Japan Agricultural Research Quarterly: JARQ
Online ISSN : 2185-8896
Print ISSN : 0021-3551
ISSN-L : 0021-3551
Volume 38, Issue 1
Displaying 1-10 of 10 articles from this issue
REVIEWS
Crop Science
  • Kiyoyuki MIURA, Shao Yang LIN, Hitoshi ARAKI, Tsukasa NAGAMINE, Makoto ...
    2004 Volume 38 Issue 1 Pages 1-5
    Published: January 30, 2004
    Released on J-STAGE: February 27, 2014
    JOURNAL FREE ACCESS
    For the introduction of low temperature germinability (LTG), seed longevity and accelerated coleoptile growth derived from foreign varieties to Japanese elite varieties to breed rice varieties for direct seeding culture in Japan, we tried to establish backcross breeding to introduce these traits with marker-assisted selection (MAS). The objectives of this study were to identify quantitative trait loci (QTLs) for LTG and seed longevity using backcross inbred lines derived from a cross between a japonica variety Nipponbare and an indica variety Kasalath in order to facilitate MAS of these traits. Five putative QTLs controlling LTG were detected on chromosomes 2, 4 and 11. A putative QTL with a large seed longevity effect was detected on chromosome 9. We bred a near isogenic line for coleoptile growth by a backcross between Kitaibuki as the recurrent parent and Arroz da Terra as the donor parent to have more rapid coleoptile growth and higher seedling establishment rate than Kitaibuki. From the above experimental data, we conclude that backcross breeding with MAS is effective to introduce genes for adaptability to direct seeding from foreign varieties in Japanese rice breeding programs.
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  • Ryouji SASAKI
    2004 Volume 38 Issue 1 Pages 7-13
    Published: January 30, 2004
    Released on J-STAGE: February 27, 2014
    JOURNAL FREE ACCESS
    A “rice nursling seedling” is the youngest stage of rice seedling transplanted by machine in Japan, and is defined as a seedling of 2 to 3 plant age in leaf number. However, changes in morphological and physiological characteristics of the seedling during this stage of development are not fully understood. This study was undertaken to obtain the ideal plant age of rice nursling seedlings which would give excellent seedling establishment. When plant age of rice seedlings was approximately 2.4, substantial photosynthesis occurred and plant length was over 7 cm, which is required for mechanical transplanting. The transplanted nursling seedlings with this age developed depending on the emerging crown roots from the first node, and it was suggested that crown roots from the coleoptilar node played a role in the absorption of water and nutrients just after transplanting. When rice nursling seedlings exceeded the age of 2.6, characters of the seedling degraded, and this was aggravated by high-density seeding. Rice seedlings with plant age of 2.5 showed the highest level of submergence tolerance among rice seedlings with several plant ages. The results suggest that plant ages of 2.3-2.5 are the ideal ages for transplantation of rice nursling seedlings.
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  • Kenzo WAKIMOTO
    2004 Volume 38 Issue 1 Pages 15-20
    Published: January 30, 2004
    Released on J-STAGE: February 27, 2014
    JOURNAL FREE ACCESS
    Labor-saving for fertilization has been strongly desired due to the shortage in labor and increasing scale of farming for rice cultivation. In order to clear these problems, the effect of application of controlled release nitrogen fertilizer (CRNF) on the different styles of paddy rice cultivation was investigated in southwestern Japan. Yield of transplanted rice grown by a single basal application of fertilizer consisting of 30% to 70% of sigmoid CRNF-100 was approximately equal to that grown by split application of ammonium sulfate under the same amount of nitrogen applied. In direct sowing cultivation under dry and flooded condition, rice yield was elevated by using nitrogen fertilizer consisting of 85% to 100% of CRNF. Approximately 30% of nitrogen applied was reduced in a single basal application with fertilizer consisting of 100% of CRNF nitrogen compared with that in split application with ammonium sulfate. Labor for nitrogen topdressing was completely saved by utilizing a single basal application with CRNF. The utilization of nitrogen fertilizer consisting of CRNF was also thought to be preservative to the environment.
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Agricultural Environment
  • Seiko YOSHIKAWA, Hiroshi YAMAMOTO, Yoshio HANANO, Akira ISHIHARA
    2004 Volume 38 Issue 1 Pages 21-29
    Published: January 30, 2004
    Released on J-STAGE: February 27, 2014
    JOURNAL FREE ACCESS
    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.
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  • Wataru ASHIHARA, Akira KONDO, Manabu SHIBAO, Hiroshi TANAKA, Katsumi H ...
    2004 Volume 38 Issue 1 Pages 31-41
    Published: January 30, 2004
    Released on J-STAGE: February 27, 2014
    JOURNAL FREE ACCESS
    Studies on the damage, biology, natural enemies and management of the economically important eriophyid mites: persimmon bud mite, Aceria diospyri, ficus mottle mite, Aceria ficus, peach silver mite, Aculus fockeui, and pink citrus mite, Aculops pelekassi in Japan are reviewed. A. diospyri and A. pelekassi mainly cause damage to the fruits of host plants. The rust symptom on persimmon fruits by A. diospyri differs among varieties. A. ficus causes economic loss in fig with leaf mosaic, leaf malformation, fruit mosaic, and fruit drop. A. fockeui injures peach leaves, reduces the sugar content of the fruit,and the damaged trees have lower vigor due to post-harvest defoliation. These mites overwinter in buds of host plants as adults. Overwintered mites begin to reproduce on the leaves after late May or mid-April. Fruit infesting mites, A. diospyri and A. pelekassi, migrate to and infest fruits after June. Since the density of overwintered A. ficus is high in large dormant fig buds, cutting of the big buds is effective to reduce mite damage in the next season. Several acaricides, insecticides and fungicides are effective against the eriophyid mites. A. pelekassi populations with dithiocarbamate-fungicide resistance were confirmed in the early 1990's and outbreaks of the mite sometimes cause severe damage to citrus fruits. It was found that some phytoseiids, a tydeid and a stigmaeid feed on these eriophyids. Phytoseiidae mites play an important role in the control of A. diospyri, A. ficus and A. fockeui populations in low densities. A marked resurgence in A. fockeui populations occurs after synthetic pyrethroids are sprayed, because they have no effect on A. fockeui but are harmful to the predators, such as phytoseiid mites.
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Agricultural Engineering
  • Mitsuji MONTA, Jun SUYAMA, Kazuhiko NAMBA
    2004 Volume 38 Issue 1 Pages 43-48
    Published: January 30, 2004
    Released on J-STAGE: February 27, 2014
    JOURNAL FREE ACCESS
    The purpose of this study is to develop a planting machine for rush seedlings. In rush seedling production systems, the use of plug seedlings has been widely popularized in Japan. However, the planting operation requires a great deal of labor and takes a long time because a large quantity of seedlings that have a few main stems and a bud are individually picked from the mother plants, and are planted in a tray by manual operations. Therefore, it is desirable to introduce machinery into the planting operation. In this paper, a semiautomatic planting machine was manufactured based on the physical properties of the rush seedling and planting experiments were carried out. The machine mainly consisted of planting unit, tray shifter, controller and air compressor. From the results of planting experiments, the success rate for planting was approximately 90%.
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Fisheries
  • Takuji OKUMURA
    2004 Volume 38 Issue 1 Pages 49-54
    Published: January 30, 2004
    Released on J-STAGE: February 27, 2014
    JOURNAL FREE ACCESS
    Shrimp aquaculture in the world has developed remarkably, however, to enable further development, new technological advances in hormonal manipulation of shrimp reproduction are increasingly important for effective stock enhancement. To develop hormonal manipulation techniques, progress in shrimp endocrinology is necessary. In this article, I review my work and related studies on shrimp endocrinology. For female reproduction, eyestalk hormones, ecdysteroids, and vertebrate-type steroid hormones were examined. Eyestalk ablation induced ovarian development, indicating the occurrence of the eyestalk hormone, vitellogenesis-inhibiting hormone. Hemolymph levels of ecdysteroids and vertebrate-type steroid hormones were not correlated to ovarian development, suggesting that these hormones are not involved in the regulation of ovarian development. For male reproduction, the androgenic gland showed distinct structural changes in relation to male reproductive activity, suggesting that the hormone has a role in the regulation of male reproductive activity. For control of shrimp reproduction, at present, no hormones are available, and only eyestalk ablation is practically used. This is mainly because endocrinology of shrimp reproduction is not yet sufficiently understood. Only a few hormones have been detailed so far, and many hormones are still unidentified. For new technological advancements in hormonal manipulation, it is necessary to characterize these unknown hormones and to synthesize useful ones for administration.
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ARTICLES
Biotechnology
  • Abu Reza Md. Mahfuzur RAHMAN, M. Obaidul ISLAM, A.K.M. Azad-ud-doula P ...
    2004 Volume 38 Issue 1 Pages 55-59
    Published: January 30, 2004
    Released on J-STAGE: February 27, 2014
    JOURNAL FREE ACCESS
    Potato extract (PE), corn extract (CE) and papaya extract (PAE) significantly enhanced plantlet regeneration from PLBs (protocorm-like bodies) when 50 mL L-1 of an extract was supplemented to the New Phalaenopsis (NP) medium containing sucrose. Among the treatments, CE 50 mL L-1 induced the highest rate (66.63%) of plantlet regeneration from PLBs. Organic extracts of potato, corn and papaya at 50-100 mL L-1 in NP medium also enhanced the subsequent growth of mini-plantlets. However, a higher level (200 mL L-1) of extract in the medium inhibited the growth of the plantlets. Among these extracts, PE at 100 mL L-1 showed the optimum effect on the acceleration of shoot growth while CE at the same concentration was optimum for root growth.
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Animal Husbandry
  • Yoshimitsu SAITO
    2004 Volume 38 Issue 1 Pages 61-67
    Published: January 30, 2004
    Released on J-STAGE: February 27, 2014
    JOURNAL FREE ACCESS
    The compatibility of two tropical grasses (Brachiaria humidicola (Bh) and Panicum maximum (Pm)) and three legumes (Arachis pintoi (Ap), Stylosanthes capitata (Sc) and Stylosanthes guianensis (Sg)) were examined at two fertilizer application levels in a tropical South American savanna region. Pairs consisting of one grass and one legume were planted on a reclaimed Colombian lowland. Changes in biomass over time, growth patterns, and the relative palatability of these species indicated by grazing preference were measured. Among the two grass species, Bh showed strong growth, even under the low fertility condition, while Pm required the high fertilizer application level for establishment and growth. Among the legumes, Sg grew vigorously, even at the low fertility level, and could compete with Bh in biomass production. Sc was less vigorous than Sg, but was preferred by cattle. The growth habit of Ap was stoloniferous and it required a long time period to make a dense sward, because its seeding rate was low due to the bigger seed size. Among the three legume species, Ap was most preferred by cattle, and Sg was the least, but was nevertheless eaten by cattle if no other legumes were present. Considering the compatibility of these grasses and legumes, the mixture of Sg and Bh produced a higher level of herbage biomass than the other grass-legume mixtures examined in this study. The Ap and Pm mixture also had good compatibility, and its palatability to cows was higher than the other mixtures.
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Fisheries
  • Yukio MAENO, Leobert D. DE LA PEÑA, Erlinda R. CRUZ-LACIERDA
    2004 Volume 38 Issue 1 Pages 69-73
    Published: January 30, 2004
    Released on J-STAGE: February 27, 2014
    JOURNAL FREE ACCESS
    Viral nervous necrosis (VNN), also known as viral encephalopathy and retinopathy (VER), is an emerging disease affecting larvae and juveniles of many farmed marine fish species in Asia, Australia,Europe and North America. Mass mortality occurred in 14-day old larval sea bass Lates calcarifer at a hatchery in the Philippines associated with clinical signs such as abnormal swimming behavior and pale-gray discoloration of the body. Histological investigations in moribund fish revealed marked vacuolation in the retina and brain. Cytopathic effects (CPE) were observed in SSN-1 cells inoculated with the tissue filtrate of affected sea bass. A piscine nodavirus, the causative agent of VNN, was detected in the affected tissues and SSN-1 cells inoculated with the tissue filtrate of affected fish by RT-PCR. Electron microscopy revealed non-enveloped viral particles, 22-28 nm in diameter, in the cytoplasm of the brain and retina of affected fish and in the cytoplasm of VNN-infected SSN-1 cells after CPE appeared. These results indicate that mass mortality of sea bass larvae in the Philippines was caused by a piscine nodavirus.
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