse planting is a technique whereby the planting stalk density is reduced by 30% (21 stalks/m2 to 15 stalks/m2), thereby reducing the material costs of producing seedlings. We found that use of the non-puddling technique reduced overall GHG emissions to 69% of those produced by rice cultivation using puddling. With sparse planting, GHG emissions were only reduced by a small amount to 93% of that of full planting.The current work shows that the appropriate mixture of sparse planting and non-puddling cultivation is necessary to obtain the greatest reduction in GHG emissions.

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Animal Husbandry
  • Nobue KANEMATSU, Reiji AOKI, Hiroyuki SHINGU, Tsutomu ASADA, Naoko MOR ...
    2017 Volume 51 Issue 2 Pages 165-169
    Published: April 01, 2017
    Released on J-STAGE: May 10, 2017
    JOURNAL FREE ACCESS

    In order to study the possibility of using lymphocyte subsets as a stress indicator, the changes of the subset proportion in peripheral blood were examined after transportation. Six 3-month-old male Holstein calves were transported for about 3 h in a lorry via an ordinary road. Blood samples were collected at the expected unloading time on the day before transport (T0), immediately after unloading (T1), 24 h after unloading (T2), and 1 week after unloading (T3). CD2, CD4, CD8, CD21, CD25, WC1, and NKp46 antigens on peripheral blood mononuclear cells were measured by flow cytometry. There was an increase in the proportions of CD25+ cells and WC1+ γδT cells at T1 and T2. The proportions of NK cells increased at T1, including an increase in the population of CD2- NK cells. CD2+ NK cells did not show any change. The proportions at T1 were lower than at T3 in CD21+ B cells. CD4+ and CD8+ αβT cells did not change significantly, although CD2+ T cells showed a trend toward reduction at T1. Consequently, CD2- NK cells and WC1+ γδT cells might offer potential as stress index for calf transport.

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Fisheries
  • Mitsuo SAKAI, Kotaro TSUCHIYA, Luis MARIATEGUI, Toshie WAKABAYASHI, Ca ...
    2017 Volume 51 Issue 2 Pages 171-179
    Published: April 01, 2017
    Released on J-STAGE: May 10, 2017
    JOURNAL FREE ACCESS

    The vertical migratory behavior of jumbo flying squid (Dosidicus gigas) was recorded in the Humboldt Current region off Peru in 2007 by ship-based tracking with acoustic tags for two days and a pop-up archival transmitting (PAT) tag for two weeks. Two squid (measuring 74.0 cm and 110.5 cm in dorsal mantle length, respectively) were tagged with acoustic tags. The larger one was also tagged with a PAT tag. Tracking data indicated that both squid dived to a depth of 1200 m in the daytime. Although the PAT tag was not recovered, its seven-day summary data that was recovered via the Argos satellite system suggest that D. gigas off Peru engage in diel vertical migration, where the squid also migrate to near the sea surface at night. Conversely, two daytime migration patterns were observed: migration to mid-waters above the oxygen minimum zone (OMZ) at depths between 200 and 800 m, and migration to deeper waters. During descents to 1200 m, the squid increased its descending velocity in the OMZ. We also discuss the biological implications of that diel vertical migration.

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  • Toshiyuki TANABE, Hidetada KIYOFUJI, Yugo SHIMIZU, Miki OGURA
    2017 Volume 51 Issue 2 Pages 181-189
    Published: April 01, 2017
    Released on J-STAGE: May 10, 2017
    JOURNAL FREE ACCESS

    The vertical distribution of juvenile skipjack tuna Katsuwonus pelamis was investigated in the tropical western Pacific (0-25°N and 130-160°E) based on midwater trawl sampling from October to December in 1992 to 1996. Most juveniles were sampled between depths of 40 and 120 m, that is, at depths ranging immediately above and below the thermocline, and at temperatures between 20 and 30°C. Relatively lower temperatures were observed in the pelagic zone of the research area from 1992 to 1994 (period of a shallow thermocline), in contrast to relatively higher temperatures from 1995 to 1996 (with a deep thermocline). The vertical distribution of skipjack juveniles became shallower from 1992 to 1993, whereas it became deeper in 1995 and 1996. These findings suggest that the vertical distribution of skipjack tuna during the juvenile period changed annually relative to the vertical temperature profile. Moreover, fluctuations in vertical temperature are believed to affect the expansion or contraction of the vertical habitat of skipjack juveniles in the pelagic zone. The mean standard length of juveniles collected in 1994 at a depth of 80-100 m in the North Equatorial Counter Current area was significantly larger than that of juveniles collected at 40-60 m. These findings suggest that the vertical distribution of juvenile skipjack tuna becomes deeper in line with their growth.

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  • Kaoru HAMANO, Yukio MAENO, Sirimas KLOMKLING, Dusit AUE-UMNEOY, Isao T ...
    2017 Volume 51 Issue 2 Pages 191-197
    Published: April 01, 2017
    Released on J-STAGE: May 10, 2017
    JOURNAL FREE ACCESS

    An epizootiological study of 230 wild Penaues monodon collected from a set net in the seashore of Klong Khone, Samut Songkhram, Thailand was conducted from December 2012 to November 2013. Each month approximately 20 wild P. monodon were tested for the following five pathogenic shrimp viruses: yellow head virus (YHV), white spot syndrome virus, infectious hypodermal and hematopoietic necrosis virus, taura syndrome virus, and infectious myonecrosis virus (IMNV). Among all P. monodon individuals, 45.7% were positive for YHV, which causes yellow head disease that is commonly encountered in Thai shrimp cultivation. Overall, pathogenic viruses were detected in 80.9% of all the shrimp; however, IMNV, which has yet to be identified in Thailand, was not detected in any shrimp. This finding suggests that there is a link between the prevalence of pathogenic viruses in wild shrimp and the outbreaks of viral diseases in farmed shrimp.

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