巻号一覧
35 巻, 7 号
選択された号の論文の4件中1～4を表示しています
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Diljit Singh VIRK1960 年 35 巻 7 号 p. 179-186
発行日: 1960年
公開日: 2007/05/21
ジャーナル フリーPhenotypically striped (+/ps) F1 individuals of several silkworm strains were irradiated with 4000r (1210r/min) in different stages viz., advanced embyronic stage, first, second and third larval stages in order to investigate the number and size of spots due to the elmination of ps-carrying chromosome fragment.
Spots were not visible on the body of larvae given X-ray treatment in the third larval stage.
It was found that the number of spots was maximum, medium and minimum in individuals X-rayed in second larval, first larval and advanced embryonic stages.
As regards the size of the white spots experimental results indicated that it decreases with an advancement of X-irradiated stage of growth in the silkworm.
Number and size (diameter in microns) of spots do not appear to be correlated and interdependent. It may plausibly be thought that these two phenomena are controlled by different mechanisms.抄録全体を表示PDF形式でダウンロード (710K) -
Yukio YAMADA1960 年 35 巻 7 号 p. 187-196
発行日: 1960年
公開日: 2007/05/21
ジャーナル フリーOptimum structure of poultry breeding flock which maximizes genetic progress is studied theoretically, when combination selection based on individual and family records is applied to females and simultaneous selection based on full-sib and half-sib family records is applied to males. This involves the number of sires, dams mated to each sire and daughters from each mating. If the population size were fixed these variables can be transformed to the selection intensities, the fraction of males and females saved for breeding. The optimum structure of the flock is then synonymous to finding out optimal fractions of males and females to be saved in order to give maximum progress for a given trait. The maximum gains are dependent only on the selection intensities which are applied to males and females. Numerical solutions were obtained by means of a digital computer, and the problem was discussed from viewpoint of practical poultry breeding.抄録全体を表示PDF形式でダウンロード (720K) -
Seiji MATSUMURA1960 年 35 巻 7 号 p. 197-204
発行日: 1960年
公開日: 2007/05/21
ジャーナル フリーDormant seeds of Triticum monococcum flavescens were exposed to X- and γ-rays at the dosage of 10 and 20kr. Growth of seedlings, single spike fertility and chromosome aberrations of X1 plant and gene mutations in X2 were compared for acute and chronic irradiation. At acute irradiation with X- and γ-rays treatment was given either immediately before sowing or the irradiated seeds were kept for 30 days in storage at room temperature (about 20°C) or at 5°C. Also, the effect of β-radiation by 32P was examined for comparison.
The relation between the inhibition of seedling growth and dosage, temperature in storage and irradiation time coincides roughly with the relation between the percentage of induced sterility and all those conditions. X- and γ-irradiations were far more effective at 20kr than at 10kr. In the case of 30 day storage, γ-rays inhibited the growth of seedlings and reduced the fertility stronger than X-rays, while irradiation applied just before sowing showed the reverse relation. It was further observed, especially with γ-rays, that low temperature had the strongest inhibitory effect. At 10kr acute γ-irradiation was more effective than the chronic one, while at 20kr the reverse relation was observed.
The frequency of chromosome aberrations and gene mutations was strikingly higher at 20kr than at 10kr. Irradiation just before sowing and 30 day storage at low temperature were more effective than storage at room temperature fter irradiation. The effect of γ-irradiation was less.
The effects of β-irradiation were unexpectedly slight. It was found from another experiment with seed absorption of 32P solution that the actual dosage of β-rays was very low.抄録全体を表示PDF形式でダウンロード (745K) -
I. X-ray irradiations by small dosesBungo WADA1960 年 35 巻 7 号 p. 205-211
発行日: 1960年
公開日: 2007/05/21
ジャーナル フリーEffects of X-ray irradiations by small doses on mitotic cells were studied by Tradescantia test in vivo. A considerable number of chromosome bridges were obtained in staminal hair cells of Tradescantia irradiated by 2r, 4r, and 8r X-rays.
Biological significance on results obtained in in vivo observations were discussed in comparison with those in fixed preparations.抄録全体を表示PDF形式でダウンロード (849K)
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