1. In the nucleus of the salivary gland cell of the Chironomus larva which has just hatched from the egg, four thick and short chromonemata are visible. In telophase of the preceeding mitosis of the salivary gland cell eight chromonemata are thought to conjugate into four pairs and become four chromonemata.
2. The four chromonemata become gradually longer and larger, getting the matrixes around then. They are thought to be very unbalanced state and are easily broken, because the elongation and enlargement of the chromonemata and the matrix do not go parallel.
3. In every one of these four chromosomes two conjugated chromonemata becomes gradually to be separated and are seen to run parallel in some cases, to twist each other or to fit inside each other in other cases. Sometimes the chromonemata are seen to be composed of tertiary chromonemata (Sinoto and Yuasa 1925).
4. Then the chromonemata are broken into the banded structure. The chromonemata are often seen clearly when stained the salivary chromosome with aceto-carmine solution after the treatment with the aqueous solution solution of KCl, KNO₃ KOH, NH₄OH or NH₄Cl and softening or destroying the matrix (Yuasa and Sinoto 1950).

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1. In the tetraploid Allium odorum (n=2x=16), the variations of chromosome number were observed in meiosis in spontaneous as well as artificial conditions. The chromosome number series of n=9, 11 to 19, 31, and 32 were counted in the first pollen mitosis.
2. The chromosome numbers in pollen mitosis are distributed almost equally on both sides of n=16 in the spontaneous variation, but in the artificially intensified condition, both at both the lower and higher temperature, the frequency in each chromosome number decreases on the side of n_??_16, consequently the percentages on the other side of lower complements increase (Fig. 3).
3. The observed frequency in each group of the chromosome numbers 16-16, 17-15, 18-14, 19-13, 20-12, agrees well with that calculated by method of POISSON distribution.
4. A pair of satellited chromosomes was found at the normal metaphase plate in the pollen mitosis of this phylogenetically autotetraploid plant. They are distributed equally as other complements in pollen grains.

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1) Aegilops 及び Triticum の核型を決定し, その変化はゲノムの変化と一致することを明かにし, 次の核型式を定めた。
AA………a₁ b₁ c₁ d₁ e₁ f₁ g₁
BB………a₂ b₂ c₂ d₂ e₁ f₂ g₁
DD………a₃ b₃ c₁ d₁ e₁ f₃ g₁
2) Triticum の核型において, 1)ゲノムを同じくする種は常に同じ核型をもち, 2)ゲノムを異にする時は, そのゲノムに相当する核型の部分が異ることから, ゲノム核型の平行変化説を提唱した。
3) Aegilops squarrosa の核型は, Triticum のDDゲノムと同一の核型である。
4) 核型分析の結果, この属のゲノム分析の研究を助長するものと考える。

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It seemed difficult to obtain tetraploid plants of rice by the soaking of seed into colchicine water solution. The following method was found to be good: to germinated seed on moistened sand in a dark incubator, and after the elongation of first internode out of the hull, to apply lanoline paste containing 3% of colchicine on the first note, or a drop of 0.1% water solution on a small piece of absorbent cotton winded round the first node (4 times a day for 3 days). Thus, seedlings thickened by the effect of colchicine were selected after a week, and were cultured in pots with sterilized soil.
A half or more of them died during the seedling stage; the percentage of death was found to be different with the variety. Varieties of “Continental” group seemed somewhat higher in the percentage of death than “Insular” varieties.
After the heading, panicles (or chimaeral parts of a panicle) showing some characteristics of tetraploid are found in some 10% to 25% of the thickened plants. And the plants raised from the seemingly tetraploid seeds were found to be tetraploids in 40% to 50% of cases. The lower the fertility of seemingly tetraploid panicles, the higher the frequency to gain tetraploid plants in the second generation.
By the above mentioned method, 120 varieties of various districts of Eastern Asia were treated, and tetraploid strains were obtained from 74 varieties.

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種間における交雑歩合は, 花粉及び雌蕋の能力が温度その他の条件によるためか, 現在迄の報告は結顆歩合が低く, また種々別々である, 即ち種間交雑難易の比較またその原因を探求しようとするために行われた圃場試験結果には無理がある。よつて花粉管伸長及び雌蕋機能の最適温度20°Cにおいて, 実験室内において子房内に花粉管の伸長する歩合を以つて結実とみなし比較検討した。
A. moschata×Pepo 26.2%
moschata 種の品種内において会津系品種を母とした場合の方が干潟系を母とする場合より歩合が高い。
B. Pepo×moschata 20.5%
Pepo 種の品種内において有蔓系品種を母とした場合の方が無蔓系品種を母とする場合より歩合が高い。
C. Pepo×maxima 29.4%
Pepo 種の品種内においてはBと同様。
D. maxima×Pepo 37.5%
maxima 種の品種内においては Delicious 系品種を母とした場合の方が Hubbard 系品種を母とする場合より歩合が高い。
E. maxima×moschata 40.5%
maxima 種の品種内においてはDと同様。
F. moschata×maxima 77.4%
moschata 種品種内においても干潟系を母とした場合方が会津系を母とする場合より歩合が高い。
種間におる交雑親和力は種によつて大きな異を齎し, 種内においても, 品種系統により明かに親和力大小を認める。

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Segmantal analyses of all the 16 types of X-ray induced reciprocal translocations in T. aegilopoides (aT1-aT7) and T. monococcum (mT1-mT9)have been completed as given in Tab. IV, in which the frequency of reciprocol translocations of each of the seven chromosomes are also summed up.
In the hybrid, mT1×aT4=f-eg/fe-g, two types of gametes, (f-e) and (e-g), are expected to be functional. In fact, when the stigmas of the hybrid were pollinated with normal pollen grains, the frequency of the fertilized female gametes, (f-e) and (e-g), amounted to 56.52% and 43.48%, respectively. However, when the stigmas of the normal plants were pollinated with the pollen grains of the hybrid, that of the functional male gametes, (f-e) and (e-g), amounted to 89.01%/ and 10.99%, respectively. These results indicate the competition between (f-e) and (e-g) pollen grains in the rapidity of growth.
RT-method was applied for linkage studies of the X-ray induced mutations as well as spontaneous characters, and 7 linkage groups have been established (Tab. VIII). 4 cases of the recurrence of identical mutations were recorded as given in Tab. V.
In an attempt to combine the chromosomes into larger rings, successive crosses among the established RT-types have been made. Consequently all possible combinations of rings and pairs from the 14 Einkorn chromosomes have been realized, giving a series of structural hybrids comparable with the well known situation in Oenothera. Fertilities of thus synthesized individuals having those chromosome constitutions are discussed in regard to the meiotic behavior of ring complexes.
Permanent structural hybrids are expected to be synthesized from the cross-combinations involving lethals, one associating with d- and another with f-chromosome, as given in Tab. IX.

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