1963 Volume 32 Issue 4 Pages 311-318
From his histological observation on the seed coat of varieties of turnip KONDO (1933) found that there are two types, that is Type A; in which epidermal cells of the seed swell with water and Type B; in which epidermal layer appears to be only membranous. The seed coat of the Type A is dominant over the Type B in turnip (SHIBUTANI 1952). In the previous paper on local varieties of turnip, the author reported that varieties of the Type A are distributed in the western Japan, while those of the Type B in the eastern Japan. Both turnip and non-heading mustard (n=10group) belong to the same group in Brassica.
For this study the author collected several local varieties of non-heading mustard in Japan and investigated their various characters, especially the histological type of the seed coat, in order to establish the relation between the kind of non-heading mustard and the type of the seed coat and to discuss the distribution of seed-coat type in Japan.
The results of the investigation are summarized as follows:
1. The local varieties of non-heading mustard in Japan are classified as shown in table 4.
2. The epidermal layer of the seed coat in varieties belonging to B. pekinensis, B. chinensis, B. campestris, and B. narinosa is of the Type B in most of the cases, with a few cases of the Type A (Hiroshimana and Yamato-mana) and of the mixed type (for example, Sangatsuna).
3. The seed coat of varieties belonging to B. japonica is of the Type A in every case, so that it is certain that the seed-coat of B. japonica is fundamentally of the Type A unlike other species.
4. In B. Rapa and B. campestris varieties distributed in the eastern of Japan produce seeds of the Type B, while those distributed in the Kansai region produce seeds of the Type A.
5. From this investigation on non-heading mustard in Japan, it is concluded that varieties distrib uted in the eastern Japan produce seed of the Type B in general, while those distributed in the western Japan produce seeds of the Type A, similar to the distribution of seed-coat type in local varieties of turnip.
6. Many of these varieties have hairy leaves. so that it is presumed that these local varieties have originated from a hairy variety.
7. The bolting season of varieties cultivated in the warm region, except for Kyona group, were usually earlier than those of varieties cultivated in the cool region.
8. Based on the above mentioned results, the author discussed on the origin of B. japonica and the gene of the Type A.