1. This report concerns with the results of the author's observation on the characteristics and the types of pairing of chromosomes in the reduction division of P.M. Cs. in the F
1. hybrid (2
n=14) which was produced by crossing
R. trifidus Thunb. (2
n=14) ×
R. ribisoidesMatsum. (2
n=14).
2. In this hybrid, the characteristics of
R. trifidusare found in the cyme, the glandular hair, the wrinkles of petals and the color of stems (red-purple), while the characteristic of
R. ribisoides in the wool on leaves and stems. On the other hand, with regard to some characteristics, e. g. the size of flowers, the shapes of leaves, the serrate and stipule, this hybrid is intermediate of its both parent plants.
3. The peduncle of this hybrid, stands, at first. upright like that of
R. trifidus, and then it turns downwards like that of
R. ribisoides. This is a case of dominance change.
4. The types and frequency of pairing of the chromosomes in the metaphase of the first reduction division of P.M. Cs. in this hybrid are as follows: 7II (35.5%), 6II+2I (40.9%), 5II+4I (18.3%), 4II+6I (4.3%) and 3II+8I (1.1%).
5. There are two kinds of pollens in this hybrid; the pollens having contents and the empty pollens. The ratio of their occurrence being 45:55.
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