Japanese name: カブ（蕪） Scientific name:Brassica rapa var. rapa
[Overview]
An annual or biennial grown for its root, which is used as a vegetable.
The root swells into an oblate to conical shape, and large ones reach about 20 cm in diameter.
The root is mostly white, but there are also purple, red, green and yellow cultivars.
The basal leaves are alternate, oblong to lanceolate and 30–60 cm long, entire or in some cases deeply pinnately lobed.
The leaves on the flower stalk clasp the stem at the base.
The flowers are borne in racemes at the stem tips and are yellow with 4 petals.
The fruit is a siliqua about 6 cm long with a beak-like pointed tip, and it splits open when ripe.
The seeds are spherical.
[History]
It has been cultivated in Europe since before the Common Era, and in Japan it is recorded as early as the 8th century; it is thought to have arrived in quite ancient times by way of China or the Korean Peninsula.
It became one of the important crops in the Heian period, and many cultivars were developed in the Edo period.
[Uses]
The root is mainly used as a vegetable, and the leaves are also used.
[Cultivation]
Pests include aphids, cabbage worms and armyworms.
