Early experimental crosses between species of these two genera had been sterile or nearly sterile, but large-scale experiments by Soviet agronomist
Georgi Dmitrievich Karpechenko using
Raphanus sativus and
Brassica oleracea were remarkable because some of the plants produced hundreds of seeds. The second generation were
allopolyploids, the result of
gametes with doubled
chromosome numbers. •
P0:
Raphanus 2n_R = 18 x, a new crop in agriculture
Brassica 2n_B = 18 •
F1: sterile hybrid n_R + n_B • Some of
F1 spontaneously doubles their ploidy, resulting in the fertile allopolyploid 2n_R + 2n_B As Karpechenko realized, this process had created a new
species, and it could justifiably be called a new
genus, and proposed the name
Raphanobrassica for them, but the earlier name
Brassicoraphanus has
priority. Plants of this parentage are now known as
radicole. Karpechenko wanted a plant with leaves of a cabbage and the roots of a radish, but got the opposite. It is useful as fodder for livestocks, but not humans. Two other fertile forms of
Brassicoraphanus are known by the following informal names: • The
Raparadish group are allopolyploid hybrids between
Raphanus sativus and
Brassica rapa, used as
fodder crops • The
Radicole group are allopolyploid hybrids between
Raphanus sativus and
Brassica oleracea, used as
fodder crops •
Raphanofortii is the allopolyploid hybrid between
Brassica tournefortii and
Raphanus caudatus Currently, it is thought that a great part of the
flowering plants have some hybridization and polyploidization among their ancestors. ==Taxonomy==