Brassica juncea is a natural amphidiploid hybrid (AABB
genome, 2n = 36) of Brassica rapa (AA genome, 2n = 20) and
Brassica nigra (BB genome, 2n=16). The species is
mainly self-pollinated, but 20-30% cross-pollination was reported.
Inter-specific crosses are possible between B. juncea and
other mustard relatives. However, most hybridization events have
required human intervention to achieve.
Brown mustard has been listed as a weed species.
The species is fast growing and has a broad range of growing
Brown mustard is grown primarily for culinary purposes (edible
leaves, stems and seed; cooking oil from the seeds). The essential
oils from the seeds have been used in ethno-botany.