Brassicoraphanus Explained

Brassicoraphanus is any intergeneric hybrid between the genera Brassica (cabbages, etc.) and Raphanus (radish). The name comes from the combination of the genus names. Both diploid hybrids and allopolyploid hybrids are known and share this name.

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.^{[1] [2] [3]}

• P0: Raphanus

2 n _{R} = 18 x, a new crop in agriculture Brassica 2 n _{B} = 18

• F1: sterile hybrid

n _{R} + n _{B}

• Some of F1 spontaneously doubles their ploidy, resulting in the fertile allopolyploid

2 n _{R} + 2 n _{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.^[4]

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.^[5]

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^[6]

Currently, it is thought that a great part of the flowering plants have some hybridization and polyploidization among their ancestors.^[7]

Bibliography

• Terasawa. Y.. 1933. Crossing between Brassico-raphanus and B. chinensis and Raphanus sativus. Japanese Journal of Genetics. 8. 4. 229–230. 10.1266/jjg.8.229. free.
• Lee . Soo-Seong . Lee . Sun-Ae . Yang . Jungmin . Kim . Jongkee . 2010-11-27 . Developing stable progenies of ×Brassicoraphanus, an intergeneric allopolyploid between Brassica rapa and Raphanus sativus, through induced mutation using microspore culture . Theoretical and Applied Genetics . en . 122 . 5 . 885–891 . 10.1007/s00122-010-1494-3 . 21113703 . 22306496 . 0040-5752.

External links

• Observed Instances of Speciation

Notes and References

1. Karpechenko . G. D. . Georgii Karpechenko . December 1928 . Polyploid hybrids of Raphanus sativus X Brassica oleracea L. . . 17 . 305–408 .
2. Book: Karpechenko, G. D. . Classic papers in horticultural science . 1989 . The Blackburn Press . 9781930665064 . Janick . J. . 442–525 . Polyploid hybrids of Raphanus sativus L. X Brassica oleracea L. . Georgii Karpechenko . 1928.
3. Karpechenko . G. D. . Georgii Karpechenko . December 1928 . Polyploid hybrids of Raphanus sativus X Brassica oleracea L. . Zeitschrift für Induktive Abstammungs- und Vererbungslehre . en . 48 . 1 . 1–85 . 10.1007/bf01740955 . 116381242 . 1617-4615.
4. Book: [{{google books|plainurl=yes|id=qBGpLizYW-IC|pg=PA573|text=radicole}} Chemistry and world food supplies : the new frontiers, Chemrawn II : invited papers presented at the International Conference on Chemistry and World Food Supplies, Manila, Philippines, 6-10 December 1982 ]. 1983 . Pergamon Press . 0080292437 . Shemilt . L. W. . Leslie Shemilt. 1st . Oxford . 573 . 9557528.
5. Book: Meneely, Philip Mark . Genetics: genes, genomes, and evolution . Dawes Hoang . Rachel . Okeke . Iruka N. . Heston . Katherine . 2017 . Oxford University Press . 978-0-19-879536-0 . Oxford . 249 . 951645141.
6. Choudhary . B. R. . Joshi . P. . Singh . K. . 2000-10-10 . Synthesis, morphology and cytogenetics of Raphanofortii (TTRR, 2n = 38): a new amphidiploid of hybrid Brassica tournefortii (TT, 2n = 20) × Raphanus caudatus (RR, 2n=18) . Theoretical and Applied Genetics . en . 101 . 5–6 . 990–999 . 10.1007/s001220051572 . 22139768 . 0040-5752.
7. Otto . Sarah P. . Whitton . Jeannette . 2000 . Polyploidy: incidence and evolution . . 34 . 401–437 . 10.1146/annurev.genet.34.1.401 . 11092833.