II.3. BRASSICA CROPS (BRASSICA SPP.) – 191
Figure 3.31. Phylogenetic tree for the subtribe Brassicinae, based on PAUP analyses of the
chloroplast DNA restriction site/length mutations shared by two or more taxa/accessionsNotes: PAUP is a computational phylogenetics programme for Phylogenetic Analaysis Using Parsimony that
infers evolutionary trees (phylogenies), Tree length in this tree is 489 steps, consistency index is 0.491.
Tree topology indicates how accessions are related, and branch length (numbers above the branches)
indicates the minimal number of mutational steps occurring during the evolution of a particular taxa.
Mutations unique to a given species and to the genus Raphanus (number indicated in brackets at the end of a
branch) should be added to determine terminal branch length. ANC indicates a common hypothetical
common ancestor.
Source: Warwick and Black (1991). © Canadian Science Publishing or its licensors.
B. nigra
B. nigra is amongst the oldest recorded spices, being noted in the Sanskrit writings of
about 3000 B.C. as “Sarshap” (Prakash, 1961). However, little is known about B. nigra’s
true centre of origin. Hemingway (1995) placed it in Irano-Turanian, Saharo-Sindian
region (Figure 3.32). However, Prakash and Hinata (1980) favoured an origin in Central
and south Europe. Its use as a commercial spice ensured its very early, widespread
distribution across Europe, Africa, Asia and India, and its dehiscing siliques ensured its
persistence. The crop was grown for the sharply pungent chemical (allyl isothiocyanate)
released when the crushed seed was mixed with a small amount of water, in the same way
that B. juncea powdered mustard is used today. Until the 1950s B. nigra was the world’s
major source of pungent mustard, but because it shatters as soon as the pods are ripe
it required hand harvesting. Thus, it was replaced in a single decade by highly pungent