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Volume 32, Issue 3
Displaying 1-4 of 4 articles from this issue
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Population structure of the barley variety, “Iwate Mensury No. 2”Kanji GOTOH1957 Volume 32 Issue 3 Pages 75-82
Published: 1957
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSThe genetic structure of 5 local strains of the barley variety, “Iwate Mensury No. 2” was analyzed. Differences found between strains in agronomic characters were of statistical nature (Tab. 1.). A strain obtained from the Tohoku Nat. Agr. Exp. Sta. included a wide range of variation in the type index of young plants and in the date of heading coverning 22 days. This strain included 6 of 8 genotypes expected from all combinations of three pairs of marker genes (S s, Hs hs and Wh wh). It was found that type III (S hs wh) was predominant in all strains and amounted to 100% in the southern strains, D and E (Tab. 5 and 6). Increasing tendency of spring habit type and of type III in the southern locations was striking.
Data obtained for this variety were compared with those reported for another mixed barley variety “Hosogara No. 2”. and it was found that the obtained results were in general similar.
It may be worth mentioning that the southern strains of both varieties consisted of spring habit plants, and that a wide range of variation in the date of heading was found in their northern strains. It was assumed that the latter phenomenon may be connected with a variability within those strains regarding the response to short day length. Thus, the conclusions derived from the data obtained for “Hosogara No. 2” were further strengthened by the results of new experiment with “Iwate Mensury No. 2”.View full abstractDownload PDF (715K) -
Complementary Lethal Genes in RiceHiko-Ichi OKA1957 Volume 32 Issue 3 Pages 83-87
Published: 1957
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSAmong a number of crosses between rice varieties, lethality of F1 plants was found in two crosses. It was shown that this hybrid inviability was due to a set of “complementary dominant lethals”.
It is generally found that when distantly related varieties of rice are crossed, a few F2 plants show a poor growth. In a cross showing this phenomenon typically, the underlying genes were analyzed. It was found that a set of duplicate genes, A1-a1 and a2-A2, are concerned, and that possessing two A's, i.e. A1A1, A2A2 or A1A2, is necessary for normal growth. These genes may be said as “complementary recessive lethals”. since the recessive alleles, if combined, produce a lethal effect. It was discussed that this type of duplicate genes may be widely spread among rice varieties, and may work as an isolating barrier between distantly related varieties.View full abstractDownload PDF (439K) -
Variation induced in Pearl's medium when transferred from the Kozi medium (2)Syuiti Mori1957 Volume 32 Issue 3 Pages 88-99
Published: 1957
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESS1. We have previously noted that Drosophila melanogaster, which has long been reared in the Kozi medium, changes some of its hereditary characters when transferred to Pearl's medium (Mori and Yanagishima, 1957). To ascertain whether these changes of characters were the results of selection among random variations or the results of causal variations in connection with the change of environmental conditions, a series of new experiments were planned. Stock strains maintained in the Kozi medium were separated into two groups (α and β groups), and each group was again separated into two strains-those maintained in the Kozi medium (αK and βK strains) and those cultured in Pearl's medium (αP and βP strains). Variations of characters found after these treatments were examined at every 5 generations and compared with the results previously mentioned.
2. Speaking in general, the variations observed in the previous experiments reappeared in the present experiments, i.e.., in Pearl's medium, the ability of egg laying was increased (ca. 2.5 times) (Tables 1 and 2) and the rapidity of development of larvae was accelerated (ca. 3-21 hours) (Tables 4, 5, 6, 7, 8, 9).
3. In some points, however, the results were different. In the present case, 1) the rapidity of development of pupae was not accelerated, 2) the preference to substrata for laying eggs was not changed, and 3) the F1 individuals of the crossing of K and P strains showed the abilities of egg laying similar to their mothers and their developmental rapidities were intermediate between both strains (or may even be said as being slightly maternal).
4. In conclusion, it seems to me that the principal variations of characters, at least, that are exhibited in Pearl's medium when transferred from the Kozi medium, are those induced directly by the change of environment and not those caused by the selection of random variations, and that these variations have hereditary natures.View full abstractDownload PDF (4852K) -
I. Linkage relationship among markers controlling the host-range and the plaque-typeYoh TANAMI1957 Volume 32 Issue 3 Pages 100-108
Published: 1957
Released on J-STAGE: May 21, 2007
JOURNAL FREE ACCESSThe present paper deals with the host-range mutation in T2 bacteriophage and some new linkage relationships among genetic markers controlling the host-specificity and the plaque-types are described.
The mutation rate of T2hc (phenotype hc) was about 10-7, and that of T2ht (phenotype ht) was about 10-4-10-5.
Crosses between any pairs of independently arising 10 hc-mutants have failed to yield recombinant, indicating that the hc-mutation tend to occur at a single genetic locus.
However, recombination experiments between a T2ht-mutant and any one of the T2hc-mutants have shown that these two mutants may occur at least two different loci, respectively.View full abstractDownload PDF (956K)
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