The present study focused on “norabo-na” and “komatsu-na” (a Japanese native variety) - two types of leafy vegetable cultured around Tama River.
“norabo-na”, a species of Brassica napus, whose leaves and stems are edible, has traditionally been grown in areas surrounding Tama River.
However, its genetic origin has not yet been identified, and it is necessary to develop its cultivation techniques.
Genetic analyses of “norabo-na” and the above-mentioned species of B. napus were conducted.
According to the results, varieties of “norabo-na” have the same place of origin, and, therefore, it may not have originated from specific species of B.
napus. A study of the cultivation of “norabo-na” was also conducted, and the results suggest that pinching its main stems strongly improves the quality of the flower stalks.
The Japanese native variety of “komatsu-na” (Brassica rapa L. var. perviridis) is a leafy vegetable developed by a producer (born in 1918) living in Okamiyato, Sekido, Tama City, Tokyo Prefecture, through self-seed production.
The morphological traits and characteristics of the Japanese native variety of “komatsu-na” are different from those of the leafy vegetables that originated from Tokyo Prefecture. An analysis of the seed type of the Japanese native variety of “komatsu-na” suggests that the variety may have developed through many crossings within species/strains of leafy vegetables, Brassica, distributed in the Chubu region and northern areas.