Japanese Journal of Tropical Agriculture
Online ISSN : 2185-0259
Print ISSN : 0021-5260
ISSN-L : 0021-5260
Volume 36, Issue 1
Displaying 1-12 of 12 articles from this issue
  • 1. Yield and yield components of direct seeded rice plant in Muda area
    Hiroyuki HIRAOKA, Nai Kin HO, Genshichi WADA
    1992 Volume 36 Issue 1 Pages 1-7
    Published: March 01, 1992
    Released on J-STAGE: March 19, 2010
    JOURNAL FREE ACCESS
    The grain yield and yield components of direct-seeded rice plant were studied for two seasons, 2nd season in 1988 and 1st season in 1989, in the Muda Irrigation Scheme, Malaysia. The coefficient of variation based on the sampling unit of each yield component (including seedling number) under identical field conditions was much higher in direct-seeded plants than in transplanted ones, especially in number of plants per unit area.
    A high correlation was found between the yield and the spikelet number per m2 as seen in transplanted plant in the tropics, while there existed no correlation between the yield and the ripening percentage. The spikelet number per m2 was strongly affected by the panicle number per m2, but not by the spikelet number per panicle. The panicle number per m2 was governed by the established seedling number per m2. Therefore, the yield and the spikelet number per m2 were related to the established seedling number. It is noteworthy that when the established seedling number per m2 exceeded 180, its contribution toward further yield increase was not distinct. When the established seedling number per m2 was less than 150, the yield declined sharply in proportion to the decrease in the established seedling number. Seedling establishment of 150-200 plants per m2 is considered to be optimal for obtaining stable rice yield in the Muda area, and, for achieving higher yields, it is important to reduce the spotty areas where the seedling establishment is less than 150 plant/m2.
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  • Keiji MOTOMURA, Yosihisa HIGA, Seiichi MURAYAMA, Yukio ISHIMINE
    1992 Volume 36 Issue 1 Pages 8-13
    Published: March 01, 1992
    Released on J-STAGE: March 19, 2010
    JOURNAL FREE ACCESS
    RT61A line and RT61B line were isolated by recurrent backcrossing, in which Oryza rufipogon K61 line was used as the initial female parent and O. sativa c.v. Taichung 65 as the recurrent pollen parent. The phenotypes of the RT61A line and the RT61B line were identical to that of Taichung 65 except that RT61A line have one-half sterile pollen (semisterile) and RT61B line represent complete pollen and seed fertilities. In order to elucidate the genetic mechanism of this sterility and its restoration an investigation was conducted by following crossing experiment between Taichung 65 and RT61A line, and RT61B line.
    When RT61B line was crossed with Taichung 65, all of the offspring showed complete pollen and seed sterilities, indicating that this line have a male sterile cytoplasm and no fertility restoration gene and Taichung 65 also does not have this gene. When RT61A line was crossed with paternal Taichung 65, the resulting F1 was segregated into pollen semisterility and normal seed fertility individuals and complete pollen sterility and seed sterility individuals at a ratio of approximately one to one. This phenomenon coincided with a segregation pattern from monoallelic genes and can be explained as follows. RT61A line had male sterile cytoplasm and a pair of fertility restoration genes in heterozygous status. In the next generation when this line is crossed with Taichung 65 having recessive genes for restoration fertility, therefore, heterozygous individuals will have pollen semisterility and normal seed fertility and homozygous individuals for recessive genes will have complete pollen and seed sterility. When the heterozygous individuals were self-pollinated, they produced all normal seed fertility plants in F2 progeny while their pollen fertility was normally in one-half individuals but semisterile in the other. There were no complete male sterile plants. Such mode of inheritance indicated gametophytic one, that is, pollen grains having dominant restoration gene were normally developed, while recessive pollen grains were degenerated in a certain stage of pollen development. On the other hand, all F1 and F2 individuals obtained by crossing Taichung 65 as a maternal parent with paternal RT61A line showed normal seed and pollen fertilities, thus indicating a possibility that cytoplasm of Taichung 65 will offer normal developed pollen grains of both dominant and recessive genes. Such a possibility was confirmed because, when 18 F2 individuals were selected at random and crossed with the sterile line, these individuals were found to consist of three groups as follows: 7 F2 individuals which yielded all progeny of normal seed fertility and pollen semisterility without segregation, 6 F2 individuals which yielded seed and pollen sterile plants and normal seed fertile and pollen semi-sterile plants at a ratio of one to one, and 5 F2 individuals which yielded progeny of seed and pollen sterilities only.
    From above results, it was concluded that the male sterility and its restoration found in these lines was induced by interaction with cytoplasm and a single locus for fertility restoration and the mode of restoration was gametophytic.
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  • Kojiro HASEGAWA, Masao SOBAJIMA
    1992 Volume 36 Issue 1 Pages 14-20
    Published: March 01, 1992
    Released on J-STAGE: March 19, 2010
    JOURNAL FREE ACCESS
    Experiments were conducted to analyze the effect of strapping of secondary scaffold branches with covered, insulated wires (partial girdling) on fruit set, quality and flower bud formation in young persimmon trees, cvs. Saijo, Izu and Matsumotowase-Fuyu. The strapping treatments were performed by using covered, insulated wires 2.0 mm and 2.6 mm in diameter at 20 days after full bloom.
    1. In the control treatment of cvs. Saijo and Izu, numerous summer shoots appeared and the fruit set percentages were low. After two strapping treatments in cvs. Saijo and Izu, the occurrence of summer shoots was suppressed and the fruit set percentages increased. In the control treatment of cv. Matsumotowase-Fuyu, the occurrence of summer shoots was low but the fruit set percentage was high. After the application of strapping treatments in cv. Matsumotowase-Fuyu, the fruit set percentages increased.
    2. The fruit sizes in cvs. Saijo, Izu and Matsumotowase-Fuyu increased and the coloring degree was promoted by two strapping treatments. The fruit weight in cvs. Saijo, Izu and Matsumotowase-Fuyu increased by about 1.2 and 1.3 times, 1.3 and 1.3 times, 1.4 and 1.4 times, respectively after the application of two strapping treatments with covered, insulated wires 2.0 mm and 2.6 mm in diameter compared with the control treatment. The number of seeds in the three cultivars subjected to two strapping treatments was smaller than that in the control treatment.
    3. The number of flower buds inside the winter bud on the shoot in cv. Matsumotowase-Fuyu increased after two strapping treatments. The number of flower buds in which the differentiation and development reached the sepal formation stage in cv. Matsumotowase-Fuyu increased by about 2.2 times and 2.6 times, respectively after two strapping treatments with covered, insulated wires 2.0 mm and 2.6 mm in diameter as compared with the control treatment. The number of flower buds in the part, of the spring cycle shoot with in the shoot which experienced a summer cycle in cv. Saijo, increased after two strapping treatments and the number of flower buds in which the differentiation and development reached the sepal formation stage increased by about 1.7 times and 1.8 times, respectively after two strapping treatments with wires as compared with the control treatment.
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  • Hiroyasu MICHIYAMA, Akira ENDO, Hitoshi SUZUKI
    1992 Volume 36 Issue 1 Pages 21-27
    Published: March 01, 1992
    Released on J-STAGE: March 19, 2010
    JOURNAL FREE ACCESS
    It was observed that the female flower clusters, which give rise to fruits at harvest time, developed according to the same arrangement as a 2/5 phyllotaxis on the inflorescence axis of castor-oil plants. The male flower clusters developed in the lower part of the axis in the same way as the female ones. In a female flower cluster, one flower (the first flower) developed terminally on the axis of the flower cluster. Two flowers (the second flowers) developed at the opposite position in the lower part of the axis of the first flower. The third and higher order flowers behaved in the same way. As a result the inflorescence of this flower cluster was considered to correspond to the dichasium. The number of fruits per dichasium was the largest in about the fifth female dichasium counted upward on the inflorescence axis. These findings suggested that the number of female dichasia on the inflorescence axis, the number of fruits per dichasium, the number of seeds per fruit, and the seed weight controlled the seed yield per inflorescence in castor-oil plants. The number of leaves and leaf area of the main stem were positively correlated with the seed yield, the number of fruits and the number of female dichasia of the primary inflorescence. The leaf area of the main stem showed a closer correlation with these yield components than the number of leaves on the main stem. The number of leaves and the leaf area were not correlated with the other yield components, i.e., the number of fruits per dichasium and the 100-seed-weight.
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  • Hiroyasu MICHIYAMA, Ryozo YAMAMOTO
    1992 Volume 36 Issue 1 Pages 28-36
    Published: March 01, 1992
    Released on J-STAGE: March 19, 2010
    JOURNAL FREE ACCESS
    In the inflorescence of castor-oil plants, the dichasia developed as a spiral on the inflorescence axis, with the male dichasia developing in the lower part of the axis and the female ones in the upper part, while in the boundary part, mixed dichasia developed. Within a dichasium, the higher the order of the flower was, the later the flower bloom occurred. The male flowers started to bloom a little later than the female flowers. Blooming proceeded from the flowers in the lower position to those in the upper position on the inflorescence axis when flowers of the same order were observed. The female flowers bloomed in the same way as the male flowers with one exception. In the case of the female flowers, only one flower developed in the uppermost dichasium on the inflorescence axis, and the flower bloomed as early as the flowers of the lowest female dichasium. Although the flowering time of the flowers at every position hardly changed by the pinching of lateral buds on the first flowering day, the high order flowers in the dichasia, which did not bloom in the control plant, started to bloom and the flowering period of the inflorescence was prolonged by the pinching of lateral buds. The female flowers which bloomed later frequently gave rise to immature fruits at harvest time. The flowering period of an inflorescence was about 10 days in the control plants, and the period seemed to be important for the determination of the number of fruits per dichasium on the inflorescence axis. Also the number of dichasia on the inflorescence axis increased and the male flowers started to bloom earlier in the late-season culture.
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  • 1. Studies on water absorption ability of cowpea (Vigna unguiculata (L.) WALP. var. unguiculata)
    Juichi ITANI, Naoki UTSUNOMIYA, Shoji SHIGENAGA
    1992 Volume 36 Issue 1 Pages 37-44
    Published: March 01, 1992
    Released on J-STAGE: March 19, 2010
    JOURNAL FREE ACCESS
    The water absorption ability of cowpea (Vigna unguiculata (L.) WALP. var. unguiculata) was examined by comparing the values of the respiration rate in roots and the dry weight of roots per leaf area with the corresponding values in other leguminous crops. None of these values were higher in cowpea than in other legume species. This suggests that the osmotic and passive water absorption abilities of cowpea are lower than those of the other crops. However, it was found that cowpea had deeper root system than other legumes, and the root further developed vertically when the plants were exposed gradually to water stress. It was suggested by the subsurface irrigation treatment that such deep roots play an important role in the vegetative and reproductive growth in cowpea. The taproots that penetrate into deep soil layers appear to absorb and transport water to the upper parts of plant under drought conditions.
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  • Hiroaki INOUE, Bunjiro TAKAHASHI, Kazushi SHIRATO
    1992 Volume 36 Issue 1 Pages 45-50
    Published: March 01, 1992
    Released on J-STAGE: March 19, 2010
    JOURNAL FREE ACCESS
    1) Studies on the pollen morphology and fertility in four cultivars of Avocado (‘Zutano’, ‘Bacon’, ‘Fuerte’and‘Mexicola’) using scanning electron microscope (SEM) and optical microscope were carried out from 1986 to 1987 in Japan.
    2) The dried pollen grains were mainly spherical in shape with a thorny or granular surface depending on the cultivars, and they were binucleate. Based on microscopic observations, no germ pores was delicated on the surface of the pollen grains.
    3) The fertility rate during flowering was higher than that before flowering for each cultivar, and it was higher in‘Fuerte’, followed by‘Zutano’, ‘Bacon’and‘Mexicola’in this order.
    4) The size of the pollen grains of all the cultivars ranged from 25 to 72μm in diameter, and the fertile pollen grains were larger than the sterile (infertile) ones.
    5) The number of pollen grains of the fertile pollens reached a peak when the pollen grains model sizes of 44μm, 39μm, and 37μm for‘Fuerte’, ‘Zutano’, and‘Bacon’, respectively, and no peak was observed in‘Mexicola’. Additionally, the higher fertility rate and the larger the grain size of pollen the higher the fruit yield of the cultivars.
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  • Suchila TECHAWONGSTIEN, Eiji NAWATA, Shoji SHIGENAGA
    1992 Volume 36 Issue 1 Pages 51-57
    Published: March 01, 1992
    Released on J-STAGE: March 19, 2010
    JOURNAL FREE ACCESS
    Four cultivars of chilli pepper (Capsicum annuum L.) obtained from different regions were investigated for the effects of water stress applied at various stages of development on their growth and yield. In a plastic greenhouse, the stress treatment was applied at the seedling and mature stages by withholding water supply, and rewatering when severe wilting symptoms persisted throughout the night. Mature stages were divided into three 10-day intervals, namely pre-anthesis, anthesis and post-anthesis stages. All the cultivars were able to tolerate the stress for almost the same period of time at the same treatment stage, but the plants treated at the seedling stage were able to tolerate the stress for a longer period of time. This phenomenon may be ascribed to the fact that the water loss of the plants treated at the seedling stage was lower than that of the plants treated at the mature stages. Plant growth and yield were more appreciably affected by stress at the seedling stage than at the mature stages in all the cultivars. This observation suggests that prolonged and gradual stress at the seedling stage suppressed the growth and yield more significantly than brief and rapid stress at the mature stages. Huay Siithon (HS) was less affected than Deshi Morich (DM), which belongs to the same variety conoides as HS, while Yatsubusa (YB) was more affected than Khonkaen University cluster (KC), which belongs to the same variety fasciculatum as YB, especially in the mature fruit yield. These observations suggest that the genetic background acquired through adaptation to natural conditions may influence the differences in the plant responses to water stress.
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  • 1. Effect of zinc concentration in the solution culture on the growth and content of chlorophyll, zinc and nitrogen in corn plants (Zea mays L.)
    Hisamitsu TAKAHASHI, Ryuichi OHYAMA, Hidenobu YAMAGISHI
    1992 Volume 36 Issue 1 Pages 58-66
    Published: March 01, 1992
    Released on J-STAGE: March 19, 2010
    JOURNAL FREE ACCESS
    Studies were carried out on the effect of zinc at different concentrations in the nutrient solution on the growth and content of chlorophyll, zinc and nitrogen in corn plants. The four levels of zinc concentrations were 0, 0.005, 0.05 and 20 ppm in solution culture.
    The values for the height of the 0.05 ppm plants were the largest as compared to those of the other plants throughout the growth period. Especially, the 0 and 20 ppm plants were shorter than the 0.05 ppm plants. The number of leaves of the 0.05 ppm plants was larger than that of the other plants.
    The values for the fresh and dry weights of the 0.05 ppm plants were the largest as compared to those of the other plants except that they were slightly smaller than those of the 0.005 ppm plants at harvest time.
    The chlorophyll content of the 0.005 ppm plants was the highest during the vegetative growth stage, but the highest in the 0.05 ppm plants after the tassel flowering stage.
    The total nitrogen content of the 0 and 20 ppm plants was higher than that of the 0.05 ppm plants. The soluble nitrogen content of the leaf blade in the 0 and 20 ppm plants was higher than that of the 0.05 ppm plants, and it was the highest in the 0 ppm plants. The higher the zinc concentration in the nutrient solution, the higher the insoluble nitrogen content was.
    The ratios of the content of soluble nitrogen to total nitrogen in the 0, 0.005 and 20 ppm plants were higher than those of the 0.05 ppm plants, especially, they were the righest in the 0 ppm plants.
    These results suggest that zinc deficiency inhibits the growth of corn plants and disrupts the chlorophyll synthesis in the leaf blade as well the nitrogen metabolism.
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  • Toshiaki OHTAKA
    1992 Volume 36 Issue 1 Pages 67-70
    Published: March 01, 1992
    Released on J-STAGE: March 19, 2010
    JOURNAL FREE ACCESS
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  • Toshiro NISHIGORI
    1992 Volume 36 Issue 1 Pages 70-76
    Published: March 01, 1992
    Released on J-STAGE: March 19, 2010
    JOURNAL FREE ACCESS
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  • Katsukuni YAMAMOTO
    1992 Volume 36 Issue 1 Pages 77-80
    Published: March 01, 1992
    Released on J-STAGE: March 19, 2010
    JOURNAL FREE ACCESS
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