Abstract
In the previous paper on the local varieties of turnip, the author reported that the varieties of European-type are distributed in Eastern Japan, while the varieties of Japanese-type are distributed in Western Japan. In this research the author collected 28 local varieties of turnip from the north-western part of Central Japan and investigated their various characters to establish the border line between the distribution areas of European and Japanese types.
1. Many of these local varieties produced the seed of the B type and 22 varieties have hairy leaves; these characters are the special feature of European type.
2. In most of these varieties the root form is globe or conical and that of a few varieties is long-conical.
In color of the root, most varieties have pigments (red, purple or green) and only 3 varieties have white roots.
3. It is observed that these varieties were more hardy against the cold and slower in bolting than the Japanese-type varieties.
4. From these characteristics and distribution of varieties, it is certain that these local varieties in the northwestern part of Central Japan are classified into five groups.
5. It was found that the varieties which have hairy leaves, (hairy character is a dominant factor in European type turnip) are distributed eastwards of the line, connecting the northern part of Kyoto Prefecture-the northern part of Siga Prefecture-the border line between Siga and Gifu Prefectures.
On the contrary the varieties which produce the seeds having the A type seed coat, that is a dominant factor in Japanese-type turnip, are found in the area westwards of the line, connecting the central part of Fukui Prefecture-the western part of Gifu Prefecture-the southern part of Gifu Prefecture (Figs. 1 and 2).
6. The author considered that the distribution of turnip varieties of two different types might have been controlled not only by the ecological factors but by other factors such as historical and social ones.
