In 1928, Embryo rescue (ER) was first used to obtain hybrids from wide crosses in crop plants known today as hybridization.  ER techniques are among the oldest and most successful in vitro tissue culture protocols used with plant species. ER refers to a series of methods that promote the development of an immature or lethal embryo into a viable plant. 

Since Raphanobrassica, an intergeneric hybrid between R. sativus and B. oleracea, was reported by Georgii Karpechenko in 1928, a number of intergeneric and interspecific hybridizations between Brassica species of the U triangle and R. sativus have been produced; the U triangle refers to the ancestral A, B, and C genomes that have given rise to modern Brassica crop species.