𝐈𝐧𝐭𝐞𝐫𝐠𝐞𝐧𝐞𝐫𝐢𝐜 𝐜𝐚𝐛𝐛𝐚𝐠𝐞 x 𝐫𝐚𝐝𝐢𝐬𝐡 𝐡𝐲𝐛𝐫𝐢𝐝𝐬.

𝑥𝐵𝑟𝑎𝑠𝑠𝑖𝑐𝑜𝑟𝑎𝑝ℎ𝑎𝑛𝑢𝑠 𝑐𝑣. BB1 was developed by Lee Soo-Sung and his team at the National Institute of Horticultural & Herbal Science in South Korea.

It was rezgistered as a cultivar on 07/15/2004.

This was the first cultivar resulting from a cross between cabbage (𝐵𝑟𝑎𝑠𝑠𝑖𝑐𝑎 𝑟𝑎𝑝𝑎) and radish (𝑅𝑎𝑝ℎ𝑎𝑛𝑢𝑠 𝑠𝑎𝑡𝑖𝑣𝑢𝑠).

This new vegetable, named “Baemoochae” (배무채), is derived from:

배 (bae) = abbreviation of baechu, Chinese cabbage

무 (mu) = daikon radish

채 (chae) = vegetable / edible greens

Thus meaning: “cabbage–radish vegetable”, or more naturally “greens derived from cabbage and radish”.

Its phenotype is intermediate between its two parents: it resembles a heading Chinese cabbage, with thick petioles, and a pungent taste and flavor typical of radish (sulforaphane).

Young plants are hispid before becoming completely glabrous, with a leaf morphology inherited from radish.

Its siliques have a somewhat aberrant morphology, with a spongy section inherited from 𝑅𝑎𝑝ℎ𝑎𝑛𝑢𝑠, and a dehiscent section splitting into two valves inherited from 𝐵𝑟𝑎𝑠𝑠𝑖𝑐𝑎.

Its root is short, swollen, with a white epidermis. It is fibrous and not harvested.

Its life cycle is annual.

It is self-fertile, a trait inherited from 𝐵𝑟𝑎𝑠𝑠𝑖𝑐𝑎 𝑟𝑎𝑝𝑎.

Its white flowering, probably inherited from radish, is induced by vernalization (more than 15 days of temperatures below 10 °C).

Sowing is therefore preferably carried out in mid-August, for a harvest at the end of October (60–70 days to maturity).

Radish contributes numerous resistances to diseases and pests affecting cabbage, such as clubroot and root-knot nematodes (𝑀𝑒𝑙𝑜𝑖𝑑𝑜𝑔𝑦𝑛𝑒 𝑠𝑝𝑝.).

Since the 1950s, many attempts had been made to hybridize cabbage and radish, but they were all more or less unsuccessful.

Lee Soo-Sung and his team refined the protocol, which is described in the patent that was filed.

Here is a summary:

In the spring of 1986, pollinations were carried out using Chinese cabbage: 𝐵𝑟𝑎𝑠𝑠𝑖𝑐𝑎 𝑟𝑎𝑝𝑎 𝑠𝑢𝑏𝑠𝑝. 𝑝𝑒𝑘𝑖𝑛𝑒𝑛𝑠𝑖𝑠 𝑐𝑣. 'Teabaek' as the female parent, and radish 𝑅𝑎𝑝ℎ𝑎𝑛𝑢𝑠 𝑠𝑎𝑡𝑖𝑣𝑢𝑠 𝑐𝑣. 'Bulam3', a daikon type, as the male parent.

The embryos, 10 days after pollination, were cultured in vitro.

These plants were all allodiploid and sterile.

Allotetraploidy was induced by colchicine treatment.

The self-fertility of the obtained allotetraploids was tested, and among them, the plant coded OV115C was selected for its ability to produce self-pollinated pods.

On this individual, anther culture was performed using the technique of Keller and Amstrong (1960).

This technique makes it possible to obtain homozygous haploids, which are then polyploidized to produce theoretically highly uniform diploids.

A total of 33 embryos were produced.

These individuals were selected as a family line. However, even after several generations, the line remained very unstable.

Microspore culture was therefore implemented.

This technique, relatively similar to the previous one but more precise, made it possible to obtain 9 individuals.

This line, named OAM, was self-fertilized.

The obtained seeds were then sown in the field, producing stable individuals yielding approximately 300 pods per plant with an average of 1.7 seeds per pod.

Resulting in the cultivar BB1.