II.3. BRASSICA CROPS (BRASSICA SPP.) – 195
Swede or rutabaga could have originated in medieval gardens where turnips and kale
grew side by side (McNaughton, 1995b). There is general agreement that the winter or
biennial form of B. napus originated in northern Europe. On the other hand, forage rape
almost certainly evolved from the oilseed form.
Cultivation of oilseed rape in Europe was under way by at least the Middle Ages
(Appelqvist and Ohlson, 1972). It is only in relatively recent times that B. napus oilseed
forms have been introduced to other parts of the world (Figure 3.34). B. napus did not
arrive in China or Japan until about 1860-70, with the coming of European traders (Liu,
1985; Shiga, 1970). European immigrants introduced the forage and root crop forms into
North and South America in the 17th and 18th centuries. In China, Japan and Korea
B. napus proved to be more productive than the indigenous oilseed forms of B. rapa.
Today most of the oilseed rape produced in China, Japan and Korea is harvested from
B. napus cultivars that have been bred from interspecific crosses between introduced
B. napus and the older indigenous B. rapa cultivars (Shiga, 1970). B. napus is less
adapted to the Indian sub-continent due to the short days and warm growing conditions.
Commercial production of the oilseed form did not occur until 1942 in Canada and 1969
in Australia.Figure 3.34. Dispersal of the B. napus species from a proposed centre of originNotes: Distribution occurred throughout Europe in the 16th century, the Americas in the 17th and
18th centuries, and China and the Far East in the 19th century.
Source: Modified from Liu (1985).
B. juncea
B. juncea appears to have a much longer history than B. napus, even though it is also
the result of an interspecific cross (B. rapa × B. nigra). Fraction 1 protein data (Uchimiya
and Wildman, 1978) and chloroplast DNA analysis established that B. rapa functioned as
the female parent in the formation of this species (Erickson, Straus and Beversdorf, 1983;
Palmer, 1988; Palmer et al., 1983; Song, Osborn and Williams, 1988a, 1988b; Warwick
and Black, 1991; Yang et al., 2002). However, Qi, Zhang and Yang (2007) reported that
some Chinese phenotypes may have evolved with B. nigra as the maternal parent. They
investigated the nuclear internal transcribed spacer (ITS) regions of ribosomal DNA from
15 different Chinese vegetable phenotypes and one oilseed form (pictures of the
16 phenotypes, including 2 root forms, are provided in the publication). They found that
four of the accessions, including the oilseed form, apparently had B. nigra as the maternal