Historically the brassicas are one of the earliest domesticated crop plants by man. It is mentioned in several ancient scripture and literature and might have been cultivated as early as 5000 BC. There is evidence of its cultivation in the Neolithic age (Chang 1968). Seeds of mustard were found in the Channhu- daro of the Harrapan civilization ca. 2300-1750 BC (Allchin 1969). Aryans used Brassica species as condiments and for oil. However, the use of oil was still more commoner with the non-Aryans than with the Aryans. Thus it is evident that in a period of over 3500 years, mustard came to occupy an important place in the diets of Indian people as a source of oil and vegetable.
The origin of B. juncea is conflicting. The Middle East seems to be the place of origin since the putative parent species; B. nigra and B. campestris would have crossed. (Olson 1960, Mizushima and Tsunoda 1967). From there it soon spread to Europe, Africa, Asia, India, and the Far East (Hemingway, 1976). It had arisen more than once with different progenitors and in different localities i.e., China, Eastern India, and the Caucasus the present-day two centers of diversity (Hemmingway 1976, Prakash and Hinata 1980). Biochemical and molecular studies support this finding and further provide evidence for the existence of two geographical races, Chinese and Indian (Vaughan et al.1963, Vaughan and Gordon 1973, Song et al 1988).
The Brassicaceae contains about 3500 species and 350 genera and is one of the 10 most economically important plant families (Warwick et al 2000). It is distinguished on the basis of the presence of conduplicate cotyledons (i.e. the cotyledons are longitudinally folded around the radical) and/ or two-segmented fruits (siliquae), which contain seeds in one or both segments, and only simple hairs, if present. Crop Brassicas encompass many diverse types of plants, which are grown as vegetables, fodder, or sources of oils and condiments. The oleiferous Brassica species, commonly known as rapeseed-mustard, are one of the economically important agricultural commodities. Rapeseed-mustard comprising eight different species viz. Indian mustard, toria, yellow sarson, brown sarson, gobhi sarson, karan rai, black mustard, and taramira, are being cultivated in 53 countries spreading all over the globe.
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