NATIONAL INSTITUTI: OF GI:NI:TICS(JAPAN)ANNUAL REPORT
No.4.
(l 953)-~oo~_PUBLISHED BY

THE NATIONAL INSTITUTE OF GENETICS(MISIMA, SIWOKA.KEN, JAPAN)

1 954

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NATIONAL INSTITUTE OF GENETICS (JAPAN)
ANNUAL REPORT
No.4 (1953)

Contents
Page

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General statement
Abstract of diary for 1953 .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..
Staff
Council'.... .. ..
..
..
..
.. ..
Research program for 1953.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..
Researches carried out in 1953 .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ....
A. Human genetics.. .. .. .. .. .. .. . . .. . . . . . . . . .. .. .. .. . . . . .. .. . . . .
Genetics of microcephaly
B. Genetics of some mammals .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. . .
1. The tortoiseshell male cat and its sterility.. .. .. .. .. .. .. .. ..
2. Studies on T locus in the wild Japanese mouse Mus musculus
molossinus.
C. Cytology and genetics of tumors..
1. Karyological study on the MY-mouse carcinoma..
2. Karyological study on the MY-mouse sarcoma.
3. Karyological study of some non-transplantable tumors.
4. A study on the transplantability of the MY-mouse sarcoma
and carcinoma~.
5. On a non-transplantable ascites tumor in inbred mice.
D. Silkworm genetics and biochemistry ".
1. Influence of the incubation temperature on the developmentof multilunar and multistar markings of the silkworm ....
2. A possible, sub-threshold effect of multistar modifiers for thedevelopment of multilunar spots,
3. On the intermediate type appearing in "retarded" strains ..
4. Studies on the action of the gene causing malformation ip.
the silkworm;. . . . . .. .. . . . . .. .. . . . . . . .. . . . .
5. Genetical and biochemical studies on yellow lethal larvae (II)
6. On the respiratory enzymes and several other enzymes concerned with the T. C. A. cycle in the mid-gut epitheliumof the silkworm (Bombyx mori L.)
7. Pterin obtained from the silkworm (Bombyx mori L.)
E. Population genetics of some insects and a land-snaiL.........
1. The lycaenid butterfly Neozephyrus

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2. The land-snail Bradybaena
29
3. Drosophila rufa.... .. .. .. . . . . . . . . .. .. . . . . . . . . . . . . .. . . . . . . .. 29
F. Genetics of some cereals ... _.. .. .. . . .. .. .. .. .. .. .. .. .. .. .... 29
1. Tetrasomic gigas-plants in the offspring of nullisomic dwarfs
and analysis of their additional chromosome pair ... . . . .. 29
2. Chromosome aberrations in einkorn wheat induced by X-rays 30
3. Measurement of X-ray dosage for inducing mutations...... 31
4. Inter-racial differences found in the variety of barley "Hosogara No.2"__. . . .. . . . . . . . . .. . . 31
G. Cytology and genetics of Nicotiana
32
1. Cytogenetical problems in Nicotiana.. .. .. . . . . . . . . . . . . . . . . . . 32
a. A new amphidiploid32
b. Continued investigation of synthesized N. tabacum........ 33
c. Octoploids of synthesized N. tabacum .... _. _. . . . . .. .. . . . . 33
2. Cytogenetic studies on the Genus Nicotiana. V.
33
a. Reduction divisions in hybrids between N. tabacum and33
three other species
b. Reduction divisions in the hybrids between the N. tomentosa
group and three other species
34
c. Reduction divisions in hybrids between N. Sanderae andthree other species . _.. .. .. .. .. . . . . .. .. .. .. . . . . .. . . . . .. 35
3. Genetical studies on the mid-rib proportion and the leaf-shape36
in tobacco plants
4. Mutations in tobacco induced by X-rays.. .. .. .. .. .. .. .. .. .. 38
H. Genetics, cytology and biochemistry of some phanerogams.. . . 39
1. Sex relations in artificially produced tetraploids of Melandrium
album.................................................... 39
2. Ring formation in the meiosis of Allium scorodoprasum var.
viviparum '" . .. .. .. . . .. .. . . . . .. .. .. . . . . . . .. .. .. .. . . .. .. 41
3. Inheritance of flower color of F 1 hybrids in the Swiss giant
pansy....
..
42
4. Analysis of coronal anthocyanins in various strains of theJapanese morning glory (Pharbitis Nil)
43
5. In)leritance of doubleness in Zinnia elegans L... .. .. .. .. .. .. 45
6 . Karyotaxonomic studies in Poaceae I.
45
I. Genetics and Cytology of some lower organisms, . . .. .. .. 47
1. Studies on the methionine-requiring strain of Ustilogo maydis 47
a. Reversion of methionine-requirement by two-step mutations................................ _.. .. .. .. .. .. .. .. .. .. .. 47
b. Methionine-requiring and sulfonamide-resistant characters. . 49
2. Electron-microscopical studies on the structure of Paramecium
candatum by means of ultra-thin sections................ 49
3. Formation of tobacco mosaic virus in plastids ..... _.. .. .. .. 51
ii

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4.

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Electron-microscopic studies of a bacterial virus attacking
Pseudomonas solanacearum E. F. SMITH.. • • . . . • . . • • • • •• • .
J.. Improvement of some useful plants .. . . . . .. . . . . . . . . .. .. .. . . . .
1. Improvement of sugar beets by means of induced triploidy.
2. Further investigations regarding the degree of heritability
and the number of effective factors in the eggplant
3. Studies on polyembryony in Citrus. . . .. .. . . ..
K. Studies on competition, .. . . .. . . .. .. .. .. .. .. .. . . . .
1. Competitive ability of F 1 hybrids in barley.
2. Further studies on competition between diploid and autotetraploid plants of barley.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..
3. Competition studies on diploid and autotetraploid plants ofrice...... ..
.. .. ..
..
.. .. .. ..
.. ..
4. Competitive ability of thirty varieties of upland rice against
the so-called "red rice"..................................
5 . Competition and spacing in one dimension in plants .. . . .. . .
L. Theoretical studies and technical note
1. Theoretical studies in the breeding technique of autogamous
crop plants
a. Change in the value of heritability of quantitative charactersin hybrid bulks and plant progenies in autogamous plants
b. Heritability and the number of individuals to be selected..
2. A new chemical "Substance F" for inducing doubling of.. . . . . .. . . . . . . .. .. . . .. .. .. . . . . .. . . . .
chromosomes

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4

GENERAL STATEMENT
The scope of activity of the Institute was extended during thecurrent year by the addition of a new department, that of Biochemical Genetics. This addition was intended to meet the increasing demand from the recent trend of genetics in general.
Most of the research programs from previous years were continued to this year. These include fundamental investigations on
tobacco plants in cooperation with the members of the Misima
Branch of the Hatano Tobacco Experiment Station of the Japan
Monopoly Corporation, and genetic researches on egg productionof poultry under the auspice of the Whole-Japan Association of
Poultry Genetics. Some works were completed and published or
are in press. Also, many new research programs were undertaken.
A new house for mouse and rat breeding was completed. Thisis constructed and equipped according to the plans of modern
mouseries in Europe and America. It is 88.2 umbo (350 square
meters) in floor area, and contains four rooms for mouse breeding and two for rat breeding, besides a working laboratory, anassistants' room with a bedroom annex, a food kitchen and storage space. It has an automatically regulated heating system
and a simple but effective device for ventilation. The cage racks
are hanging and movable. This building can house from 8,000
to 9,000 animals. There are about 6500 mice and 500 rats now
in it. Most of these animals are progeny of 15 strains of miceand 4 strains of rats which had been bred for several years in
the Zoological tnstitute of Hokkaido University. Eleven new inbred strains of mice useful for medical and biological purposes
were presented after the completion of the house by the kindnessof Dr. W. E. HESTON of the National Cancer Institute at Bethesda, Md. and Prof. L. C. DUNN of Columbia University, NewYork.
An area of more than two acres was added to our experimental
field by the removal of an old factory building which had stoodclose to the main building of the Institute.
1

The library has been expanded by the arrival of new books,
periodicals and reprints. Dr. GOLDSCHMIDT has continued to sendin reprints and current numbers of scientific journals which haveamounted to 780.
To our Drosophila stocks were added 27 useful composite stocksof D. melanogaster kindly presented by Prof. H. J. MULLER of
Indiana University.
K~ HAYASIU and S. NAWA were appointed researchers in the new
Department of Biochemical Genetics. M. TSUJITA, B. SAKAGUCIU,
T. ENDo, T. IINO and S. TSUDA were transferred from the Department of Physiological Genetics to this new department. T. TAIRA
was appointed a member of the Department of Physiological
Genetics. M. KIMURA took a leave of absence for a year from
July 1953 to study mathematical genetics in the Department of
Genetics, Iowa State College. H. ETO, Assistant Professor ofTokyo University, and Y. OZAKI, Lecturer in The National Institute of Public Health, were appointed Associates of the Institute.
M. TSUKAMOTO, who had been head of the Department of Administration since the founding of the Institute, was 'transferred to
Sizuoka University. His ability and effort had contributed a great
deal to the completion and expansion of the Institute. He was
replaced by K. OTOFUJI.
T. KOMAI was invited to the International Congress of Scientists
for Cultural Freedom held in July in Hamburg. He also attended the Fourteenth International Zoological Congress held in Copenhagen in August as delegate of the Japan Academy, and theNinth International Congress of Genetics at Bellagio, North Italy,
held in the same month. H. KIHARA and Y. SINOTO also attended this International Congress of Genetics, KIHARA as a vicepresident. The latter also represented Japan at the EleventhCommittee Meeting of IUBS at Nice, France directly before thecongress. SINOTO was nominated a mem~r of the PermanentCommittee of the International Congress of Genetics.
Y. HANDA, Assistant Professor of Wakayama Medical College,
stayed one year at the Institute to prepare himself for the professorship in human genetics in the college. Three new research
students were admitted during the year, working on special subjects under the direction of the staff.
2

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The Genetics Society of Japan held its Twenty-fifth General
Meeting on the 7th and 8th of November 1953. It was attended
by more than 300 members.
Among the foreign visitors to the Institute during the current
year were Dr. A. WOLSKY of Science Cooperation Office for South
East Asia of UNESCO, Prof. M. W. YOUNG of Howard University, Washington, D.C., Dr. G. TAYLOR and Dr. J. MORTON of
ABCC, Hiroshima, Dr. Chang of FAO, UNESCO, Drs. N. PARTHASARATHY, A. B. SARAN, M. B. VNARASINGARAO of the Indian
Agricultural Research Institute, New Delhi, India, Prof. J. G.
KIRKWOOD of Yale University, Prof. P. J. FLORY of Cornell
University, and Dr. L. PRIGOGINN of Belgium.
The following grants were received during the current year
by our staff. These grants have been of great aid to our research
projects.
From the Fund for Grants-in-Aid to Institutes of the Ministryof Education: to K. OGUMA, for: The project of breeding ofmouse and rat strains for medical and biological purposes - V
5,530,000.
From the Fund for Grants-in-Aid to Cooperative Investigations:to T. KOMAI and co-workers (including K. SAKAI and M. KIMURA),
for: Researches in population genetics-V530,000.
Y. TANAKA and co-workers (including M. TSUJITA), for: Fundamental and applied genetics of the silkworm~V440,000.
S. MATSUMURA and co-workers, for: Researches on the physiology of crop plants under standardized temperature, humidity andday-light conditions-V380,000.
From the Fund for Grants-in-Aid to Investigations on Applied
Sciences: to Y. TANAKA, for: Research on artificial control of
diapause in the wild silkworm, Antkeraea pernyi- V 450,000.
M. TSUJITA, for: Researches on the genetics and selection ofabnormal eggs in the silkworm-V150,000.
From the Fund for Grants-in-Aid to Individual Workers: to
K. OGUMA and co-workers (including T. KOMAI and K. TUTIKAWA),
for: Breeding and preservation of strains of rats and mice useful for medical research purposes-V720,000.
K. SAKAI, for: Population-genetic studies on the contamination of rice crop by mixture of "red rice"- V90,000.
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From the Fund for Grants-in-Aid to Young Research Workers,
to T. END6, for: Genetics of flower colors-¥30,000.
S. TSUDA, for: Studies on the propagation of bacteriophages-¥20,000.
From the Fund for Grants-in-Aid for Promotion of Improvement of Agricultural Techniques of the Ministry of Agriculture
and Forestry: to K. SAKAI and co-workers, for: Comparative
studies between pedigree method and bulk method in breeding ofautogamous plants-¥100,OOO.

•
ABSTRACT OF DIARY FOR 1953
January 29. Eighth meeting of the Board of Councillors.
January 31. Fourteenth meeting of Misima Geneticists' Club.
March 18. Board meeting of Association for the Propagation of
the Knowledge of Genetics.
March 28. Fifteenth meeting of Misima Geneticists' Club.
April 18. Sixteenth meeting of Misima Geneticists' Club.
May 20. Seventeenth meeting of Misima Genetists' Club.
June 18. Ninth meeting of the Board of Councillors.
June 'Zl. Second general meeting of Whole-Japan Association of
Poultry Genetics.
July 25. Eighteenth meeting of Misima Geneticists' Club.
August 21. Nineteenth meeting of Misima Geneticists' Club.
September 29. Twentieth meeting of Misima Geneticists' Club.
October 24. Twenty-first meeting of Misima Geneticists' Club.
November 6. Joint meeting of the National Committee of Genetic
Researches and the National Committee of Researches inAnimal and Plant Breeding of Japan Science Council. Committee meeting of the Genetics Society of Japan.
November 7, 8. Twenty-fifth general meeting of the Genetics
Society of Japan. General meeting of the Society of Chromosome Research.
December 9. Meeting of Arrangements Committee for the International Genetics Symposium.
December 21. Twenty-second meeting of Misima Geneticists'
Club.
4

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STAFF

Department and Laboratory Heads
Kan OGUMA, D. Ag., Director
Yoshimaro TANAKA, D. Agr., D. Se., Head of Department of Morphological Genetics
Taku KOMAI, D. Sc., Head of Department of Physiological Genetics
YO TAKENAKA, D. Sc., Head of Department of Cytological Genetics
Mitsuo TSUJITA, D. Agr., Head of Department of Biochemical
Genetics
Kan-ichi SAKAI, D. Agr.
Seiji MATSUMURA, D. Agr.
Kozo HAYASm, D. Se.
Tosihide H. YOSIDA

Part-time Staff and Research Associates
Hitoshi KIHARA, D. Se., Professor of Kyoto University
Sajiro MAKINO, D. Sc., Professor of Hokkaido University
Yosito SINOT6 D. Sc., Professor of International Christian University
Hideo ET6, D. M., Assistant Professor of Tokyo University
Kazuo FURUSATO
Yoshinari KUWADA, D. Sc.
Flora Alice LILIENFELD, D. Ph.
Yasunosuke OZAKI, D. M.

Junior Investigators
Moto KIMURA
Kanji GoTOH
Akira MIYAZAWA
Bungo SAKAGUCm
Toru END6
Kiyosi TUTIKAWA
Tetuo IINO
Toshifumi TAIRA
Saburo NAWA
Seizo TSUDA
Assistants-12
5•

Department of Administration
Kan-ichi OTOFUJI, Head of Department
Sumiyoshi Sumo, Head of General Business Section
Masao MIYAZAWA, Head of Finance Section
Naomi MATSUBARA
Hiroko NAKANO
Junzo KADOWAKI
Clerks, Typist, Telephone operators, Chauffeurs, Field laborers,
Janitors, etc.-I8
Mis'ima Branch of Hatano Tobacco Experiment Station
Masao TANAKA, Head
Flora Alice LILIENFELD
Seiji IMAI
Assistants-4
Whole-Japan Association of Poultry Genetics
Kan OGUMA, President
Yoshimaro TANAKA, Vice-President and Director of Researches
Association for Propagation of the Knowledge of Genetics
Kan OGUMA, President
Yo TAKENAKA, Managing Director
Seiji MATSUMURA, Managing Director•
COUNCIL

YO K. OKADA, Director of National Science Museum, Chairman
Seishi KAYA, Professor of Tokyo University, Vice-Chairman
Tanemoto FURUHATA, Professor of Tokyo Medical and Dental College
Eikichi HIRATSUKA, Director of Agricultural Technique ResearchInstituteTakeo IRUMANO, President of Japan Monop<?ly Corporation
Seizo KATSUNUMA, President of Nagoya University
Riichi KAWAKAMI, Head of Department of Biometry, National
Institute of Public Health
Makita KOGURE, Professor of Tokyo College of Agriculture andTechnology
Kiyoshi MASUI, Professor of Nagoya University
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Toshitaro MORINAGA, Head of Department of Physiology and Genetics of Agricultural Technique Institute
Waro NAKAHARA, Director of Cancer Research Institute
Masanori NAKAIZUMI, Professor of Tokyo University
Toshio SAIT6, Governor of Sizuoka Prefecture
Yusuke SUMIKI, Professor of Tokyo University
Yftshi UCHIMURA, Professor of Tokyo University
Bungo WADA, Professor of Tokyo University
RESEARCH PROGRAM FOR 1953•

Tanaka Laboratory
Unstable genes in the silkworm-TANAKA
Genetics of "retarded" strain of the silkworm-TANAKA
Genetics of malformations in the silkworm-TANAKA
Photoperiodic effect on diapause of the wild silkworm Antheraea
pernyi, and the genetics of diapause-TANAKA and ONIMARU
Artificial mutation in the modifying genes of "multilunar"character-TANAKA
Matsumura Laboratory
Radio-genetic studies on wheat-MATSUMURA and FUJII
Studies on Agropyrum, a close relative of Triticum-MATSUMURA
Nullosomic plants found among the progeny of pentaploid hybrid
wheat-MATSUMURA
Breeding of wheat .strains resistant to rust-MATSUMURA andHIRATSUKA (Tokyo University of Education)
Studies on the relation between the quality of radiation and mutation-MATsuMURA "and ETC) (Tokyo Univ.)
Induced mutations in tobacco plants by X-ray irradiation-KIHARA,
MATSUMURA and FUJII
Breeding of triploid sugar beet-MATSUMURA et a1.
Yoshida Laboratory
Studies on sex chromosomes in insects-YOSIDA
Experimental cytology and developmental genetics of tumorsYOSIDA and ISHIHARA
Genetics of cancer susceptibility of mice and rats-YosIDA and
ISHIHARA
Genetics of cancer found in Drosophila-YosIDA and ISffiHARA
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Karyology of normal and tumor cells in man-Y OSIDA and OMURA
Takenaka Laboratory
Origin of sex differentiation in higher plants-TAKENAKA
Cytogenetics of Nicotiana-TAKENAKA
Cytogenetical studies op the effect of mitosis-inhibiting substances-TAKENAKA
Cytogenetical studies on the effect of mutagens-TAKENAKA
Studies on sterility in Citrus-FURUSATO
Studies on polyembryony in plants-FuRusATo
Studies on the origin of polyploidy in Citrus-FuRUSATO
Studies on triploid water-melon-FuRusATo and MIYAZAWA
Studies on triploid tobacco plants-FuRusATo and MIYAZAWA
Karyology of Gramineae--TAKENAKA and TATEOKA.
Collection and preservation of useful varieties of plants-TAKENAKA
Komai Laboratory
Genetics of human microcephaly-KoMAI, KISRIMOTO (Nagoya
Univ.) and OZAKI
Population genetics of the land-snail Bradybaena-KoMAI
Population genetics of some species of Drosophila-KoMAI and
TAIRA
Genetics of blue sclerotics in man-KOMAI, OZAKI and KUNII
Studies on tumor susceptibility in mice-TUTIKAWA
Studies on lethal genes in rats and mice--TuTIKAWA
Studies on phenocopies in mice-TuTIKAwA
Studies on viability in mice-TuTIKAWA
Breeding and preservation of mouse and rat strains useful for
medical investigations-MAKINo and TUTIKAWA
Sakai Laboratory
Competition between individual plants of different genetic constitutions-8AKAI et a1.
Theoretical and experimental studies on selection in plant breeding-8AKAI
Genetics of fruit crops-8AKAI, GOTOR and SUZUKI
Genetics of quantitative characters in tobacco plants-8AKAI and!YAMA
Population genetics on land rice and "red rice"-8AKAI et a1.
Local differentiation·of races in barley-GoTOR
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Theoretical studies on population genetics-KIMURA
Genetics of right- and left-handedness in plant organs-KIMuRA
Tsujita Laboratm"yDevelopmental genetics in the silkworm--TsuJITA and SAKAGUCm
Biochemical genetics on insect materials-TsuJITA, SAKAGUCm and
NAWA
Heredity and selection of abnormal eggs in the silkworm-TsuJITA
and SAKAGUCm
Studies on phenocopies in the silkworm-SAKAGUCm
Biochemical genetics on lethal strains in the silkworm-SAKAGUCHI
Cyto-chemical studies on mitochondria-TSuJITA, SAKAGUCHI and
TSUDA
Studies of the technique of ultra-thin sectioning in electron microscopy-TSUJITA and TSUDAElectron-microscopical studies on cell inclusions-TsuJITA andTSUDA
Electron-microscopical studies on the propagation of bacteriophages-TsuJITA and TSUDA
llayashi Laboratory
Studies on chemical composition of anthocyanin in races of Canna-HAYASHI
Chemical analysis of coloring substances of various varieties ofmorning glory and their genetic behavior-HAYASm and ABE
Chemical composition of pigments in maples and alpine plantsHAYAsm and ABE
Biochemical genetics of Ustilago-IINo
Studies on the effect of chemical substances on mutation-IINo
Studies on the aquirement of metabolic capacity in fungi-IINo
Gene analysis of flower colors-END6
Analysis of environmental f~ctors in the appearance of flower
colors-END6
Research Students and Research Subjects
Kyozo WATANABE: Genetics of protozoa
Yasuo SUZUKI: Population genetics of cultivated plants
Taro AKIYAMA: Genetics and breeding of Citrus
Yoshihiko KAWAGUCHI: Biometry
Toshio OMURA: Cytology of cancers
9Chiaki MATSUI: Morphology and variation in bacteriophages
Kozo NAKAMURA: Cytogenetics of Agropyrum
Toyo MITARASHI: Fundamental morphological studies of animalcells
Takatada KAWAHARA: Improvement of rMes of poultry
Yasuo OTA: Cytogenetic studies on morphological characters of
Citrus
Shinya IYAMA: Population-genetics of land-rice•

10

RESEARCHES CARRIED OUT IN 1953

A.

HUMAN GENETICS(Report by Taku KOMAI)

Genetics of Microcephaly
This study was completed during the current year, and the result wasreported at the Ninth International Congress of Genetics held at Bellagio,
North Italy, in August 1954. Altogether 143 cases of microcephaly consisting of 93 males and 50 females were collected by the cooporation ofProf. K. Kishimoto, M.D., of Nagoya University and Y. Ozaki, M.D., of
the Institute of Pulblic Health. Of these, 64 (44.8 per cent) are progenyof first-cousin marriages. No authentic case of purely non-genetic microcephaly is included in this list. At least the great majority of these cases
seem to be due to a recessive autosomal gene. The incidence of the geneamong the Japanese population was estimated by means of the formula:q=c (1-k)16k-15c-ck 'where q stands for the incidence, k the rate of first-cousin marriages
among the parents of the affected individuals and c the rate of first-cousin
marriages in the whole population. The value 0.0034-0.0063 was obtained for q, according to whether 0.04 or 0.07, or some other value between
these two, is chosen for c. This value for the incidence of the gene in
the Japanese population coincides well with 0.0043-0.0062, the corresponding value obtained for the Swedish population by Book et al. by meansof an entirely different method. The rate of mutation of the gene wasestimated on the assumption of an equilibrium state of the incidence ofthe gene in the population by means of the formula:m=(1-j)[aq+(1-a)q2] ,where m" denotes the mutation rate, f the fertility of the abnormal individuals as compared with that of normal individuals, and a the mean coefficient of inbreeding. The value (2.20-7.57)x10- 5 was obtained for m,depending on the values of c, a and q.

B.

GENETICS OF SOME MAMMALS

1. The Tortoiseshell Male Cat and its Sterility(Report by Taku KOMAI)The Japanese common people have a traditional interest in the tortoiseshell male cat. Also, the incidence of the gene for orange coat color,11which is an essential component of the tortoiseshell pattern, is apparently
two or three times higher in Japanese cats than in European cats. Thus,
it is certain that we come across tortoiseshell male cats more often thanour European colleagues, and we should have a better chance to find the
key to the solution of this old puzzle of genetics. The writer has continued to collect materials of this type of male cats, and found more thanfifty of them, together with records of their parents and litter mates.
Special attention has been paid to a search for reports of the birth of
more than one tortoiseshell male from the same mother. Since the writer's
hypothesis concerning the origin of the tortoiseshell male and its sterility
postulates a crossing over between the X and Y chromosomes in a paternal
spermatocyte, such an occurrence would virtually invalidate the hypothesis. So far all available records conform to the hypothesis, and noauthentic case of the birth of more than one tortoiseshell male from thesame mother has been found. Intensive cytological study by T. Ishiharaof the testes of tortoiseshell male cats is in progress.

2. Studies on T locus in the Wild Japanese Mouse,
M.us musculus molossinus(Report by Kiyosi TUTIKAWA)

To examine whether the locus T, which is known to be mutable inboth domestic and wild M.us musculus (Dunn and Gluecksohn-Schoenheimer
Table 1. Results of test-crossing to a wild population by Brachy T 1+
Total

•

13
20

.

Offspring
Wild parent
!j1

0

185
21029
318
42132
5323
43122
42131

I Brachy

8

9
1
6
1
2

5
11
4
4
4
3

~

-------sI

5
5

4
6
4
3

19

17

....
....
....
-....

7
2

2
1
-3

2
4
-6

6
3

444

4321
42134
0

Normal

425

4462

-9
I

12

I

Tailless

....
....
....
....
....
....
-

....

5

10
5
5
,

....

I

~58

9
12
7
8

--s6
11
7

----rs'50, Dunn and Morgan '53), is also mutable in the Japanese mouse, M.m.
molossinus, some wild animals of the latter subspecies were crossed toanimals of the T strain kindly provided by Prof. L. C. Dunn. The results
are shown in Table 1. The six males and six females used were wild
mice trapped in a barn in our Institute. Following Dunn's method, eachmouse was crossed to a Brachy TI+ mouse derived from outcrossing
with the original tailless line. All the six females of molossinus tested
gave only normal and Brachy offspring (27 normals and 31 Brachys),while two of the six males produced some tailless animals besides normals
and Brachys (9 normals, 3 Brachys and 6 tailless), and four produced
only normals and Brachys (19 normals and 17 Brachys).
If this new tailless character is due to the presence of an allele (orrather pseudo-allele) of t which might be designated as t"n, then tailless(Tit) and normal (tl/t m or tolt m) progeny should be expected from the testcross of this tailless with the known tailless lines (Tlt l or TltO). Suchprocedure is now in progress.
The average tail length of the F l Brachys in the reciprocal outcrosses
was greater than in the Brachy musculus animals used for the test. This
indicates the presence of a modifier or modifiers which inhibit the effectof the T gene to some extent.
Comparative studies of the number of vertebrae and other skeletal features of wild samples from different localities are also in progress.

C.

CYTOLOGY AND GENETICS OF TUMORS

1. Karyological Study on the MY-mouse Carcinoma(Report by Tosihide H. YOSIDA),.

The MY·mouse carcinoma is a gland cell carcinoma originally developed in the D-strain mouse, established by the present author as a transplantable tumor (Yosida 1952). The present report deals with cytologicalobservations of this tumor.
1. Abnormal nuclear divisions: It has been reported by many investi·
gators of tumor cytology that mitotic abnormalities are most common
phenomena in tumors. In the cells of the MY-mouse tumor also, various
types of abnormal mitosis have been observed. Multinucleate cells andmultipolar spindles are of common occurrence. Polyploid cells are frequently found. Atypical arrangement of chromosomes on the metaphase
plate, abnormal swelling of chromosomes and c-mitotic chromosomes arealso common. Displacement of chromosomes on the metaphase plate, andhollow metaphase plates are likewise noteworthy. Coalescence or irregular
agglutination of chromosomes, which is usual feature of degenerating13

cells, is also rather frequent.
2. Chromosome numbers of tumor cells: The number of chromosomesin these tumor cells fluctuated around 40, cells having 39 or 40 chromosomes being the commonnest (Table 1).
Table 1. Chromosome numbers in tumor cells of
the MY-mouse carcinoma.
No. ofChromoNo. ofcells obs.

154 I 49 I 45 I 441 48 I 41 140 I 39 I 38 I ~ I 36 I 36 134 I 33 I Total
11111111121318171112111211111 32

3. Morphological analysis of chromosomes: It seems noteworty that,besides the cells with abnormal mitosis, cells showing regular mitosis
were also observed. The latter are the tumor strain-cells. In the Takizawa quinone-carcinoma and the Ehrlich ascites carcinoma, the author
has observed tumor strain-cells characterized by the presence of V-shaped
chromosomes of medium size. In the tumor strain-cells of the MY-mouse
carcinoma such V-shaped elements were never found. Small dot-likechromosomes, constricted chromosomes, and chromosomes with trabants
were rather common. A fact worthy of notice is that the chromosomeswith trabants are generally longer than those in the MY-mouse sarcoma
cells described in the following report.

2. Karyological Study on the MY-mouse Sarcoma(Report by Tosihide H. YOSIDA)

The MY-mouse sarcoma is a transplantable sarcoma established by theauthor (Yosida 1952). It is a kind of spindle-cell sarcoma originally developed in one mouse of the inbred So-strain, which was derived from thecross S-strain x mixed-strains. Observations on the chromosomes of thistumor have revealed the following facts:Various types of mitotic abnormalities, such as multinucleate and polyploid cells, multipolar mitosis, and atypical arrangement of the chromosomes, were observed. A noteworthy fact is that, besides showing abnormal mitosis, regular mitotic cells occur. These cells are undoubtedly thestrain-cells of this tumor.
The number of chromosomes in these strain-cells may be counted ingood metaphase figures. Cells having about 40 chromosomes are mostcommon. This shows that the MY-mouse sarcoma, like the MY-mouse
carcinoma, is characterized by having diploid strain-cells.
All the chromosomes were of the normal rod-type. No evidence has
14,been found for the presence of any V-shaped element such as observedin the Takizawa quinone-carcinoma and Ehrlich ascites carcinoma. Futhermore, constricted chromosomes, dot-like chromosomes and chromosomeswith trabants were often observed, much as in the MY-mouse carcinoma
described above. The differences may be found, however, that such abnormalities in chromosome configurations in this tumor occur with lower
frequency than in the MY-mouse carcinoma, and that the chromosomeswith trabants are much shorter than those in the latter. The cells of
this tumor are characterized by possessing trabant-bearing chromosomes
which are smaller than any of the other chromosomes. Such elements
were never found in the MY-mouse carcinoma.

3. Karyological Study of some Non-transplantable Tumors(Report by Tosihide H. YOSIDA),•

We often encounter spontaneously developing or artificially induced tumors which do not show any transplantability to other hosts. It is wellknown that the transplantability is in many caseS genetically controlled.
It is highly probable, however, that besides such a genetical factor, someother factor affects the transplantability. This report deals withkaryological observations of some non-transplantable tumors.
The materials used in the present study were No.9 mammary carcinoma(originating in B-strain mouse), No. 10 mammary carcinoma (B-strain), No. 12
tumor (non-transplantable ascites tumor originating in B-strain), No. 20
mammary carcinoma (S-strain) and BE mammary carcinoma (E-strain).
We have tried several times to transplant these tumors to animals of thesame strain as that in which the turner originated, but without any success.
Karyological observations of these tumors have revealed very few cellswith regular mitosis. This observation suggests that the karyologicalstate, is an important factor controlling transplantability of tumor cells.

4. A Study on the Transplantability of the MY Mouse
Sarcoma and Carcinoma(Report by Takaaki ISHIHARA and Tosihide H. YOSIDA)

The MY-mouse sarcoma is a spindle-cell sarcoma which developed in a
So-strain mouse. This strain was originated from hybrids between Sstrain and mixed strains, and has been inbred for many generations. The

15

transplantability of this tumor showed a considerable difference according
to the strain of the host used. First, the transplantability was examinedin four strains of mice and in a number of transplant generations (Table
1). As shown in the table, this tumor is difficult to transplant to theoriginal So-strain mice. Its transplantability to the S- or D-strain increased with the transplant generations, while that to the B-strain decreased.
Next, experiments were undertaken to transplant the tumer to various
other strains such as Sk, D, S, C3H, DBA/2, A, SWR and Swiss albino.
The results obtained are shown in Table 2. The transplantability into
C3H, DBA/2, A, SWR and Swiss albino was zero, whereas the highest
transplantability (87.5%) was found for the Sk-strain mice. No strain having 100 per cent transplantability was found. The behaviour of the transplanted tumor was very characteristic to each strain. For instance, thetumor grafted into the Sk-strain mice showed an active growth, and thehosts usually died of the tumor 19-25 days after transplantation. The Dstrain mice died of the tumor 24-84 days after inoculation. Although thetransplantation to C3H, DBA/2, A, SWR and Swiss albino usually showednegative results, grafts inoculated into C3H and DBA/2 degenerated gradually, after showing some temporary developmental changes.
The MY-mouse carcinoma is a gland cell carcinoma which originallydeveloped in a D-strain mouse. This tumor showed 100 per cent transplatability to the D-strain mice in the 1-7 transplant generations (Table 3),
but decreased to 80.2 per cent in the later transplant generations. On theother hand, the growth rate of the graft in the S-strain mice was considerably lower in early transplant generations. From the above findings, it
seems clear that this tumor undergoes changes in transplantability withthe progress of the transplant generations, decreasing in the original
strain and increasing in other strains.
Table 1. Transplantability of the MY-mouse sarcoma according tostrains of mice and number of transplant generations.

~generation

1-8

18-24

82-88

Strain

S
D
B

So

%

%

82.4 (71)0(1)
74.4 (47)44.1 (84)70.6 (17)59.8 (82)0(18)
52.6 (86)The-figures in parentheses denote the number of mice used.

16%62.2 (57)76.5 (84)
0
(12)

-

..

..

Table 2. Transplantability of the MY-mouse sarcoma according tovarious Istrains of mice.
--

StrainNo. of miceused

Results of transplantation
Positive

--

Sk
D

S
C3H
DBA/2

SWR
Swiss
A

16
34
53
36

I

14
26
33
0
0
0
0
0

f3
10
8
10

% of positive
results

Negative
2
8
20
36
6
10
8
10

I

87.5
76.4
62.2
0
0
0
0
0

Table 3. Transplantability of the MY-mouse carcinoma according to strains of mice and numberof transplant generations.
~
Transplant~eneration

Strain

•

~
D
S
B

1-7

%

100 (12)60.8(46)77.7(18)

13-24%

80.2(41)72.5(46)26.0(15)

The figures in parentheses denote the number ofmice used.

5. On a Non-transplantable Ascites Tumor in Inbred Mice
(Report by Tosihide H. YOSIDA and Takaaki ISHIHARA)

An ascites tumor developed spontaneously in a B-strain mouse in thecourse of an inbreeding experiment in our laboratory. Transplantation
experiments of this tumor to many mice of the original B-strain and also
to animals of other strains were performed by using the usual transplantation technique for ascites tumors, but without success. The transplanted cells in all cases began to degenerate soon after transplantation. Vari0us tumor tissues were also inserted under the epidermis of the host by
the usual technique for solid tumor, but the transplantation was never17

successful.
Autopsy revealed considerable hypertrophic change in the spleen, liverand lymphatic gland, but the kidneys had remained nearly intact. A
tumor-like mass had developed in the dorsal part of the peritoneal cavity.
The abdorminal cavity of the tumor-bearing animal was swollen by theaccumulation of the hemorrhagic asctites.
Histological observations of various organs:
Liver: It was observed that lymphoid cells, lymphocytes and neutrophilleucocytes had infiltrated into Glisson's sheath, but none of them wasfound in the hepatic lobes.
Spleen: Remarkable infiltration of lymphoid cells was observed.
Kidney: In the Malpighian bodies many lymphoid cells were observed,
especially in the Bowman's capsules or around these tissues.
Tumor-like mass in the dorsal region of the peritoneal cavity: The
component cells looked very similar to lymphoid cells. There were many
mitotic figures. Based on these observations, this tumor was assumed torepresent a type of lymphatic leukemia, although any definitive conclusion
is premature as yet.
Cytological observation: The ascites of the tumor-bearing animal was
examined by using the acetic orcein smear technique. Many cells which
had the character of lymphoid cells were found. The cytological featuresof these cells are somewhat similar to those of the ascites tumor in mice.
Each cell contained one nucleus in many cases, more rarely two or three.
Many mitotic figures were found, so that a chromosomal survey was feasible. It is noticeable that although agglutination, coagulation, displacement and stickiness of the chromosomes were often observed, no cell witha regular metaphase figure was found. From the above karyological observations it is concluded that the non-transplantability of this tumor is probably due to the lack of regular mitotic cells which should constitute thestem line of the tumor and play a decisive role in its growth.

D. SILKWORM GENETICS AND BIOCHEMISTRY
1. Influence of the Incubation Temperature on the Development ofMultilunar and Multistar Markings of the Silkworm(Report by Yoshimaro TANAKA)

The eggs of a given strain of silkworm were divided into two groups
and incubated under different temperatures.
a) High temperature section: Eggs were incubated at 25°C for 11-14
days, from immediately after laying until they hatched.

18"b) Low temperature section: Eggs were kept at 15°C for 14 days, thenremoved to 25°C and kept for 4-5 days until the emergence of thecaterpillars.
The larvae were reared at ordinary room temperature from July toAugust, and the markings in the adult stage were observed. The results
are shown in Table 1.
Table 1. A List of Effects of Different Temperatures for
MuItiIunar and Multistar Spots
-

-.

-

.

Low temperature

High temperature•

Lot No.
Standard type

* I "Plus ::J'Minust, Standa~d I "Plus"*1 "Minus"~%

532 III L4-8
100.0
532 l 17 L 4.-8
98.0
532 l 21b L 4-10 100.0532 l 41 L 4-9
22.4
532 l62 L 5.8
94.1
533 l 11 L4-8
82.1
533 l 17 L 4-8
95.3
533 l 62 L 5.8
97.1
532ms12 ms 6-10
73.7
532ms32 ms 8.9.10 88.2
532ms82 ms8
100.0
532ms9 ms 0
100.0
533ms32 ms 8.9.10 81.2
100.0
533ms82 ms 8533ms9 ms 0
100.0

%

0
0
0
76.8
0
17.9
0
0
26.3
11.8
0
0
0
0
0

0
2.0
0
0.8
5.9
0
4.7
2.9
0
0
0
0
18.8
0
0

%

%

91.9
7.2
100.0
75.1
49.2
98.0
35.4
4.7
91.2
53.3
98.8
65.1
55.1
100.0
99.6

%

8.9
92.8
0
24.9
50.8
2.0
64.6
95.3
8.8
19.6
1.2
34.9
44.9
0
0.4

%

0
0
0
0
0
0
0
0
0
27.1
0
0
0
0
0

* "Standard" of each strain.

* Larvae with more numerous spots than the standard type.
~

Larvae with less numerous spots than the standard type.

It can be seen from the table that the high temperature reduces thenumber of spots, while the low temperature increases it, almost without
exception. In lot No. 532 1 41, for example, the standard type and the" minus" type form 22.4% and 76.8% respectively of the whole hightemperature group, while the "plus" type is only 0.8% in contrast to
75.1% standard type and 24.9% "plus" type but no "minus" type among
the low temperature group. In No. 532 1 17, similarly, nearly all thelarvae, 98%, reared at high temperature had the standard type markings,
while in the low temperature section the great majority (93%) of larvae
19were of "plus" type.
Exactly the same result has been obtained in the multistar lines. For
example, in No. 532 ms 9 the 0 type occupied 100% of the high temperature lot, while it appeared in only 65% of the larvae reared at low temperature, the rest (35%) being provided with one or two star spots on the
8th segment.

2. A Possible Sub-threshold Effect of Multistar Modifiers forthe Development of Multilunar Spots(Report by Yoshimaro TANAKA)

As the multistar is a recessive gene (ms), and the multilunar strains
usually have the diminant allele (+m.) for multistar, it is natural that
the F 1 between them develops no multistar spots. Nevertheless, I havefound a case which suggests that the modifiers of the ms gene may induce
the development of multilunar spots when ms is involved in the heterozygous
state, though no ms marking itself appears.
The L 5 •6 •8 strain is characterized by brown spots appearing usually on
the 5th, 6th and 8th segments. Rather exceptionally, the spots occur oneither the 4th or 7th segment or on both, but never on the 9th and 10th
segments.
In the F l , the variability of the number of multilunar spots increased
considerably, and the spots were often extended to the 9th segment. This
was not the case with the F l between the L 5 • 6 • 8 strain and the normal(+L+m.).

3. On the Intermediate Type Appearing in "Retarded" Strains(Report by Yoshimaro TANAKA)

In the dominant as well as the recessive "retarded" strains, and also
in their hybrids with normals, there often appear some "intermediate"types. These larvae are somewhat smaller than the normal ones, but arelarger than the retardeds, although the distinction is not always sharp.
They are also intermediate between both types in growth rate.
The results of experiments with these individuals have disclosed thatthe intermediate animals can be either undergrown normals or welldeveloped retardeds. One cannot tell which until he has accomplished theprogeny test of these animals. Another tool for making this distinctionis the linkage relation between the retarded and the larval marking or
blood-color genes in the second linkage group, because the retarded is20•

assumed to be due to a chromosome aberration in the second chromosome.
Thus it may be concluded that the cause of appearance of the intermediate type is mainly environmental. It is, however, premature to
exclude a genic cause in this case, because there is a tendency for thefrequency of the intermediate type among the offspring of intermediate
parents to be higher than that among the offspring of other types. The
existence of some modifiers influencing the growth of the silkworm seems
to be plausible.

•

4. Studies on the Action of the Gene Causing Malformationin the Silkworm(Report by Mitsuo TSUJITA and Bungo SAKAGUCHI)•

The malformation in a mutant strain om appears on the dorsal andventral sides of several segments ranging from the 5th segment anteriorly
and posteriorly. Its characteristics were described in the Annual Report
No. 1.
The previous report dealt with the effects. upon the penetrance of thismalformation gene of environmental conditions, especially temperature of
15°-25°C. and dilute hydrochloric acid in an early developmental stage.
It has been shown that the rate of appearance of the cripped larvae canbe changed within a wide range from 0 to 100%.
The experiments were performed as follows: Eggs were kept at 25°C.
for 10-15 hours, incubated at 15°C for 7 days, and then kept in a cold
room at 5°C, for 60 days. After this refrigeration, they were subjected
to treatment by dilute hydrochloric acid. The larvae hatched from theseeggs were examined and the degree of penetrance of the gene was. estimated. The results obtained are shown in the followin2 table.
It is clear from the table that the most sensitive period of the malformation gene to environmental factors, especially temperature or stimulation
by hydrochloric acid, is of very short duration, from 10 to 15 hours after
oviposition. This sensitive period exactly corresponds to the early stagesof embryo formation, i.e. the time during which cleavage nuclei migrate
under the egg shell and form an epithelial layer, and some of them start
to invaginate to prepare for blastoderm formation.
In order to make clear the mechanism of the appearance of the malformation in this period, we have undertaken biochemical studies of the early
developmental stages of the mutant embryos of the period from 5 to 100
hours after oviposition. As the first step of the experiment the activity
of cytochrome oxidase was examined.
Method: 10-15 hours after oviposition, each batch of the normal and21

Table 1. The rate of appearance of crippled larvae after treatmentof the eggs with low temperature (15°C)

~
M. R.

E~

20-25 hours

25-30 hours

1-3~ MR N M 1-3
00
MR N M ~ MR
MR N M ....

N M

Lots treatedwith low temp. 350
Control

15-20 hours

10-15 hours

£

eo

£

£

0456 25481 5.2 256 198 454 43.6 284 278 562 49.5

0350

258 286 544 52.6 256 286 542 52.8 251 265 516 51. 4 258 297 555 53.5

N: Numbers of normal larvae, m: Crippled larvae. MR: Ratio of.
crippled larvae.
T.O.: Time spent at 25°C after oviposition
E.L.: Experimental lots

mutant strains was halved, and one half was incubated at 25°C and theother at 15°C. The activity of cytochrome oxidase was measured after
5, 10, 15, 20, 40, 60, 80 and 100 hours. For this measurement 0.5 gr. of
eggs was taken from each lot at the fixed time mentioned above, an isotonic solution of sucrose weighing three times as much as the eggs wasadded, and the whole was ground in a homogenizer. The homogenizedsolution was used as enzyme solution. Cytochrome C which was used as
substrate was obtained from an extract of the heart muscle of cattle.
The cytochrome oxidase was measured by a WARBURG manometer.

...
m

8

25°C c~= o.rom
15 C - - 0 - -

° {__

+

•

2

0510

20

40

60

80

100

(time after oviposition (hrs))
Fig. 1. Cytochrome oxidase activity in the eggs ofnormal and mutant strains.

Results: The experiment was repeated four times, and each time about
the same result was obtained. In the lot of the mutant strain incubated22

t

at 25°C, the activity of the enzyme increased rapidly for 10-20 hours
after oviposition; later the rate decreased. In the normal strain, however,no rapid change in enzyme activity was found during the same period,
and the increase was uniform and gradual (Fig. 1).
Both strains arrived at nearly the same rate of 02-uptake about 100
hours after oviposition.
In the lot incubated at 15°C, the enzyme activity was weaker than in
the lot incubated at 25°C, in both the normal and mutant strains. As in
Fig. I, the activity in the normal strain showed a linearly rising curve,
but in the mutant strain the increase was rather irregular during 30 to
40 hours after oviposition. No striking change as found in the hightemperature lot occurred, and the curve of increase resembled that of thenormal strain.
It is clear from these findings, that the sensitive period of the malformation gene coincides with the .time when the activity of the respiratory
enzyme shows abrupt changes under high temperature. It is also shownthat this change is less pronounced at the lower temperature. It is morethan probable that these two phenomena, the sensitivity of the malformation gene and the abrupt change in the activity of the respiratory
enzyme, are causally connected. Based on this finding we are now planning further studies along this line.

5. Genetical and Biochemical studies on yellow lethal larvae (II)(Report by Bungo SAKAGUCHI and Mitsuo TSUJITA).

In a previous report (Annual Report No.3, 1953), the maternal inheritance of a yellow lethal strain in the silkworm was described. Biochemical
studies of the lethal yellow larvae with special regard to pterin pigment
were continued. Our special interest was in the direct cause of the larval
death which was apparently due to imperfect differentiation of the mandibular cuticle and incomplete hardening of the cuticle layer of thehypodermis.
Biochemical experiments with the normal and the mutant strains carriedout in 1953 yielded the following results:Pterin: It was confirmed by Nawa et al. that the so-called leucoptrin-B
was identical with isoxanthopterin. This pterin is contained in the epidermal
tissue of normal silkworm larvae. The nature of the so-called xanthopterinB remains obscure. We are now studying its chemical structure. The
estimation of the amounts of xanthopterin-B in normal (+), lemon (lem) ,lethal yellow (lem l ) , and white-egg lethal yellow (lem!; WI) was reported
in the Annual Report No.3.
23

Amino acids: In order to detect various kinds of bound and free aminoacids, and to determine their relative amounts in normal and lethal yellow
larvae immediately after the 1st moulting, extracts of the two aminoacids obtained from the hypodermal tissue of the larvae were examinedby paper chromatography following AWAPARA's procedure (1948).
These amino acids were· analyzed by means of two-dimentional
paper-chromatography. The developments of extracts on the filter paper
were saturated with solvents of phenol (0.1% NH 40H, + 15%) butanol
acetic acid (n-butanol 4: acetic acid 1: water 1), lutidine-coIIidine (lutidine
1: collidine 1) and pyridine. The positions of the amino acids developed
were determined by spraying 2% ninhydrin.
. Nearly twenty kinds of amino acids were detected in the epidermal
tissue of both + and leml strains. Remarkable differences were foundfor several amino acids shown in Table 1.

•

Table 1. Differences in amino acids 'extracted from epidermal
tissue of normal and lethal yellow larvae.
Types of amino acids=::::~.

Amino acids

Phenylalanine
Tyrosine
SerineCystineHistidineFree amino acids

Bound amino acids

Strain

+

1eml

+

*
*
*+

±
±

±

1eml

-

+

-

-

+
+
+
-

*+
+
+
+

The table shows that the reaction of phenylalanine, tyrosine, serine,
cystine and histidine is weaker in the lethal lemon larvae than in thenormal larvae, and that the reaction of bound amino acid is weaker inthe latter than in the former.
Phenoloxidase activity: By using a WARBURG manometer, the phenoloxidase activity of the epidermal tissue in the larvae directly after the 1st
moulting of the strains, +, lem, lem l , and lem l ; Wl> was measured. A
homogenate of the tissue was prepared as the crude enzyme solution, andphenylalanine, tyrosine and dopa in 0.02 M. concentration were used as
substrate. No activity of phenylalanine oxidase was recognized in thehomogenates of any of the strains. No difference in the activity oftyrosinase could be found among the strains. The dopa oxidase activity
in both the normal and the lemon larvae was a little stronger than in thelethal lemon or white egg-lethal lemon larvae.

24

...

•

Relation of pterin to phenolase activity: In order to ascertain the parttaken by pterin in the phenolase activity, a homogenate prepared fromlarval epidermal tissue of the normal strain was used as a crude enzyme
solution. The solution was poured into the small flasks of the manometer
apparatus which contained in its side arms tyrosine or dopa and synthetic xanthopterin or isoxanthopterin solution. It was found from this invitro experiment that isoxanthopterin inhibited tyrosinase and dopa oxidase
activity, and that xanthopterin promoted the activity of both enzymes.
Uric acid: The uric acid contained in the larvae immediately after the
1st moulting of the strains +, lem\ lem l ; WI was measured by means of
indirect FOLIN-WU and HARDEN methods.
The results of the experiment are presented in Table 2.
Table 2. Amounts of uric acid in +, leml and leml ; WI strains.
Methods
Strains,...

Indirect Folin-Wu
mg/g dry matter

+

3.7

leml
leml ; WI

2.2
1.5

Hardenmg/g dry matter

5.3
3.0
2.3

The table shows that with both methods the relative amounts of uricacid have been found to be + >leml>leml ; WI'
Cytochrome oxdase: The cytochrome oxidase activity during the 1st
moulting in the + and lem l strains was measured according to the procedure described by SCHNEIDER and POTTER (1943). The oxidase activityof the normal strain was significantly higher than that of the yellew
lethal strain.
General consideration: It may be said from the experimental results
reported above that the action of the gene leml is directly related to theexcessive production of xanthopterin-B and that this abnormality has aneffect upon other metabolic activities such as melanin-uric acid- andtryptophan-metabolism, and also upon the respiratory enzyme activity.

6. On the Respiratory Enzymes and Several Other Enzymes
Concerned with the T. C. A. Cycle in the Mid-gut
Epithelium of the Silkworm (Bombyx mori L.)(Report by Bungo SAKAGUCHI and Mitsuo TSUJITA)
Th~ complex of enzymes implemental in the reactions of the citric acidcycle is called cyclophorase. It has been established that the respiratory

25

enzyme activity and cyclophorase activity are closely related to mitochondria.
Microscopic examination of cyclophorase has indicated that it is essentiallya suspension of intact mitochondria, and the enzyme activity has an
intimate relation to the structure of the mitochondria.
We have studied the relation of the respiratory enzymes to mitochondria,using Paramecium caudatum and the silkworm (Bombyx morl L.) as
material. As far as we know, few studies on the cyclophorase system ofthese materials have been carried out.
This present report deals with the respiratory enzymes and several
other enzymes belonging to the cyclophorase system found in the mid-gut
epithelia of silkworms.
The mid-gut epithelia of silkworm larvae (3rd to 4th day after 5th
instar) were ground in 0.25 M sucrose solution in a Waring Blendor,
and this suspension was used as the enzyme solution. SCHNEIDER-RoTTER'S
method was applied for detection of cytochrome oxidase and succinic
dehydrogenase, and GREEN'S method was applied for the detection of
enzymes belonging to the cyclophorase complex. Sodium succinate orcytochrome C was added to the enzyme solution as substrate, and theactivities of cytochrome oxidase and succinic dehydrogenase were measured
by the amounts of oxygen uptake (mm 3 ) for 1 ml of homogenate per hour.
The results of the experiment are shown in Table 1.
Table 1.
Substrate .
Sodium succinate
Cytochrome C

Concentration Oxygen uptake mm 3of substrate crude enzyme solution
mm3

74.6
120.9

5/100 M
1/1000 M

In another experiment the reducing power of succinic dehydrogenase
was measured in TUNBERG tubules by using methylenblue (M/15,000) as
indicator. The presence of this enzyme was substantiated by the factthat the reducing power of the homogenate was stronger than that of thecontrol, and its activity was suppressed by malic acid (M/30). The activity
of cytochrome oxidase was suppressed by KCN (M/lOO).
The results of an experiment designed for detecting the enzymes concerned with the TCA cycle, and the effect of ATP upon them are shownin Table 2.
As shown in Table 2, five enzymes of the TCA cycle were detected in
the homogenate, and the activity of these enzymes was strongly activatedby ATP.
From the results of these experiments, the following conclusion may be

26•

Table 2.
Substrate•

Pyruvate+
ATP
Citrate+ATP
Oxaloacetate+
ATP
Succinate+ATP
cc-Ketoglutalate+
ATP

Oxygen consumption (mm 3)(homogenate/ml/hour)

Concentration
(Mol)

7.6

2/100

44.0
2.8
9.3
39.5
89.0
39.5
89.0
27.8
49.0

2/100
2/100
2/100
2/100

deduced: The cellular respiration in the mid-gut epithelium of silkworm
larvae is probably carried out according to WARBURG-KEILIN'S system and
KREBS' cycle. The fact that ATP, added to the homogenate of the midgut epithelium, increases the activities of several enzymes belonging to
the TCA cycle supports this view. Furthermore, it seems that the complex
of enzymes is closely related to mitochondria which are contained inabundance in the two kinds of cells, cylindrical and goblet, occurring in
the mid-gut epithelium.

7. Pterin Obtained from the Silkworm (Bombyx mori L.)•..

(Report by Saburo NAWA)

We previously isolated a pteridine from eggs and larval epidermis of
the normal strain of silkworm, and tentatively named it leucopterin-B.
We have subsequently succeeded in obtaining this compound in a crystalline
form. The following data provide evidence for the identity of leucopterin-B
with isoxanthopterin (2-amino-4, 7-dihydroxypteridine).
Leucopterin-B has no characteristic melting point and decomposes attemperatures above 300°C. It is soluble in alkali, but almost insoluble inneutral or acidic media and common organic solvents. The presence ofthe pterin may be detected even in an extremely dilute aqueous solution
on account of the strong fluorescence; an aqueous solution of leucopterin-B
produces a strong purple fluorescence. The UV spectra of leucopterin-B
and isoxanthopterin in 0.1 N NaOH are superimposable.
Leucopterin-B:

max (mp.)log 6

min (mp.)

log 6

255
340

(4.07)(4.16)

290(3.45)

27

Isoxanthopterin:(4.09)
290(3.48)(4.19)
Anal. Calcd. for C6H~02N5: C, 40.22; H, 2.80; N, 39.11
C, 40.77; H, 2.96; N, 39.24
Found.
The various synthetic 7-hydroxypterins are closely related to one anotherin many respects (e.g., solubility, fluorescence, UV spectra), and paper
chromathography provides the simplest means for their characterization.
The compounds were submitted to several chemical reactions which at·tacked the side chain, only, and the Rf values of the respective compounds
before and after the reactions were measured. Thermal decomposition,oxidation by alkaline Mn02 or KMn04; reduction by aluminium amalgam
and esterification were used for characterization. No inconsistency between
leucopterin-B and isoxanthopterin could be observed with respect to thevarious reactions: the analytical data and UV spectra also agreed. The
inertness toward all of the reactions suggested the absence of a functionalgroup, and the lack of identity with compounds with simple alkyl side
chains was apparent from paper chromathography. These findings showthat leucopterin-B is identical with isoxanthopterin.
It seems that the yellow pigment contained in the larval epidermis of
the mutant "lem ", tentatively named xanthopterin-B, is a pteridine
derivative, but its chemical nature is still obscure.
We are endeavoring to clarify the chemical nature and physiologicalproperties of xanthopterin-B, and the relationship between the pterins andtryptophan metabolisms.

E.

255
340

POPULATION GENETICS OF SOME INSECTS
AND A LAND-SNAIL(Report by Taku KOMAI)

1.

The Lycaenid Butterfly Neozephyrus

As stated in the Annual Report No.3, the females of Neozephyrus iaxila
have four color and marking types which are due to triple-allelic genes.
This was shown by statistical analyses of thirteen samples from various
localities in Japan (Amer. Nat. 87: 87-95, 1953). The fourteenth sample
more recently obtained from Takatuki between Kyoto and Osaka also
conforms to this interpretation, as indicated below:Type
0
A
B
AB
Total
94
Number
11
2
73
8
100
%
11.70
2.13
77.66
8.51
p=0.055
q=0.628
r=0.340
O'D=0.023
D=-0.023
p+q+r=1.023
2pq=0.0691
28•

2. The Land-snail Bradybaena•

The study of population genetics of this polymorphic land-snail was
continued through the current year. The three genotypes AA (yellow
banded), AB (brown banded) and BB (brown unbanded) were comparedfor growth rate and power of resistance to low temperature. A statisticallysignificant difference has been found in the growth rate between the ABgroup and the AA or BB group, at least for the young stage reaching 4
mm in shell diameter. The double dominant AB group grow more rapidly
than either single dominant homozygotic group (AA or BB). In the powerof resistance to low temperature - 5.5°C, there is an apparent distinction
between the AB and AA groups on the one hand and the BB group on
the other.
The results of analyses of 97 samples from 81 localities conform wellto the interpretation of polymorphism which assumes triple-allelic genes.
On the basis of these findings, as well as of those by previous authors onother polymorphic animals the general mechanism of the formation andmaintenance of polymorphism has been investigated.

3. Drosophila rufa•

T. TAIRA is working on the dimorphism found in females of this species.
This dimorphism may be recognized in the banding of abdominal segments.
The "dark" type has banding similar to that in the male melanogaster,while the "light" type has banding like that in the female melanogaster;
the dark marking is completely dominant over the light. Populationgenetic studies are in progress on natural populations and laboratory
populations. So far it has been found that the heterozygote has someselective advantage in competitive mating over either the homozygote.

F.

GENETICS OF SOME CEREALS

1. Tetrasomic Gigas-plants in the Offspring of Nullisomic Dwarfs
and Analysis of their Additional Chromosome Pair
(Report by Seiji MATSUMURA)

Gigas-plants with 42 chromosomes (1IV+19u) are called a-g-gigas,
according to the orginal 7 different a-g-dwarfs having the sterile chromosome configuration 20 u . They could be called D-nulli- and AB-tetrasomics.
These combinations are to some extent compensating, owing to the factthat the additional chromosome of a gigas-plant is in every case semi-29homologous to the lacking D·chromosome of the given dwarf line.
SEARS' nullisomics I-XIV, deficient in a chromosome pair of the A or
the B·genome, have been used in crosses with my a-g·gigas, in an attempt
to find out the chromosomes to which the additional chromsomes of the
AB·tetrasomic gigas-plants correspbnd. From the results of crossing
between Nulli-VII and a-g·gigas, it has been assumed that the additional
chromosome in the a·gigas is the same as SEARS' VII, which belongs to. the A-genome according to LARSON and hence can be called aA. Accord·
ing to SEARS' analysis, my a·dwarf corresPQnds to his Nulli·XXI, and thechromosome XXI is semi-homologous to VII. Thus, SEARS' finding that
VII and XXI are semi·homologous has been confirmed by my results.
As to the additional chromosomes in the a· and I·gigas, the disagreements
between SEARS and myself await further investigation.

2. Chromosome Aberrations in Einkorn Wheat Induced by X-rays(Report by Seiji MATSUMURA)
In order to study the relation between the frequency of chromosome
aberrations and the quality of X·rays, dormant seeds of Triticum mono·
coccum were exposed to X-rays of different wave lengths, at the same
dose (8,100 r, 95 r/min.). For the sake of comparison, the thickness of thefilter was adjusted in inverse proportion to the wave length; that is, at
80 KVP no filter was inserted into MATSUDA'S Type KXC-17 apparatus(tube type STO-200-3), while at 130 KVP a filter of 0.3Cu+0.5AI, and at
180 KVP one of 0.8Cu + 1.5AI was used. At 50 KVP, irradiation wasapplied by another apparatus, a Modified Type KR-75 (tube type XDW-10)
with 0.5AI filter. The data are shown in Table 1. The results obtained
Table 1. Relation between wave length of X-rays and frequencyof chromosome aberrations in T. monococcum (Dosage
8,100 r 95 r/min.) (1953)
Voltage

Filter(KVP)
Control
50
80
130
180

No. of No. of ears with aberrations
observed
6n+ 21 @+5n
®+4n*
ears

I

-

24

0.5AI

46
47
61
116

-

0.3Cu+0.5AI
0.8Cu+l.5AI

-

-

1
5

'" Counted as two aberrations.
30

I

4
1
2
3

No. ofaberrations(%)-

o (0.00)-

4 (8.70)
3 (6.38)
3 (4.92)
8 (6.89)

1
-

..
..

last year could not be confirmed.
investigation.

3.

This unexpected outcome awaits further

Measurement of Xray Dosage for Inducing Mutations(Report by Hideo ETO, Seiji MATSUMURA and Taro FUJII),The question to be answered was, whether irradiation was even in all
points of the field of exposure in our MATSUDA'S Type KXC-17 apparatus(200 KVP, 3 rnA) with the tube Type STO-200-3. The dosages were
measured at a distance of 15 em at many points by MATSUDA'S dosimeteror "r "-meter. The data are shown in Fig. 1, where the dosage in thecenter is arbitarily designated as 100 and is larger on the cathode sidethan on the anode side. Thus, it has been found advisable to place theexposed material on a rotating table, at a relatively short distances fromthe tube focus. Also, the data of measurements at different distances showthat the dosage is exactly inversely proportional to the square of the distance.
The dosage was also measured of another apparatus for Grenz-rays
with the tube Type TX-20 (20 KVP, 10 rnA) by a Siemens' Universal
Dosimeter. It was 140 r/min. at a distance of 23 em. Therefore, thesmall Grenz-ray apparatus should be very useful.

Fig. 1. Distribution of X-ray
doses in tube STO-200-3.
Distance 15 cm,
A: anode, C: cathode.

•4.

Inter-racial Differences Found in the Variety of Barley" Hosogara No.2"(Report by Kanji GOTOH)

This experiment was designed to obtain answers to the following questions. First, to what extent has the differentiation between races of thesame variety in crop plants, which have been grown in widely separated
localities for a long time, progressed under the influence of the distinct
environmental conditions? Second, how great is the difference between
the original population of a variety and the geographical races derived
from it? Third, to what extent has natural selection taken part in the
racial differentiation?
A barley variety "Hosogara No.2" was used for a preliminary series
31

of experiments. This variety was derived from the variety "Hosogara"
more than 30 years ago, and it is known that it includes some distinct
genotypes, such as, "Wechseltyp" and the "pure winter habit type".
Seven population samples were obtained from various localities in Japan,
ranging from Kitami, Hokkaido (44 ON) to Kurashiki, Chugoku district(34°N).
Progeny of these local samples grown in Mishima under the same
conditions were compared with one another. The progeny of local samples
from the southern localities have more tillers than those from the northern
localities. The average ear length of the progeny of southern samples was
greater and the density of spike was lower than those of northern samples,
and the differences were statistically significant. The difference in yieldamong these local samples was also significant, and the southern samples
showed the general tendency of having smaller but more numerous grains
per plant than the northern samples. Of the plants developed from seeds
s0'Yn in our experimental field on February 28 and on March 30, all of
the three southern races produced ears, while very few or none of thenorthern races did. These data show that there is an inter-racial differencein the photoperiodic response. Futhermore, it was found that this variety
had higher competitive ability than the three tester varieties, but theinter-racial difference in this character was not significant, so far as shownby this experiment. Finally, it has been found that the Hs gene, which
controls the development of hair on leaf sheath, is distributed in thenorthern races, and the s gene, which controls the appearance of shortbasal bristles, is distributed mainly in the northern races though in low
frequency. Further work is in progress to elucidate the mechanism ofdifferentiation of these races, as well as of some other varieties.

G.

CYTOLOGY AND GENETICS OF Nicotiana
1.

Cytogenetical Problems in Nicotiana(Report by F. A. LILrENFELD)a. A new amphidiploid.
F 1 hybrid between N. paniculata and N. plumbaginifolia exhibited at
MI mostly 01l+22 r or (1-2)n+(20-18)r. Sometimes single trivalents occurred. In early MI the univalents were concentrated at the poles. Spindle
often curved or tripolar. All pollen empty, unreduced giant grains very
rare. The amphidiploid-two plants-in general habitus very similar toF 1 hybrid, scarcely more vigorous. Flowers larger, also stomata, not much
but significantly, larger. Meiosis was examined in one of the two plants.
MI showed regular pairing, except for occasional 1-2 univalents. One

32

•

•

,

•

large bivalent was usually found off the equatorial plate. Its division was
delayed. Furthermore, a small fragment could be detected in almost all
PMC's.
The amphidiploid was on both sides fertile. Pollen fertility, evidently
highly dependent upon the supply of nourishment, extremely variable,from 0 to 36% (of healthy looking pollen grains). Seed setting likewise
variable, best results obtained with the plumbaginifolia parent as pollinator.
b. Continued investigation of synthesized N. tabacum.
The amphidiploid of the hybrid N. sylvestris x tomentosiformis wascrossed with Dixie Bright (as mother), a commercial variety. As previously
reported, F 1 showed pronounced hybrid vigor and was very healthy throughout the whole vegetation period. Pollen fertility on the average reaching-up to that of Dixie Bright, but female fertility much lower. Most of
the 29 plants taken at random from a larger F 1 had 15-19% of the seedfertility of Dixie Bright (grown side by side), the whole range extending
from 7 to 29%.
c. Octoploids of synthesized N. tabacum.
In contrast to the normal appearance of octoploids of normal N. tabacum,
this octoploid made a highly abnormal impression with its thick, deformed
leaves. From 25 plans exhibiting such a habitus, 12 flowered very latein autumn. Five were more closely examined. Three of them were true
octoploids, one had an octoploid subepidermal layer under a tetraploid
epidermis, and in the remaining one the situation was just the other way,i.e. a tetraploid subepidermal layer and an octoploid epidermis. No seeds
were obtained, probably as a result of unfavorable conditions (low temperatures) at the time of seed setting.

2. Cytogenetic Studies on the Genus Nicotiana. V.
(Report by YO T AKENAKA)

a. Reduction divisions in hybrids between N. tabacum and three otherspecies.
The three species, N. trigonophylla, N. undulata and N. rustica werecrossed reciprocally with N. tabacum. The crosses N. tabacum x N.
trigonophylla, N. undulata x N. tabacum and N. tabacum (Odaruma) x N.
rustica (Afghanistan) gave some seeds, while no seeds were obtained fromthe three remaining crosses. No report on the hybrids N. tabacum x N.
trigonophylla and N. undulata x N. tabacum or their reciprocal crosses
has been published, so far as I know.
In external characters· the F 1 tabacum-trigonophylla is somewhat smaller
than N. tabacum, the leaf form is intermediate between those in the33parents, and the flower colour is a pale red. F 1 undulata-tabacum ismore similar to N. tabacum than to N. undulata, but its flowers are paleyellowish red, showing an intermediate color between the two parents.
The morphology of F 1 tabacum-rustica agrees with that of KOSTOFF'S
description of the reciprocal hybrid (N. rustica x N. tabacum). These
three hybrids were all vigorous.
All the hybrids mentioned above showed considerable irregularities in
the meiotic behaviour of the PMC's. Polysporous PMC's were often observed, and the hybrids were completely sterile.
At first metaphase in F 1 tabacum-trigonophylla, 0-11 bivalents, mostly
5-6, were counted. In F 1 trigonophylla-tomentosa and F 1 trigonophyllatomentosiformis, KOSTOFF (1941-43) observed 2-10 and 0-8 bivalents,
respectively. Accordingly, the chromosome conjugation in F 1 tabacumtrigonophylla is assumed to be caused mostly by semihomologous chromosomes between the trigonophylla genome and the tomentosa subgenome,
not the sylvestris subgenome, of N. tabacum. In F 1 undulata-tabacum,
0-8 bivalents, mostly 3-5, were observed. In F 1 tabacum-rustica, 1-10
bivalents (also multivalents) were formed at the first metaphase and many
secondary associations were observed at first and second metaphases.
CHRISTOFF (1928) and TRENOVSKY (1935) also observed a small number ofbivalents in F 1 rustica-tabacum, while KOSTOFF (1941-43) found manybivalents, as many as 5-24, in the same hybrid. The cause of these different results was not determined.
b. Reduction divisions in the hybrids between the N. tomentosa groupand three other species.
The three species, N. glauca, N. sylvestris and N. paniculata, werecrossed each with N. tomentosiformis or N. otophora as follows; N. glauca
x N. otophora, N. sylvestris x N. otophora, N. sylvestris x N. tomentosiformis, N. paniculata x N. otophora and N. tomentosiformis x N. paniculata.
Among the above five crosses, N. glauca x N. otophora, N. sylvestris x N.
tomentosiformis and N. paniculata x N. otophora produced some germinating seeds.
The hybrids N. glaucaxN. otophora and N. paniculataxN. otophora,
to my knowledge, have never been reported. The hybrid N. sylvestris x
N. tomentosiformis was studied by KOSTOFF (1938), GREENLEAF (1938) and
CLAUSEN (1941). Among the hybrids closely related to it, N. sylvestrisx N. tomentosa was studied by GOODSPEED and CLAUSEN (1928) and KOSTOFF(1930), and N. sylvestrisxN. Setchellii by CLAUSEN (1941).
The leaf form of F 1 glauca-otophora resembles that of N. glauca but
is not as shiny as that of N. glauca. The flower form is somewhat
campanulate zygomorphic, showing a resemblance to N. otophora. The
flower colour is yellowish green.
34

•

•

•

The external characters of F 1 sylvestris-tomentosiformis agree with thedescription of many previous investigators. The F 1 paniculata-otophora
is intermediate between the two parents regarding size and shape. The
flower shape is somewhat campanulate zygomorphic, resembling N.
otophora, but the flower colour is of a greenish yellow similar to N.
paniculata.
The reduction divisions in the PMC's of the above three hybrids arevery irregular, and the PMC's are frequently polysporous. Accordingly,
no seed was yielded.
At the first metaphase of F 1 glauca-otophora, 1-9 bivalents, mostly 4-5,
were observed. Trivalents were rarely observed; still more rarely multivalents. At prophase, until diakinesis, remarkable heteropycnotic bodies
were seen in the nucleus, usually one, and rarely two.
At meiosis of F 1 sylvestris-tomentosiformis, 0-7 bivalents occurred withthe mode at 4. These chromosome configurations generally agree with thefindings of KOSTOFF (1941-43) and GOODSPEED (1934).
At the first metaphase of F 1 paniculata-otophora, 3-10 bivalents wereobserved. GOODSPEED (1934) observed 0-4 bivalents in F 1 paniculatatabacum, while KOSTOFF found 2-12 bivalents in the same hybrid.. From
the author's investigations of F 1 paniculata·otophora and KOSTOFF'S studies
on F 1 paniculata-tabacum, the paniculala genome is believed to conjugate
mostly with the tomentosa genome rather than with the sylvestris genome.
c. Reduction divisions in hybrids between N. Sanderae and three othersJleCies.
N. longiflora (n=lO), N. plumbaginifolia (n=lO), N. repanda (n=24)
and N. suaveolens (n= 16) were <;fossed with N. Sanderae as the pollinator.
The crosses N. longifloraxN. Sanderae, N. plumbaginifoliaxN. Sanderae
and N. suaveolensxN. Sanderae gave some seeds.
In external characters, the F 1 longiflora-Sanderae and F 1 piumbaginifoliaSanderae are intermediate between the respective parents but the flower
colors are red, resembling the fathers. F 1 longiflora-Sanderae was examinedby CHRISTOFF (1928) and ISAKOVICH (unpublished, after KOSTOFF 1941-43),
but F 1 plumbaginifolia-Sanderae has never been reported, so far as I know.
The morphology of F 1 suaveolens-Sanderae agrees with that of KOSTOFF'S
description of the same hybrid.
At diakinesis in the PMC's of F 1 longiflora-Sanderae, the chromosome
conjugations 9n +1 I, 1m +8n and 1m +7 n +2 I were most frequent. At thefirst metaphase the chromosome conjugation 9n+1I was mostly observed,
followed by the conjugations 1m+7n+1I, 1m+8n and 8n+3;, in the citedorder. The chromosome conjugations agree with ISAKOVICH'S findings in thesame hybrid (after KOSTOFF 1941-43). The meiotic chromosome behaviourof F 1 plumbaginifolia-Sanderae is the same as in F 1 longiflora-Sanderae.
35

According to the observations on the meiosis in the F 1 hybrids longijloraSanderae and plumbaginifolia-Sanderae, it is assumed that there are somehomologous or semihomologous chromosomes between the sanderae genome
on one hand and the longijlora or plumbaginifolia genome on the other.
At the first metaphase of F i suaveolens-Sanderae, 1-7 bivalents, mostly 3-4,
were found. KOSTOFF (1941-43) observed 0-4 bivalents in the same hybrid.
The cause of the difference between the author's and KOSTOFF'S observations has not been studied.

3. Genetical Studies on the Mid-rib Proportion and the Leaf-shapein Tobacco Plants.
(Report by Kan-Iehi SAKAI and Shin-ya IYAMA)•In the Annual Report No. 3 for 1952, we have reported the result of
our experiment dealing with the genetic analysis of the mid-rib proportionand the leaf-shape in tabacco hybrids in the F 2 and two backcrosspopulations.
In order to pursue further studies on the same problem, 47 kinds of F sprogeny together with their parental varieties were examined for thesecharacters in a randomized block experiment with four replications.
One of the two parental varieties, White Stem Orinoco, is very high inthe mid-rib proportion and has slender leaves, while the other, the Holmes
variety, is the lowest in this proportion and has rather round leaves.
The mean values as well as the second degree statistics were comput,edin the plant populations for these two characters; the results obtained arepresented in Table 1.

•

Table 1. Mean values and estimated variances of mid-rib proportion andleaf-shape in Pi (White Stem Orinoco) and P 2 (Holmes), estimated variances of F s prog~ny means (Vi's), estimated covariances between F 2 individuals and their F s progeny means (WF2fFs) and means of estimated variances
within F s progenies (VFs)'
Mid-rib proportion
Mean
(%)

White Stem Orinoco
Holmes

35.46
23.85

Vi's
WF2/FS
VFs

-

-

i

I

I

Leaf-shape index

Second degree
statistics

Mean

4,17013.06076.81345.90068.5042

35.97
57.61

36

-

I

Second degree
statistics

5.942312.7269
50.9189
51.9089
38.5153•

According to Mather's principles, the variance component due to additiveeffects of genes (D), that due to their non-additive effects (H), and that
due to the non-genetic effects of the environment for individual plants(EI ) and for progeny means (E2 ) were partitioned. The estimated valuesof such components of variance are presented in Table 2.
Table 2. Estimated values of D, H, E I and E 2 for the mid-rib·
proportion and leaf-shape in tobacc9 plants in the
1963 experiment.

Mid-rib proportion
Leaf-shapeDH

8.036690.9467

18.481361.48843.90039.34281.36672.2280From these estimated values, the heritability of the character in the F 2
and Fa populations as well as that of the progeny means in the Fa generation and the number of effective factors for the two characters werecomputed (Table 3). The three heritability values were obtained from

~D
2
'
VF 2

~D
·~D
4
V _ - and 2 _ ,respectively. The number of effective factors
V Fa
Fa bulk

was computed as K,I =(p -15.)2
I

4D 2

(V )2

and K,2 = ~
V; _
..
VFa

•

Table 3. Heritability values and number of effective factors forthe mid-rib proportion and the leaf-shape in tobacco plants.
Number of effective
factors

Heritability in,
Mid-rib
proportion
Leaf-shape

K2

Fa progeny

KI

0.407

0.690

4.19

4.77

0.784

0.893

1.29

1.86

F 2 bulk

Fa bulk

0.320
0.672

I

I

Correlation between mid-rib proportion and leaf-shape in the Fa progenies
has been found to be
r=-O.724
which is highly significant at the 1 per cent. level.
It is concluded from this experiment that the number of effective factors
for the mid-rib p.roportion is four or five, and that for the leaf-shape is
one or two. These results are in good agreement with those obtained in
37

1953.
For the purpose of breeding tobacco strains with low mid-rib proportion,
direct selection of individuals among F z populations with respect to thatcharacter seems to bring about little success on account of the low heritability found. It· is suggested that the breeder should make line selection
among the Fa progenies or plant selection within the F z or Fa bulk, by
taking leaf-shape into consideration with the aid of an appropriate selection index, because the leaf-"shape shows a rather high negative correlation
with the mid-rib proportion and has a high heritability.
The appropriate selection index, I, constructed from the present data isshown below:I=X I -0.352Xz ,where Xl and X z stand for the mid-rib proportion and the leaf-shape index,(width of the leaf/length of the mid-rib) x 100, respectively.

4. .Z\I1utations in Tobacco Induced by X-rays(Report by Seiji MATSUMURA and Taro FUJII)

Dormant seeds of Nicotiana tabacum (Dixie Bright 101) were exposed tohard X-rays at 180 KVP, 3 rnA, without filter. The dosage was 15,000,
30,000 and 50,000 Y. At the highest dosage, the germination rate of theseeds was reduced. Table 1 shows the relation between the frequency ofchromosome aberrations in the PMC's and the X-ray dosage.
Table 1. Relation between X-ray dosage and frequency of chromosome
aberrations in Dixie Bright 101
No. of NorFrequency
No. of plants with aberrationsof transDosage observ.mal
edlocation
2411
plantsIlv+ 2211 121V + 2011 13IV+1811 12311+21 \ 2411+fr. per PMC

-

11

11

-

-

15,00030,00050,000

66
52
25

52
38
10

12
18
8

1
5
2

2

-

.-

1
1
1

-

.-

I

2

I

0.00
0.21
0.54
0.72

The frequency of chromosome aberrations especially translocations per
PMC increased in proportion to the dosage. Identical chromosome aberrations were observed in two or three inflorescences of the same plant.
Many Xz-plants of both varieties, Bright Yellow and Dixie Bright 101
38fwere examined. Various kinds of morphological abnormalities were detectedamong them. Several Xa- and X4-pedigrees were bred, and several kindsof mutants, such as early, small round, narrow, dwarf, shrivelled, variegated, mottled, yellowish green, yellow petiole, etc. appeared by segregation.
The "early" mutant flowered about 2 weeks earlier and was a little
smaller than the normal plants. But its leaves seemed to be of goodquality and its early flowering may be of great advantage in tobacco
breeding.

•

H.

GENETICS, CYTOLOGY AND BIOCHEMISTRY OF
SOME PHANEROGAMS
1. Sex Relations in Arlificz"ally Produced Tetrap/aids ofMelandrium album(Report by YO TAKENAKA)

Seeds and young plants of Melandrium album were treated withcolchicine in the spring of 1950. The most favorable concentration andduration of treatment for inducing polyploidy were found to be 0.02% and48 hours, respectively. Of the 56 treated plants which attained maturity,
27 were tetraploid, including 12 females and 15 males. These polyploids
were used in crossing experiments carried out in 1951-1953. The results
obtained are as follows:
Crossing experiment I.

tParents
4x.sf. x 4x~'Parents
4x.sf. x 2x~Offspring
11.sf. and 76~ plants
Crossing experiment II.
Offspring
12.sf. and 10~ plants

The chromosome complement of M. album is 22a+2X in the female and
22a+X+ Y in the male. Accordingly, the tetraploid males and females
mentioned above must have 44a+2X+2Y and 44a+4X constitutions
respectively. This chromosome constitution in the male was confirmed
cytologically.
Under neither the wild nor the cultured condition has any noticeable
numerical difference between male and female plants been observed. The
author has found 56 females and 54 males among the 110 plants cultivatedin 1951, and 41 females and 46 males among the 87 plants which matured
in 1952.
These ratios are approximately to 1: 1. However, Crossing Experiment39

I yielded 11 females and 79 males among 90 plants, while Crossing Experiment II resulted in 12 females and 10 males, approximately a 1: 1
ratio, among the 22 plants. There must be some special cause for theconsiderable discrepancy from the 1: 1 ratio found in Experiment I.
WARMKE and BLAKESLEE (1939) suggested from the results of their observations in M. dioicum that XY pollen grains represent 90% or evenmore of all the pollen grains produced by the male tetraploid plants of
the 44a+2X+2Y constitution. T.ONO (1939) reported that the proportionof XY pollen grains could reach as high as 91% in the colchicine-induced
tetraploid males of M. album.
Of the 101 PMC's observed by the author, 86 had the chromosome
conjugation type producing XY at both poles; 9 were of the XX- (or YY-)
type, and 6 belonged to various other modification types. These figures
are in very good agreement with those found by W ARMKE and BLAKESLEE,and ONO.
According to these observations, the above Crossing Experiment I
should give about 90% plants of 44a+3X+ Y type, 5% of 44a+4X type'and 5% of 44a+2X+2Y type, while Crossing Experiment II should produce
females of 33a+3X type and males of 33a+2X+ Y type in equal numbers.
The results of chromo.some counts on the root tips of 32 male plants(including two male intersexes) among the 79 offspring of Crossing Experiment I were as follows:
Chromosome
Number ·of
Chromosome
complement
plantsnumber4x+l
45a+3X+Y3
45a+2X+2Y
1
4x
44a+3X+Y
21
45a+2X+Y1
44a+2X+2Y
1
4x-l
43a+3X+Y2
44a+2X+ Y
1
4x-2
42a+3X+ Y
1
3x+4
35a+3X+2Y
1
The above chromosome survey reveals that 27 males arose from fertilization by XY pollen and 3 by YY pollen; and that in the remaining two
males, pollen grains of other chromosome constitutions participated in
fertilization. These results are in good agreement with the expectation,and sustain the findings by Westergaard in M. album and by W ARMKE
and BLAKESLEE in M. dioicum.
The 11 females obtained in this experiment had the chromosome complement 44a+4X. The number of female plants surpasses the expected
figure, and the XX pollen may be assumed to 'have an advantage over the
XY- and YY-pollen at fertilization.
40

f

..

In the third experiment, a female tetraploid with 44a+4X was crossedwith a tetraploid male with 44a+3X+ Y, and the following result was
obtained:Crossing Experiment III.
Parents
Offspring
4x~ x 4x~26~ and 21~ plants
The sex ratio in the offspring of this cross is nearly 1: 1. The tetraploidmale, 44a+3X+ Y, should produce XX and XY pollen in equal numbers
and a sexual of 1: 1 ratio should be expected in the absence of certation.
The results obtained by these experiments may be summarized asfollows:1) The Y chromosome has a strong male-determining potency and 2)
stable and normal tetraploid dioecious plants can be produced.

2.

Ring Formation in the Meiosis of AlHum Scorodoprasum
var. viviparum(Report by YO TAKENAKA)

The somatic chromosome number has been determined as sixteen by
many investigators, e.g. KATAYAMA (1928), MORINAGA and FUKUSHIMA (1931),
T AKENAKA (1931), Y. ONO (1935) and KURITA (1951). In a previous paper
the present author hinted at the possible hybrid origin of this species
from his observations of rings at meiosis and two chromosomes of strikingly different shape and size represented singly in the somatic chromosome
complement. According to KURITA, the two somatic chromosome setsshould be identical in both size and shape. The author tried to elucidate
this discrepancy by a study of meiosis in this plant.
The 16 chromosomes may be classified into 7 types designated by the
first 7 letters of alphabet. The somatic chromosome complement has beenfound to consist of 4a and 4b, 2c, 2d and 2e, plus one f and one g. The
g-chromosome has a strikingly large satellite on its short arm.
In diakinesis of the PMC's, a large chromosome ring consisting of 6
chromosomes usuaIly appears, besides 5 bivalents of which two frequently
show a secondary association or formation of a quadrivalent. At MI, one
large chromosome ring and 5 bivalents are usuaIly found. The ringconsists of 6 chromosomes, which do not show a zig-zag arrangement of
the Oenothera-type. Therefore, disjunction at AI does not separate theparticipating members of the two sets as in Oenothera. All the division
figures foIlowing AI show a somewhat irregular behaviour, but the youngpollen grains are not abortive. Nevertheless, no seeds are obtained, since
the plant is predominantly vivip~rous. Small bulbils are formed from41

most of the young flower buds, and only exceptionally a few open flowers
are to be seen.
From the above results the author assumes that the plant is a hybrid
originated from a natural or artificial cross between two related species
whose chromosome complements have become differentiated by translocations, inversions or deficiencies in the course of evolution.

3. Inheritance of Flower Color of F1 Hybridsin the Swiss Giant Pansy(Report by Toru ENDO)

In a previous report, paper-chromatographic analyses of the pigment
constituents in the petals of ten varieties of pansy, and the inter-relationships between them were briefly described. The present report deals withthe analysis of the genetical behaviours of the pigment components foundin nine F 1 hybrids, which were produced by the crossing of Pure White(as the pollen parent) with the remaining nine varieties.
The results show that the flower color of F 1 hybrids of the two maternalvarieties, Coronation Gold and Giant Orange, was pale yellow, and thiscoloration was brought about by a smaller quantity of the same threekinds of xanthophylls as those occurring in the maternal plant, Coronation
Gold. However, the two carotenes detectable in the maternal Giant Orange
have vanished completely in the F 1 hybrids.
In the F 1 hybrids from the red-flowering pansies, Raspberry Rose,Fire
Beacon and Alpenglow, segregation has been observed to a certain extent,
probably owing to insufficient fixation of the parent strains. The flower
colors of the hybrids were generally pale reddish-purple or purplish, andthe pigments were localized in the posterior petals or in the marginal
portion of all petals. The F 1 hybrids from Lake of Thun also underwent
slight segregation, and the pigments were completely or incompletely
eliminated from the area outside of the smaller blotches. The F 1 hybridsof Berna segregated into three types: Berna, Lake of Thun, and rarely
the Mont Blanc type. The hybrid of the Berna type is different in patternfrom the parent Berna in that the blotched area is smaller and the adjacentportion is purplish white.
The F 1 hybrids derived from Mont Blanc, which is orginally of the
blotched type, have developed the so-called felix or eat's whisker, composedof many stripes in the blotched parts. In F 1 hybrids of Coronation Goldand Lake of Thun, all petals were pale yellow and the blotched parts
were small. However, in some of them a bluish pigmentation appeared in
the marginal portion·of the petals.
42•

4. Analysis of Coronal Anthocyanins in Various Strains of
the Japanese Morning Glory (Pharbitis Nil).
(Report by Yukihide ABE)•

Aiming at the elucidation of the genetical behavior of anthocyanins in
the Japanese morning glory, in which the genes controlling the flower
color variation have been analysed in detail by T. HAGIWARA and others,
I have recently carried out some basic experiments concerning the analysisof anthocyanin-constituents in flower petals of thirty strains and of their
F 1 hybrids, by the paper-chromatographic method. In these studies theoriginal spots were marked on chromatographic paper with 1% methanolichydrochloric acid extracts of fresh petals, and various solvent-mixtures
were used for irrigation. The results obtained are briefly summarized in
the following lines.
1) Throughout all the plant materials employed, some 16. different
kinds of anthocyanin-spots were detected, which could be classified into
three main groups with regard to the glycoside types:(A) Free (or acylated) glycoside group, in which are included:
Pelargonidin} glycosidePelargonin
Peonidin(two kinds)
PeoninCyanin(8) Complex glycoside group, rather intimately combined with some
unknown substances (X, X', or X"):
Pelargonin+X+ X + X'
Peonin+X"(C) Co-pigmented glycoside group (co-pigments more or less loosely
combined with the substances):
Pelargonin
Peonin+ co-pigment
Cyanin2) The anthocyanins appearing in the corollas of different flowers,
which were used for analysis at their full blooming stages, are shown in
the following table.
In all the strains belonging to the broken-colored group, the total
anthocyanin content was usually smaller than in the pure-colored group.
The anthocyanins occurring in the parts of the petal that have undergone
a striking change from purple to red in an otherwise purple corolla, andfrom blue to purple in a blue corolla, and also from red to purple in a
red corolla, have been found to belong to the same pigment system asthat found in the basal part of the ground color.
3) Analysis of anthocyanins occurring in F 1 hybrids have given the

I

I

43

Anthocyanin-system
Flower Colors

Aglycones

Type of
Glycoside~:~argon~in_l~e~~idin I Cyanidin--- - - I f - - - --- ----3)----~-(a) Broken blue (+"'U
2)+PT)-broken purple A,AB,BC,C(+mu pr) group(b) Pure blue (+mu+PT)":'" pure purple AB,ABC,AC,BC(+mupr) group(c) Broken
magenta(mg+PT)-broken red A,AB,B,BC(mgpr) group(d) Pure magenta (mg+PT)-pure red (mg AB,ABC,BCpr) gro~p

10

~
10

l

o
l

2

±

l

6

4

1

o

l

3

±
l

3

l
o
o
l

±

1) 'Genotype proposed by T. HAGIWARA; 2) AB represents the anthocyanin of both (A)-type and (B)-type as major pigment constituents, etc. 3)
Relative amount (in 10 parts) of anthocyanins in the petals; 4) Wild typeis pure blue (P8Cy2BC).

following results:
Blue (+mU +PT, P2)8Cy2 BCl) x Purple (+mu pr, P5Cy5 ABC) F 1 Blue (P9Cy1 BC)Blue (+mu+PT, PSCy2 BC)xRed (mgpr, P18p 2 AB) Blue (P8Cy2 BC)
Red (mgpr, Pl8P 2 BC) x Purple (+mu, P5Cy5 ABC) Purple (P6Cy4 ABC)Blue (+mU+PT, P8Cy2 BC)xWhite (+mUpr+oac+ T) Blue (P7Cy3 BC)
Red (mgpr, Pl8P 2 AB)xWhite (mgpr+o",+or) Red (P19P1 BC)
White (+mum+o"'c+T)xRed (mgpr, Pl8P 2 AB) Purple (P7Cy3 ABC)White (mgpr+o",+or) x White (mgpr,+"''''c + T) Light red (P19P1 AB)
1) Glycoside type. 2) Pl-pelargonidin, P-peonidin, Cy-cyanidin.

4) From these paper-chromatographic analysis, it may be surmised thatthroughout the whole pigmentation stage of petals, the relative amount ofpeonidin to pelargonidin remains unchanged in every strain of the broken
and pure magenta-red group, but that the proportion between the cyanidinand peonidin-content varies to a remarkable extent, as has been observedin some strains of the broken and pure blue-purple group, where pelargonidin
was never found. With regard to the glycoside type, the AB-type appearedin place of the original A-type, and the total anthocyanin content (about
2 times in maximal amount) showed a rapid increase during the 24 hrs.
up to full blooming, accompanied also by the production of (C)-type
anthocyanins. A decrement of the (A)-type anthocyanins takes place
during the same period. In the strains in which such pigment increment
could not be observed, the total anthocyanin content was usually small,

44

•

•.

and the glycoside type in the corolla was either A or AB.
Moreover, it may be pointed out that a bluish tinge caused by +PT is
by no means due to the combination of different anthocyanins, and that+mg or mg controls the number of OH-groups in the side benzene nucleus.
Methylation or demethylation seems to be effected by other factors.

5. Inheritance of D()Ubleness in Zinnia elegans L.
(Roport by Kanji GOTOR)..

I

It is well known that in Zinnia elegans the frequency of flower heads
exhibiting doubleness in a population rapidly decreases in a few years,
when seeds are taken continuously under an open-pollinated condition.
The object of the present study was to investigate this degenerating processfrom the genetic standpoint. In 1950, a reciprocal cross was carried out
in the variety Pumila scarlet between the completely double, No. 4-5, andthe completely single, No. 4-1. The F 1 hybrids between the completely
double (B type) and the completely single (A type) showed the so-called
E type described previously (Annual Report of this series, No.2). No
difference was observed between the reciprocal F 1 hybrids. The 208 F 2
plants were grown in 1951 and were classified according to their flower
types into ten classes. It has been confirmed by observation of theseplants that the difference between the completely single (A) and completely
double (B) types was ,governed by three Mendelian genes. Thus, the B
type might be recovered in the F 2 population in the ratio, 1: 64. This
type yields only a few seeds. The A type, as well as the subtypes similar
to it, shows a much higher fecundity than the B type or its subtypes,
because they have many tubular florets. Thus, if the pollination by insects
is carried out at random,. a general degeneration of an open-pollinatedZinnia population will inevitably ensue. .

6. Karyotaxonomic Studies in Poaceae 1.
(Report by Tuguo TATEOKA)

Various investigators have made cytological studies concerning both themorphology and behavior of the chromosomes in various grass species in
Europe and the United States, while only a few works along such lines
have been done on Japanese materials. The prsent author' is studying thesomatic chromosomes of Japanese grasses and endeavoring to elucidate
their taxonomic relationships from the karyological standpoint. In 1953,45

the somatic chromosomes of the following species of Poaceae were observed:
Somatic chromosome
numberSpeciesPleioblastus chino
Sasa purpurascens
Sasa sp.
Hordeum murinum
BrachYPodium sylvaticum var. luzoniense
Elymus sibiricus
Bromus japonicus
Calamagrostis Langsdorffii
C. hakonensis
C. arundinacea var. brachytricha
Agrostis flaccida
Phleum pratense
Alopecurus japonicus
Beckmannia syzigachne
Helictotrichon Hideoi
Trisetum sPicatum
Koeleria cristata

48
48

48
28
18

28
14

28
28,56
42,56
56
42
28
14
14

28
14+1 supernumerarychromosome
14+2 supernumerarychromosomes

28
28
20
70
56
42
28
48
28
42
28
28
ca. 77
28
28
28
70
56

Deschampsia flexuosa
Milium effusum
Anthoxanthum odoratum
A. jaPonicum
Hierochloe alPina
H. odorata
Phalaris arundinacea
Leersia oryzoides
Dactylis glomerata
Festuca rubra var. pacifica
F. parvigluma
F. japonica
Poa Komarovii var. shinanoana
P. annuaP. acroleuca
P. nipponica
P. Matsumurae
P. pratensis
Briza minor

10

46

,

B. matima
14
Melica nutans
18
M. Onoei
18
Glyceria acutijlora
20
G. ischyroneura40
G. lithuanica
20
G. alnasteretum
20
Torreyochloa viridis
21
Moliniopsz"s japonz"ca50
Hakonechloa macra, 50
Phragmz"tes japonz"ca48
Eragrostz"s ferruginea
80
Cynodon Dactylon
40
Arundinella hirta
56
Echinochloa Crus-galli
54
Panz"cum bisulcatum
54
Setaria viridis
18
S. autumnalis
36
Isachne globosa
60
Imperata cylindrz"ca var. Koenigii
20
Miscanthus sinensis
40
Microstegium japonicum
20
Arthraxon hisPidus
36
Bothridchloa parvijlora
40
Ischaemum anthephoroides
72
Coix Lacryma-Jobi
20
From observations· of the somatic chromosomes of the species listed
above, some taxonomic information was obtained for the following groups:
the tribe Chlorideae; the genera Torreyochloa, Poa, Milium, Calamagrostis,
Beckmannia. Bromus and Briza.

1.

GENETICS AND CYTOLOGY OF SOME LOWER
ORGANISMS

1. Studies on the Methionine-requiring Strain of Ustilago maydis(Report by Tetsuo IINO)

a. Reversion of methionine-requirement by two-step mutations.
The inferior reversion type (IR), originating from the methionine-requiring strain (mel) 4-24 of U. maydis, is characterized by its restricted
growth in media lacking in methionine, but it sometimes happens that47

successive subcultures recover a normal growth rate and change into thestable prototrophic type (IR') (Annual Report No.3, 1952). In order tothrow some light upon the genetic background of this phenomenon, thechange of the growth type was thoroughly investigated, and the genetic
segregation carefully analyzed.
Each stock of fourteen IR-clones, which had been screened out from aminimal plate culture of strain 4-24, was subcultured (at 30°C) in several
series of test tubes containing 1 ml of liquid media which was renewed
every 72 hours. For all the series and generations, a part of each subculture was sampled and the change in growth type of the cells wasobserved on plate cultures.
In 93% of the series examined, IR' -cells appeared in one to six subcultures, and being at a selective advantage, they increased rapidly in proportion to the IR-cells, and eventually the whole culture changed into theIR' -type. During this process, the mixed culture of IR- and IR' -cells did
not contain any cells of the intermediate type between IR and IR', andthe single-cell cultures isolated from the mixed culture produced only pureIR- or IR'-clones.
The analysis of genetic segregation was carried out with chlamydospores
which had been produced by the conjugation of IR or IR' with the wild
strain (+)5 or isoleucine-requiring strain (ih)5-91. The chlamydospores
were obtained by injecting the desired combination of cultures into ayoung pop-corn plant in a greenhouse. They were sown on complete agar
media and each segregant was isolated by micromanipulation. The
nutritional requirement was examined by means of auxanography.
Eleven out of the fifteen chlamydospores derived from (IR x + ) segregated
IR and + in a 2: 2 ratio, and the remaining four produced + alone. All
fourteen chlamydospores derived from (IR' x +) produced + alone, since
IR' is phenotypically indistinguishable from +. The chlamydospores
derived from (IRxill) segregated IR and ill in one case, and IR·il l and +in six cases; in every case two IR or ih segregants were found among
the four. Finally, four out of the five spores derived from (IR' X ill)
segregated + and ih in a 2: 2 ratio, while one spore produced IR· ill besides+ and ih.
These data of the segregations lead us to assume that mel and IR, as
well as IR and IR', differ from each other in one gene, and that the genes
controlling the mel and IR characters are closely linked, or else are allelictogether. The production of + alone from all the four chlamydospores
derived from (IR x +) may be explained as due to mutation of IR to IR'
during the course of the crossing experiment. Further investigation isneeded to decide whether the segregation of IR ·ih from IR' x ih is due toa suppressor mutation of IR to IR' or it is a back mutation of IR' to IR.
From the observations of the successive clone cultures and from the48

,segregation analysis, it is assumed that the methionine-requiring strain
4-24 changes to the IR-type by a mutation of the mel-locus or of anotherlocus closely linked to it, with the IR-type mutates in turn to the IR/-type:thus the dispensability for supplemented methionine has been recoveredby a two-step mutation.
b. Methionine-requiring and sulfonamide-resistant characters.
The concurrence of sulfonamide-resistance with methionine-requirement
has b.een observed on the m -1 step mutants in some bacteria such as
Escherichia coli (KOHN and HARRIS, 1942) and Salmonella enteritides(FUJINO and others, 1950). This phenomenon has been regarded as anevidence of the fact that para-aminobenzoic acid (PABA), an antagonistof sulfonamide, takes part in the m-1 reaction.
From the data examining the response to nutrients of the methioninerequiring strain 4-24 of U. maydis, it is assumed that the m-1 step isblocked. This strain shows a distinct response to methionine, but responds
neither to cysteine, homocysteine, choline, PABA nor to any combination ofthese (IINO, 1952). This strain and the wild strain 5 were cultured in several
series of synthetic methionine-glucose media (MG-media) and minimal
media, both containing 0 to 2 X 10- 2 mol of sulfanilamide (SA). The growth
rates of these strains were compared by counting the number of viablesporidia in the cultures. No significant difference such as that found inbacteria was observed between these strains in either set of cultures.
Inhibition of the growth appeared at the cone. of 10- 4 mol, and came tothe maximum at 2 x 10- 3 mol. The inhibition was not of a fungicidal butof a fungistatic nature in the range under 2 x 10- 2 mol and 120 hours.
A SA-resistant mutant M5008 has been screened out from the wild
strain 5 which had been grown on MG-media containing 2 x 10- 3 mol of
SA. The strain M5008 showed resistance against SA which was twenty
times greater than that of the original strain. Although the requirementof this strain for methionine was tested, no experiment gave a positive
result, showing that this strain has no methionine-requirement.
The most effective antagonist against SA-inhibition is PABA in all thestrains mentioned above. Adenine and hypoxanthine show less effective
antagonisms against SA. Methionine has, however, no antagonistic effectwhen supplemented alone.

2. Electron-microscoPical Studies on the Structure of Paramecium
caudatum by Means of Ultra-thin Sections(Report by Mitsuo TSUJITA, Kyozo WATANABE and Seizo TSUDA)

Cytological and genetical studies of Paramecium aurelia have been
carried out by many authors, notably by CHEN ('40), PREER ('50) and49

SONNEBORN ('49-'50). Few studies, however, have been made on Parame-dum caudatum.
The present report deals with the results of an electron-microscopical
study of the fine inner structures of Paramecium caudatum carried out
by us by means of ultra-thin sections.
A strain of Paramecium caudatum was used as material. The protozoa
were kept in the nutritional liquid in test tubes in a constant-temperatureroom regulated at 25°C.
The animals to be fixed were gathered by utilizing their galvanotaxis.
Several fixatives were used: neutral osmic acid, Champy's fluid, Flemming's fluid without acetic acid, Carnoy's solution and 95% alcohol. Of
these neutral osmic acid gave the most favorable results for ultra-thinsectioning. The fixed materials were dehydrated by passing them throughthe alcohol series (50%, 70%, 80%, 90% and absolute),. and then imbedded
in n-buthyl methacrylate catalyzed by 2% benzoyl peroxide. The materials
in this plastic substance were cut into thin sections of about 0.1 p. thickness with a Spencer's ultra-microtome. The sections were examined bymeans of a J. E. M. III type electron microscope at 50 K,V.
The results of observations of these ultra-thin sections may be summarized as follows:The cilia cover all the pellicle as well as a part of the inner surface ofthe gullet. A kinetosome is present at the base of each cilium. Some of
the kinetosomes of the pellicle are attached to two cilia (fig. 1). Eachcilium shows a fibrillar structure which is apparently similar to that of amyofibril.
The macronucleus (vegetative nucleus) is filled with granular or filamentous bodies, mixed with granules of smaller sizes. These granules areoften found in abundance in the peripheral region of the nucleus, and they
seem to migrate into the cytoplasm through the nuclear membrane.
The micronucleus (sexual nucleus) is filled with small granular or filamentous bodies, but large granules like those observed in the macronucleus
are not found.
A great number of mitochondria-like granules, spherical, ellipsoidal or
filamentous in shape, are scattered in the cytoplasm. The ectoplasm
immediately beneath the pellicle has a fibrous structure, in which filamentous granules run almost parallel.
The examinations of the longitudinal and horizontal sections of the
granules, reveal that the periphery of the granule appears to be of dense
structure, into which the electron rays do not penetrate. The inner
structure of the granule seems to consist of fine particles. But this inner
structure of the granule requires further study.
In the living material, the endoplasm granules stain with Janus green
B, but not with neutral red. The majority of them show a positive NADI'S
50

reaction, turning bluish, which indicates that they belong to the cytochromeoxidase and cytochrome complex. Furthermore, the granules isolated by
the ultracentrifuge show their similarity to the respiratory enzymes.
In the sections of the material fixed with Champy's fluid or Flemming's
fluid without acetic acid, the granules turn reddish purple or reddish by
Altman's or Altman-Kull's test, and they stain bluish black or black withiron haematoxylin. The granules are dissolved in Carnoy's solution or
95% alcohol.
From the observations described above, it may be safely said that these
granules represent a kind of cell organ which is comparable to themitochondria in the cells of higher organisms.
Minute particles scattered in the cytoplasm between the mitochondrial
granules seem to represent the so-called microsomes.
Two types of food vacuoles can be discriminated under the electron
microscope. One has vesicles with food substance surrounded by a protoplasmic layer which contains short thread-like bodies. These seem to bedisintegrated mitochondria which participate in the secretion of digetive
enzymes. The other type of food vacuole contains many granules, sphericalor ellipsoidal. These granules do not dissolve in Carnoy's solution, andthey can easily be distinguished from the mitochondrial granules in thecytoplasm.

3.

Formation of Tobacco Mosaic Virus in Plastids(Report by Mitsuo TSUJITA and Seizo TSUDA)

This work was carried out in collaboration with J. HIDAKA and H. MURANO
in Hatano Tobacco Experiment Station, Japan Monopoly Corporation.
Since KAUSCHE and RUSKA (1940) assumed the formation of tobacco
mosaic virus in green plastids, and published an electron micrographshowing filamentous particles protruding from a chloroplast fragment, theidea that chloroplasts are the site of virus formation has been supported
by some investigators. Recently LEYON (1953) examined leaves infectedwith beet yellows virus with an electron microscope, and he observed thecharacteristic filamentous particles. As these filamentous particles were
found in association with chloroplasts, LEYON thought that the former had
been extruded from the latter. He also carried out investigations of theleaves infected with the virus and came to the view that at least someviruses are formed within the chloroplasts.
We have examined the relation between the virus development andchloroplasts with the help of ultra -thin sections, and the following results
were obtained.
Material and method: Normal young healthy tobacco leaves, and leaves
51

Fig. 1. Chloroplasts in normal condition.
Fig. 2. Chloroplasts in leaves 5 days after infection. Leaves 10 days after infection.
Fig. 3. Masses of filamentous bodies can be seen here and there in the cytoplasm.
The masses containing filamentous substances show hexagonal shape.
Fig. 4. Leaves 10 days after infection. A great amount of filamentous substances
can be seen in the cytoplasm.

52

..

,

5 and 10 days after infection were used as materials. As fixing fluid, neutral
osmic acid of various concentrations was tried. This fixative, however,preserved the cells very poorly, especially the cytoplasm. Next LEYON'S
fixation method was followed:-The material was fixed in 0.5% osmium
tetraoxide at pH 7.0 for 1 hr., washed in running water for 2 hrs, treatedwith 0.5% formaldehyde for 1/2 hr, washed in running water for 1 hr,then treated with 0.3% chromic acid for 1 hr and washed.
This fixation procedure gave fairly good results. Therefore, healthyand diseased leaves were fixed according to this procedure, and the changes
in the chloroplasts were examined.
The fixation procedure in the healthy and diseased leaves was followed
by dehydrating and embedding. The specimens' were embedded in n-butyl
methacrylate. The material in methacrylic resin was cut with a knife
made by the Japan Microtome Institute. The sections were treated withamyl acetate to dissolve the methacrylate.
Results: Chloroplasts in normal conditions are shown in Fig. 1. They
have no membrane, and contain grana and stroma. Chloroplasts in leaves
5 days after infection are shown in Fig. 2. The chloroplasts have undergone some changes, with a small quantity of filamentous material present
within them. However, we have not ascertained the relation which thesefilamentous bodies might have similar bodies, shown in Fig. 3.
In leaves 10 days after infection a great amount of the filamentous
material is found. Some of these bodies are scattered in the cytoplasm,
and they look as if they were protruding from the chloroplasts. Massesof filamentous bodies are also seen here and there (Fig. 3). The masses,
which are bundles of filamentous bodies, show a hexagonal shape in crosssection. These masses seem to be derived from the infected chloroplasts.
In another section a great number of filamentous bodies were present
in the cytoplasm (Fig. 4). Whether these represented artificially disentangled bundles of filamentous bodies or natural disintegration remains
obscure.
As already reported by several authors, the production of filamentous
substance in infected cells was recognized also in our preparations. However, it was rather interesting that conspicuous masses of filamentous
substance were found in the infected cells.
Since I WANOWSKI (1903) first described intrac~llular amorphous andcrystalline inclusions particularly in the epidermal cells of tobacco plants
infected with mosaic virus, they have been made the object of investigations by many authors. Recently, STEERE and WILLIAMS (1953) studied the
crystalline inclusions occurring in hair cells of Turkish tobacco and foundthese crystals to consist 'apparently of nothing else than particles of tobacco
mosaic virus and volatile solvent. It is interesting that the shape of thedissected masses of filamentous substance is almost hexagonal, suggesting53

that they are crystalline bodies.

4. Electron·microscopic studies of a bacterial virus attacking
Pseudomonas solanacearum E. F. Smith(Report by Mitsuo TSUJITA and Chiaki MATSUI)A strain of bacterial virus infecting Pseudomonas solanacearum E. F.
SMITH B19 was purified by differential centrifugation at 26,000 g for 60
min, 59,000 g for 60 min. and 20,000 g for 120 min. The electron-microscopeobservation of this virus showed that it is a spherical particle approximately
70-80,um in diameter. The virus particle shows a rather rough surface,and apparently has some internal structure.
The host bacterial cell infected with the virus is filled with very small
protoplasmic particles, as well as some new virus particles. It was further
observed that the membrane of the infected bacterial cells had ruptured
after a latent period, and liberated the proliferating new virus particles.

J.
1.

IMPROVEMENT OF SOME USEFUL PLANTS

Improvement oj Sugar Beets by means of Induced Triploidy(Report by Seiji MATSUMURA)

The results of the experimental work carried out during 1940-'52 byseveral collaborators were published in a book, written in Japanese withan English summary. The contents are as follows:
I. History of our studies on triploid sugar beets (1940-'52); by S. MATSU:MURA.
II. Induction of triploid sugar beets and their characteristics; by S.
MATSUMURA and A. MOCHIZUKI.
III. Genetic and cytological studies on the genus Beta. V. Productionof triploid seeds; by A. MOCHIZUKI.
IV. Studies in polyploid varieties of sugar beets; by S. NAGAO and M.
TAKAHASHI.
V. Physiological characteristics of early developmental stages of diplo·
and tetraploid sugar beets in water culture; by S. HOSOKAWA, I. •SAWAI and M. SHICHIJI.
VI. Results of experiments with polyploid sugar beets; by S. HOSOKAWA,
J. NAKAJIMA, K. KATO and T. TAKEDA.
VII. Results of various experiments with triploid sugar beets; by Agri·cultural Department, Nippon Beet·Sugar Manufacturing Company.
54

VIII. Improvement work with sugar beets by means of triploidy. A
concluding review; by S. MATSUMURA.
Since the weather was unusually unfavorable, especially in the summerof this year, the results of experiments performed were somewhat divergent.
Some of the American resistant varieties showed the best results and next
to them our triploid variety, 3n-l, a combination of No. 4398 (398-4x) x 162(2x). This combination was compared with the original diploid hybrid
No. 398 x 162 in only one experimental field. There was no significant
difference between the two. Further investigation must be awaited. By
comparison of several other triploid varieties, 2 new triploid combinations
seem promising.

2. Further Investigations Regarding the Degree of Heritability
and the Number of Effective Factors in the EggPlant(Report by Kanji GaTOR)"

Adequate estimation of heritability of quantitative and aggregatecharacters is important for effective selection. In the present study theheritability of three characters in the eggplant was estimated by meansof the parent-offspring regressions in the F 2 and Fa generations. It wasalso attempted under the same design to resolve the variation into its
components, and to estimate the number of effective factors governing the
given traits by the procedure proposed by MATHER (1949).
Two crosses out of five previously examined, namely, Florida high bushx Sendai-naga No.1 and Turuboso-sen-narixTaiwan-naga were chosen as
materials. The degrees of heritability for the period from seeding toflowering, fruit shape index, and fruit weight were 65--78, 60--75, and40-60% respectively. The heritability for the fruit shape index and fruit
weight estimated by parent-offspring regression was relatively low, as
compared with the heritability in the broad sense, where the variances of
F 1 were used for the estimation of the environmental variances. From
this finding it has been concluded that the F 1 variances used as environmental variances of the segregating generations give too large or too.
small values, according to the traits.
The marked differences between the F 2 variances of both crosses may
be interpreted as due to the effects of individual genes governing such
traits. This assumption has been verified by the comparison of frequency
distribution in the F 2 , and its appropriateness has been shown by examination of the relationship between the effects of genes and the degree ofheritability.
The estimated number of effective factors is generally low, but it has
been found that the factors having plus or minus effects are probably
55

concentrated in one of the parent varieties.
Various segregants or recombinants were observed in the Fa of thecross, Florida high bush x Sendai-naga No. I, and the range of thesegregation reached almost the whole range of variation occurring in thecultivated varieties of this plant found in Japan. It may be expected inpractical breeding to obtain many new variants from such cross combinations.

3. Studies on polyembryony in CUrus(Report by Kazuo FURUSATO)

Observations on the number of nucellar embryos per seed were carriedout. After fertilization, formation of embryos from the nucellar cells
begins in the neighborhood of the embryosac. It seems that fertilizationis necessary for nucellar embryogenesis, since in fruits developed byhormone treatment no seeds are formed. Fertilization in Citrus requires
a longer time than in many other phanerogams, taking 2-8 days to accomplish. The zygote remains dormant for about one month, and thenbegins to develop. Nucellar embryogenesis starts either shortly before orafter the beginning of development of the fertilized egg. Gradually more
and more nucellar embryos are formed. They do not develop simultaneously, and embryos in various growth stages may be found.
The number of embryos per seed varies according to species. In C.
Unshu x C. Natsudaidai the average number of embryos was found to
be 12.3, with a wide variation ranging from 1 to 29. In C. Unshu x C.
leiocarpa var. tumida the number averaged 14.3, and in C. Unshu x
Poncirus trifoliata 16.8. It remains to be investigated whether different
pollinators are responsible for these differences.
Sometimes monoembryonic seeds are found in usually polyembryonicseed species. It is difficult to decide whether these embryos are derived
from fertilized eggs, or are of nucellar origin. For this one must observe
the morphology of the seedlings.
The possibility of artificial control of the number of embryos in polyembryonic species is being examined. It has been found that water andgrowth hormones have a reducing effect on the number of embryos. In
the fruits of C. Unshu and C. Natsudaidai injected with water or MH-30
at an early stage, seeds containing decreased numbers of embryos, evento a single embryo, were found. The cause of this change is unknown.
It remains to be investigated whether the reduction in number of embryos
goes hand in hand with that of the nucellar embryos when the fruits aretreated with water or hormones.
.

56

..

,

K.

STUDIES ON COMPETITION

1. CompetiUve Ability of F 1 Hybrids in Barley(Report by Kan-Ichi SAKAI and Kanji GOTOR)..

Five inbred barley varieties and ten F1 hybrids were tested for theircompetitive ability by using two tester varieties. The competitive ability
was measured by the increments or decrements in dry plant weight,
number of culms and weight of heads in mixed plantings in relation to
the two testers, and by comparing them statistically with the results ob-,tained in pure stands concerning the same characters. Planting was madeindividually in rows 50 cm apart with 12 cm inter-hill spacing. Experiments
were conducted by the split-plot design with four replications.
F 1 plants in pure-stand plots generally showed a marked heterosis forvarious characters in comparison with the parental varieties in pure-standplots. Their heading was generally one to six days earlier than the cor·
responding average of their parents. The competitive ability of the F1
hybrids, however, was on the average inferior to that of their parents,and only in relatively few cases did the F1 hybrids surpass the parental
varieties in that ability. It was found also in this experiment that ingeneral the most vigorous hybrids had the lowest competitive ability, andthose with rather moderate heterotic vigor were best in competition.
It is therefore concluded from this experiment that the competitive abilityof plants of this species should be considered as a character quite independent from vigor.

'2.

"

Further Studies on Competition between Diploid andAutotetraploid Plants of Barley(Report by Kan-Ichi SAKAI and Yasuo SUZUKI)In 1953, diploid and autotetraploid races of seven varieties of barley
were examined for their competitive ability. The seeds of the races tobe examined and of the plants with which they had to compete were seeded in alternate hills in rows. The inter-hill spacing was 12 cm and the
distance between adjacent rows was 40 cm. The experimental plots werearranged according to the split-plot design with three replications. The
experiment involved, besides single and mixed plantings of diploid andautotetraploid races of each variety, mixed plantings of both races withthe diploid race of a standard tester, for the sake of comparison of thecompetitive ability between fourteen chromosome races. Data on an individual plant basis were taken for dry plant weight, number of culms,
and number and weight of heads.

57

Analysis of variance of the data suggested that the effect of competition, as well as the interaction between competition and chromosome race,
was highly significant for all the four characters. It was found throughout the experiment that the autotetraploid races were almost always inferior in their competitive ability to the diploid prototypes, and that the
autotetraploids derived from diploid races Df high competitive ability had
higher competitive ability, and those derived from diploid races of low
competitive ability had lower competitive ability.
It is interesting to find whether doubling of the chromosome number inpomozygous races of plants tends in general to decrease the competitive
ability of the plants, since this ability would surely play ~ certain role in
the evolution of plant species.

3. Competition Studies on Diploid and Autotetraploid
Plants of Rice
(Report by Kan-Ichi SAKAI and Yasuo SUZUKI)

The diploid and autotetraploid races of four varieties of rice plant,
Oryza sativa L., were examined for their competitive ability. Seedlingsof the races to be examined and of the races with which they had tocompete were planted in alternate hills in the row. The inter-hill spacing
was 12 cm and the distance between adjacent rows was 30 em. The experimental plots were arranged according to the split-plot design withfour replications. Data on an individual plant basis were taken for dry
plant weight, number of culms, weight and number of panicles, andweight of grains.
Analysis of variance of the data showed that the effect of competition
was highly significant for all the five characters. It was found that the
autotetraploid races in this species tended to be more or less inferior in
their competitive ability to the diploid prototypes.
It is found that the conclusion drawn from another experiment thatthe autotetraploid barley races were bad competitors against the diploid
prototypes also holds true for the present species.

4. Competitive Ability of Thirty Varieties of Upland Rice.
Against the So-called "Red Rice"(Report by Kan-Ichi SAKAI, Shinya IYAMA and Takeo MEGURO>le)As was reported in the Annual Report No.3 for 1952, the upland-rice>Ie
Head agronomist of the Laboratory of Upland Rice Breeding of the Ibaraki
Prefectural Agricultural Experiment Station.

58

..,

cultivation in Japan is often contaminated by the so-called "red rice".
This variety belongs to the subspecies Indica and is inferior to the ordinary rice both in quality of grain and in yield. It often gets into thefield and grows as a weed among the upland rice. It is likely that someupland rice varieties would suffer relatively less from this contamination
than others.
In 1953, we undertook an experiment to examine intervarietal differencesin competitive ability of varieties of upland-rice at the E~perimental Farmof the Agricultural Experiment Station in Isioka, Ibaraki Prefecture. This
report deals with the results of the experiment.
Seedlings of thirty varieties of upland rice were transplanted to the experimental farm plots both in pure-stand and in mixture with the seedlings of the "red rice". Plants were grown in a split-plot experimentwith three replications. Data were taken on plant height, plant weight,
number and weight of panicles as well as weight and number of grains,
each on an individual plant basis.
Analysis of variance of the data obtained showed, without exception,that the effect of competition was highly significant. It was found thatmost of the uplant rice varieties were bad competitors against the redrice, while a few, not more than five, were found to have higher than,or at least equal competitive ability to, the latter.

5. Competition and Spacing in One Dimension in Plants..

(Report by Kan-Ichi SAKAI and Yasuo SUZUKI)

Competition between two varieties of barley differing in competitive
ability was examined under various interplant spacings. Seedlings of thestronger variety (SZ) were individually space-plant~d in rows, either alone
in pure stand plots or alternating with plants of the weaker variety (SS)in mixed plots. The distance between the adjacent rows was fixed at 70
cm in order to avoid any influence from this factor. Spacing between
the adjacent plants in a row was made at 2, 4, 8, 16, 32 or 64 cm, according to the experimental plan. Plants were grown in a split-plot experiment with three replications. Measurements were made on dry plantweight, number of culms, and number and weight of heads on an individual plant basis.
Data obtained from this experiment were analysed statistically. It hasheen found that the effect of distance between plants within rows upon
the competition pressure operating between them is very marked: the increments due to competition in plant weight, number of culms, and in
number and weight of heads have been shown to be adversely proportionate to the logarithm of the logarithm of the distance between plants.
59

The relation has been found to fit well to the equations of a straight line
as follows:
Y1=113.4007-136.0274 Xi for number of culms,
Y 2 =109.3955-130.3571 X 2 for number of heads,
Y 3 =171.6113-215.2887 X 3 for weight of heads, andY 4 =248.2951-189.0116 X4 for plant weight.
The XI in the above formulas stands for loglO(log2 XI), where XI represents the distance between adjacent plants in the row.
It is conceivable from the result of the present experiment that as longas in~ividuals of a wi,ld species are few in number and scattered in a
spacious area, they will not suffer from any intraspecific competition.
However, when the population becomes fairly dense, the individuals will
inevitably have to compete with one another. Thus it is likely that whena plant species continues to propagate within a small range of habitats,and increase in density within a limited area, natural selection due to intraspecific competition will become quite effective.

L.

THEORETICAL STUDIES AND TECHNICAL NOTE

1. Theoretical Studies in the Breeding Technique of Autogamous
Crop Plants
a. Change in the Value of Heritability of Quantitative Charactersin Hybrid Bulks and Plant Progenies in Autogamous Plants(Report by Kan-Ichi SAKAI)In the breeding practice of agricultural crop plants, how to make successful selection with regard to any economic character is often one of themost important problems. This is because most economic characters show
extremely low heritability. This report deals with theoretical investigations
on the possible change in the value of the heritability of a given characterin hybrid bulks and in plant progenies of autogamous plants.
(A) Heritability in hybrid bulks.
If the phenotypes corresponding to the three genotypes, aa, Aa andAA from an Aa-hybrid are related as -dr<, h.. and dr<, respectively, themean phenotypic value of a given F n bulk will be2:-1

ha , since the threegenotypes in that population appear in a frequency of

6Q

21(1_~1_):
2
n- 1

2~-1: ~ (1- 2~-1)·

The contribution of gene A-a to the variance ofF", bulk must then bee"'2:~~I)da2+e:'~~I)ha2+El ,where E 1 stands for the non-heritable component of variation of single
individuals.
Provided that a number of polygenes besides A -a affect the samecharacter and the total heritable variation within the bulk is the simple
sum of the contributions made by the individual genes, the total variancebecomes2"'-1- 1)(2"'-1-1)
1 ,~F", (Bulk)= ( ~ D+
4"'-1

H+E

in which D=2:.dt2
t

and H

2:.ht 2 •t

The heritability of the character must then be,h(F", (Bulk)=

1_ _
1 )D
2"'-1

1)(1 +K),- - +E2(

D 1--2"'-1. 2"'-1

1

where K stands for HID. For a given value of heritability, h 2 , for theF 2 generation and a value of K, relative values of D and H are readily
computed from the following relation, taking the value of E 1 as unity,
4

D= 2
'
--2-K
h2
which is derivable from the relation,

l-D

..

2

2
1--2- D+"4 H +E1

h F2= 1

. (B) Heritability of means of F", plant-lines derived from selected
plants in F"'-l bulk population.
F", lines derived from F"'-l plants consist of either one of the following
three genotypes with respective frequencies and with respective meanvalues as follows:
Lines:

from Aa.
individuals

from AAindividuals

Frequencies:
Mean value of lines:

61

from aaindividuals

12"-1 h a •The whole mean of mean values of plant-lines is

Varianceof means of F" plant-lines is then1)d a + (2"-2-1)
4"-1 ha +E(1- 2"-222

2 ,where E 2 stands for the non-heritable components of variance of the meansof lines. The formula is again rewritten, as in the previous case, as:

The heritability of the mean values of a given character observed in
the F" lines will be

Table 1 shows an example of results of some computations in several
successive generations. The computation is made, as is seen in the table,
for h 2 F 2 =0.1, the K values being taken as 0, 1, and 10. Each plant line
is supposed to include twenty plants for measurement.
Table 1.

I Bulk I Line I Bulk I Line
0
0
0.22

K
H
D
E

0.1

F2
Fa
F,
F5
F6
F7
Fs
Fg
FlO
Fl l
F 12

0.1
0.14
0.16
0.17
0.18
0.18
0.18
0.18
0.18
0.18

Bulk

5
1.55
0.31

1
0.235
0.235
0.05

0.69
0.77
0.80
0.81
0.81
0.81
0.82
0.82
0.82
0.82

I 1
0.1
0.15
0.17
0.18
0.19
0.19
0.19
0.19
0.19
0.19

I Line I Bulk I Line

0.05 I
0.64
0.74
0.78
0.80
0.81
0.82
0.82
0.82
0.82
0.82

62

1
0.1
0.15
0.19
0.21
0.22
0.23
0.23
0.23
0.24
0.24

10
5
0.5
0.05
0.51
0.65
0.75
0.80
0.83
0.85
0.85
0.86
0.86
0.86

I 1
0.1
0.16
0.22
0.27
0.30
0.31
0.32
0.33
0.33
0.33

0.05
0.41
0.57
0.70
0.79
0.84
0.88
0.89
0.90
0.90
0.91

It is suggested from these computations that the most efficient method
for the successful breeding of superior genotypes with respect to any
character with heritability as low as 0.1 should make use of the Qulkmethod for several generations followed by selection for that character
among the greatest possible number of plant-lines.

b. Heritability and the Number of Individuals to be Selected(Report by Kan-Ichi SAKAI)The number of individuals or lines to be selected among a given population of individuals or lines of a segregating generation is a function of
the value of heritability of the character.
Let the phenotypic value of each individual or line in the F n generation
be Y, which would distribute normally with variance V. If we would
select any individuals or lines having Y greater than a fixed value y ' ,they will be those falling in the shaded area q in Fig. lA, having a meanvalue of Y s • If Y be transformed to a variate, u, with unit variance andmean at zero, that is u=(Y -y)/1/ V, then the value of u' = (Y' -Y)/1/V
corresponding to any given value of q may be ascertained from a tableof the normal probability integral.
The selection differential expressedin the standard deviation, i, then becomes•_ :VB-¥' _A~

Z

Z= 1/v =uB=q'
where z is the ordinate of the unit
normal curve at the deviate u' . The
expected genetic gain, .dG, in the next
F n + 1 generation will then be2.dG = h2 iVV. =h 1/ V ~
q ,

y.
u

-1

Y

IV y'

0

1

uI

I--T---.jB

in which h 2 is the corresponding_........
heritability of that character in the F nppopulation. Assuming that the valuesof the character of each F n + 1 line, P,
are normally distributed with a mean
Fig. 1value P and variance V', the proportion of progenies having P greater than Y', that is the shaded area Q in
Fig. lB, will be calculated as
63

1 (P_P)2dp= r~

Q= roov I e --2- lFV
h=y, 21rV'

_zt1

2

e
dt
Jt=t,V21r'
1, Y'-Y-h2VV~
in which t=V"t- and f= ~-: = - - VV,_~(L. If we assume
that V' = V in case of any character with low heritability, thent'=u' -h2~ .
q

The value of Q becomes
1

Q= r~

t2

1 e --i dt
Jt=ul- h2~ V2n'qwhich may also be ascertained from a table of the normal probability
integral.
Now anyone line among the progeny of the selected individuals or lines
has a chance of Q of having a greater. value than Y'. The minimum
number (N) of individuals or lines which should be selected in the F"
generation in order that the F"+l progeny would contain at least one
superior line of that level in 99 cases out of 100 is given by the solutionof the equation
N~ logO.Ol

log (l-Q) .
The following table (Table 2) presents results of some calculations con·Table 2. The minimum number of individuals or lines to be selected (a)and of those to be grown for the selection (b) in relation to various
values of heritability (h 2 ) and intensities of selection (q)
--

----

-

q

0.1

h2

a

0.01
0.05
0.10
0.20
0.30
0.40
0.50

43
37
32
24

18
14
,

11

I

b

420
370
318
238
179
140
108

I

I

0.05

I
a
88

74
61
41
29
21

16

64

I

b

1741
1475
1206
810
571
406
301

I

0.01
a

428
329
238
188
73
43
28

I

b

42728
32900
23717
18778
7222
4279
2711

"',1

cerning the minimum number of individuals. or lines. to be selected. in. thebulks or groups of plant lines of some successive hybrid generations.

2. A new Chemical "Substance F" for Inducing Doublingof Chromosomes(Report by YO TAKENAKA)
Colchicine, as a chemical agent causing doubling of chromosomes, wa,sfirst discovered by BLAKESLEE (1937) and is still much in use. Also
acenaphtene introduced by KOSTOFF (1938) serves the same purpose and isbeing used extensively. WITKUS and BERBER (1944) have reported veJ,"atrine
and LEVAN (1947) recommends iso-colchicine also as polyploidy inducing
agents. According to PARTHASARATHY (1941), fresh extract of Gloriosa
superba caused doubling of chromosomes in root tips, and KUMAR (1953)
reported that gloriosine extracted from its tubers gave similar results.
The "Substance F" was first extracted from tubers of Colchicum andnamed by SANTVY and REICHSTEIN (1950), and its chemical structure wasdetermined by UENO (1953) as follows:-•

The author examined the effect of this alkaloid upon plant tissues by
the following methods:(1) Tumor tests on growing root-tips soaked in water solutions of thissubstance in different concentrations.
(2) Dwarf-Tumor tests in seedlings germinated from seeds soaked in
the same solutions.
(3) C-mitosis tests in growing root-tips dipped in the same solutions.
The tumor tests on growing root-tips were repeated six times withmaterials of Allium Cepa, Allium scorodoprasum var. viviparum and Vicia
faba in the spring of 1953. These experiments yielded somewhat larger
tumors in concentrations from about 0.1 to 0.01% of this substance thanthose obtained from the same concentrations of colchicine. But concentrations of this substance over 0.1% showed some necrotic effect, whilecolchicine of the same concentrations produced only small tumors.
The dwarf-tumor tests in seedlings were carried out three times withvarious Brassica and Raphanus species in the spring of 1953. The seedsof these species were soaked in solutions of different concentrations of65

"Substance F" and also in colchirie solution of the same concentrationsfor 28 and 43 hours. The seedlings from the treated seeds were counted.
The number of dwarfed seedlings carrying tumors caused by " SubstanceF" treatment, in all the species and concentrations, was somewhat smaller
than that obtained from colchine treatment.
Onion root tips treated for 24 hours with this substance in 0.05% concentration showed some cells with beautiful figures of C-pair chromosomes,
which suggest the occurrence of tetraploid sets of chromosomes besides
perhaps octoploid sets. Furthermore, some nuclei showing irregular andabnormal mitosis similar to those found in colchicine treatment were
found.
In the autumn of 1953, seeds of Melandrium, Brassica and Raphanus
were treated by various concentrations of this substance. The proportionof polyploid individuals among the plants germinating from these seeds
may be determined next spring, and this will give us a key to evaluate'
the efficacy of "Substance F" for this purpose.

66

PAPERS AND BOOKS WRITTEN BY THE MEMBERS OF THE STAFF

-.

.
i

A-

FUJII, T. 1953. Morphologically different twins among the offspring of a wheat
hybrid. Jap. Jour. Genet. 28: 105-109.
FURUSATO, K. 1953. Defective growth in Citrus due to chromosome irregularity in stock. Kankitsu 5 (5): 48-50.
- - - - 1953. Studies on the polyembryony in Citrus. Jap. Jour. Genet. 28:
165-166.
GOTOH, K. 1953. Genetic studies on eggplant (Solanum melongena L.) I.
Regression analysis of quantitative gene action. Genetica 26 (516): 445-452.
1953. Genetic studies on eggplant (Solanum melongena L.) II. The
heritability of some quantitative characters and estimation of minimum
number of genes. Genetica 26 (5/6): 453--4.67.
- - - - 1953. Inter-racial differences in a barley variety "Hosogara No.2".
Jap. Jour. Genet. 28 (4): 166.
1953. The significance of natural selection in breeding. Iden 7 (5):45-48. 7 (6): 44--47.
1953. Inter-racial differences in a barley variety" Hosogara No.2".
(Abstract) Jap. Jour. Genet. 28(4):166.
ISHIHARA, T. 1953. Some observations on transplantability in two mouse tumors.
Jap. Jour. ZooI. 12:397--403.
KOMAI, T. 1953. Three Japanese pedigrees of typical brachydactyly. Jour.
Hered. 44: 79-85.
1953. Composition of wild population in the lycaenid butterfly Neozephyrus taxila. Amer. Nat. 833:87-95.
KOMAI, T., A. S. At. 1953. Genetic studies of the pierid butterfly Colias hyale
poliographus. Genetics 38:65-72.
KOMAI, T., K. KISHIMOTO and Y, OZAKI. 1953. Genetic studies of human microcephaly. (Preliminary report). Proc. Jap. Acad. 29:219-223•
KOMAI, T., Y. OZAKI and W. INOKUMA. 1953. A Japanese kindred of hyperphalangism of thumbs and duplication of thumbs and big-toes. Folia Hered.
Path. 2:307-312, lpl.
KOMAI, T., and R. TAKAHASHI. 1953. Translation of Th. Dobzhansky's "Genetics and Origin of Species" Third edition. 1-348. BaifUkan Tokyo.
MATSUMURA, S. 1953. Origin of Wheat. 1-124. Iwasaki Shoten Tokyo.
1953. "Artificial mutation" "Genome theory" in Current Theory of
Genetics. 181-241, 243-286. Hokuryukan Tokyo.
1953. Improvement of sugar beet by means of triploidy. 1-134. Sciencesha Tokyo.
1953. Chromosome analysis of the Dinkel genome in the offspring ofa pentaploid wheat hybrid IV. gene-analysis. Rep. Kihara Inst. BioI. Res.
6: 38--48.
MATSUMURA, S. and T. fuJII. 1953. Studies on mutation in Nicotiana inducedby X-rays (Abstract) Jap. Jour. Breed. 3(1):54.
1953. X-ray induced mutations in einkom wheat (Abstract)
Jap. Jour. Genet. 28:175.
MATSUMURA, S. and A. MOCHIZUKI. 1953. Improvement of sugar beet by means

67

J

I.

l

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