Japanese Journal of Breeding
Online ISSN : 2185-291X
Print ISSN : 0536-3683
ISSN-L : 0536-3683
Volume 27, Issue 1
Displaying 1-9 of 9 articles from this issue
  • Norio MURAKAMI, Kazuo ASAMA, Hei-ichi ITO, Takeshi ITO
    1977 Volume 27 Issue 1 Pages 1-12
    Published: March 01, 1977
    Released on J-STAGE: May 16, 2008
    JOURNAL FREE ACCESS
    This study has been made over periods of 2 and 3 years using ll8 potato varieties grown at Hokkaido Prefectural Konsen Agricultural Experiment Station. The purpose of the study is to estimate the genetic coefficients of variation, heritabilities, genetic and phenotypic correlation coefficients of the each seven leaf and flower characters and six starch characters (Table 1, Fig. 1). Furthermore, relationships between these characters and tuber yield, starch content and starch yield were studied. The principal results obtained were summarized as follows ; (1) The genetic coefficients of variation were observed to range from 4.8 to 22.3%, 3.7 to 18.3%, and 15.0 to 34.7% for leaf, flower and starch characters, respectively (Table 3, 5, 7). (2) The heritabilities for leaf, flower and starch characters were observed to rang from 44.0 to 75.9%, 54.5 to 85.0%, and 55.2 to 65.2%, respectively. Especialy, the heritabilities of the number of petals, petole index, style length and sepal length were shown to be more than 70%, and hence it may be considered that these characters have high selection efficiency (Table 3, 5, 7).
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  • M A, YAMAGUCHI H
    1977 Volume 27 Issue 1 Pages 13-18
    Published: March 01, 1977
    Released on J-STAGE: May 16, 2008
    JOURNAL FREE ACCESS
    The present experiments were carried out to flnd out the caffeine enhanccment of the damage induced by physical and chemical mutagens in rice. It may be noted that enhanced radiation damage occurred when caffeine treatment was given immediately after irradiation. In the treatments of alkylating agents, on the contrary, caffeine was found to have an effect if it was applied af.ter a while.
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  • Toshiro KINOSHITA
    1977 Volume 27 Issue 1 Pages 19-27
    Published: March 01, 1977
    Released on J-STAGE: May 16, 2008
    JOURNAL FREE ACCESS
    A specific relationship between the nuclear genes and the genetic factors of cytoplasms as a consequence of cytoplasmic mutation was confirmed from the genetic interaction between the pollen fertility restoring genes and the sterile cytoplasms which were induced by gamma irradiation from the normal (N) cytoplasm, The two complementary genes Rf4 and Rf5 responsible for S1_-2 cytoplasm were different from those for S cytoplasm of spontaneous origin, and F3 lines having a genotype S1_-2 Rf4Rf4Rf5Rf5 Were bred true to the pollen fertility restored types, N or S.S.a. In the pollen fertility restoration for S1_-3 cytoplasm, an epistatic relation of two alleles (Rf6 and Rf7) which are different from S and S1_-2 showed various segregation ratios depend-ing on parental genotypes. Although the segregation mode of two additive genes was similar to those in S cytoplasm, the new genes Rf8 and Rfg were responsible fcr S1_-4 cytoplasm. Thus there is the specific relation between the pollen fertility restoring genes and the genetic factors of the male sterile cytoplasms. It is probable that the cytoplasmic mutations occurred in the strain H-2002 which contains normal (N) cytoplasm and diverse genotypes on pollen restoration and then the combination between the altered cytoplasm and the recessive type of the specific pollen fertility restoring genes indicated male sterility. If the maintainer and fcrtility restorer lines for the induced cytoplasms were selected based on the inheritance mode of pollen fertility restoration, they are also available for the use of the male sterility in hybrid seed production.
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  • Katsuhiko KONDO
    1977 Volume 27 Issue 1 Pages 28-38
    Published: March 01, 1977
    Released on J-STAGE: May 16, 2008
    JOURNAL FREE ACCESS
    The diploid species and cultivars of Calefellia studied showed complete and normal chromosome pairing at metaphase I in meiosis. Thirteen F1 hybrid combinations between diploid species of Camellia showed similar patterns of meiotic chr-omosome configurations and chiasma frequencies at metaphase I. These hybrid combinations showed a single chromosome configuration of 15I_I In these hybrid combinations the chiasma frequencies deviated only slight from those of their parents. Metaphase chromosome pairing in meiosis I in hybrids of Calvzellia was not sufflcient to assign distinct genome fermulas for the properties of different chromosome sets in various s pecies. The presence of partial pollen sterility shown in many cultivated taxa of diploid Camellia was not correlated with chromosome configurations at metaphase I in PMC's. The sterility and partial sterility shown in diploid Caleeellia taxa might be due to eithel-genetic differences or cryptic structulal difEerences or chromosomal differences. Since cultivated Camellia is longeval tree or shrub and is artificially selected for economic purposes, all genetical and cytological factors discussed have been accumulated and foimed into more complicated genomic constitutions.
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  • Hirotada YAMAGATA, Takatoshi TANISAKA
    1977 Volume 27 Issue 1 Pages 39-48
    Published: March 01, 1977
    Released on J-STAGE: May 16, 2008
    JOURNAL FREE ACCESS
    Effects of heat-shock treatment following irradiation at an extremely low temperature were examined on radiosensitivity, mutation frequency and response to selection of quantitative traits. Seeds of rice variety Gimbozu were irradiated with various doses of γ- or X-rays at about -70°C, followed by immediate soaking into the water of which temperature was adjusted to 0, 30 and 60°C, for 2 sec. to 6 min. Striking decrease of radiation-induced injuries was observed, as measured in survival rate, seedling height and seed fertility in the M1 generation. Within the ranges of temperature and time for shock in this experiment, the radio-protection effect increased as temperature and time increased, LD50 in 60°C-2min. -shock being about 2. 5 times as high as that in irradiation at room temperature. These effects of heat-shock treatment may be resulted Lrom the restricted mobility of free radicals due to extremely low temperature during irradiation, the restricted recombination among long-lived radicals and the accelerated metabolic activity at raised temperature immediately after irradiation at low temperature. Higher dose irradiation followed by the heat-shock treatment brought about a marked increase of the obtainable highest mutation frequency in three quantitative characters, heading date, culm length and panicle length, and also in qualitative characters except seed fertility : the frequencies of mutants per R unit in all these characters did not differ from those in usual irradiation. In contrast with these results, the frequency of mutants in seed fertility was clearly decreased. Both genetic gain and heritability in heading date and culm length were also proved to be significantly increased by the heat-shock treatment. From these results, it may be concluded that the heat-shock treatment is an effective method for enhancing the relative frequency of genic mutations to that of gross chromosomal aberrations.
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  • Ken-ichi HAYASHI, Takakazu YAMAMOTO, Masahiro NAKAGAHRA
    1977 Volume 27 Issue 1 Pages 49-56
    Published: March 01, 1977
    Released on J-STAGE: May 16, 2008
    JOURNAL FREE ACCESS
    Inheritance of leaf photosynthesis in rice and relationships between leaf photosynthesis and various characters were studied with infrared analysis of net C02 exchange method in a cross experiment between Japanese variety Nakate Shinsenbon(P1) and USA variety CP-SLO (P2) F1 mean for leaf photosynthesis in terms of apparent photosynthesis (Pa) was very close to P1 that was the low parent in Pa. F2 segregation in Pa distributed in a wide range from P2 to even lower than P1 Moreover, a bimodal distribution, one mode corresponding to P1 with a predominant number of plants and the other mode corresponding to P2 with much less plants, was clearly established. Hence, we concluded that the expression of leaf photosynthesis would be controlled by single major gene and that low leaf photosynthesis is dominant. Pa significantly correlated negatively with specific leaf area and positively with leaf areal nitrogen content in F2 progeny. Significant partial correlation existed only between Pa and leaf areal nitrogen content, indicating that areal nitrogen content is the major factor associating with Pa. Still, other undetected factors are indicated to be equally involved in the expression of Pa. In F2 progeny, Pa did not correlate with days to heading, culm length, panicle length and length/width ratio of grain. It neither correlated with some characters controlled by single major gene such as esterase isozyme, apiculus color, awn presence, and blade pubescence, indicating that gene(s) controlling Pa may not link with any of them. Besides, a possible effective introduction of glabrous habit into Japanese rice was demonstrated by the absence of any signiflcant difference in seven agronomic characters between glabrous and pubescent F2 plants. In conclusion, with its rather simple manner of inheritance and its independency from various agronomic characters, leaf photosynthesis can possibly be increased by inten-tional selection in future rice breeding.
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  • Torao GOTOH
    1977 Volume 27 Issue 1 Pages 57-69
    Published: March 01, 1977
    Released on J-STAGE: May 16, 2008
    JOURNAL FREE ACCESS
    The need for early maturing cultivars is one of the problems Lacing wheat breeders in southwestern Japan. From this point of view, several experiments were conducted to get information on the photoperiodic and thermal responses of wheat cultivars in southwestern Japan. To find the effective natural day length of wheat, an experiment was performed changing light intensity of the frrst and the last 4 hours of a 16-hour photoperiod. The experiment showed that the minimum effective light intensity in the first 4 hours is 10lux and in the Comparing these results with the intensity of the last 4 hours is 20 lux (Figs 3 and 4). morning light and evening twilight, the effective day length in Fukuyama (34° 30' N) was assumed to be the astronomical day length +49 minutes. Considering the fact that the length of twilight is inversely proportional to the peripheral velocity of the earth's surface at a given place, the effective day length and the mean temperature for wheat at heading time and one month and two months before heading time were estimated for all parts of Japan as shown in Fig. 5.
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  • Hiroshi FUJIMAKI, Susumu HlRAIWA, Kinya KUSHIBUCHI, Sachihiko TANAKA
    1977 Volume 27 Issue 1 Pages 70-77
    Published: March 01, 1977
    Released on J-STAGE: May 16, 2008
    JOURNAL FREE ACCESS
    Genetic nlale-sterile mutants of rice were induced by the gamma-rays of Co6^0 and a chemical mutagen ethyleneimine. The sterility of these mutants was affected by a pair of recessive alleles. No pollen grain was observed in their anthers. The utilization of male-stcrile mutants was discussed in relation to recurrent sclection schemes and backcross-breeding systems fcr rice improvement.
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  • [in Japanese]
    1977 Volume 27 Issue 1 Pages 78-82
    Published: March 01, 1977
    Released on J-STAGE: May 16, 2008
    JOURNAL FREE ACCESS
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