1964 Volume 33 Issue 2 Pages 117-124
Cryptotaenia japonica HASSK., hence forward referred to by its generic name alone, is a member of Umbelliferae. It is a herbaceous perennial plant indigenous to the Far East Asian temperate zone and is commonly cultivated throughout Japan as a vegetable crop. It grows widely in the mountainous regions of the country in wild state and is called as“Mitsuba”in Japanese.
Thirty-six wild-grown stocks and five cultivars of Cryptotaenia, collected from various parts of Japan, were cultivated in Sakai, Osaka prefecture. The morphological and ecological studies were made during 1955-1958 on varietal differences among the cultivars and characteristic differences between the wild strains and the cultivars of Cryptotaenia, . The geographical differentiations among the wild strains were also investigated.
1. In comparison with the wild strains, all of the cultivars had generally more valuable morphological characters as a vegetable crop and uniformity among the cultivars. Green color of the leaf and stem, erect plant type and large size of the plant are very distinctive features. On the contrary, the wild strains showed a wide range of variations in characters and the plants generally tended to be more prostrate in plant type, but there was no apparent relation between the characters and geographical conditions of the native habitat.
2. In regard to the bolting and flowering time, all of the cultivars and the wild strains collected from warm climate zones showed the tendency of earlier bolting and flowering than those from cooler climate zones. It was found that the time of bolting and flowering of the wild strains is related to the latitude and temperature of the areas where they were collected.
3. Varietal differences of premature bolting of the cultivars distributed in both Kanto and Kansai districts were investigated by means of four different sowing trials at different time. It was found that the cultivars of Cryptotaenia can be divided into two main ecological types, namely the Kansai Ao-mitsuba of early-bolting and the Kanto Shirokuki-mitsuba of the late-bolting. Both types seem to have been selected for the special methods of cultivation in these two districts.
4. A similar geographical trend as seen in the bolting and flowering time was found in the seed dormancy of wild Cryptotaenia collected from cool climate zones when they were sowed immediately after harvest, while strains having none or shallow dormancy were found in both of the cultivars and the wild strains collected from warm climate zones.
Effective treatments for breaking the seed dormancy are also investigated, and a chilling pretreatmemt at 5°C for 10-60 days was effective, but the optimum period of chilling varies with strains.