Raphanus sativus var. hortensis ("Daikon")

Japanese name: ダイコン （大根）
Scientific name: Raphanus sativus var. hortensis

[Overview]
A biennial thought to be of cultivated origin.
The place of origin is unknown, but plants thought to be the wild ancestor are said to be common in the Mediterranean coastal region.
The leaves arise from the root in a rosette; most are pinnately divided to the midrib or pinnately compound, but some are entire.
The flowers are borne in racemes at the stem tips and are white and four-petaled.
The fruit is a silique that is constricted between the seeds, has a long beak-like tip, and does not split open even when ripe.
The shape of the root varies with the cultivar, for example:
thick, long cylindrical ones such as Miyashige-daikon and Miura-daikon
thin, long ones that reach 1 m or more in length, such as Moriguchi-daikon
flattened round ones such as Sakurajima-daikon
elongated round ones such as Shogoin-daikon
and others.
The root is usually buried in the soil, but in some the upper part extends above ground.
The skin is usually white, but can also be reddish purple, green or black.

[History]
Central Asia is said to be one of its places of origin, from which it spread to China and the Mediterranean coast.
In Japan it appears in records in the 700s.

[Uses]
The enlarged root is eaten.
It is also called Suzushiro, and is one of the Seven Herbs of Spring, added to nanakusa-gayu (seven-herb rice porridge).

[Cultivation]
Propagate from seed.
It dislikes acidic soil, so apply lime.
Because it has a taproot, the soil must be dug deeply and carefully.
It prefers a cool climate and becomes susceptible to pests and diseases in midsummer.

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