Shokubutsugaku Zasshi

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1. Through the“three point-experiment”containing three factors, i. e. k for the“Tombo”leaf, t₂ for the faintly coloured tube, and r for the white flower, such conclusion that these factors belong to a linkage group was given. The order of these factors′ loci on the chromosome may be probably t₂-k-r.
2. And also the factor l′ for the shade of flower-colour, c for the white flower with coloured stems, and perhaps a for the apical flower, belongs to the linkage group (“Tombo”Linkage Group),
3. The development of pigments in tubes requires both factors R^t and C that is responsible to the colour-production in the corolla.
4. The tube of white flowers of cR or cr type is always light yellow, and the white flower with the coloured tubes is one of Cr type.
5. The botten-coloured tube characterized by having the colour only at the botton of tubes, behaves as a recessive to the normal.
6. The cross-over percentage 8.95±0.465 takes place between k and t₂, but, in some case, 28.00 was given.
7. The two cases which the linkage value varies in proportion to the number of hetero-factors of the F₁ that contains factors belonging to the same linkage group, were observed. And the deviation of the linkage value in the one case was numbered to 22.24 from 17.5. Though the cause of the linkage variation in such condition is still not clear, we may be able to explain the cause, if it may be possible to suppose that the vigor of the F₁ plant varies with the number of the plant′s hetero-factors. For the fact that F₁ plant is vigor or not, probably seems to affect the frequency of cross-overs.
8. The cross-over percentage between r and t₂ is 41.89.
9. The cross-over percentage between r and c is 22.00.
10. The close linkage having the cross-over per cent. about 1 or 1.87 takes place between r and l′.
11. The new character, apical flower is a recessive to the normal, as the evidnece reported by Mr. Imai, and the factor a concerning to this character probably breaks the cross-over having the frequency 32.5% with k.

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